Lucy in the sky with deadly radiations 4: the REAL sky this time

[king of nowhere]

Part 0: Introduction and goals

Welcome to the fourth iteration of kerbalism grand tours by king of nowhere.

The first mission was the first kerbalism grand tour, though it still used some facilitated isru mechanics. it featured an extremely cool mothership, though in retrospect - knowing what I now know - I can see a dozen of mistakes and poor decisions in its construction.

The second mission did another grand tour at hard level without isru. It had a fully disposable - and much less ambitious - mothership, which is not as cool.

The third mission used the outer planet mods to increase the number and distance of the targets. It lasted 330 in-game years, using nuclear reactors to perform isru with the full kerbalism rules.

Now I need something more. After completing a challenge, I want to push farther and outdo the previous mission. What more can I do than a grand tour with OPM?

A grand tour of the real solar system (rss), of course.

I've always known I'd have to end up there. It's the ultimate goal. The real solar system is a lot bigger than the stock system. This roughly triples the deltaV cost to do anything, as outlined in the deltaV map

What does it say about this game that a google search for deltaV map returns hundreds of kerbal maps and only one for the real solar system? Made for the rss mod, not for the actual solar system, at that

It also triples travel time, which means more malfunctions, and more resources needed for life support.

I've been reluctant to convert to rss because it's generally assumed to go together with realism overhaul. Which gives you more efficient engines and fuel tanks to bring them in line with their real counterparts, but also adds extra nuisances like ullage gases, limited ignitions - how do they mix with kerbalism already limited ignitions? - nerfed reaction wheels, and a lot more stuff that I'm unsure how to cope with. Like, I don't know if I can replenish my ullage gas stockpile by isru, and having to add rcs would require rcs thrusters - with the 6-copies redundancy policy, how many parts would I need to add? What of lag?

To keep things simple, I decide to forego realism overhaul and use stock parts. So, the third grand tour, with A'Tuin, was already very complicated. Now I'm trying to do the same, with the same resources, but tripling the deltaV requirements.

The one saving grace I have is that it's a lot easier to find water in rss than it was in opm. In the previous mission I had a narrow list of available sites for refueling, this time I can do it almost everywhere. In particular, using the moonlets of mars as refueling station will make exploration of the inner system possible at all.

 

I must foreward eventual readers (wait, is there even someone who actually reads all my excessively lenghty reports?). This is my fourth mission of this kind, and I lean heavily into what I learned in the previous missions. I keep those reports as a kind of diary to myself, first and foremost - but I try to make them accessible to other readers too. It's getting harder as I keep getting more familiar with the mods and taking things for granted. Should I talk in detail about the complicated mechanics of kerbalism isru? How much shall I discuss kerbalism mechanics like part failures and stress? I fear that, even if I do try to explain stuff, a lot of this will come off obscure to someone not familiar with my previous missions - that is, the half dozen people who may have read my reports in full. I also can't explain everything fully again, becase then the narration would become repetitive and boring to someone who already knows those missions. And as I said, I write those reports mostly for myself, I do reread them on occasions, and I don't want to reread stuff I already know all the time.

So, a lot of extra details that are explored in my previous reports are not repeated here. I'll still try to make it as readable to someone new as I can

Edited November 30, 2022 by king of nowhere

[king of nowhere]

Part 1: Projecting A'Twin and picking the crew

My previous mothership A'Tuin was already very well designed, tackling very efficiently most of the problems posed by long duration missions with part failure and life support. I did realize during the mission it could still be improved, though. So my first hope was using an improved version of A'Tuin. 

For start, A'Tuin had way too many oxidizer tanks. Those were needed to land and take off from Duna, but even then, there was too much. By converting some of those LF/Ox tanks to pure LF tanks for the nuclear engines, I could gain close to 1000 m/s.

Then there was the limitation of having to carry around fuel for landing. A mission to Moho started from Ike, returned to Ike, and in all the trip to Moho I had to carry around the fuel needed to land on Ike, as dead weight. If I made some drop tanks that could be detached and left in Ike orbit, it would increase efficiency. That could gain maybe another 1000 m/s, getting to 8 km/s available deltaV.

That's nowhere near enough. First, I need to add 100 tons of water for prolonged life support, as well as having bigger landers to account for the higher deltaV requirements. So a lot of that extra deltaV will be eaten up. Second, even 8 km/s isn't enough for a roundtrip Mercury mission. At least 10 are needed.

The only way to get that much deltaV was to get rid of all the dead weight unnecessary for the trip. Not just the fuel required to land, but also the heavy mining equipment, and the heavy nuclear reactors, and even the heavy chemical engines.

So I made the new mothership with the same general structure of A'Tuin - a shell of fuel tanks on the outside, with the living space inside protected from radiations - but I split it in two in a way that would allow a heavy mining module to stay behind, while the exploration module can trek much farther. This ship being basically A'Tuin made of two twin parts, I called it A'Twin.

1.1) A'Twin mothership

Spoiler

The general design is the same as A'Tuin: an external shell of fuel tanks to act as radiation shield. A sturdy bottom with plenty of mining equipment to land and refuel. Nuclear engines to maximize vacuum deltaV, with some chemical engines for higher thrust during takeoff and landing.

This ship is designed to be split in the middle, though. I also have to leave a crew with both parts; I can't leave the mining rigs alone for 30 years in space without maintenance.

It complicates design a lot. I have to keep up with 6-fold redundancy for both sections of the ship, providing multiple life support. I'm still keeping a crew of 9; for tradition and challenge, but this time it is also somewhat justified: 3 to stay with mining module (which has been dubbed Trypophobia), and 6 to go with the exploration module, named Cylinder. Of those 6, three will land and three will remain on board.

This also dictates the split of greenhouses, hitchhicker containers, and Dolphin escape pods.

I did use more modded parts from the near future launch vehicles. In particular I did use some 7.5 meter fuel tanks to save on part count, and a 5 m docking port to join the two ships because it was structurally more stable. I did not instead use the larger reaction wheels, because I want them to still be manually interchangeable by EVA construction. I'm also still using my personally modded parts, bigger versions of stock parts that have the same mass/efficiency ratio and save parts. So, the Nerv3 and Wolfhound3 engines, and the huge convert-o-trons.

I also edited the kerbalism config files to have the greenhouses produce food in a continuous stream instead of having to be harvested manually every 200 days (50 days with the real clock); this saves a lot of hassle in having to manually stop time warp to harvest food dozens of times.

Schematics of the Cylinder module, from above

The Cylinder module is made to maximize deltaV. Without the mining material, life support stuff is very small compared to the large ship. I also loaded the minimum of oxidizer - 50 tons, sufficient for four trips of the heavy lander, which will cover the four large moons of Jupiter. DeltaV is over 11 km/s; of course, exact amount depends on oxidizer loaded and shuttle ships docked.

It's got 90 tons of water, which - using the old A'Tuin as a reference, and keeping in mind that a real year is roughly 3 kerbal years - should give me more or less 60 years of life support.

Nitrogen supply was improved by using monopropellant tanks. Monopropellant is 87% nitrogen by mass, and monopropellant tanks are much more convenient than pressurized gas tanks. I couldn't use this storage method in the past because a mistake in the kerbalism chemical processes caused most of that nitrogen to be lost, but now it's been fixed and I can recover it almost in full. That's 16 tons of nitrogen, over five times what A'Tuin carried, and for a reduced crew. The reason is that nitrogen in rss is a lot harder to find; more of this on the Nitrogenie in a Bottle subsection.  To carry that much nitrogen, I'd have needed a hundred pressurized tanks.

The main nuclear reactors, supplying the 20000+ electricity/second required for isru, are of course with the Trypophobia mining module; but Cylinder still needs to grow its crops, which requires too much electricity to supply with RTGs. I'm also pretending that the plutonium for the RTGs - which is bound to run out in a few decades - is constantly renewed by the nuclear reactors on board, so I have to provide nuclear reactors. The kerbopower reactors weight less than half a ton each and provide 60 electricity, which is enough for this purpose. They can also be handled in EVA construction, which will be useful to stow them away in case I have to aerobrake hard.

Schematics of the Cylinder module, from below

The interior looks almost empty, because it's a lot larger than A'Tuin while all the really big stuff is going in the other module. Still, fitting two Dolphins inside this wasn't easy.

While most consumables are stored in condensed form for practicality and efficiency - water to store oxygen, hydrazine to store nitrogen and hydrogen, which will also be converted into ammonia - I did include a large tank for each resource. This will simplify management, allowing me to go longer in time warp before I have to stop and activate some chemical process.

The Trypophobia mining module was a lot harder to design. It has to have all the mining drills in contact with the ground, so it had to go on the bottom. The Cylinder module has to have all the nuclear engines, so it must be bigger than Trypophobia, to envelop it and still have the engines leaning out. Trypophobia is the smaller module, but it must have all the really bulky parts.  Fitting all that without making an even bigger ship - A'Twin is already pushing past 7000 tons with all the shuttles, 50% more than A'Tuin - was a logistic nightmare. Especially because I can't just stack stuff on top of each other, I must be able to remove broken parts. Still, I managed.

Schematics of the Trypophobia module, from above

Schematics of the Trypophobia module, laterally.

Both the nuclear plants and the large convert-o-trons can be detached if they get broken. I included additional uranium stockpiles because in the previous mission I had to keep dragging a heavy broken reactor only for its uranium stockpile. The inner greenhouses are so cramped they can barely be seen, but I don't have to ever repair them, so it's fine.

I keep being surprised that the Dolphin isn't clipping into anything.

I would have liked to also put the radiators there, but there just isn't room. Then I remembered the nuclear engines need cooling too, so it's not too inappropriate to put them on Cylinder. They are just 12 tons anyway.

Schematics of the Trypophobia module, from below

Compared to A'Tuin, I did put bigger nuclear plants (Excalibur, producing 3000 Ec/s instead of 2000) and more drills. The thing is, there are already 480 tons of convert-o-trons; it makes sense that they should be the limiting factor (see A'Tuin's mission, subchapter 0.2, for a detailed explanation on kerbalism isru and why it requires so much stuff). Especially after determining that the nuclear reactors break more easily. A'Twin also keeps twice as much liquid fuel as A'Tuin, requiring somewhat bigger isru. They must go on the outside, because they generate a lot of radiations that would hurt the crew without some bulky tanks between them; but their thermal vulnerability complicates aerobraking. However, with the higher orbital speeds of the real solar system, I don't expect aerobraking to be much viable regardless.

On the plus side, realizing I didn't need all 12 large reactors to carry water electrolysis, I assigned six of them to uraninite purification. This means I can resupply on uranium a lot faster; A'Tuin needed 5 years to replenish its uranium stock because the refining process was so slow. A'Twin takes 100 days (equivalent to 1 kerbal year, but it holds twice as much uranium as the old ship).

Previously I said I wouldn't use the rhino engines because, while they'd be ideal, they only have 2 allowed ignitions, making them very unpractical for manuevering. However, I found out that I really did not have room at the bottom for more engines; so to cut down their number I had to compromise. Anyway, since I was using near future parts, I finally gave up and used something better: the cougar engine. Basically it's like the rhino, but 5% lighter, with 7% more thrust, and 5 more seconds of Isp. Oh, and it works at sea level too, though that only simplifies launching from Earth. I said I didn't want to use parts that were strictly better than stock, but what the hell, I'm facing a rss grand tour with parts that were nerfed to be used in stock; if I use something 5% better, it doesn't change anything.

Trypophobia alone has 2000 m/s, but that of course goes down a lot when A'Twin is whole. As a result, not much high thrust deltaV. At first, I wanted to be able to land on the Moon, but it's impossible in the current setup; not enough deltaV when using high thrust. However, after a few calculations, I realized it's unpractical anyway. The fuel spent to land and take off from the Moon would be too much to be worth the effort and make that place a viable refueling spot. Especially not when I know there's water on Phobos. And having the large oxidizer tanks required for a Moon landing would cut too much into the low thrust deltaV. A'Twin can still land on Triton, which requires 1000 m/s, and with that it can land everywhere in the outer system except on Jupiter.

How the two parts fit together when docked, without shell. I made sure to leave plenty of vertical space, didn't want one of those spare engines to hit a Dolphin

Docked Trypophobia seen from the cupola on Cylinder. The lateral fit is really tight

A brave engineer crawls through the narrow space between the two modules to enter the mothership interior

Flying inside A'Twin

A'Tuin had all its parts carefully arranged to hold the various shuttles, so they'd be shielded from radiations too. For A'Twin, I considered briefly the proposition, then I didn't even try. Too complicated to fit. Especially because, with more deltaV required, everything has to be bigger. Over 90% of the living space is protected; what's left out will cause a little bit of radiation exposure, but it's small enough that the radiation detox units can counteract it.

Finally, there are no antennas in the schematics because I forgot them and I added them later.

1.2) Spider heavy lander + Hartman rover + Mars/Mercury extensions

Spoiler

Moon, Io, Ganymede, Europa, Callisto. Five large moons that require some 4000 m/s for a round trip to land. If it was one or two moons, I could use disposable stages, but five is too much. I need a lander that can pull off that kind of deltaV.
Fortunately, while those moons require as much deltaV as Tylo, they are not Tylo. They have much lower gravity, so I can get away with lower thrust - making a reusable landing more practical.

Spider heavy lander, with the rover Hartman. Yes, I know, spiders have 8 legs, but calling this thing ant or beetle just wouldn't do.

I want all my landers to also work as rovers, but this one is very heavy, it's too unpractical to put all that on wheels. So I made a design that can drop a lander on the surface, then pick it up to return to orbit. Hence this design. The Hartman rover adds very little mass to the lander - since the heaviest part, the crew pod, was needed in any case.

I called it Hartman because of the peculiar way it's got to dock with Spider, using the two pistons to push itself up.

Sequence of Hartman docking with Spider

It makes me think of the rover doing push-ups. Which in turn reminded me of sergeant Hartman, from the full metal jacket movie, who was always ordering people to do push-ups as punishment. I named the rover after him.

While this way to dock the rover may look unnecessary complicated, it's really the best I could conceive to ensure the lander would stay symmetrical through all the descent. Also, putting robotic parts in contact with docking ports is kraken bait, so attaching the docking port itself on a piston, while potentially simpler, was out of the question.

The rover does not have backup life support. It can survive 10 hours without, and it's not meant to ever be far from its taxi. Six redundant life support modules would have been too heavy. I made similar considerations for the old Horseshoe, and this one needs twice the deltaV.

One final note: I didn't put any landing struts. The small ones were too short for the cheetah engines, the large ones were too heavy. I'll just have to make sure landing will be extra soft.

But even 4400 m/s won't be enough to land on Mars and Mercury, so I had to add disposable stages for those planets.

By the map, Mercury requires 6000 m/s. That's too much for a single high thrust stage, so I included a simple extra stage.

The Spider lander docked with the Mercury descent stage

The Mercury descent stage brings deltaV to 6500 m/s. It adds 70 tons, which would be a ludicrous mass for a stock lander, but can't be avoided here.

Mars is a lot more complicated. By the numbers, Mars should need 7500 m/s. But Mars has an atmosphere, which can be used for aerobraking. In theory.

First of all, stock parachutes won't work. They don't open with less than 0.01 atm pressure, and on Mars you get that maybe at the bottom of the Schiaparelli crater. They also don't open at orbital speeds, so I used some inflatable thermal shields as parachutes.

The Spider lander docked with the Mars descent stage

And they do good braking. They slow down Spider from 3500 m/s to 1000 m/s. Unfortunately, at that point the lander crashes on the ground.

Sure, of course I must start the rockets a bit earlier. The problem is, aerobraking is extremely limited in the upper atmosphere. And in the lower atmosphere, where braking is substantial, you are already very close to the ground. The moment when you finally start to see your parachutes doing some real good is the moment when you have to brake with your rockets, thus losing most of the benefit of having parachutes in the first place.

This is why I added 6 darts to the contraption. I needed extra high thrust to come down fast in the atmosphere and maximize aerobraking, and then still have the time to stop before landing.

I worried a bit about Spider's completely antiaerodinamic shape for ascent, but Mars atmosphere is a lot thinner than Duna's. It's no problem. Heck, I had to put 6 large inflatable shields just to get some decent slowing down from orbital speed.

In the end, the Mars descent stage manages to be lighter than the Mercury stage, despite the higher deltaV required, meaning that aerobraking is doing its job.

1.3) Clamp light lander

Spoiler

Spider is a good lander for the large moons and small planets, but it's very heavy. Carrying it around with the taxi will require a lot of fuel - and remember than everything in rss costs more deltaV, including moving between moons. So, for the sake of saving fuel, I did include a smaller lander. It will actually perform most of the landings, because there are many more small moons than big ones.

The Clamp rover

It's based on the old Horseshoe rover, because that was a good design. Basically, I pulled the crew cabin down and backwards so that it would be symmetric. The lateral tanks obstruct the view a bit; the previous mission I decided that a good IVA visual was worth sacrificing some efficiency, this time I took the opposite approach. Then I removed four engines, because this thing is meant to land in places with less than 0.1 g and its thrust is already overkill (but I still need 4 for redundancy, in case I have to shut down one and its opposite). Then, since the deltaV requirement was lower, I also removed the extra fuel tanks - but for the reduced engine mass, I still gained deltaV in the end.

The rover arm is completely useless here, because rss doesn't have surface features. It doesn't even have ground scatter objects. But I like having it there, just to pretend that I could be using it.

I called this rover Clamp because the two lateral tanks make me think of a clamp squeezing the crew pod. It keeps the tradition of naming rovers after simple objects.

1.4) Fat Man taxi

Spoiler

With the mothership and lander established, the missing piece of the architecture is the taxi (see A'Tuin mission subchapter 1.4 for a more detailed dissertation on the taxi and its role).

The previous taxi only had to carry around a 15-tons lander. This time the lander is 55 tons, and it needs more deltaV. So the taxi will need to be a lot bigger. On the other hand, when it has to carry around only Clamp it will have a light payload, and a big taxi will be inefficient. This means a modular taxi that can be split depending on its payload.

It's based on the design of Trucker, which was an excellent compromise between crew comfort and mass.

The Fat Man taxi, basic configuration. It's got 8 km/s with a 14 tons payload, simulating Clamp

The Fat Man taxi, heavy configuration. It's got 6.5 km/s with a 55 tons payload, simulating Spider

Given the deltaV requirememnts of rss, I won't be able to pull stunts like the 8 km/s manuever to visit the moonlet in the radiation belt. And by the way, the radiation belt of Saturn is huge, and I can't land a kerbal in the inner moons. I'm not sure I can on Jupiter. Anyway, it's enough deltaV to do all I need. It also has supplies for one year.

Those reaction wheels look silly in their position, but I had no other place that could be easily reached by EVA construction to switch out broken parts - I did fill all the hitchhicker containers with spare parts.

1.5) Nitrogenie in a Bottle Titan lander and nitrogen harvester

Spoiler

In the previous mission, I did pretend to not know where the resources would be. This time I probably won't. The deltaV costs are too high, I can't always go somewhere while also keeping the fuel to come back. In any case I did check resources first to make sure the mission was possible.

Well, water was abundant. Yay!

But there was no nitrogen. Nothing, anywhere. Except on Pluto, which makes a terrible refueling place.

Ok, I can't mine nitrogen from the ground. But there is another source of nitrogen: the atmosphere of Titan. The biggest moon of Saturn has a thick atmosphere that would require a dedicated lander in any case; it also has low gravity, making it possible to orbit entirely with nuclear engines, and with limited deltaV once one gets past the atmosphere.

Nitrogenie in a Bottle. The deltaV is expressed at 50 km altitude on Titan, which is about where it can reach with propellers

Detail of the chemical factories. It wasn't easy to fit all that stuff - always with 6 parts redundance - within a single cargo bay

Nitrogenie in a Bottle flies up with propellers up past 50 km, where the pressure is 0.1 atmospheres. From there the Nervs have almost full power, and they can push the plane to orbit.

Here in the hardest test: can this plane get to orbit with a broken engine? I gave it plenty of reaction wheels to compensate for asymmetrical thrust

Here I'm particularly glad that I can store nitrogen as monopropellant; otherwise it would have required a couple dozen large pressurized tanks, each bigger than the cargo bay, and it would have turned the plane into an aerodinamic nightmare.

Synthesizing hydrazine (monopropellant) requires hydrogen and oxidizer in addition to nitrogen, so Nitrogenie in a Bottle brings some of them down from orbit. It takes 2 tons of oxidizer and 3 of water (to be electrolyzed for hydrogen) to fill the 6 ton tanks of monopropellant. It can do that in a couple weeks, it takes more in case of malfunctioning hardware but it's still an acceptable time. Four trips refill the tanks of A'Twin.

If you wanna grow your crops

I can make your wish come true

Nitrogenie in a bottle

Naah. I'm a good scientist, but a terrible singer.

Nitrogenie in a bottle has no redundant life support. It can operate remotely. It has a crew cabin, because I have to bring down a crew the first time to plant a flag; but if the life support gets broken, I can always bring the plane back to orbit and send it down to mine uncrewed.

All things considered, it's very mass efficient. It would have taken 18 tons of drills to mine nitrogen, and here a plane with 32 tons of dry mass can do the job and land on Titan too. On the down side, it adds 100 parts and a lot of chemical plants, which will worsen lag.

1.6) Milly the Windmill Vanus ascent vehicle + Dagger Venus exploration plane

Spoiler

Venus is a lot like Eve, in that you should not use rockets at sea level. Well, on Venus they just don't work, 90 atmospheres is too much. I had to uncheck the pressure limits on parts, else every stock part would explode for the pressure in Venus lower atmosphere. So, the best thing is to use propellers to get past the atmosphere.

The main difference between Venus and Eve then is not that the first has an atmosphere 14 times more dense and 4 times higher. No, that matters nothing when you have a propeller that can lift you out of it. The main difference is that once you get past the atmosphere, on Eve you need 3 km/s orbital speed. On Venus, 7 km/s. Dear old Helicopterocket could orbit Eve and it only weighted 44 tons. To get enough deltaV, I needed to attach additional stages to that setup. And then I had to make bigger propellers. The end result is not pretty, and it weights 200 tons, and it's got 200 parts. But it does its job. For a Venus ascent vehicle, that's all you can really ask for.

Milly the Windmill in all its rotory glory

Even getting there was complicated. Parachutes do not work on Venus; the game says too much aerodinamic pressure, they break instantly. Even though the cargo is descending at 10 m/s. On the other hand, as the cargo is descending at 10 m/s in the dense atmosphere, I realized I could skip the parachutes as long as I had engines that could take that kind of impact. Hence the darts. I pushed down their boosters to ensure they'd touch the ground first.

I also put in an oxygen bottle and some food on the pod; turns out, even on an external seat, the astronauts can still feed themselves if there are resources on the ship. I suppose my scientists devised a straw-like mechanism for it. So I won't be in too much hurry for docking. My scientists, on the other hand, did not devise a way to change the kerbal's diapers when they are on the external seat, so they still recommend I recover the crew as fast as possible and use the straw feeding only in an emergency.

As for the actual flight...

The aerodinamic lines spin quickly and chaotically in a way that a still frame won't convey

The problem is that the air pressure is such that it bends the propellers as they try to move within. They keep changing angle all the time, hence the chaotic appearance of aerodinamics. The aerodinamic interface also doesn't help, because lift is changing all the time, you can't even see it.

But the net result is positive, and I did ensure that Milly does lift and fly. At the top speed of 4 m/s it takes hours to reach the upper atmosphere, and no chance to time warp. Even for that I devised a countermeasure: I made sure that the rocket can keep pointing upwards on its own if I tell it to keep antiradial over the surface. I'll just leave the game in the background. Like I do whenever I'm loading the mothership. Or when I'm executing a long manuever. Or...

Really, when doing those mission, I spend more time with the game in background waiting for it, than actually playing.

But I always want to explore planetary surfaces. Even when I don't do it, I still require that my vehicles have the capacity for it. So I also made an expendable plane, to use for exploration. I called it Dagger for its narrow shape. Doesn't take much wing surface to fly on Venus.

Dagger exploration plane

Despite those diminutive propellers, it can actually fly fully vertical in the lower atmosphere. The docking port on the cupola will be removed before descent, to give a good view. It has comfort for the crew, enough that I could make a tour of the planet with it if I wanted. Which is good, because I won't be able to pinpoint landing accurately, I will need to fly Dagger from its landing point to Milly.

I was at first reluctant to add 10 more tons. Then I considered, when the ascent vehicle is 200 tons, adding 10 tons for a nice exploration plane makes no difference whatsoever.

1.7) Service Probes + Wings reconnaissance probes

Spoiler

I removed some science experiments to the Wings, because they weighted over a ton. Scanner experiments add a lot of mass. And I rearranged stuff a bit to try and keep the center of mass more or less in the right place.

The lateral engine is a backup, in case the first breaks

The Service Probes are still going to be used to swap the large engines. They are identical to those of A'Tuin. You can't improve on perfection.

1.8) Dolphin Escape pod

Spoiler

Yes, all my escape pods are going to be called Dolphin, forever.

I took the compact design I used on A'Tuin, and I added the missing water tank.

The new Dolphin iteration

The result has supplies for one year and three months, because real years are longer than kerbal years. It won't be enough to return from Pluto, but it is enough to return from anywhere around Jupiter. Which means, if I can send A'Twin in orbit with a periapsis closer than Saturn, I can evacuate the crew.

As in the previous iteration, rtgs and parachutes are stored inside for protection.

1.9.1) The importance of being Adai - selecting crew members for resistance to stress

Spoiler

The voyage of A'Tuin lasted 320 kerbal years, and during that time it experience rougly one critical malfunction every 10 years, leading to 30-something malfunctions. With the 6-fold redundancy policy, A'Tuin can fully take that kind of damage.

In the scaled up real system, A'Twin can be expected to still take around 300 years. Except that they would be real years, each one lasting 3 kerbal years. Malfunction rate, on the other hand, is the same. I can therefore expect 100 critical malfunctions. Ok, A'Twin can probably tank that too. Still, I'll do anything to reduce that number.

And most malfunctions were not caused by age, but by crew stress. Every time a crew member would get to 100% stress, something bad would happen - occasionally a loss of a resource, occasionally a broken component. I did immediately notice, though, that not all kerbals would get stressed. Four of the nine members of the A'Tuin mission always remained at 0% stress. The other five increased stress with time. Yes, there is a variation in how resilient individual kerbals are.

After some inquiries, I got told that it's a random factor linked to the kerbal's name. The name gets used as a key to generate a random number, which dictates stress level as between 66% and 133% of average level. This ensures that the same kerbal will always have the same resilience.

So instead of just hiring 9 hobos highly trained professionals and getting them on the ship, I hired a bunch and put them in orbit for a long time, and registered their stress levels. I picked the three pilots, engineers and scientists with the least stress after two years in orbit in a flying hotel, which I dubbed Hotel above California. More in the next subsection.

Jeb got to 22% stress in that time. He's got a good level, he's confirmed for the mission. Bill and Bob are also confirmed. The algorithm was made to make the core crew strong.

Val got to 26%, which is better than most - average was 30% - but still not good enough. Val was one of the five that got stressed in the previous mission. Getting pilots with low stress was hard, of the original batch of 24 (8 kerbals per type) only one pilot was better than Valentina. I had to hire a couple dozen other pilots to get another good one, monbrio - and at 24% he's still the least resilient crew member. I know from the previous mission that Jeb, with his 22%, didn't get any stress - the TV could reduce his stress more than it accumulated. While Val, with her 26%, did get stressed slowly over time. Not sure where 24% will fall - wait, what am I saying? By the time I write this, the crew is landed on Phobos and been in space for two years (I wouldn't take the time to write a full report if I wasn't sure the mission was working at first). And I can indeed confirm that even Monbrio is at 0% stress. I've got a great crew.

The champion in this ranking, though, is Adai Kerman. Adai remained at 20% stress - and with the most resilient getting stressed half as much as the least resilient, and some hapless participants reaching up to 39% stress, Adai's value is the lowest possible. Congratulations, Adai.

Stress breakdowns can still occur when the crew is not stressed, but they are a lot less likely.

1.9.2) Welcome to the Hotel Above California

Spoiler

Such a lovely place

Such a lovely place

Floating up in space

What's with this mission and outdated musical references anyway?

The Hotel Above California weights 470 tons, a big launch on its own right, and hardly the most efficient way to test stress level in astronauts. But what the hell, I have infinite money.

Here orbiting over Lake Victoria

Hotel Above California as it transits above California

A better view of the hotel

I tried to simulate the same conditions aboard A'Twin: one hitchhicker container and 2 greenhouses per kerbal, plus a Mk3 pod every three. All comforts available. At first I wanted to also turn on the TV, but then a lot of kerbals would have 0% stress and this interfered with the collecting of experimental data.

Detaching the return pod and using their RCS to deorbit. The broken pod will be docked by a functional one

Those reentry pods also let me carry the crew down fast when I'm done.

No, not too fast. I still have to do it 8 times. So, since this isn't really part of the mission, and I'm apparently growing less patient with age, after deorbiting the first pod - in the picture - I brought down the hotel with alt-f12.

Anyway, the Hotel was also prone to be hit by the misalignment bug (even two images above you can see the greenhouses on the left side scrunched up) and was known to spontaneously explode - more than once it did that just upon being loaded. It looks cool, but it won't be missed.

Edited April 13, 2023 by king of nowhere

[king of nowhere]

Part 2: Launching A'Twin, while fending off the krakens

Launching to rss requires much more deltaV, requiring some really colossal launchers. So colossal, in fact, that they often broke my pc.

I did succeed at launching every single part regularly. But the numerous glitches forced me to use the cheat debug menu to fix them.

2.1) Launching Cylinder

Spoiler

Cylinder has its own engines with over 10 km/s deltaV, but it's got very low thrust, can't use it to get to orbit. In fact, I'm launching it most empty. I'm keeping about 15 minutes of nuclear burn time, which is the time I have before falling back in the atmosphere. The payload to orbit is in the 1000 tons range.

The normal way to launch a really big payload is with asparagus stack, which has the advantage that it can be expanded indefinitely. However, Cylinder looks too delicate to push it up all through the central column; I'm afraid the sides would collapse. So I tried an elaborate launch tower that would distribute the push of the engines on all the structure.

It didn't go well.

Adding insult to injury, it probably wouldn't have made it to orbit anyway

So I went for asparagus. And it didn't crash, which was reassuring. It also loaded pretty fast (a few minutes, which for a 1100 parts ship is good).

Each of those boosters is a 500-ton tank, propelled by 19 vectors. The central ones use cougars - basically rhinos that work at sea level

The lateral tanks kept colliding during stage separation, though

And after discarding the outer ones, which were strutted to Cylinder, the docking port started bending

I was using 1.12.0 at the time, because I thought it was the more recent version. But it has a lot of problems with autostruts not working properly, which is why I'm having so many problems with docked parts wobbling. I didn't knew there was a more recent version that fixed that. The mission of Navis Sideralis Neanderthalensis would have been a lot different if I had known in advance.

At the time, my plan was to reinforce the docking port was to manually place struts with EVA construction after docking, and manually remove them before undocking. Considering that another issue I had with Navis Sideralis Neanderthalensis is that the struts thus placed would get deleted every time the ship was reloaed into physical range, I suspect it wouldn't have worked.

this time nothing broke, but it will run out of fuel before orbiting

Still the general system works, so I improved on that. I added another series of boosters, for the deltaV, and I put more and better struts. I shifted down the external boosters so they'd have less time for colliding with the main stack, and I put sepratrons on them. There were still bugs and glitches.

Like this. Look at the gaping hole in the side of Cylinder, and the fuel tanks dropped on the left. According to the game, they are still part of the ship, though. Had to reload the ship from a different file

Or this; notice the lack of engines on the last fuel tank, and the discarded engine plate amid the boosters

At some point I was even about to scrap the mission entirely, because the rocket wouldn't load on the pad at all, and the game would crash. Then I discovered it was a matter of the craft file getting corrupted. Good thing I saved a dozen different launcher variants with different names, so I didn't have to restart from scratch.

But eventually, I got it right.

Just a look at the mess of fuel tanks and struts

MaxQ. Even with a ship this big, drag is still significant compared to gravity. Of course, Cylinder is one of the least aerodinamic object I ever launched

The sepratrons doing their job. The spent boosters are still in the 150-200 tons range, so they are barely being moved. But at least they are not swinging inward

Another set of boosters detached, still 8 ktons of rocket

I am launching more vertically than I normally would, for two reasons. First is the terrible drag caused by Cylinder. But even more important, the last 1800 m/s will be achieved with low thrust engines (twr about 0.25, because the tanks are almost empty). I must achieve a high apoapsis to gain the time to circularize.

Last bunch of radial boosters discarded

And final piece of the rocket too. From here, Cylinder will reach orbit on its own power

I put some extra engines inside the shell, because Cylinder has some oxidizer tanks that are worth using. Those are discarded after running out of oxidizer

Finally, after 8 minutes of low thrust burn, circularization is complete

First big payload, done!

At this point I tried to save the game. The game just got stuck there, doing nothing. I told it to go to the tracking station. No answer. I could pilot the ship normally, but every attempt to save the game or leave the ship would not work. And after quitting the game, the autosave was stuck to before the launch.

This bug was common for all launchers. I can launch them, but I can't get the game to save the progress after launching.

However, all the testing I did with alt-f12 didn't cause similar issues. I was able to save halfway through testing. So I determined the only way to get the various parts of A'Twin to orbit was to cheat them into orbit. But of course I'd launch them for real at first. Launch them for real, quit the game, restart, then cheat them to orbit. Only a couple of the smaller pieces could be brought to orbit without this glitch.

2.2) Launching Trypophobia

Spoiler

Cylinder required 30 ktons of launcher to get 1 kton to orbit. A 3% mass fraction; real rockets are in the 5-10% range, but real rockets have better engines and better fuel tanks than stock.

Now the second big piece, Trypophobia. This one is even bigger, at 1200 tons of dry mass. And it doesn't have 2000 m/s low thrust deltaV that I can get almost for free. Well, I just need to add moar boosters. And by "boosters", I really mean "1 kton fuel tank with 19 vectors underneath".

At 40 ktons and 1520 parts, it pulverizes the record just set by Cylinder as the biggest thing I launched.

And yet, it doesn't look so big. Until you realize where the flag normally is relative to the launchpad

Those are 684 vectors, plus a smattering of other engines

Some more pics of the titanic display of power that is this rocket. Entire civilizations rise and fell and consummed in all their history less energy than this single rocket

Unfortunately, such a titanic rocket entails an equally titanic lag.

Do notice that in the 30 seconds video, the game only advances 2 seconds.

Lag, of course, never deterred me from using my megaships. If it did, I'd have stopped with the DREAM BIG before even completing assembly. However, lag deterred my pc, which did struggle for the last couple of years to keep up with my growing ksp insanity, until it finally decided to draw a line. And crashed the game completely.

I tried to launch many times (a half dozen, actually. But with those kind of loading times, it took two whole afternoons). Always the game crashed before orbit.

Ok, I must launch something smaller. I removed a set of boosters while trying to optimize the trajectory . I missed orbit by 200 m/s.

So I kept the version with one less set of boosters, but I did add some extra fuel to the first stage. And by "some", I mean "some 3000 tons".

The final rocket

That finally did it. By less than 100 m/s.

Discarding a stage above the amazon river delta. I'm launching from Kurou; I'll take every small advantage I can get

There are always a few nose cones that get stuck in the ship after being jettisoned

The rearward-looking cupola; how could I live without one?

Of course, I still had to fight glitches. Look at the misplaced drill on the left. I had to restart this launch

Of course, after all that was done, the game was bugged and I had to bring Trypophobia up by cheat menu.

2.3) Launching everything else

Spoiler

Compared to the humongous effort of launching the two big pieces, everything else was comparatively easier and succeeded without much trouble - aside from the aforementioned bug preventing the game from saving, of course.

The Hotel Above California was launched with a smaller asparagus.

Doesn't look that big after the previous ones

It still puts up an impressive light display

Last stage jettisoned, the small on-board engine is there for orbital adjustment

Any time of year

Any time of year

You can find it in LEO

NEXT!

Cylinder and Trypophobia came in orbit spent of any fuel. Also with minimal amounts of water and uranium, I was discarding any possible mass to make it easier. Now I need some way to refuel them.

I never gave a name to this rocket, actually.

Finally something aerodinamically sound! It almost looks like a real rocket

The final vehicle, in space. It has some small issues with the engines overheating the probe core to which they are attached, but for a handful of degrees it won't explode

And docking with Cylinder. I even gave RCS to this vehicle, something I haven't done since the DREAM BIG

Of course, it would take multiple such missions. However, since this rocket also is affected by the bug, I launched one just for show, then I just added all the fuel I needed to the version of A'Twin I would actually cheat to orbit.

Milly the Venus ascent vehicle looked like it could be problematic, with its totally antiaerodinamic propellers. But it went up without a glitch, with a 10 kton rocket

It helps that it can use Milly's own fuel

For the Clamp, I decided to do something different and pack it up inside a nose cone cargo bay, one of the new parts available with near future launch vehicles.

A 5 ton cargo bay for a 14 ton rover is probably not the most efficient solution

But it does certainly look good!

After leaving the cargo bay, Clamp circularized on its own power.

Dagger was launched as the tip of a rocket. I gave its wings 0 angle of attack, relying on different height on the wheels to take off, and the arrangement lets it stay on top of a rocket without generating lateral lift.

It doesn't even look too silly

The final stage, above the amazon river delta. It's actually got a lot more fuel than it strictly needed

I thought I could do the same for Nitrogenie in a Bottle, but it wouldn't do. The Titan plane has more wing surface, and while it can fly straight at first, at the first small disturbance the lateral force exherted by the wings will be too much, and the rocket cannot compensate. Or rather, it can compensate, but the aerodinamic force on the point will crack it in two.

The failed attempt at launching Nitrogenie in a Bottle. It invariably tries to flip

So I had to put it in an aerodinamic fairing. What's a bit more mass at this point?

To save time, I launched Spider attached to both its extensions, in a sort of unholy sandwitch. It was just a matter of using a slightly bigger rocket

Surprisingly, drag didn't capsize nor broke this rocket

Being built as an ascent vehicle with lots of deltaV, Spider is best suited to finish ascent on its own

Fat Man, faithful to its name, is also an aerodinamic challenge. But once more, it wasn't a big deal. Nothing that a bit of extra thrust couldn't fix.

After all the other ridiculous launch vehicles, I don't even feel like commenting on this one

2.4) Orbital assembly

Spoiler

Assembly was straightforward. Clamp and Dagger were in orbit as the only vehicles small enough that they didn't crash the game. For them, I did a normal rendez-vous. Everything else, I just teleported in range of Cylinder. I briefly considered teleporting each vehicle in a random orbit and doing the actual rendez-vous, but really, do I have to show that I can rendez-vous two vehicles in earth orbit?

The Dagger, docking first

A bit of a funny story for Dagger; it has that adapter tank to connect the command pod with the rest, and it's only there because the shape looked good - I mean, this plane is not supposed to do anything extreme, I can afford to sacrifice a bit of effectiveness to aesthetics. It's supposed to be empty, but the launch left it full of fuel. And it has two spider engines for orbital manuevering, to help with docking and then with deorbiting. Well, since I already jettisoned what was supposed to be the main engine during rendez-vous, I instead had to use them to run the full manuever, which included close to 1000 m/s of burn. At TWR 0.004 or something like that. For the final intercept, I started braking half an orbit earlier.

The Clamp

Fat Man takes place

And Nitrogenie in a Bottle

And finally Milly

At this point things get interesting, because I ran out of space. Some of those shuttles are really unwieldy.

I decided I needed an additional sets of docking ports on the side. This is also the moment I finally realized I forgot the antennas. So I set to send up a smaller vehicle and do some EVA construction to fit them.

Doing EVA construction is always dangerous. I got this RUD for accidentally materializing a docking port clipped inside a fuel tank

Docking ports placed, but the Mars descent stage can't dock because of... steric incumbrace, we can call it

The Mars descent stage has no control, so a Service Probe must come to its rescue. If it can even find its way in this maze of hapazardly docked junk

Also, look at how hard Milly is wobbling in the background. As I said, no autostruts past docking ports in this version. Who the hell had that idea? That's the one single issue for which you can't use anything but autostruts.

Finally, the Mars descent stage will dock on the other side

Cylinder is ready with all the shuttles

You may have noticed that the A'Twin shown in the cinematics doesn't have stuff docked laterally. Which can only have one explanation: this version of A'Twin will get eaten by a kraken, and will be replaced. So much for spoilers.

Trypophobia was left last, because it will increase lag most.

First, approaching

Slowing down and stopping while close before getting in position. Neither of those modules is very manueverable, drifting would be a great problem

I took a lot of pictures of this docking, because it's quite spectacular, but it also figures heavily into the cinematics, so I won't post them.

Docking is not terribly simple, but it's reliable. It's pretty much guaranteed that the two modules will get stuck without being able to dock. And I never managed to find which parts actually got stuck. But a mild push with the engines of Trypophobia can generally put the two modules moving towards each other again. If it doesn't, just give it another push. Never had any problem.

Except this one time, not sure what exploded or why

Yeah, I am docking two starships worth trillions of dollars, and the way to go when they get stuck is to push harder.

Finally, A'Twin fully assembled in orbit

I only loaded half the liquid fuel, thinking it would suffice to reach Mars

Most important, through all this docking, the loading and reloading of A'Twin into physical range, I never had the alignment bug manifest. Well, not too much, some parts got misaligned

Like this cargo bay

But nothing that would compromise the mission. That was my main worry, that the alignment kraken would destroy A'Twin. Seems like it's not happening, and I can start the mission.

Edited November 30, 2022 by king of nowhere

[king of nowhere]

Part 3: To Mars and Phobos

A'Twin goes to Mars and resupplies on the small moon Phobos.

The ship is doing fine, though I initially underestimated the deltaV requirements. The krakens are still attacking.

3.1) The alignment bug strikes again

Spoiler

I'm in LEO and I have to wait one year for the Mars transfer window, I may as well go to the Moon. I open up ksp full of optimism in this new day, finally having assembled the ship in orbit after months of bugs crashing the game. Here's what I found after the canonical five minutes of waiting for A'Twin to load; my acute observational skill allowed me to detect that the ship is not quite in the same shape as I left it the previous time.

A'Twin after being struck by the alignment bug

And here I thought that after assembling the whole thing without drama, nothing bad could happen anymore.

But it's ok. Bolt got equally twisted during its mission, and nothing ever broke and the bug eventually reverted spontaneously. Looks like the ship can still fly, although I will probably need to adjust thrust in a few engines.

Fat Man after the alignment bug

Fat Man also suffered from the kraken, but with a bit of trial and error I managed to keep flying straight - by reducing two engines to 50% and 60% thrust. Not ideal for something that already has low thrust, but in the list of indignities I have to suffer in one such mission, it won't even break the top 10.

So I sent Fat Man to the Moon - something that will be recounted in the next subchapter - when at some point I got a message that A'Twin was out of electricity. How is that even possible? Nuclear reactors produce electricity and a tiny bit of xenon. I did tell the reactors to discard the xenon if there is no storage space available, and they work just fine when I control the ship. But when it comes out of physical range, those kind of authomated instructions tend to glitch. So at some point A'Twin decides that it doesn't want to dump xenon anymore, and it stops the nuclear reactors entirely. Ignoring the message would lead to the whole crew freezing (in shadow) or cooking (in sunlight) in minutes, an aspect of kerbalism I already decried. The bug reverts as soon as the ship comes into physical range, which would not be a problem with a normal vessel, but it is for one so ponderous to load. So I change ship and go back to A'Twin. After five more minutes of loading time, I find this

A'Twin after the alignment bug strikes twice

Ok, this... this is an actual problem. It probably won't fly straight in this condition. But let's not be too pessimistic, I know that bug sometimes reverts, maybe it will get fixed by the time I'm back from the Moon.

So I go back to the Moon landing, and when I'm coming back I again get the electricity message. I have to load A'Twin again. After more loading time, I am finally announced that the game is ready by the sound of an explosion. I didn't have time to take a picture, but here's what I found.

Perhaps I could rename Cylinder into spiral staircase...

It's not apparent from the pictures, but A'Twin broke into a dozen pieces too.

I shut down the game and didn't play ksp for several days. I tried to import the saves on an older version of ksp, the same one where I run the successful A'Tuin mission, but they were incompatible - not just the saved games, but also the craft files. I was about to scrap it all.

Then, while answering a completely unrelated question in the forum, I mentioned that autostruts were unreliable because they didn't cross docking ports anymore. And I was told there was a more recent version of ksp to update to, that solved this bug. So I went and got the 1.12.3, and this time the game didn't break. Thanks are due to @Lt_Duckweed for pointing it out to me. Now I will have a task that will keep me holed up in front of my pc throughout all the summer... yeah, maybe it would have been better for me if this didn't work.

Anyway, saved games are still incompatible, so I had to restart. This time I send up A'Twin as one big piece, to save time, but I will still have to replay the Moon landing.

3.2) We choose to go to the Moon right now because it's slightly more convenient than doing it later

Spoiler

Going to the Moon is not too different than going to Mun, except that it takes a lot more deltaV.

There is also inclination to account, but as long as you meet the Moon as it's crossing your plane, it's insignificant. Injection deltaV is pretty small anyway.

The burn required for a lunar transfer

Fat Man has low thrust, and the first time it had to use some engines at low power to compensate for the misalignment, giving it even less thrust. I need several apoapsis raising manuevers.

In other circumstances it would be unremarkable, except that raising apoapsis passes through the radiation belts.

Only 4% of radiation damage taken in the manuever, no real problem. And only 160 m/s for capture.

Good windows, but those bars in the middle ruin the view

Landing on the Moon - in rss in general - is a bit different than in stock, because you need a lot more deltaV, but you can still get away with lower thrust. Spider thrust is a bit overpowered, it should work just fine with six terriers. On the plus side, those long cheetah engines double as landing struts.

Various phases of landing. Landing takes roughly 1800 m/s

Unleashing Hartman

Planting the flag

Those pictures come from the first landing, when Hartman was also hit by the misalignment bug - if you look closely, you can see it on the wheels. So it was basically impossible to drive, and I did return to orbit immediately.

The second time I had no problems, and there was a second biome not too far, and so I did take a detour

Hartman driving on the Moon

Tackling some slopes at speed, though nothing compared to Slate or Wal

Hartman is a weird rover. Different from anything else I did drive. I normally make rovers with a large base, but here mass was too much of an issue; so instead I gave it powerful reaction wheels to keep straight. It reacts differently, and it took me a while to adapt, but in the end I can rate it as adequate to drive on the Moon.

Returning to Fat Man

And planning the rendez-vous with A'Twin

It's barely available with the fuel on board, but it's possible to aerobrake

Ah, aerobraking. There were many consequences to playing with rss, some accounted for, other unpredictable. Probably the most annoying was aerobraking. Yes, I can aerobrake. I lose about 20 m//s per passage. At this rate it will take 150 passages through the upper atmosphere before the rendez-vous. Doing aerobrakes is a lot more annoying here.

And Fat Man is passing through the radiation belts, putting a time limit on the mission.

50% radiation damage, and I lost less than 1 km/s. Time to bail out and rocket brake the rest of the way

Final rendez-vous manuevers. This trip to the Moon was very expensive, but within the capacity of the vehicle. Further moons should be less challenging.

Rejoining with A'Twin

Landing executed, vehicles behave very well. DeltaV is sufficient for what it needs to do.

3.3) Third time is the charm

Spoiler

I start the mission at the beginning of year 3, because that's when I recovered the crew from the Hotel Above California after the stress test experiment. The transfer window for Mars, though, is not for another year. Which equates to 3 Kerbin years, meaning some parts will already start to break down during that time. I must already run some maintenance.

Inspecting the bunch of chemical plants, reaction wheels and radiation shields on the Cylinder module

Inspecting the outer ring of nuclear reactors and drills

Inspecting the inner ring of nuclear reactors and drills. This part of A'Twin feels like a labirynth

A'Twin is a lot more annoying that A'Tuin to inspect. Already an inspection of A'Tuin took an hour of real time; A'Twin has 50% more parts, the subdivision of the mothership into subunits doubles the redundant modules, and it's also a lot bigger, forcing more movement. What's worst, A'Tuin had a few path that one could take around the spaceship to inspect all the parts that did inspecting; A'Twin is more complex in shape, especially the area around the Trypophobia module. There isn't a clear path to navigate to inspect all the parts, and some areas are complex to reach.

Ideally, I should run an inspection once per year. In practice, I'll be a lot more shoddy. On the plus side, at the moment of this writing I am 10 years into the mission and didn't suffer a single stress breakdown - yay for selecting astronauts! So I can afford to suffer more malfunctions for aging.

After the wait, the Mars transfer. Plan is to go to Mars to refuel on Phobos.

Route to Mars. Mars injection not included, but it's about 1600 m/s for capture

Ejection + capture is some 5300 m/s. After capturing in an elliptic orbit I can aerobrake, but I can't save much on the capture itself. After capture, I will lower apoapsis until it's level with Phobos, then I will need the Phobos capture burn, which I can expect to be a few hundred more m/s (a bit more than 500, as it turned out). To be safe, I'd need 6000 m/s.

But I only have 5700. As you can see, even though I did alt-f12 A'Twin in orbit to escape all the bugs, I left it with half the maximum fuel. I am trying to run a "realistic" mission (for a given value of realistic, of course), and this entails sending to orbit the least possible amount of fuel. Why waste money on that, when you plan to make new fuel from other planets anyway? Just load the minimum fuel to reach Phobos, and get the tanks full there.

Well, it looks like I eyeballed how much fuel that would be, and I came short.

But so far, the mission goes on. At the time I was taking this decision, I still didn't knew how much deltaV it would take to capture around Phobos, and I didn't knew how much I could save aerobraking. 5700 looks like it could barely be enough to make it.

To maximize deltaV, here I am dumping all the oxidizer, and all the water I don't strictly need

A 3600 m/s burn is about 1 hour of ignition with A'Twin low thrust. Of course, will require multiple apoapsis raising manuevers. Good thing over 3000 m/s of that are still done in Earth orbit, I only need some 600 m/s for the final push in hyperbolic trajectory.

I start burning when the manuever marker comes within 15 degrees of the prograde marker; that keeps cosine losses to less than 5%, while giving me 10 minutes of useful burn time at every orbit.

One such manuever, with one engine broken and its opposite shut down for balance

Here I found another unplanned difficulty: engines seem to be a lot more fragile than they used to be.

I did run the whole DREAM BIG mission without losing a single engine. I lost a few engines on Bolt, but that was at hard level, and the engine module went a long time without repair at some point. I lost one or two engines in the whole A'Tuin mission, an exceedingly long one. This time, I'm losing engines faster than I can count.

The problem is that the engine has 50 minutes rated burn, but when it comes below 15 minutes left (later edit: 25 minutes, it turned out) it can suddenly break up at any time. I once started the burn and went to do something else - long burn time is exacerbated by the lag, I'm not going to spend a couple hours just staring at the ship slowly accelerating - and returned to find 4 engines exploded, 2 critically, just in a few minutes.

I reverted those with reloads. First, I'm still in LEO, the mission hasn't really started yet. I'm still at the point where it would be "realistically" easy to stop there and send up a new engine from the ground. Second, it's caused by a change in the game I could not know. Now I know that when the engines reach 15 minutes of remaining burn time, I must stop them and do some refurbushing. Future malfunctions will stay.

In that regard, I've been both lucky and unlucky at the same time, because I did break another couple engines around Phobos, but in both cases it turned out I was doing something wrong and I had to reload for unrelated reasons. When there are no malfunctions, and then I have to reload for unrelated reasons, and when I repeat the burn an engine explode, then the engine stays exploded, regardless that the first time it went well; in the same way if the first time an engine breaks, and I have to reload for unrelated reasons, and the second time the engine does not explode, it stays unexploded.

Another potential problem I had to face was propellers alignment. They always cause problems.

Propeller on the left getting badly bent with 4x time warp

I use 4x time warp during manuevers, they are so slow. And during that time, the big propellers on Milly whrite and shake, changing every moment. Turns out, this thing reverts completely upon exiting time warp, no problem here. Still can't wait to drop that thing and have one less worry.

Propellers on Nitrogenie in a Bottle getting pulled out of position, floating freely in space

The small propellers on Nitrogenie in a bottle also got pulled badly out of shape. I was very concerned when I saw the image above. A bit of inspection revelaed that I simply forgot to deactivate the engine and lock the rotor, as one should always do with propellers when out of the atmosphere. I stopped them, and everything got fixed. Not even a slight misalignment left. In the Jool 5 science mission, an accident of this magnitude would have totally left he propellers bent; I guess they fixed that particular bug somewhere along the versions?

Another glitch is the orbit being randomly shifted.

A'Twin after its orbit got shifted, causing the manuever to not be in the right place

Rounding errors can make small differences in trajectory, but those are generally limited. Maybe you need a few m/s correction in your interplanetary trip. I already had a more serious instance of this bug with A'Tuin, when I was orbiting Tekto and A'Tuin's orbit decreased over time. Here it's happening more often. In the picture, A'Twin lost a few thousand km apoapsis; the manuever node is defined by time, and so now it's after periapsis. Hence why I told the game to warp to the next manuever, and got shifted after periapsis. but the node is trying to replicate the same outcome of the manuever, hence why it's now 8000 m/s. Anyway, I had to reload. Remember, to reload A'Twin I need to restart the game, and then wait 5-10 minutes loading time, so it's not as easy as it is normally.

Anyway, I discovered that by manually warping to 10x and then telling the game to warp to a position, the bug does not happen. I still save before every time warp, though.

This finally concludes the long list of bugs, glitches, and other assorted problems. We can finally go back to the trip to Mars.

A'Twin left Earth orbit, heading for the red planet. 2000 m/s left, will they be enough?

Nothing crazy happened during the trip. I have to stop time warp maybe once per year to make new ammonia, and maybe every 5 years to make new nitrogen. Thanks to the handmade patch, I don't need to manually harvest the greenhouses. So, after a small course correction, it's straight to Mars.

Arrival at Mars

Fuel is a bit scarce, I need a few hundred extra m/s. I hope I can get them by aerobraking: I cannot hope to do the 1600 m/s capture burn without rockets, but if I do it in the upper atmosphere, maybe the air will supply that extra kick that can make the difference and let me land on Phobos.

At this time I am about to take a status screenshot, when I notice a strange detail. There is no "waste" in the resources tab. After a scrambled search, I conclude that there really isn't a waste container on the ship. Tragedy!

But why is a box to hold 2 kg of crap so important for a ship of many kilotons? Well, greenhouses need 3 resources to grow: water, ammonia and carbon dioxide. Water is the one needed in greater amount, I can carry up to 160 tons of it. Ammonia is synthesized from nitrogen and hydrogen, hydrogen comes from water and nitrogen is plentiful. Carbon dioxide is very inefficient to store, its pressurized tanks have very low efficiency; but it can be recycled entirely by burning waste, with a small surplus, so there is no need to carry it (the details of life support and recycling are detailed in the A'Tuin mission). However, I do need a box to store the waste from the moment it is produced to the moment it is burned. Without that small box, the system will discard the waste, and there will be no more to burn, and in a few years my big CO₂ tank will run out and the crew will starve. Humble as it is, the small waste container is a critical piece of my life support scheme.

And I can't just pop one on Mars and attach it to the ship by EVA construction, because kerbalism-exclusive parts cannot be manipulated this way. I assume the programmers haven't yet updated this thing, and I won't blame them since they work for free.

I am briefly considering if I should just make a "probe" with a waste container and a docking port, when I notice that all the spare pieces I carefully ammassed in the availble storage space have been lost. Yep, no spare reaction wheels if one break, or anything like that. Turned out, during ship construction at some moment I lost symmetry, and then I had to remake the ship, and that lost the items stored.

This decides it, I have to restart. I make use of the chance to try aerobraking, and I discover the main problem is that the nuclear reactors are very exposed, and they are heat sensitive. And I don't have enough fuel to reach Phobos if I don't save at least a few hundred m/s on the capture burn.

Maybe, if I had really tried, I could have done some EVA construction to move all the exposed parts to the back, then rocket brake for 1000 m/s or so, and then aerobrake the rest of the capture burn keeping A'Twin in a prograde asset. It could have been a cool story. But without those waste containers, and without the spare pieces, I can't go on.

____________________________________________________________

So back I am, with a new A'Twin ready for a third try. I did put the waste containers (1 for Cylinder, 1 for Trypophobia) and all the spare pieces I needed; a dozen reaction wheels for each size, a bunch of antennas, some small engines and a bit of everything I could think of. Even a spare small nuclear reactor.

Oh, and I loaded an extra 1000 tons of fuel, I don't want any more drama. Not for a simple Earth-Mars transfer.

This time I choose to not go to the Moon in this decade, because after doing it twice in a row, I'm sick of it. I'll leave it for later, and if later I can't because the ship is too broken up, I'll take the risk.

This time, during the voyage, I got the first critical malfunction

First malfunction: a life support unit on Dolphin 2

Of course, besides the impact on morale, one malfunction is nothing for A'Twin. Aside from that nothing noteworthy changed, I'll just cut straight to where I left: arriving at Mars

Looks a lot better than Duna

Status at Mars arrival

This time I have well over 3000 m/s, much more than needed. Still, that periapsis is inside the atmosphere - it starts at 125 km - because I hate being wasteful. I will need a low periapsis anyway, to lower the apoapsis gradually after capture.

First glimpse of Phobos

At periapsis there's enough friction to heat the ship red

Remember what I said about repairing engines when the remaining burn time goes below 15 minutes? I had to do it here, the burn time was too long. Felt like a car racing pit stop, trying to fix those engines in the least amount of time, to not lose any valuable Oberth effect.

Servicing the engines near Mars periapsis. It took 2 minutes of game time for the 24 nuclear engines. Congratulations to engineer Pendatte for his speed

Status after Mars capture, together with plane change manuever

I got captured around Mars with 1600 m/s. There will be no problems reaching Phobos.

3.4) To Phobos

Spoiler

Now I have to aerobrake until A'Twin apoapsis will be level with Phobos. It will take about 1000 m/s

Aerobraking. The heating of the nuclear reactors prevents a lower periapsis

A'Twin can lose 60 m/s in a single pass, so it takes some 15 of those. Man, I'm hating aerobrake in rss.

Then 700 m/s to reach Phobos

A fair bit more than I estimated initially, so it's likely my second attempt - the one scrapped for the lack of crap - would have failed regardless.

Near Phobos!

I've never added the cost of landing on Phobos to the calculation. For those of you who don't know (a double unlikelyhood: it's already unlikely that someone is reading those reports in full, what are the chances someone with so much passion for space exploration wouldn't know Phobos?), Phobos is a tiny, tiny moonlet, barely 20 km in radius. A man could get to orbit by jumping, but they'd have to be careful to take a small jump, least they just escape the gravity altogether.

Phobos is so tiny, its sphere of influence is only 40 km in radius over the surface. In the picture above I'm still outside of the sphere of influence, but I have to start braking already

A teeny tiny moon, but a very big floating rock

Captured around Phobos

I'm in orbit at 6 m/s. I could give a small push to lower periapsis, and then lithobrake. Surface gravity is less than 6 mm/s², or 0.06% g

A couple of nice pictures taken around Phobos. The scenery is beautiful

Gravity in fact is so low, the SoI so small, that I cannot perform a resource survey. That requires a minimal altitude of 50 km, and that's already outside the SoI!

Not that resource survey is really useful (See A'Tuin mission, subchapter 3.1, for how resource survey was too confusing to tease out useful data), but it's part of keeping up pretence. So instead I sent the Clamp rover on the ground to biome-hop (I did drive on Gilly, but even I am not so crazy as to try it here) and find resources

Detaching Clamp (in the center, upside down) and trying to districate it from the jungle of other vessels

Landing

Landing was quite peculiar; I hit the ground at orbital speed, something like 5 m/s, and then I bounced and I was about to make almost a full orbit before landing back, 8 hours later. So I turned around and pointed the rockets downward. It's very rare that one has to perform a landing pointing the rockets up.

News are pretty bad. In my initial scan I merely checked that there are all the resources needed - water, uranium, ore. But I didn't check how much and where. As it turns out, Phobos does not have all three in the same biome, so I have to land and mine uranium someplace, and then make a suborbital jump and mine fuel with the stockpiled uranium. No, it's not a big deal, that suborbital jump will take 10 m/s at most, it's just a nuisance. And since I dedicated the big chemical factories to uranium refining, it won't be nearly as slow as it was with A'Tuin.

Worse, there is only water in one biome. And ore level is 3%. It's extremely low, and refueling will take a long time. But there's nothing to do about it; Deimos has no uranium. I have to refuel there. And then send Cylinder to Venus, and come back and use Phobos again. And then send Cylinder to Mercury, and return and use Phobos again.

Still, could be worse. This moonlet is so small, if there was realism there probably wouldn't be enough water to mine in the whole Phobos.

A'Twin about to land

Another weird fact about Phobos: orbiting is so slow, and it rotates extremely fast, completing a rotation in 7 and a half hours. Rotation speed at the equator is half the orbital speed. And so it is very difficult to target biomes, because in the hours it takes for your ship to finally fall to the ground, the ground has moved so much underneath, you're in a completely different spot than the one you aimed at!

On the plus side, even if you land in the wrong place, you can make a suborbital jump. Or three, or ten. They are just so cheap.

About to land. No need for a retroburn to cushion the blow

Bad idea! A'Twin bounced up!

Bouncing at 2 m/s, it will now take 4 and a half minutes just to reach apoapsis, and about just as much to come back. In those 9 minutes, Phobos will have rotated enough that I'll probably land in a different biome. Had to - again - use the rockets to stop.

On the surface

Now I have to rejoin Clamp to the mothership. I can perform a landing on the roof

A'Twin seen from the approaching Clamp

Landing on top of a docking port. I tried the central one, but there was too much stuff around for comfort

Phobos is so small, A'twin is still visible even from orbit. Then again, massive A'Twin, with its 7000 tons, is but an ant crawling on a boulder. Phobos is diminutive only by the standards of celestial bodies

Now refueling can start.

3.5) You better get used to Phobos

Spoiler

I barely had time to deploy the drills, that I was greeted by an old enemy: the no ground contact bug!

Ore abundance 9%, but this is the place for mining uranium; it's got no water

The ground contact bug is not too bad. It goes on and off, and while it stops mining while it's active, it spontaneously reverts, and so it only make me lose time. Which means more malfunctions, so it's not completely trivial, still it's something that can be endured.

Everything set up, I activated time warp. Imagine my surprise when I saw A'Twin sink into the ground.

For once, I can't even come up with a quip

This bug happens sometimes when on Phobos surface. Didn't have the chance to test it on other planets. I activate time warp, and sometimes all goes well, and sometimes this happens. I can mitigate it by time warping slowly; if the ship starts sinking, I stop time warp and try again. This way I save the 5-10 minutes needed for reloading.

100 days later, uranium is full

I also took the chance to make radiation shielding. I didn't put it at first to save weight on Earth launches, because I knew it's a byproduct of mining. Now A'Twin is truly complete. Passing through radiation belts will be less problematic.

So now I have to make a suborbital jump to get the water. Taking advantage of Phobos rotation, I simply went straight up, letting the moon rotate under me.

Must reach the light brown biome. By the time I land, it will have moved underneath me

Landing again

This time, just before touchdown, I slowed down to 0.3 m/s, to avoid bouncing.

Mining. Production is very slow due to low ore concentration

Despite improved mining tools, it will still take 10 years to fill the tanks. That's 30 kerbal years, twice as long as any refueling A'Tuin ever undertook. But there are two factors to consider; first, A'Twin holds twice as much fuel as A'Tuin did, and second, ore concentration is 40% less than the lowest concentration A'Tuin ever mined. So mining was improved. It's just that the ship is so big and the ground so poor.

Good views during a maintenance trip

First accident: a landing light on Nitrogenie in a Bottle got broken

Those lights are maybe the only low quality parts on A'Twin. Making them high quality adds several hundred kilograms, and they are only lights, not important at all. So, even though I prefer to keep them working, their malfunction is not a problem.

Second accident: a reaction wheel on Milly

Those wheels were also low quality, because high quality wheels are twice as heavy, and Milly will be discarded soon enough, and putting two low quality wheels was more convenient than a single good quality one. Again, this accident is inconsequential.

It would take 10 years for a full refueling, but it's not needed right now. My first objective is Venus, which is not too expensive to reach. I estimate with 7 km/s I can get there and back, and this is what I load. Half a load of fuel. At year 10, A'Twin leaves Phobos for the first time.

Status on leaving Phobos

By the way, why it's 1329 parts instead of 1330? Turned out, a nose cone on Dagger get detached and is now floating in space. No idea how it happened, but Dagger will be left on Venus, and I'll not go out of my way just to get the nose cone back.

3.5) Bugs compilation

Spoiler

How many times did I write I had to do something to circumvent a bug? I thought it would be fun to collect them all in one place. Problem and Solution

- Launching most vessels will crash the game. Must send them to orbit with alt-f12

- Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

- Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

- Propellers start twisting around. No worry, it fixes once you stop time warping

- Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

- Crew transfer function may get stuck. Transfer the kerbal by EVA

- Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

- Ship occasionally sinks into ground upon time warping. Just try until it works

- Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

- I can't make manuever nodes or go eva, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

- Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

- Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens

- Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

I could swear I'm missing a few; they certainly seem more when I play. Still quite the list anyway. EDIT: the list got expanded as I played a couple more days, now it looks right /EDIT. Dealing with krakens is as difficult as traveling between planets.

Edited November 30, 2022 by king of nowhere

[king of nowhere]

Part 4: Mars and Venus

Cylinder goes to Venus, drops landers. Meanwhile Trypophobia, taking advantage of the reduced lag, sends the remaining landers on Mars. After Cylinder returns, A'Twin takes a long refueling stop to prepare for Mercury.

4.1) One becomes two

Spoiler

There's no opportunity to refuel around Venus, so there's no reason to send the full A'Twin. The mothership will be split and Cylinder will go alone. The operation is not complicated, but it is made ponderous by the size of the ship and the number of shuttles that must be undocked and shifted around.

Leaving Phobos. Due to the low gravity, it's the only place where you circularize at 30 meters from the ground

Trypophobia and Cylinder are undocked, slowly moving away. The shuttles not needed to land on Venus must be transferred to Trypophobia. Here Nitrogenie in a Bottle is released

I mistakenly undocked Hartman - due to its similarity with Clamp. Hartman lacking rockets of its own, I sent a Service Probe to grab it back

Nitrogenie in a bottle moves to one of the lateral docking ports on Trypophobia. Those are normally covered by the Nervs when A'Twin is whole

A bunch of ships being transferred to Trypophobia

Final status, Trypophobia

Final status, Cylinder

I left with Trypophobia Clamp, Spider, Nitrogenie in a Bottle, and the extra fuel tank of Fat Man. Three kerbals, though I later realized I had 2 scientists and no engineer and I had to swap crew.

Cylinder is carrying Milly, Dagger and Fat Man - which will be needed to recover the crew in low Venus orbit after the ascent. I noticed here that I didn't dump the oxidizer - it's only dead weight in Cylinder's purely nuclear propulsion. Well, I did put drain valves everywhere for a reason. With the current fuel level, I have roughly 7 km/s, which - from a bit of extrapolation of the deltaV map - should be enough for a Venus mission.

As the two modules went out of physical range of each other, lag dropped to almost nothing. Yay!

4.2) The long route to Venus

Spoiler

Earth-Mars requires some 500 m/s after exiting Earth SoI. Earth-Venus requires less than 1 km/s. So I put those two together, and guesstimated that - including the lowest Oberth effect for Mars being smaller - I should be able to get an intercept to Venus for 2 km/s.

I was wrong.

A direct Mars-Venus transfer would cost almost 4 km/s

With a total budget of 7 km/s for a return trip, I definitely can't afford this. I could get more Oberth effect with a lower Mars periapsis, but lowering periapsis would cost more than it would save.

Ok, time for the B-plan: use Earth's gravity assist.

First part of Venus transfer

A 2200 m/s burn will get me to a Earth flyby, and the gravity assist will lower solar periapsis to Venus. It will also lower solar apoapsis for a lower intercept speed. From there it's only a matter of syncronizing time for an encounter.

In stock it took me multiple passages to achieve that, as the deltaV change I could get from a single passage was limited. Here I can directly go from Mars transfer to Venus transfer in a single passage, and I don't even have to come very close to Earth. Of course, that's because in rss I'm spending more time close to the planet. Aerobraking is crappy, but gravity assist is more effective.

Second part of the Venus transfer

After the Earth gravity assist and a small plane change to push the planar node in the right place, I scan for close encounters in the future. There is one in five years where Cylinder will pass in front of Venus. Raising solar apoapsis will slow Cylinder's orbit and syncronize its passage at periapsis with the passage of Venus. Capture deltaV is only 700 m/s. Later I found that I could save two years by spending an additional 200 m/s on the correction manuever, and I went for it.

I've already entered into the rss state of mind. 180 m/s is a "small" correction manuever, and capture is "only" 700 m/s. Well, those are the numbers you can get in rss. I could have saved a couple hundred m/s by making the Venus encounter a couple years later, but more time spent in space means more malfunctions; fuel is adequate.

Three years of traveling, equivalent to 9 kerbal years, would have required several hours with A'Tuin, mostly spent manually harvesting the greenhouses and dealing with crew stress breakdowns. Now traveling is a lot smoother. With the modding on the greenhouses they no longer need manual harvesting, and the crew is never stressed. Only twice I faced stress breakdowns, after I forgot to activate the TV for Bill and he got to 36% stress before I noticed.

Once every year I have to make new ammonia. I could leave the Haber process always on, but then the ammonia recovered from the water recycler would be wasted. I can only get new nitrogen on Titan, so I'd rather not be wasteful. I have to do it for Trypophobia too, but I can activate it remotely, without the hassle of changing vessel.

Roughly every five years I have to make new nitogen, burning monopropellant in the fuel cells. This operation requires loading Trypophobia, because it produces water as byproduct; while I instructed the fuel cells to dump water if there is no storage space, that part of the automation is bugged, and I must reset it every time after a vessel leaves physical range.

Every few years I have to activate the waste incinerator to make new CO₂; just like with ammonia, I could leave it open all the time, but then the CO₂ produced by the kerbals breathing would get lost in space and wasted. If waste incineration is properly managed, the ship has a slight negative oxygen balance, and every several years it needs to replenish oxygen stock by water electrolysis. I once forgot about it, which led to crew suffocation. Ooops! That's why I save often.

Those operations are not needed for Trypophobia, which has landed and gets those resources from the ground.

I won't even mention resource consumption, because it was designed to last for the long travels between the outer planets; for those relatively short trips it's so overpowered, it's not even fun. I'd drop some 40 tons of water, if they made a significant difference in deltaV.

I run maintenance infrequently. Ideally I should do it once every year on the main reactors on Trypophobia (no idea why, but they get broken up a lot faster than anything else) and at least every three years for everything else. In practice, it's slow boring drudgery, so I try to run frequent maintenance on the 12 main reactors, which are very critical pieces, and I let everything else lag behind. It's worth noting that with no lag running maintenance is a lot faster and easier than it used to be.

Bugs keep happening occasionally, but nothing that could not be fixed by reloading.

The misalignment bug turned Cylinder into quite the artistic shape

And here for unknown reasons the game suddenly decided that all six nuclear reactors stopped working, leading to the crew dead of overheating

It will take 3 years to reach Venus. In the meanwhile, I decided to get ahead of schedule and land on Mars.

4.3) Mars and Deimos landing

Spoiler

Mission protocol dictates that a landing always requires a crew of six. Three to stay on the mothership, one in Fat Man, and two in the lander. It is not expected that Trypophobia will attempt to support a landing alone. However, the vessels docked to it are fully capable, and preparation for landing requires a lot of docking manuevers. That are done much faster if the game is not lagging because there is only half the mothership. So I decide to land on Mars without waiting Cylinder.

Upon loading Trypophobia, Nitrogenie in a Bottle breaks up in pieces, just as a reminder that bugs are not happening only to Cylinder. I now check frequently to make sure there are no new debris around

I still need a taxi (the mothership-taxi-lander architecture was discussed in previous missions); going from Phobos to Mars aerobraking requires 500 m/s, and then 1 km/s to get back from Mars. I don't have a dedicated taxi, but Nitrogenie in a Bottle can be recycled for the role. It has nuclear engines with enough capacity and an additional life support, even though it's quite small to push Spider.

Nitrogenie in a Bottle with Spider leave Trypophobia

Just a nice view of Phobos and Mars

500 m/s to enter the atmosphere

The Mars descent stage gets hit hard by the alignment bug

The Mars descent stage was the main victim of misalignment. It hasn't been properly straight since launch; it gets better or worse occasionally with reloads, but it's never in usable conditions. So I did the only thing left to do: ditch it and get a new one with alt-f12. It's an allowed use of the debug tool. Furthermore, the Mars descent stage is disposable, so I don't have to worry about the effect on aging.

A great view of Mars while servicing the engines on Spider

Aerobraking takes a long time, but eventually it's done. Nitrogenie in a Bottle raises periapsis out of the atmosphere, while Spider takes its final plunge.

At 30 km, aerobraking starts to get quite strong

30 seconds later, lost 5 km altitude and 500 m/s speed. Approaching maxQ. By the way, you can see a dart rocket is broken

15 km, speed dropped to 1500 m/s

10 km, 1200 m/s. Parachutes are getting less effective as speed is decreasing, and the ground is approaching fast. Time to activate the rockets

Mars descent stage has powerful thrusters, because it must lose a lot of speed in a short distance. Even with one engine broken

At 2 km from the surface, speed was reduced to a manageable level

The Mars descent stage is then jettisoned, still loaded with fuel and with the engines active, to prevent it from crashing on top of Spider

Spider lands, using only a tiny fraction of its deltaV

The cloud of dust in the distance is the Mars descent stage crashing on the ground

Playing golf on the surface of Mars

Mars is an interesting planet with a lot of nice places, and I entertained the idea of driving around the place. Unfortunately, while rss has great-looking planets thanks to using actual orbital images, the reality on the ground is... far less impressive.

It doesn't help that I landed in one of the most featureless, boring parts of the planet

So I went back to orbit immediately. Spider has 4400 m/s, and the complete lack of aerodinamics only caused mild losses in the thin atmosphere. I mean, I did have to use six giant shields to get some braking during descent. I reached orbit with spare fuel.

Rejoining Nitrogenie in a Bottle

And manuevering to return to Phobos, in two separate apoapsis raising

I was sloppy in lander preparation. Nitrogenie in a Bottle carries 3 tons of water and 4 tons of oxidizer that are required to make hydrazine on Titan, but are useless here. DeltaV budget is tight, I fear I have made a grave mistake in not getting rid of those 7 tons. I got back to Phobos with 40 m/s left.

Back to Phobos, without any fuel to spare

Rejoining Trypophobia

Now Deimos. Deimos is even smaller than Phobos. It does not require a dedicated lander, so I send Nitrogenie in a Bottle alone. It only has one life support system, but in case of a malfunction I still have 10 hours of air, enough for an emergency return. And anyway, what are the odds that it will break just in this short mission?

Going to Deimos is quite cheap, thanks to being far from Mars gravity well

Deimos seen from the window

Deimos has an escape speed of 6 m/s, so technically I am about to lithobrake from intercept speed

Landed. I had to stop Nitrogenie in a Bottle with rockets otherwise it would bounce for hours. Now it's stuck in midair and still won't land for a few more minutes

Nitrogenie in a Bottle had way more than enough fuel for this trip. Nothing exciting to report. Afterwards, I landed Trypophobia back on Phobos to make fuel. Trypophobia's tanks only hold one eight of the total fuel capacity of A'Twin, but it's still one year saved.

Trypophobia back on Phobos surface

4.4) The most difficult landing

Spoiler

A couple critical failures during the 3 years trip to Venus; first is a second reaction wheel on Milly; once more, it's not important. Hopefully.

Milly breaking a second reaction wheel

The second is a real blow: one of the large fission reactors.

Just two months before reaching Venus, one of the large nuclear reactors gets broken

Well, I did carry 12 for a reason. A'Twin can work reasonably well with six - indeed, refueling capacity on Phobos would not even be affected, because it's limited by ore availability in this case. Actually 12 reactors are overkill, the chemical plants cannot process that much energy anyway. But after the previous mission, where I saw that the chemical plants are extremely reliable and the nuclear reactors are very prone to breaking, I decided to carry more nuclear reactors, and it was the right decision.

So, three years later, to Venus

Venus, from the cupola of Cylinder

And more close up

Capture burn. On its own, Cylinder is quite manueverable, with decent TWR

Stuff overheating and exploding after an optimistic assessment on how low a periapsis I could afford

In orbit around Venus, status. Approximately 4 km/s left. I forgot to renew ammonia for a while, and food production has stopped; fixing it immediately

Now I have to detach Milly, Dagger and Fat Man for aerobraking. Milly and Dagger will go all the way down to the surface, Fat Man will wait in orbit to recover the crew.

To speed up operations, I dock them all together in an unholy contraption that was never meant to be

Aerobraking to the limit of overheating. In the first passage I spend some 200 m/s of fuel to make things faster, I don't want to spend months in a high orbit

Indeed, it still took 20 days to circularize. I could only shed some 50 to 60 m/s on every passage, and I had to lose 3 km/s. But finally it was time to drop Milly

To the very limit of heat resistance. I already run all the tests, I know Milly can withstand this treatment

At 90 km air resistance get a lot stronger

Reaching 10 g of deceleration in a short time. This is like an Eve reentry, but 40 km higher

Afterwards, Milly loses all lateral speed and stabilizes on a vertical fall. Fast at first

But it progressively slows down as the atmosphere gets denser. Milly has been in freefall for 15 minutes now, and nowhere near close to the ground

At 10 km, terminal velocity is 14 m/s. Pressure 57 atmospheres

7000 meters below, Milly is finally reaching the ground. Falling at 12 m/s, the darts will withstand the impact

Milly successfully landed

It took over 30 minutes for the descent phase, mostly to slowly crawl through the dense atmosphere. No, I did not dare to use time warp; in an atmosphere, it increases aerodinamic loads, breaking up stuff.

I tried parachutes during testing, but they did break apart immediately at those extreme pressures, so I had to rely on a landing apparatus that could survive at terminal velocity; luckily a few engine models have high crash tolerance.

Now it's Dagger's time, with the crew. This is a rare instance where I will bring three kerbals on a surface.

Dagger detaches and uses its tiny manuever engines to deorbit

The engines are jettisoned immediately afterwards, to free the visual from the cupola. The body of the plane is also a victim of the misalignment bug, but it can still fly, so it will stay like that.

Descent

I did not test Dagger because Mk2 parts are very heat resistant; I didn't consider the unshielded parts. Anyway, nothing broke

Spotting Milly in the distance

And flying down straight for it

Landed!

Landing Dagger only took 15 minutes, thanks to its more aerodinamic shape and using the propellers to help.

Venus atmosphere was very time consuming, but ultimately no worse than Eve. Now more than ever I can see why they decided to shrink the planets in the stock game.

4.5) The most difficult ascent

Spoiler

I did spend some time flying around in Dagger. The plane is a pleasure to drive, and the dense atmosphere of Venus allows the greatest degree of control. In fact, it's less an atmosphere and more akin to an ocean, with Dagger being a submersible ship. After all, it's 150 times denser than Earth atmosphere, and only 6 times less dense than water.

Dagger can even fly up straight without losing speed

Good views through the cupola. It takes a bit of getting used to because it's pointing backwards and the controls are inverted, though

I wouldn't have minded landing a couple hundred kilometers from Milly and getting there by plane. However, as it is I have no objectives, nowhere to go, nowhere to visit. So, after flying around long enough to complete science experiments, I move to leave the planet.

Etdania climbing the ladder first

It's not as long as that of FU Eve, but still a long climb

And from here one can get inside the seats

At least, one can get inside two seats. The one on the opposite side is too far. Anticipating this problem, I sent Bill last. He was able to get around the obstacle by moving the ladders.

By the way, the kerbals in EVA are all red or orange because the temperature of Venus atmosphere is close to the temperature that will kill a kerbal. Knowing Venus, they are really made of iron.

Bill shifts a ladder to move around Milly and climb into the seat on the opposite side

Liftoff! At this altitude, 3 m/s is the best speed I can get

The ascent will require several hours. I should get a lot of lift at sea level, but the dense atmosphere prevents the rotors from spinning fast. Maybe powerful rotors with smaller blades would have been more effective, but they'd have been wasted in the thinner upper atmosphere. Anyway, this model worked and I didn't want to try another one.

One important requirement was that Milly could fly straight on its own. In my experience, helicopters in ksp have a tendency to flip, or to spin around their axis and lose lift. I did not want to spend several hours slowly piloting this thing upwards, so I made sure I could tell it to keep antiradial compared to the terrain and be done with it. That's why I gave it 8 reaction wheels; I don't trust much authomated aerodinamic control in this game.

I started ascent and went to eat.

Half an hour later, Milly has gained six km of elevation

One more hour later, and the atmosphere is finally starting to thin, the propellers can spin faster and propel Milly to greater speed

Here I was worried, because there was one thing I didn't test: how long I could keep a kerbal on a seat. In EVA, they have 2 hours of oxygen. I did put extra oxygen on Milly, but I did not test if the kerbals in the external seats could access it. A negative answer would have killed the mission and forced me to redesign Milly with a real crew pod, much bigger and heavier.

30 km also marked a time of aerodinamic instability; while I did test Milly at high and low pressures, I never did test it in those conditions. And indeed, Milly started picking up lateral speed, deviating from the vertical, and eventually losing lift and falling. Some fiddling with the propellers control managed to bring things back under control.

At 53 km, pressure is the same as Earth surface. From now I could already start the rockets. Not sure why I activated aerodinamic forces overlay

But Milly managed to climb close to 60 km, where pressure is 0.4 bar. After 150 minutes of climb, I finally started the rockets

First stage separation. No engine broke, so Milly has a very high TWR

The third stage, after getting rid of aerodinamic covering.

Last stage. It's really nothing more than a fuel tank with three seats, but man, it's got a lot of deltaV

Am I really sending my astronauts in space on a pallet?

In orbit, preparing rendez-vous with Fat Man

Milly exceeded expectations, and I'm sorry to see it go. It climbed higher than I anticipated, and it got to orbit with 1000 m/s left. On the plus side, now I shed 250 parts, and A'Twin will be a lot less laggy.

The one sour note is that I brought a lot of science, but for a lack of sample storage space on Fat Man I could not keep them. Not that it changes the mission or anything.

From there, rejoining Fat Man with Cylinder was routine.

4.6) Back to Phobos

Spoiler

Time to return to Mars. Venus has a higher Oberth effect, so maybe a direct insertion will be possible.

Attempted manuever to reach Mars directly - ditched for being too expensive

Going anywhere from my current orbit is difficult. Cylinder is in elliptic orbit around Venus, so it's very cheap to leave by burning at periapsis, but too expensive to burn anywhere else. My options are then limited, I must exit with a fixed trajectory. Having also an inclination further restricts what I can reach.

So, I only need 2050 m/s to raise solar apoapsis as far as Mars - half Cylinder current deltaV budget of 4100 m/s. But I can only do this burn at the next periapsis - or at the same spot, one Venus year from now. And when I do that burn, and I reach aphelion, Mars won't be there. I must change the time of my orbit to meet Mars at the next aphelion. But the manuever needed to do so would be extremely expensive, over 1500 m/s. It would only leave 500 m/s for capture, and they are not enough.

Of course, I could make a smaller manuever to meet Mars in more orbits; but then, it's not really a direct transfer, I'm not gaining any time, and I may as well go for an Earth gravity assist. Which is what I did.

First part of the manuever to return to Phobos: Earth flyby

I only need 600 m/s to raise aphelion to Earth orbit, but again, Cylinder will miss Earth entirely. The closest encounter is in 3 years and requires an additional 300 m/s. Steep, but saving time is more important than saving fuel.

Leaving Venus orbit

Possible second part: direct Mars transfer after Earth flyby, on a high energy trajectory. Too expensive

After leaving Earth, Cylinder will pass very close to Mars; it's possible to force an immediate encounter with the trajectory shown. However, that requires leaving Earth with a lot of speed, it's not a Hohmann transfer - and it will result in a much higher intercept speed. 3500 m/s, which are way more than Cylinder's remaining fuel budget.

So nothing to be done, I will miss Mars narrowly in 3 years, and will have to wait several years as the orbits of Mars and Cylinder syncronize again.

Actual second part, reaching Mars in 7 years

Total cost will be 1500 m/s, leaving Cylinder with a lot of deltaV. But no, I couldn't use that deltaV to go faster.

During the trip I faced two more malfunctions; one on the gravity ring life support system.

Trypophobia's gravity ring life support system failure

That's completely irrelevant. The life support system is only a pressure control, and those are included in the greenhouses and cannot be broken. I left it low quality for mass saving, because that life support is completely unimportant. The gravity ring is still doing its job of improving crew morale. Although seeing the big ring turn red is ugly.

Second critical malfunction, a reaction wheel on Trypophobia

This reaction wheel is instead a useful piece, but I am carrying 90, it will take a lot more malfunctioning to slow down A'Twin.

Bugs also keep happening.

Here Trypophobia explodes as I sent an engineer in EVA

And here the crew of Cylinder die of overheating after the game decided that the nuclear reactors on board suddenly and inexplicably would stop working

The strangest bug was Cylinder's central fuel tank refilling its oxidizer spontaneously. The first time I assumed it was just faulty dumping, but no, every time I did dump oxydizer, the central tank got full again. And it's bad, because on Cylinder oxydizer is dead mass. Had to keep venting it at every new manuever.

Besides those couple minor accidents, time passes, and between an EVA to fix the nuclear reactors and a reload to fix a bug seven years pass and Cylinder returns to Mars.

Year 21, Cylinder returns to Mars after leaving it on year 10

Follows another round of aerobraking and then a Phobos insertion. Aerobraking this time is a lot faster, because Cylinder is more thermally resistant. It is also shaped like a parachute.

Status upon reaching Phobos

Since leaving Venus, Cylinder consumed 13.6 tons of water, in 8 years. It took 3.6 tons to make the 3 years outbound trip. 1.7 tons per year, against 1.2, why so much difference? At some point I forgot to make new CO₂ and this stopped the greenhouses, could it be why I used up less water in the beginning? Well, the 1.7 tons per year is consistent with the 0.6 tons per kerbal year I got from the previous mission, so it's probably the accurate figure. It would give me 53 years of life support, that can be stretched by shutting down the greenhouses and living on stored food. Or by only carrying a crew of three and leaving six people on Trypophobia mining water as needed. A'Twin has a longer water supply, because Trypophobia has proportionally more water than Cylinder.

Nitrogen consumption was not balanced between the landers, all in all I get a figure of 150 to 200 years worth of nitrogen storage.

It's early to say much about the rate of part malfunction, except that it seems to be once every few years, which is higher than hoped, but acceptable.

4.7) The even longer pit stop

Spoiler

Next target will be Mercury, and it will require every bit of deltaV I can squeeze out of Cylinder. Back to mining Phobos, and this time I must be full when I leave. First part, though, is rejoining A'Twin. I must again move around all the shuttles. Now that there are 280 parts less (between the Venus landers and the Mars descent stage), it's a lot less laggy.

Cylinder and Trypophobia meet again

Vessels are moved from one to the other

And not one, but two engines critically malfunction during the manuever

Come on, I barely broke two engines in the whole OPM grand tour, and now two broken in a single docking and landing manuever???? Is there some bug that wants to happen and give me a perfectly legitimate excuse to reload? No bugs? Damn.

Well, I got spares for both engines. And here I thought it was foolish to bring a spare wolfhound, as I'd be using them only infrequently...

Anyway, a routine refueling.

Landed on Phobos

8 years later, tanks are still not full, but uranium is running short

My bad. I increased uranium stockpile a lot over what was available for A'Tuin, but I didn't consider that A'Twin also holds twice as much fuel, and will thus require twice the uranium to process all of it. Well, on Phobos is not a problem, I have to take a small suborbital jump to change biome, and back.

During those 10 years, a single critical malfunction, on a reaction wheel

Final status

Finally, after almost 10 years (equivalent to 30 kerbal years, twice as long as the previously longer refueling) the tanks are full. Cylinder is ready to try for Mercury, in what will be the most difficult target deltaV-wise.

Broken parts recap

Spoiler

I want to keep track of how much stuff I break, and how much it's affecting the mission, so I prepared a list

Life support

1 life support broken on a Dolphin. I've got five more redundant pieces on it.

Nuclear power

1 Excalibur reactor broken. It was redundant. There are 12, and up to 3 can be lost before mining is slowed down.

Reaction wheels

2 large reaction wheels broken. I've still got 88 working.

Engines

1 big nerv broken. I've got 2 more spares.

1 big wolfhound broken. I've got a spare.

Low-quality parts

A landing light broken on Nitrogenie in a Bottle. Irrelevant, I don't need them.

Life support on Trypophobia's gravity ring broken. Irrelevant, the same function is included in the greenhouses.

Outdated

2 reaction wheels broken on Milly. Now Milly has done its job.

1 dart engine broken on the Mars Descent Stage. Now it's a pile of debris on Mars.

Discounting the low quality and outdated parts, that's 6 critical malfunctions so far. They felt like they were more, not much for close to 30 years of mission.

Edited February 2, 2023 by king of nowhere

[king of nowhere]

Part 5: Journey to the center of the solar system

Cylinder goes to Mercury, the most expensive planet to reach deltaV-wise. The deltaV required was in fact so high, not even Cylinder could complete the trip, requiring some creativity.

Yes, Mercury surface looks completely undistinguishable from that of the Moon. Or from that of a dozen minor bodies. Nothing I can do about it

5.1) Inward!

Spoiler

This will be hard. From preliminary attempts, it looks like even in the most favorable conditions, it takes 3.5 km/s from Mercury orbit to Venus - so it takes just as much in intercept deltaV coming in. Plus it takes 1.5 km/s from Mars to Earth, and a similar amount as capture deltaV around Mars. Taken all together, it's 10 km/s required in the most favorable conditions. Cylinder alone has 11 km/s, giving one extra km/s for correction manuevers and for whatever condition may not be favorable. I'm not sure it can be done, but I do have a B plan otherwise.

Anyway, that's to say that I want to maximize deltaV as much as possible. I'm not going to dump any water - the capacity to spend a dozen additional years waiting for the cheapest trajectory is worth far more than a few dozen m/s - but I do want to dump the mined ore I still have on board. I distinctly remember putting in an ore container with a drain valve exactly for this purpose, but I can't find it anymore...

There is was, it got clipped into a water tank during one of the many reworks!

I did some EVA construction to move it in an exposed position, now it's on the side of the cupola.

A journey begins

At first, I use Tripophobia to push Cylinder and raise apoapsis without using Cylinder's own fuel. Trypophobia doesn't have all that much fuel, though, and must keep some in reserve to land back on Phobos. I save maybe 300 m/s this way. Still, this mission is so tight, anything can make a difference.

At the moment of splitting, I finally do what I've been postponing since the last docking: fix the broken engines.

Service Probe 1 moves

And grabs a wolfhound 3 engine

And here with a Nerv 3, while Nitrogenie in a Bottle changes docking position

Spider stays on cylinder, obviously with the Mercury descent stage. Fat Man also stays with Cylinder, it will be needed to lower apoapsis of the lander once at Mercury. The additional tank of Fat Man stays too, not much because I plan on needing it for Fat Man, but because it's an extra fuel tank.

Clamp and Nitrogenie in a Bottle remain on Phobos with Trypophobia. Now that I dropped several landers, those operations are a lot faster.

I am ready. To reach Mercury saving fuel I have, of course, to take multiple gravity assists.

Part 1: From Mars get a Earth flyby, for 1560 m/s. Lower perihelion all the way to Venus

This first stretch is pretty straightforward. I take a gravity assist from Earth to lower perihelion enough for a future Venus flyby. It will take a few years before Venus actually passes nearby.

It is worth noting that the 10791 m/s figure is almost accurate. It's actually close to 11 km/s, because for unknown reasons when I dumped excess oxidizer (which is not used by Cylinder) the central tank did not empty. Then I will drop a lot of mass when landing Spider, getting rid of all that oxidizer; but on the downside, I will need to burn some fuel with Fat Man to carry Spider to low Mercury orbit and back to the mothership. I'm not sure how that combination affects my deltaV, probably it gives me a little extra.

Cylinder leaves Mars

It's also worth mentioning that I'm spending more than I should on those Mars ejection. Best as I can tell, it's because from Phobos orbit I have less Oberth effect. So I have an intercept speed of 1500 m/s when coming from Earth, with a close periapsis using all the Oberth effect, but it takes 2000 m/s to get back to Earth (of which I already paid some by using Trypophobia's fuel earlier).

Or maybe it's because when I come from Earth I only need to get captured in an elliptic orbit and aerobraking does the rest, but coming out of Mars I must first raise apoapsis. Probably a mix of both.

Part 2: refining the Earth flyby

In this second piece of trajectory, I further refine the Earth gravity assist to syncronize with the passage of Venus. In 3 years I will get a Venus intercept, without any additional cost.

Part 3: further refining Earth flyby

But! A 500000 km Venus flyby is still an intercept, but it will require upwards to 100 m/s to actually pass close to Venus and get a gravity assist. I must try to be efficient with those course corrections. An additional tiny change makes for a more accurate Venus flyby in three years. Once I make sure to pass within a few planetary radii of Venus, there's no point trying to refine the trajectory further; I still don't know where exactly I'll take the gravity assist, and the game is not accurate in predicting trajectories so far in the future. But perfecting the Venus flyby will only require a few m/s now. 

To perform those very precise manuevers, I shut down Cylinder's main engines and use the smaller engines of Fat Man to push the mothership.

P.S. DeltaV in the lateral bar dropped to 8000 because I stopped fuel transfer from Fat Man, so now the game counts all that fuel as dead weight too.

Earth flyby, passing over Japan

In my previous A'Tuin mission, it took me several passages to lower Kerbol periapsis to Eve. This time the first passage did the trick; gravity assists are more effective in rss. I can hypothesize that it takes three times as much deltaV to perform similar manuevers, but the spheres of influence being 10 times bigger results in 10 times more deltaV gained in a flyby.

Trypophobia lands in a particularly uncomfortable place

Meanwhile, Trypophobia landed back on Phobos. The irregular topography of the moonlet, together with its low gravity, make for some very annoying landings. You generally fall on a ravine and slide down halfway around the planet before stopping. With some luck, you're still in the same biome.

With a fill of uranium, Trypophobia changes biome to get fuel

This valley is very pretty, though

While I wait, I must still service the main nuclear reactors every year. Strangely, no other part of the ship needs regular maintenance now; not even the small nuclear reactors on Cylinder. I haven't found a reaction wheel in need of fixing in decades. Life support and antennas are still getting roughed up. I think it's because of the "encourage redundancy" option, it says it reduces malfunctions if you have more redundant parts of a certain kind. I have over 100 reaction wheels, but less than 50 life support systems and antennas, so reaction wheels are having their lives prolonged. But it does not explain why the nuclear reactors on Trypophobia need so much maintenance and the ones on Cylinder do not.

And the Venus flyby is getting closer.

Part 4: first Venus flyby

This time, a single Venus gravity assist is not enough to lower perihelion all the way to Mercury, so I make sure to eject into a resonant orbit: 179 days 20 hours, against 225 days of Venus orbital time, ensures a 4:5 resonance. Cylinder will meet Venus again 899 days later. Since the Earth flyby was very accurate, now I only need 3 m/s of course correction.

Year 35, one of the main dishes gets broken. I had 6 for a reason.

Part 5: second Venus flyby

So far, the path was straightforward. But now, I have to decide how to approach Mercury. The best way, as already established with A'Tuin going to Moho, is to meet Mercury at perihelion. But this means I have to take the last Venus flyby when it's opposite to Mercury perihelion. So this next Venus flyby focuses on that: Notice the 0 degrees inclination compared to Venus, which makes possible to intercept the planet in another point of its orbit.

Part 6: Third Venus flyby, and aftermath

Immediately after the second Venus flyby, I start planning the third. A couple small manuevers (yellow and purple, 64 and 10 m/s) ensure syncronization with Venus in another year, lowering the perihelion where I need it. So far all the correction manuevers have been very efficient, requiring around 100 m/s total.

However, now I must face the problem of inclination. Mercury is at its higherst point away from the ecliptic at perihelion. Pushing the planar node there would require way more orbital energy than I have, and even then, it would result in a very high inclination over Mercury - around 10 degrees, which would increase intercept speed crazily. Alternatively, I will have to match orbital inclination in solar orbit. At 4 degrees is a lot less than Moho, but in rss it's gonna be super duper expensive: 2780 m/s, the cyan manuever node.

Well, first I'll take the Vensu flyby, then I'll see if I can do anything to improve.

Part 7: getting a Mercury intercept

So, I managed to shave a bit off the planar correction, now it's "only" 2670 m/s. On the plus side, this matching of planes reduces orbital speed relative to Mercury; sneaking a bit of retrograde burn while at it further improves on getting closer to Mercury's orbit. It results in less than 2000 m/s of intercept speed. I was planning to spend up to 4 km/s to go from Venus to Mercury, this is 4.5 km/s, only a slight extra cost.

The alternatives weren't any cheaper: the following pic is the attempt to skip the plane change by pushing the planar node over the intercept.

Alternative manuever: do not change plane, meet Mercury at planar node

As you can see, it results in 5400 m/s intercept speed, way more expensive than the double manuever. There's nothing to be done, I have to spend those 2700 m/s.

Alternatively, I could reload way back to the second Venus flyby, change trajectory so that I would have the third Venus flyby at the planar node with Mercury. I could use the gravity assist to match orbital inclination with the innermost planet. But then I'd not be meeting Mercury at periapsis, which would probably compensate for any other saving. Given the hassle involved, I'm trying that only if I'm really desperate.

Meanwhile, look at the oxidizer amount. Last pic it was 18k. But the pic before, it was 10k. And before that, it was 18k again. Did I just randomly gained oxydizer?

Well, it's another bug. When leaving Mars, I dumped all the oxidizer that wasn't in Spider's tanks, because Cylinder has nuclear engines. But I still found oxidizer in the central tank. I assumed I forgot to dump it, with all the times I reload the game for disparate reasons, maybe I did reload to a time before I dumped oxidizer. And the second time I found the tank full, I thought, maybe I forgot again. But eventually I realized the truth: the oxidizer tank was refilling itself.

And no, it's not good. Cylinder does not use oxidizer. That is dry mass as far as I'm concerned. At best, it's a nuisance that I have to vent in space before every manuever, losing 0.5 m/s because the drain valve is oriented opposite to the engines. At worst, I forget to drain it and have to repeat the manuever. Just wonderful.

Part 8: sacrifice 200 m/s for a faster Mercury intercept

The original plan involved a 60 m/s manuever to syncronize with Mercury's passage in 6 years. By spending 460 m/s I can instead meet Mercury in 1 year. Lowering aphelion results in 200 m/s less intercept speed, so I'm spending 200 m/s to save 5 years. Time is stuff malfunctioning, and 200 m/s probably won't change anything. I can always reload the game if they do.

Part 9: Mercury intercept

And finally, after 9 years of bouncing around planets, I reach Mercury. But the question is, will I have enough fuel to return to Mars? I'm afraid it will depend on how much I can aerobrake on a Mars intercept if I really have to...

Arrived at Mercury

Which looks pretty good from orbit. I like the bluish palette

Capture burn

In orbit of Mercury

Before landing, I want to make sure I can leave. It will save time if I have to reload.

It's hard to get exact numbers accounting for the dropping of Spider, but I have somewhat between 4 and 4.5 km/s left. If I can get back to Venus with 3.5 km/s, then I may be able to return to Venus with some good aerobraking. I won't have the fuel to return to Phobos, but once in Mars orbit Trypophobia can come tow Cylinder.

Unfortunately, inclination is still biting me. Raising aphelion to Venus is easy, but I must either raise the planar node, or change plane...

Projection of leaving Venus

It would take almost 4 km/s to get a Venus intercept. Which would leave basically nothing for Mars injection.

Luckily, I had a few real life weeks to worry about whether inclination would make a return trip from Mercury impossible within Cylinder's deltaV budget, and I already had an alternative plan to take. One that would require less hassle than trying to approach Mercury on a planar node.

5.2) Never get out of bed without a B-plan

Spoiler

When I first designed A'Twin, I was sure 11 km/s would be enough to go anywhere; if they weren't, it's not like I can get much more anyway. But the more I've been playing with rss, the more I realized just how ludicrous the deltaV budget is for someone used to stock. And the more I started to doubt that perhaps 11 km/s would not be enough after all. So I started to form a plan.

The plan is very simple. Fat Man has supplies for one year, in case I had to deal with some very distant moons. And it has a lot of deltaV. So instead of capturing Cylinder in Mercury's orbit, I merely slingshot past it, while dropping Fat Man. Fat Man does the injection burn, it orbits Mercury. Then a few orbits later Cylinder returns to Mercury - by the law of gravity assists, it will return with the exact same intercept speed it had before. And then Fat Man will make a rendez-vous.

It's certainly the easier among the alternatives I have, the one requiring less reloading.

I also had an alternate plan to arrive at Mars without fuel, an do a partial aerobrake - I cannot get captured all the way in a single passage, but maybe I can aerobrake for 400 m/s, escape Mars in a resonant orbit, and return a few years later 400 m/s slower. It would have been cool if it worked, but luckily, I won't have to try that.

So, first step is to reload a few months before the Mercury capture. Then find a resonant orbit for Cylinder, that will let it return to Mercury in no more than one year.

Part 9b: will flyby past Mercury instead of getting captured

The task is not trivial, because Mercury is small and Cylinder is coming in fast, and so I only have a small control over my trajectory; but I did find this one, a 3:4 resonance with Mercury's 88 days orbit, leading to a new flyby in 351 days.

Undocking Dolphin 2

I thought, Fat Man alone has supplies for more than 1 year, no problem there. It also has basic comforts. However, it is not the best environment to leave 3 kerbonauts for one earth year. With little space, they will get plenty stressed. So I decided to dock a Dolphin to Fat Man. It doubles life support, it doubles crew space, and the ion engines of Dolphin ensure I'll not be losing deltaV.

Dolphin 2 manuevering to dock with Fat Man

Conveniently, it can fit on the back without disturbing the nuclear engines.

And then to dock with Spider

This is what will orbit Mercury

After some EVA construction to move a docking port, I also added a Wings to the ensemble, because I wanted to run some research.

As you can see, it has food and oxygen for over two years. Water supply readings are not accurate because the game does not take properly into account the water recycler; that recovers roughly 80% of the water, so quintuple the result shown and you've got a reasonable estimate. "Living space: modest" will cause some stress with the crew, but it shouldn't be too much of a problem. At worst, they will destroy some pieces.

DeltaV readings are unreliable as usual, but a calculation shows 4500 m/s without dropping the lander, discounting ion engines entirely. It will take some 3000 m/s between capture and circularization, but then Spider will become a lot lighter - it's over 100 tons right now, it will go down to 15. Hopefully, this will stretch the remaining fuel to greatly increase the deltaV; I will need some other 3000 m/s to rejoin Cylinder, but I can guesstimate that I will have enough, with a few hundred m/s spare. And then I can also use the xenon, it's got to be worth something in an emergency.

Fat Man manuevers to get the proper apoapsis for capture. Yes, I'm also using the ion engines. Their contribution is negligible, but why not?

By the way, I'm not bothering to fix the malfunctioning life support on the cupola because I've got 5 more, and as long as it stays malfunctioning it can't get criticall broken.

Fat Man performing the capture burn

Capture speed is still 1700 m/s. I am in the same trajectory that Cylinder was using to get captured the first time.

Passing very close to the surface, to maximize Oberth effect. Actually, I accidentally crashed the first time I did this

Highlighting the different trajectories of Fat Man and Cylinder

In orbit. Well, with just a little bit of periapsis raising

Before lowering apoapsis, I take advantage of the high apoapsis to detach Wings into a polar orbit, for science.

Detaching Wings A

Which goes to its own science orbit

It doesn't have any effect on the overall missions, but it feels good doing it.

Then I start lowering apoapsis; Spider has only what it needs to land from a circular orbit.

During apoapsis lowering, one engine got broken

And properly ejected

That's a bother. I have spare engines, but they are on Trypophobia. Meanwhile, Fat Man is at reduced thrust. Both for the missing engine, and because I have to reduce power to the others to balance for asymmetrical push.

After a few orbits, circularization is almost complete. The Mercury descent stage has a few hundred extra m/s, and I plan to make good use of them.

Detaching Spider

Fat Man moving away, seen from Spider's cabin

Descent commencing

I am using the strategy of pointing slightly above retrograde to keep vertical speed near zero. Not much for the deltaV gain, which is small when the ship has a lot of thrust like in this case. But mostly because it's easier. I did test the Mercury descent stage this way, and it worked the first time. I did try a normal suicide burn, and I could not find the proper altitude to start.

Detaching the Mercury descent stage

Not sure why the game shut down the engines on Spider upon staging. I detach the descent stage while it's still got a bit of fuel, so that it will fly away from Spider. Still, I should have included something to spin it laterally; I never got hit by the spent descent stage in the several attempted landings, but there were a couple of near misses.

Landing

Landed!

According to the deltaV map, it takes 3060 m/s to orbit Mercury, I should be just fine. The objective of using all the fuel of Spider was accomplished.

After all the effort it took going here, I wanted to drive a bit with Hartman. There is a biome boundary in 20 km, a good excuse for a short trip.

Terrain in rss is so smooth, you can go fast

I traveled 20 km, now will have to get back to Spider

I also spent a full week on Mercury, to finish some slow-going science experiment. This was a problem, because I'm not in an equatorial orbit and therefore planetary rotation is moving Spider away from Fat Man. I considered waiting a full Mercury day, unfortunately Spider doesn't have enough supplies for it. I had to launch with 10 degrees inclination, and spend fuel on Fat Man.

Leaving Mercury

Made it to orbit, with 50 m/s left

Now I have to wait one year for Cylinder to arrive.

5.3) To catch the mothership on the fly

Spoiler

One year passed. It's time to control Cylinder and make the course correction for the flyby. Curious, why it's pulling on a side?

Fortuntely, it's nothing a reload can't fix

I also get another critical malfunction, but to a part that doesn't matter.

Critical malfunction to a converter. But the chemical plant function is still working

The convert-o-trons have two functionalities: converter, and chemical plant. Converter is the stock function, the overpowered isru that I'm not going to use. Chemical plant is extracting carbon from regolith, hydrogen from water and uranium from rock, and that's the function I need. So, while red, that convert-o-tron is still perfectly functional.

I even left the converter functionality in low quality, because high quality would add 8 tons.

Ok, time for another trajectory.

Return part 1: get a high aphelion

For this last Mercury flyby, I want to get the best combination possible of high aphelion and low inclination compared to Venus. I'm basically returning in the same trajectory that I used to get captured by Mercury. Which is convenient, because I also want to get a good trajectory to get a rendez-vous with Fat Man, and this will have a similar Mercury periapsis.

Meanwhile, Fat Man prepares to leave.

Get ready to leave. Recover Wings A

Fat Man status

The deltaV gauge is wrong, I have some 3500 m/s. Or maybe it's including the xenon. Anyway, I said I'd need 3 km/s for this manuever, and I have them.

The crew is a bit battered. Close to 50% radiation damage because Fat Man was making short passes in Mercury's radiation belt - a faint one, but over one year it adds up. I did not move them away because I knew they'd live, and it would have been expensive. They are also over 20% stress; they'll start to recover once they're on the mothership.

Planning the rendez-vous

For the rendez-vous, I started by raising Fat Man apoapsis, because it's 1000 m/s I won't need to burn later. At this point I could have syncronized the orbit perfectly to reach periapsis exactly in the same moment when Cylinder was passing there. But it would be pointless, because I'd then have a 1700 m/s intercept speed, I'd wiff out of physical range in a few seconds. 

Instead, I plan to pass at periapsis a few minutes before Cylinder. This way Fat Man will start to gradually accelerate with its low thrust, while Cylinder overtakes it.

Rendez-vous, with planned manuever of Fat Man

And this is how I plan to make this rendez-vous. Cylinder is coming in at 1700 m/s. Fat Man will start a few minutes earlier at 1400 m/s. It will leave Mercury on a trajectory very close to that of Cylinder. Cylinder will still move 300 m/s faster, and will leave Mercury one hour before Fat Man. Somewhere along the way, the two will pass close enough. Then I will make a rendez-vous with the navisphere.

Halfway through the burn. Cosine losses are not a big deal, thanks to longer orbits even a 10 minutes burn time is acceptable

Burn completed. Now the two ships are bound to pass within a few hundred km from each other

On the navsphere, prograde is no longer aligned with target; it's time for some correction burns, here to move closer to the target while slowing down compared to it. DeltaV is still overstated

Speeds almost matched, still enough deltaV. The game still does not recognize the rendez-vous

Rejoined with Cylinder, with a few hundred m/s to spare

Fat Man started with 250 tons of fuel, it kept 2 in the end. Nothing like using your hardware in unplanned ways and making it to the end with the last drops of fuel to spice up a mission.

Now have to disassemble this monstruosity into which I turned Fat Man.

Wings A takes its place back. An engineer will move the docking port too

Dolphin 2 returns to its place. The fit is very tight, I was worried there was clipping involved that I didn't see, but it enters smoothly

5.4) Return trip

Spoiler

Now I have to find the best way to pick a gravity assist from Venus. I have two options: I can match inclinations (plus a prograde component), or I can raise aphelion until a planar node is on Venus orbit. Both turn out to have similar costs, somewhere around 3300 m/s.

Return option 1: match inclination to reach Venus

Return option 2: expand orbit to overlap planar node with Venus

But matching planes does not work as well: Cylinder's orbit would then have little energy compared to Venus, and so the gravity assist would not be strong enough to reach Earth without some help. So, I go with option 2. I also find a way to make it a bit cheaper. That both those options will get a Venus encounter immediately is just a lucky coincidence.

Return part 2: to Venus. DeltaV gauge is a bit off, I actually have 6200 m/s. I have no idea why in this screenshot the windows are bigger

The Venus flyby set Cylinder to touch Earth orbit.

Return part 3: after Venus flyby, to Earth, to Mars orbit

Earth won't be there after the Venus flyby - it was exceptionally rare for it to happen with Venus -  and meeting it will require a mild correction burn to syncronize orbit (85 m/s, yellow node). An additional course correction, mostly a plane fix - those are the most expensive - will refine the Earth flyby (33 m/s, purple manuever). The gravity assist won't be enough to reach Mars directly, aphelion will still be a bit shy of Mars (red orbit); You can see Earth periapsis at 147 km, just 7 km before atmosphere begins. I literally cannot squeeze any more deltaV out of this gravity assist. I'd need to eject in a resonant orbit and get another Earth flyby for it. However, since fuel is now plentyful, I am instead using another correction manuever (67 m/s, cyan manuever) to raise aphelion.

Now that the whole stunt with Fat Man saved fuel and I don't need to conserve, I'm being a bit more wasteful in fuel in order to save time.

Passing close to Earth one last time. I actually went close to the Moon, maybe a gravity assist on it would have been possible

Flying over central America. I actually entered the atmosphere for a little bit

Now all that's left is to syncronize with Mars. I have two options: a big 1000 m/s burn that will result in meeting Mars in two years, or a small 60 m/s burn that will reach Mars in 8 years. After calculating the fuel left, I go for the first: when possible, always save time.

Return part 4: after earth flyby, to Mars

Purple burn is the aforementioned 1000 m/s burn; the yellow burn is still the one to raise aphelion to Mars, shown in part 3 already.

And so, after three more years without accidents...

Mars!

I don't recognize that basin, but it certainly is scenic

At periapsis, showing how aerobraking is contributing

Turns out I can aerobrake for a few hundred m/s without breaking anything. Maybe my C-plan of saving the mission by taking multiple gradual aerobrakings in subsequent years was actually feasible. Even then, though, it would have required many years, because of Mars slow orbit.

After capture

Indeed, aerobraking saved some 200 to 300 m/s on the capture. Those are not enough to reach Phobos, but I knew I'd need Trypophobia to come collect Cylinder. For now I have enough to fix inclination, then I aerobrake until I reach Phobos, then I spend what fuel I have left to raise periapsis.

After I've done that

From this orbit, it will only take a few hundred m/s for Trypophobia to reach Cylinder. In the outbound trip, the mining module was only able to supply a bit of deltaV, but then Cylinder was sporting full tanks, over 4700 tons of mass. Now it's completely spent and much lighter to tow along.

Trypophobia reaches Cylinder

But the propellers on Nitrogenie in a bottle had gotten completely destroyed in the meanwhile

How did that happen? I did shut down the rotors and lock them.

Well, turned out, I did set up a hotkey to activate/deactivate the rotors, hoping to make things easier when I reach Titan. But I used the same hotkey I'm using to start mining operations, thus I accidentally reactivated the rotors. Have to reload to before Trypophobia left Phobos, maybe one hour of gaming. Could have been worse.

I used the drain valve to orbit Phobos. And even to get into an escape trajectory

Now I reached Cylinder again, but the alignment bug struck. Reloading fixed it

I surely have got plenty of broken reactors there

By the way, I've been quite lucky with malfunctions because I had plenty of those, but most of them noncritical. I am leaving the nuclear reactors in their yellow state for the same reason mentioned earlier: they can't get broken any worse until I repair them. I may need to fix a couple once I'm on Ceres, where there is a decent ore concentration.

This time I could rendez-vous the two halves of A'Twin without accidents. Third time is the charm

5.5) Usual Phobos business

Spoiler

Once more, I go through all the trappings of rejoining A'Twin. I also immediately take the chance to fix the engine on Fat Man

Servie Probe 2 goes to grab the engine

After removing this nerv, I will also be able to discard the broken reaction wheel

There, new engine in place

Rejoining the two twins

The 5 m docking port a few meters before docking

And then it's back to Phobos to mine. It's routine enough manuever that it doesn't require any more description.

I did got a couple of good pics from it, though

Good landing pic

Landed on Phobos

All considered, it took 15 years to get to Mercury and back. Those 15 years saw 3 malfunctions, of which only 2 actually matter. Now I'm back to mining.

I'm going to mine until I run out of uranium, which should fill the tanks perhaps to two thirds. Then I'll biome-hop, to get more uranium. Then I'll reach Vesta, it's a simple transfer and I'm sure I don't need full tanks for it. Vesta has a good biome for ore and water, but it lacks uranium in the same spot, hence why I want to have a full complement of uranium. This way I can only land on Vesta once, I get as much fuel as I can, then away for Ceres, where finally I will find uranium, water and ore in the same spot.

Meanwhile I used up 20% of my nitrogen stockpile, i.e. monopropellant. In 50 years. Ok, I have enough for a couple more centuries, I'm in no hurry to get to Titan.

Another couple of nice pics...

...taken during a repair tour

And actually nothing bad happened during refueling, and nine years later I run out of uranium, as predicted.

Strange, the previous time it took 10 years to get the tanks full, and now 9 years to get them to 70%. Either the no ground contact bug was more active, or having so many broken reactors glitches performance somehow.

Leaving highlands (water biome) for midlands (uranium biome)

However, I see that Ceres itself is in a good position for a transfer right now, and if I go to Ceres I will find uranium to mine and won't have to bother carrying it. So, maybe change of plans? But that will go in the next chapter.

Status when considering a Ceres transfer

Bugs compilation updated

Spoiler

How many times did I write I had to do something to circumvent a bug? I thought it would be fun to collect them all in one place. Problem and Solution

- Launching most vessels will crash the game. Must send them to orbit with alt-f12

- Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

- Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

- Propellers start twisting around. No worry, it fixes once you stop time warping

- Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

- Crew transfer function may get stuck. Transfer the kerbal by EVA

- Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

- Ship occasionally sinks into ground upon time warping. Just try until it works

- Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

- I can't make manuever nodes or go eva, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

- Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

- Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens

- Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

- Docking ports do not undock (NEW!). This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

- Actual reliability time is different from what it should be (old, but I'm so used to it I stopped considering it a glitch). Just check more often the parts that get broken more often

Broken parts recap

Spoiler

I want to keep track of how much stuff I break, and how much it's affecting the mission, so I prepared a list

Life support

1 life support broken on a Dolphin. I've got five more redundant pieces on it.

Nuclear power

1 Excalibur reactor broken. It was redundant. There are 12, and up to 3 can be lost before mining is slowed down.

Reaction wheels

2 large reaction wheels broken. I've still got 88 working.

Engines

1 big nerv broken. I've got 2 more spares.

1 big wolfhound broken. I had a spare.

1 small nerv broken. I've got 2 more spares.

Communication

1 RA-100 dish broken. I've got 5 more redundant pieces. After that, I still have more non-relay antennas.

Low-quality parts

A landing light broken on Nitrogenie in a Bottle. Irrelevant, I don't need them.

Life support on Trypophobia's gravity ring broken. Irrelevant, the same function is included in the greenhouses.

1 Converter broken. Irrelevant, converter is the stock isru functionality that I'm not using. I need the chemical plant functionality, and that one is still working perfectly.

Outdated

2 reaction wheels broken on Milly. Now Milly has done its job.

1 dart engine broken on the Mars Descent Stage. Now it's a pile of debris on Mars.

Discounting the low quality and outdated parts, that's 8 critical malfunctions so far. They felt like they were more, not much for close to 50 years of mission.

Edited November 30, 2022 by king of nowhere

[king of nowhere]

Part 6: 44% of the asteroid belt

A'Twin visits Ceres and Vesta, which together make up 44% of the asteroid belt by mass.

I also discovered anomalies!

6.1) There is no such thing as a simple Hohmann transfer in rss

Spoiler

I have to go from Mars to Ceres, it will be a simple Hohmann transfer.

I can be so naive at times.

Here I'm trying to see if I can vent excess ore as a form of propulsion. Not worth the effort, I can get maybe 1 m/s from it

Planned route for Ceres

I'm also at the right time because the time for the transfer falls exactly when I am on the planar node, saving the need for a plane change. Inclination is fairly steep, at around 7° (didn't think to highlight it in the screenshot).

But as usual, most of the difficulties are made by the game itself. I have a new bug, the disappearing encounter. For you see, as I tried to refine the encounter above...

The encounter disappeared!

And then it reappeared in a different place. I tried to have the same exact value of deltaV in the manuever, but it didn't fix. Restarting the game seems to have some effect. Otherwise, the best thing is to already know where the encounter is, and go blind. But I can't see how much deltaV will be for the capture burn. It's going to be steep, because Ceres is too small for a good Oberth effect.

Burn is going to be very long. Interface lies, it's about one hour. But because I am in high orbit, I'm getting minimal cosine losses

Long burn is also the reason I'm not lowering periapsis first. On a burn this big, it is probably convenient to first lower periapsis on the point of the burn, to get more Oberth effect. But A'Twin as too low twr to take advantage of that, and it would have horrible cosine losses.

The burn is long enough, I have to split it in two with a pause to service the engines. I'm not sure exactly when they become worn, but 20 minutes until the end of their nominal time seems right.

It wasn't.

One engine broke for material fatigue, with 22 minute burn time remaining

Turns out, I can service the nervs already at 30 minutes burn time remaining. That's more than half their total burn time (52 minutes). This is definitely a change over older versions of kerbalism.

I started making the repair tour at 25 minutes, and so far nothing else broke for material fatigue.

Anyway, now that the long burn is done, I can finally refine the trajectory and see how much injection will cost.

2714 m/s for injection. Plus some 500 m/s to land

Running some calculations with my datasheet, it turns out I have 2100 m/s nuclear and 800 m/s high thrust. Total 2900, 300 m/s short. I can gain something if I dump water and uranium, but not enough to gain 300 m/s.

So... I have to reload, then. looks like I needed to load more fuel after all. On the plus side, I get to revert the malfunction on the engine.

So I reload back, and I mine some more fuel and I wait for a good transfer window for Vesta. I wanted originally to go to Vesta, and later to Ceres, because Ceres is a better base from which to reach Jupiter. I only went to Ceres because I had a convenient transfer window.

The transfer window is 200 days later (notice the calendar, 55:300 while the Ceres manuever was at 55:130).

Manuever to Vesta

Unfortunately, Vesta is not sitting conveniently on the planar node, forcing a very expensive plane change (green manuever).

And the intercept is not much cheaper because of it. The whole trip is over 6000 m/s. While I am sure that some optimization can bring that number down somewhat, and A'Twin does have that deltaV if it fills the tank completely, that would require spending several more years at Phobos. On the other hand, I got to really appreciate how convenient was the previous transfer to Ceres. And I only was missing a smidgen of deltaV.

So, change of plans again. I reload back to the Ceres manuever. This time I dump water preemptively - I can get rid of 140 tons of water, and still have enough for 20 years. I can also drop some 50 tons of uranium, as Ceres has it. If I make my ship lighter before the ejection burn, I can get those 300 m/s I was missing (by the way, I wonder why a unit of uranium has a mass of 11 kg. Other resources have the mass of 1 liter at standard conditions, but uranium density is 19 kg/L). I'm also dropping some oxidizer, I don't need 800 m/s high thrust.

Here we are again! I did not get rid of all the uranium because I must still transfer it manually from every single reactor before I can dump it

And the pause to fix the engines. This time with 25 minutes remaining burn time, and nothing broke. Also, last picture of Mars for a long time

And the status after leaving Mars

This time I saved over 60 tons of fuel. According to the datasheet, I have 3200 m/s, which are enough - barely - to land.

Notice how I also kept a high Ceres periapsis, to simulate the lack of Oberth effect for the long slow burn. Not that Ceres would give much of an Oberth effect anyway.

One year to Ceres, was uneventful.

Ceres. I'm already burning for capture

Near periapsis I also activated the chemical engines, as I have more oxidizer than needed. I could have dumped some more of it - Ceres gravity is so low, I could land with the nervs alone - but I discovered there is very little gain in dumping oxidizer completely. Sure, the wolfhounds have half the Isp of the nuclear engines; but on the other hand, that oxidizer mass also gets to contribute to thrust. And those oxidizer tanks would be empty otherwise. So as long as there isn't enough oxidizer to make a big difference on the total mass of the ship, keeping some oxidizer has virtually no effect on deltaV. I could drop it all, and gain maybe 50 m/s.

Anyway, I am in orbit of Ceres.

In Ceres orbit

I'll need roughly 400 m/s to land, and I have - cue the dramatic music while I run the calculations - 550. An easy landing.

6.2) At Ceres

Spoiler

Descent

Last second suicide burn

And for the first time in this mission, I got to use the high thrust cougar engines! I was starting to wonder why I was carrying them around.

IVA view of the burn

Unfortunately the cougars are not too spectacular when seen from the cupola. Also, the symmetry looks good when seen from behind the ship, but from the cupola the flames cover each other. Maybe I should have swapped places for the cougars and the fission reactors?

stopped in midair shortly above the ground

And thus I made it to Ceres with 25 tons of fuel left. Even a simple direct transfer between two close planets required well over 5 km/s.

Servicing stuff. With the low gravity, it's more convenient to just hover above the ground

Hovering above the ground with gravity is kinda annoying, so I tried to activate the cheats and reduce gravity, to float better. Unfortunately, this had the unintended side consequence that gravity was too low to counteract the dwarf planet's rotation, so A'Twin started to orbit while I was servicing it. And then it crashed into the ground.

I always like those kind of views on the inside of A'Twin

And we have the first malfunction for this chapter! Goodbye radiator

Radiators are meant to vent the heat produced by the nuclear reactors. Except that, with the kerbalism reworking the parameters of said reactors, they don't produce heat anymore. I sometimes forget the radiators retracted, and nothing bad happens. I still put in the radiators because I want to simulate a realistic mission, but this malfunction does not jeopardize the mission.

Planting the flag, in natural light. It makes for a suggestive atmosphere, but you can't see much of what you're doing

I could compensate for that by using lights, except that 1) lights are bugged, when you have more than a half dozen they stop working, and 2) my megaships lag enough already.

It's time to start looking for a Vesta trajectory. Vesta is on a similar orbit with Ceres, periapsis is very close, Ceres has higher apoapsis. The main difference is the inclination, that allows the two orbits to cross without overlapping. The first thing to do then is a plane change, I'll stay on Ceres until it is on the planar node.

The orbits of Ceres and Vesta, with the difference in inclination highlighted by the lateral perspective

Another malfunction: the life support on Spider

That's annoying. What's with rovers with a single life support that makes them break so often - while Dolphins with 6 keep them all working to the end?

However, it is less annoying than it looks like at first glance. As I keep mentioning, I do not give those rovers additional life support because they can fully complete their missions without one - although I give up the chance to drive long distances if I wanted. But Spider is the heavy lander for large moons. And there are only exactly 4 of those left: the four major moons of Jupiter. Those moons are also inside Jupiter's radiation belt, so I won't have the chance for a prolonged stay anyway.

Ceres is now passing through the planar node with Vesta

After 4 years on the dwarf planet, the celestial bodies are aligned to leave for Vesta.

6.3) Ceres to Vesta

Spoiler

Ascent on such a low gravity body, of course, is easy.

Still looking good, though

And here's the manuever to reach Vesta. At least the first part, the close approach bug is once more preventing me from planning all the trajectory from the start.

Planned route to Vesta, part 1. With 6000 m/s, this won't be a problem

Good thing I'm now far enough from the Sun that plane changes costs are becoming, if not cheap, at least reasonable. As mentioned, this manuever is not a periapsis lowering or apoapsis raising, but a plane change, so I'm basically burning northward.

The burn to Vesta, seen from Ceres

Seeing this, I immediately curse myself for a fool: instead of launching in an equatorial orbit and then burning to a polar exit, wouldn't it be better to just launch to a polar orbit directly? I reloaded and did just that.

But it only saved 40 m/s. Which I spent as extra to launch anyway

Now to get into an intercept I just have to syncronize the orbit to Vesta's passage

This situation is not ideal. The orbits are not concentric as they should ideally be; when I cross Vesta's orbit, I am moving towards a lower periapsis. This entails a higher intercept speed, which will manifest as radial velocity relative to the sun. For this reason, my syncronization burn also contains a radial component: I'm starting already to pull the orbit closer to Vesta. By making this manuever in solar orbit I lose on Oberth effect, but Vesta has a tiny Oberth anyway; and on the plus side, I get to couple it with a periapsis lowering burn, so I take advantage of Pitagora's theorem to pay less.

Indeed, I do experiment different degrees of radial burn:

Syncronization with a greater amount of radial burn

In this second attempt, I make a greater radial burn. You can see than now A'Twin's orbit touches Vesta at periapsis, in an indeal situation. And indeed, capture burn is now 700 m/s, much lower than the 1400 m/s that it required in the first attempt. Of course, this entails a greater syncronization burn: 1760 m/s, when in the earlier case I got away with 970. The difference is small. I suspect if I lowered periapsis to coincide with Vesta's orbit I also would need the same energy. Without Obert effect or gravity assists or other stuff to take advantage of, I have to pay the energy difference between the two orbits, and however I choose to pay it, the price is going to be similar.

Of the two trajectories, I pick the first because it arrives on Vesta 200 days earlier.

Before leaving Ceres, I connect to kerbnet. I've always wanted to do it, but I forgot in the previous planets I visited. Not that I expected to find anything. There isn't even a proper terrain scatter on those planets.

I was then very surprised when I saw not one, but 2 anomalies.

Anomalies on Ceres

I'm already leaving, but it's worth checking in the next bodies I'll visit. For now I have six years of travel.

During which I break an antenna

I broke a lot of stuff in this part of the mission. If in the previous trip to Mercury I've been lucky, with lots of malfunctions but very few critical, here I'm getting very few malfunctions, but lots of criticals.

Well, for a small antenna like that, I have spares.

As you can see, I have plenty of spares of everything

Those small HG-5 antennas aren't really needed, though. I don't think I'll ever need relay capacity from a smaller probe. But I did include it, just in case I am landing remotely in the inner moons of Saturn - where radiations are too strong to send a crew - and I need to bounce the signal past a moon. Otherwise, the regular communotron 88-88 are plenty good for everything.

Peretto changes the antenna

This marks the first time I take some spare part out of storage.

But it's not the only thing that broke in those six years; I also lost another big nerv.

The screen of the broken engine. The gap in place of the missing engine can be seen above the window

Those times I've always been careful with refurbishing the engines, but this is a failure on ignition. There is a chance in 500 every time I turn on an engine, and one in four of those will be critical. No way I could have prevented that.

Good thing I carried three extra big nervs, the downside is that I have to open A'Twin to get the spare - a long, slow process. Or do I?

There is enough of a gap in the roof to incuneate a Service Probe in it

Thus grabbing the engine

But the engine is bigger than the Service Probe, how do I bring it out without opening the mothership? Time warp. In time warp collisions are off, so I can give the probe a gentle push, time warp to 10x, and watch it move across the fuel tanks. It saves a lot of hassle on manuevering.

Why couldn't I also time warp the Service Probe on the way in? There's so much stuff inside A'Twin, there would be a huge risk of stopping time warp while the probe is clipping into something. Cue big explosions and five minutes of waiting to reload the game.

I also got a new cool bug! As I get closer to Vesta - and obviously I can't see the intercept because of the missing intercept bug - I tried to move closer by clicking on the orbit and "time warp to here". Here's what happened.

Time warp to here is bringing me to the next orbit

You see, I clicked slightly in front of the ship - likely a few days - but the game is interpreting it as the next orbit, 4 years in the future. It's only midly annoying, up until the point where I didn't see it and accidentally time warped past my Vesta encounter - the asteroid's sphere of influence is so small, it can pass by in an instant before the game realizes it should decelerate.

Close to Vesta. The missing intercept bug is in full force, but my navisphere is confirming that indeed I am going straight towards the asteroid

Vesta, finally

6.4) Exploring Vesta

Spoiler

I have plenty of spare fuel, so the various capture, descent and landing operations are not a concern. I even made sure to enter a polar orbit so I could better pick the landing biome. This time I want to investigate the anomalies, so I detach Wings A before circularizing.

Detaching Wings

By the way, you may notice how I'm at an altitude of 20 km yet very close to the ground. Vesta is like that. I actually crashed into a mountain at 40 km altitude at some point. The thing is, Vesta is not very spherical, and to model the irregular shape of the asteroid they had those extreme elevations.

After getting the data from Wings, I sent the Clamp rover to land near the anomalies. Here I got struck by yet another bug

The yellow sentence reads "all hatches obstructed, impossible to exit"

I have Clamp with the back hatch perfectly working. I tested it, and it worked. I already had Horseshoe built in the same way in the previous mission, and it worked. I brought Clamp to Phobos, and it didn't work, but I removed the ladder and then it worked. Now it's not working, again.

Well, desperate times call for desperate measures. I will move the docking port, freeing the hatch on top of the crew pod. I will move the docking port in front; docking will be more difficult, but it can be managed.

The only problem is that I can't remove the docking port because it's the root part. When a shuttle docks to a larger vehicle, the shuttle gets rewritten as part of the bigger vehicle, and the way ksp handles constructions - as a tree with a root part and everything else attached to something - the docking port becomes the first part of the shuttle. Upon undocking, it remains the root part. This problem can be simply solved by docking Clamp to somewhere else. Since it has no other docking ports, grabbing it will a claw will do.

By this time I was already out of A'Twin physical range, and I didn't want to waste fuel and time to bring it back. So I went to the ksc and cobbled up a vehicle with a claw, which I then alt-f12 to Clamp. Oh, I also had to hire an engineer for the task of moving the docking port, since my own engineer was stuck inside.

The vehicle I devised for the occasion. I'm not sure why I put a docking port on the back

The claw grabbing the crew pod, always a bit disquieting

And finally the docking port is moved and the crew can exit

Afterwards, the claw was returned to Earth and Tomtotta was fired encouraged to pursue a more exciting career.

Clamp lands

And moves by wheel

Vesta's gravity is only 2% of Earth. Vesta also rotates extremely fast, objects on the surface move at 100 m/s, almost half the orbital speed. Moving by wheels is still possible, the best way is to just pick up speed slowly and then keep the rover pointed prograde with reaction wheels. At 20 m/s it takes flight at the merest obstacle anyway.

First anomaly: a green monolith

On the other hand, braking is almost impossible - not if you want to stop in the same biome you started on. So I stopped with the rockets. Here I had another accident: in turning the rover vertical too fast, I hit the ground with a reaction wheel and broke it.

The missing broken reaction wheel, on the left

I actually did it twice. The first time I reloaded. The second time I realized I hadn't saved in 30 minutes, and I still haven't used any of my spare reaction wheels - they should be high risk parts, but so far I lost only 2 with minimal maintenance. So I'll just count it a loss and bring out a spare one.

Going to the second anomaly required a brief suborbital jump, Clamp has 2400 m/s and Vesta can be orbited with 250 m/s. The main problem is to pinpoint a landing location, with how fast the terrain moved underneath you.

Second anomaly is a snowman

Cute!

Then I recovered Clamp and finally landed A'Twin.

Braking

And landing

Look, I'm still moving at 5 m/s. I fell on an incline, and I am slowly sliding down in the low gravity. I can't save the game or do anything until it stops.

So I waited. And waited.

And waited.

I didn't want to time warp for fear of damage, but at some point boredom outweighted the risk.

Keep sliding down

Half an hour gone, still sliding

Technically still sliding, but slow enough that the game lets me save

It took 45 minutes in-game. During which I moved 300 m vertically, and probably a couple km horizontally. Because of lag, time stretched a lot longer. Even with time warp; 4x time warp is still not enough to compensate lag. Especially because time warping makes the game lag harder. Very annoying. At least I got the right biome, despite the aforementioned rotation speed making things difficult.

There are two good biomes for mining on Vesta. One has all the resources, but it has 3% ore concentration, like Phobos. Very slow mining, annoying. The other has 9% ore concentration, but no uranium. I stocked up on uranium on Ceres, so I went for this second option.

I activate all the drills, and find yet another bug! Some of my fission reactors are not working!

The lack of electricity bug

A'Twin is spending 25800 electricity/second. I have 11 excalibur reactors, each one capable of producing 3000 Ec/s. But I'm only getting 24000, as if only 8 reactors were going.

A bit of experimenting led me to discover just that: three of the reactors are indeed not working. They are active, they are running, but they do not produce.

I am sure tinkering with the save file could fix the problem, but I am afraid to make a bigger mess. I wrote a request for help, but for now I can go on.

Mine, mine, mine... three years into mining, another malfunction. Another fission reactor.

Broken fission reactor

Here I realized perhaps I could use one problem to cancel another problem. I have some reactors that are not working. And here I have a broken reactor. What if I reloaded back and prevented this one from breaking, and instead dumped one of the bugged one in its place?

A discarded nonfunctional reactor

So this shall be my policy from now on. I won't try to fix those bugged reactors. The next two times I break a reactor, I revert it by reload, and discard one of the bugged ones instead. I fully expect that I will finish this mission without half my nuclear reactors anyway.

Refueling finished

After three and a half years, uranium is depleted. The tanks are 90% full, and I'll just go on like that. I don't want to biome-hop for a smidgen of deltaV I don't really need.

Oh, and as you can see from the flag, A'Twin is still sliding down. Just slowly enough that I can save the game and time warp while at it (time warping at high speed makes you stop your residual movement, in the same way that it cancels rotation).

All in all, it took 15 years for this part of the mission.

Next step will be Saturn. I wanted to go visit a minor asteroid, but that will require a Jupiter gravity assist to change inclination. In turn, I discovered that going to Jupiter requires 3000 m/s. 3 km/s to raise apoapsis to Jupiter, change plane, then 3 km/s to get a rendez-vous with the asteroid. Then 3 km/s to return to Jupiter, and 3 km/s to return to Vesta, and I'm well above my fuel budget. Saturn-Jupuiter is less expensive, and while it takes a longer time, I don't have much of a choice.

I can go to Saturn - its moon Iapetus is very good for refueling - with a 5 km/s burn. I have 6, and I need 500 m/s to land; it would all depend on whether I can aerobrake on Titan, or my intercept speed would be too high for that. Alternatively, I can take a 3 km/s trip to Jupiter, and from there get a gravity assist to reach Saturn with a lower intercept speed. Safe, but a lot slower. I will have to see; I'll probably try the first option and reload if it does not work, just because I want to know.

Bugs compilation updated

Spoiler

The more I write bugs down, the more I realize there are other bugs that I'm so used to dealing with, I don't even remember them anymore. I thought it would be fun to collect them all in one place. Problem and Solution

- Launching most vessels will crash the game. Must send them to orbit with alt-f12

- Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

- Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

- Propellers start twisting around. No worry, it fixes once you stop time warping

- Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

- Crew transfer function may get stuck. Transfer the kerbal by EVA

- Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

- Ship occasionally sinks into ground upon time warping. Just try until it works

- Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

- I can't make manuever nodes or go eva, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

- Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

- Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens

- Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

- Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

- Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

- Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

- Crew hatch registered as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

- Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

- "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

Broken parts recap

Spoiler

I want to keep track of how much stuff I break, and how much it's affecting the mission, so I prepared a list

Life support

1 life support broken on a Dolphin. I've got five more redundant pieces on it.

1 and only life support broken on Hartman. Sucks, I can't take extended trips, but the rover has enough air to conduct landing operations safely. (NEW)

Nuclear power

2 Excalibur reactor broken.  They are redundant. There are 12, and up to 3 can be lost before mining is slowed down. (+1 NEW)

Reaction wheels

2 large reaction wheels broken. I've still got 88 working.

1 medium reaction wheels broken on Clamp. I've got 8 or 9 spare ones in storage. (NEW)

Engines

2 big nerv broken. I've got 1 more spare. Afterwards, the ship can work with less than the full complement. (+1 NEW)

1 big wolfhound broken. I had a spare. Afterwards, the ship can work with less than the full complement.

1 small nerv broken. I've got 2 more spares.

Communication

1 RA-100 dish broken. I've got 5 more redundant pieces. After that, I still have more non-relay antennas.

1 HG-5 antenna. I've got 1 more spare. After that, the mission can still use normal non-relay antennas. (NEW)

Others

1 radiator panel broken. I had 12 redundant. They should be needed to vent heat from the nuclear reactors, but they are not actually needed anyway (NEW)

Low-quality parts

A landing light broken on Nitrogenie in a Bottle. Irrelevant, I don't need them.

Life support on Trypophobia's gravity ring broken. Irrelevant, the same function is included in the greenhouses.

1 Converter broken. Irrelevant, converter is the stock isru functionality that I'm not using. I need the chemical plant functionality, and that one is still working perfectly.
Outdated

2 reaction wheels broken on Milly. Now Milly has done its job.

1 dart engine broken on the Mars Descent Stage. Now it's a pile of debris on Mars.

Discounting the low quality and outdated parts, that's 14 critical malfunctions so far.

Edited November 30, 2022 by king of nowhere

[king of nowhere]

Part 7: The flop of the rings - the two moons

A'Twin moves to Saturn, where it refills on fuel on Iapetus and on nitrogen on Titan.

The chapter title is because the rings of Saturn look very underwhelming compared to expectations

7.1) A surprisingly expensive transfer

Spoiler

I was expecting to not have any more fuel problems going forward. In OPM, the outer system was very cheap, and I was taking interplanetary transfers for a pittance. In the inner planets, rss is roughly three times more expensive, and I was expecting this relation to hold. It can take as little as 500 m/s to get from Dres to Jool, so I was expecting 1.5 km/s from Vesta to Jupiter. Nope, it's 3 km/s. For Saturn, it's close to 6 km/s. Capture around Saturn is free, I expect aerobraking at Titan to be viable, but I then need more fuel to reach Iapetus - something that requires another 1.5 km/s. A'Twin has 7.4 km/s, making this a close run.

I could finish refueling, I still had room for 350 tons of fuel. Those would translate to about 400 m/s. The process would be bothersome, though, because I am out of uranium and there's none where I landed. So I'd have to take off, land on another biome, which has uranium but only 3% ore, and wait there for a long time. Meanwhile, in the near future I have a convenient transfer window where I'll launch at the planar node - because inclination keeps being a major bother - and meet Saturn immediately, instead of requiring multiple orbits. Finishing refueling would lose this opportunity, I'm sure those 400 m/s won't be a deal breaker.

Trajectory 1

Trajectory 1 splits the burn in two times to better control my time to apoapsis, so that I can meet Saturn at apoapsis on the planar node. I start from Vesta making a push with some vertical component, then on the planar node will make the final burn. Making a huge apoapsis raising burn in solar orbit is inefficient, but Vesta is so small, it's not like I'm getting any significant Oberth effect anyway. Not to mention a 5 km/s burn with low thrust engines, I won't be anywhere near Vesta when I'll finish that burn.

The total cost is 5700 m/s. Intercept speed on Saturn is then 500 m/s, small enough that I am sure I can aerobrake it on Titan.

Trajectory 2

Trajectory 2 is the closest thing to an Oberth transfer - at least as far as the ejection burn goes. The first 100 m/s burn is just to leave Vesta - as I said, it's not like I'm getting any significant Oberth effect from it, and this way I can better plan my manuever, and not worry about cosine losses. Then a pure prograde burn to Saturn. Unfortunately, in order to get the encounter on the planar node, I have to raise apoapsis higher than Saturn.

No, meeting Saturn away from the planar node is NOT and option. Do you have any idea how much a 6° plane change costs in rss?

Anyway, this is a cheaper manuever, because I don't have to make any kind of planar correction (trajectory 1 contains a strong normal component). Only 5 km/s to Saturn. On the downside, meeting Saturn from that trajectory has an intercept speed of 2 km/s. It's probably way too much for aerobraking.

Trajectory 3

Finally, trajectory 3 uses a gravity assist from Jupiter. However, the extra speed imparted by Jupiter will cause A'Twin to pass years before Saturn. Hence that very high apoapsis, to meet Saturn in one orbit and save some time. "Only" 3 km/s to reach Saturn, which leaves plenty for braking from that weird intercept, but travel time is 30 years.

Well, trajectory 3 is 30 years, and I'll keep it as a last resort. Trajectory 2 is cheaper, but I really don't think I can aerobrake that much speed without melting the ship. Trajectory 1 is a close business; considering 1.5 km/s to land on Iapetus from Titan, I only have 200 m/s for manuevers. Still, it should work, barely.

Once more, I dump all the extra water because I am on a tight fuel budget.

Ejection burn from Vesta. And from this life, because I am burning directly towards the asteroid and I will crash on it. Had to reload and delay the burn a bit

A burn this long requires pausing in the middle to service the engines. Here a brave engineer is going to do just that

The double burn went just fine, using up the vast majority of A'Twin's fuel. Now it's time to start planning the encounter, to save some fuel on correction manuevers.

To further complicate matters, Iapetus and Titan have a large inclination difference (10°). And no, even though they are far from Saturn, they are still close enough that changing inclination is prohibitively expensive - at least if one is short on fuel. But I am planning on using Titan's gravity to enter a perfect Hohmann transfer to Iapetus. For this I would like to meet Titan on the planar node with Iapetus.

This picture is to appreciate the vast inclination difference between the two moons. Also, status: 1600 m/s left

Unfortunately, it's not something I can choose. I must touch Titan's orbit lightly, to minimize intercept speed. I must touch Titan at my Saturn periapsis. Which, of course, is as far as possible from the planar node with Iapetus.

While fiddling with the Titan encounter, I realized the gravity assist alone would be enough for Saturn capture. I was very surprised, because Titan is only slighly bigger than the Moon, and I thought it wouldn't give enough of a kick. Still, the gravity assist alone is not enough for my purposes, as it would park A'Twin in a very high orbit, from which it would be expensive to reach Iapetus. I need to use aerobraking to lose speed anyway.

Final trajectory

The trip was uneventful. I feel some nostalgia for the old trips in my previous missions, which were animated by the kerbals getting overstressed and damaging stuff, or dropping life supplies. Yeah, uneventful trips are better.

I started to keep the Haber process (replenish ammonia stockpile) constantly active. It wastes some nitrogen, but I'll soon reach a place where I can get more, no need to conserve.

Saturn approach. After Sarnus, the rings don't look like much. Fiction is always spectacularized over reality

Titan approach

Titan's atmosphere starts at 600 km. I eyeballed a 240 km periapsis, let's see how it goes.

At 500 km, atmosphere is very thin, only a couple m/s lost

At 400 km atmosphere is still thin, a dozen m/s lost. But drag is now providing 1000 kN, it's getting significant

At 300 km, drag is as powerful as the full complement of nuclear thrusters. A'Twin is decelerating fast

Just one minute later, at 250 km, A'Twin is experiencing 0.5 g of deceleration

At periapsis, the nuclear reactors are heating to dangerous levels, but they will survive. Trajectory 2, with its higher speed, would have been unfeasible

At 320 km, A'Twin is again experiencing small drag

In total, it lost 1630 m/s by aerobraking

That was a lot of aerobraking; bigger planets means more time spent in the atmosphere. Luckily, I got a good outcome at the first try. A'Twin has a fairly low Saturn apoapsis, but it has a high inclination compared to Titan. By using gravity assists to convert that inclination to higher apoapsis, I should be able to get a good Iapetus transfer.

7.2) Bouncing on Titan, aiming for Iapetus

Spoiler

Titan gives a strong enough gravity assist to get captured around Saturn, but not enough to cancel 30° of inclination in one go. I have to do it in two steps.

The plan is the same I used on Venus: get 0 inclination on Titan, then intercept Titan orbit in a different place - specifically, at the planar node with Iapetus. Then use Titan's assist to zero inclination with Iapetus.

Part 1: reducing some inclination. Still close to 1600 m/s left

The yellow manuever is a small change to intercept again Titan in 143 days (9 Titan orbits). It will reduce inclination, but not delete it completely. Periapsis is at 400 km, I want to lose some more speed because I'm still too fast. I'll come out on the red trajectory.

By the way, Saturn's single radiation belt deserves a mention here. Because it's strong enough to kill the crew in 3 hours despite maximum shielding, and large enough to encompass the five innermost moons. I must stay out of the death zone. At least it's far enough from Titan's orbit that I don't risk stumblng accidentally in the belt as long as I don't go for lower periapsis. I'll say more when exploring the inner moons, but I'll say in advance that I will only make unmanned landings there, manned landings are impossible. I was aware of it when I started.

1

The Saturn radiation belt, with 150 rad/h is too deadly to approach. But it's far enough from Titan to make it safe

Part 2 of the gravity assists, 70 days after the previous flyby

After the first Titan flyby (or second, if you count the one to aerobrake from interplanetary speed), I find a new Titan flyby in 222 days (the yellow encounter in the image). That's a lot of time, but I can't do any better without spending more fuel. This second flyby will cancel inclination, and it will directly send A'Twin in a new encounter, only 50 days later (green encounter). This new encounter is at a decent approximation of the planar node with Iapetus.

I have no idea what the red encounter is, or why it's shown there. It doesn't help that I'm writing this a couple weeks after, using my memory and the pictures to try and reconstruct what I did.

Part 2 seen from the side, to appreciate inclination

This side view is to see inclination. I did angle my view so that both Titan and Iapetus orbits look like lines; in this view, they do overlap each other in the planar node. You can see the green encounter is pretty close to that, while the current yellow encounter is as far as it could possibly be.

Still, the green is not a perfect overlapping, but it's the best I can do in this way. Unfortunately, the stock game won't show planar nodes, and I loathe using more mods. This is close enough to the node that I can reduce inclination to a couple degrees, which I can then fix with a manuever without spending too much.

Part 3, after the first Titan flyby shown in part 2, but before the flyby at the node. Trajectory 1

Now I must decide what to do with this last flyby. It's still not a perfect fit as far as plane changes go, and I must find a cheap way to Iapetus.

In trajectory 1, shown in the picture, I finish fixing inclination with a plane change. I take the chance to add other components in this burn, like raising periapsis for a cheaper intercept. The total cost is just shy of 1400 m/s to orbit Iapetus. Leaving maybe 200 m/s to land.

I can save something on the landing by detaching Cylinder and only landing Trypophobia, that can refuel and rescue its twin. However, Trypophobia is the heaviest of the two modules, so it's dubious how much this would gain. At best, I'd double my deltaV. This would give me less than 400 m/s to land, and I'm not sure they'd suffice.

Plan C is then to leave Cylinder orbiting Saturn. However, Trypophobia only has 2000 m/s on its own; even if I can land it successfully and refuel, to return to Cylinder I'll need 500 to return to orbit and escape gravity, several hundreds to rendez-vous with Cylinder from whatever orbit it's left parked at, and then with the additional mass Trypophobia should somehow still have enough deltaV to return on Iapetus and land. Doesn't seem very likely. I may use the more efficient Fat Man to transfer small amounts of fuel to Cylinder and let it come to Iapetus on its own power, but it would take decades.

I need a cheaper solution.

Again, planning before the final Titan flyby: trajectory 2

In trajectory 2 I simply overlap the planar node with Iapetus orbit. I get once more 1400 m/s to orbit Iapetus. Ok, time to get creative. Maybe instead of changing plane I have to change apoapsis.

Final trajectory to reach Iapetus after the last flyby

First is yellow manuever, in 20 days. This is just a correction manuever to get the right gravity assist. The gravity assist send me in a lower orbit (green, only visible for a short interval) with periapsis slightly lower than Titan and apoapsis lower than Iapetus. This orbit is chosen so that when I move over the planar node, I burn prograde (red manuever in 45 days, leading to red orbit) and push the planar node at apoapsis. At apoapsis I have a relatively large manuever (cyan, 67 days) that contains a periapsis raising to syncronize orbit with Iapetus, and since I'm there some smaller radial and normal components to make the orbits more similar - taking advantage of Pitagora's theorem, as long as they are smaller than the prograde burn the increase in total cost is small. This results in only 450 m/s for capture at Iapetus - after a last small correction (second yellow manuever, 224 days).

In total, it's less than 800 m/s to Iapetus.

Arriving at Iapetus. The moon is known for having starkly different colors on the emispheres

Capture burn, using the wolfhounds

In Iapetus orbit. I have 600 m/s, and I have to lose 500 m/s. If gravity losses aren't too high, I will make it

It took me 7 years to reach Saturn from Vesta, and almost two years to reach Iapetus after three gravity assists from Titan. I'm very glad for that conveniently-placed moon. Which is also the only source of nitrogen available. Even if I had to make a special plane only for it.

Preparing for descent

Iapetus has a large biome encompassing all the equator, and that biome is ideal for refueling. Very easy to get there, very convenient to leave. I get very appreciative of the rare few times the stars align to my convenience.

Descent, with the wolfhounds

More descent, but without the wolfhounds

Only 3000 units of oxidizer left, must save them for the very last phase. Fortunately, Iapetus has a low gravity, and I'll be able to brake all the way before crashing on the surface. And only 60 tons of fuel which would be a lot on anything else, but are a pittance for A'Twin. I'd have long since dumped my remaining water, if I thought 11 tons would make any meaningful impact.

35 tons of fuel left, but speed is low

Landed!

With 10 tons of fuel left, which equate to 35 m/s. After a 7000 m/s trip, that's how close I came to failing.

Iapetus is the best refueling spot, ever. It's got all the resources I need, 9% ore concentration, and the good biome is conveniently place.  Of course, Iapetus orbit is pretty crappy, and the moon is still not inexpensive to land and take off from, so perhaps it's not such a good refueling place after all. What was I thinking?

Due to the high ore concentration, I can refuel a lot faster than I did elsewhere. In fact, with this ore concentration I can use in full the nuclear reactors; if the concentration was just a bit higher, I would have to slow down mining or face power shortages.

A x1000000 time warp showing the speed of fuel mining

Crew dead for a kraken attack!

Electric shortages, though, are still a problem. Not because I don't have enough power generation - I do. But at high time warp, the game somehow becomes convinced that I lack electricity, and I end up with 0 charge. This does not seem to affect the game, until the moment when I exit time warp. Then the game suddenly realizes I have no electricity, and shuts down life support. One second later the game realizes I actually have electricity again, but with time warp still active, the damage is done.

I found that I can counter this bug two ways; first, by saving before stopping warp, and second, by clicking on the 1x instead of using the comma button - because it seems 1x speed is fine, and 1000000x speed is fine, and it's the intermediate speeds that cause the bugs.

After less than 3 years, the tanks are already 75% full.

A'Twin before leaving Iapetus

The next phase of the mission involves exploring the inner moons of Saturn. It's not going to be very expensive, I don't need full tanks.

And here I really am looking for trouble, am I?

7.3) There's life on Titan. Bugs and krakens, to be precise

Spoiler

As expensive as Iapetus is to reach, it is still my best base to achieve a bunch of targets: explore Saturn, explore Jupiter (whose moons are too big to land on), explore a comet. A comet will require a Jupiter gravity assist to change inclination, so two of those three targets require going to Jupiter. The gas giant is not in the proper alignment, so I start by going to the other moons of Saturn.

Take off

Orbiting Iapetus

I will return to Iapetus, so Trypophobia does not need to come. I split away Cylinder. I only leave Spider with Trypophobia, as none of the moons of Saturn is big enough to warrant its use.

Splitting A'Twin once more

They say devil is in the details, though, and no matter how thoroughly your testing is, there's always going to be something you missed. In this case it's the docking between Spider and Trypophobia.

Failed docking between Spider and Trypophobia. See how the left side is being blocked by a nuclear reactor

The nuclear reactors are leaning outwards, and they block the flat top of Spider, preventing it from making full contact with the docking port. The nuclear reactors I dropped were both on the inside ring, so there's no empty spot to use.

Well, nothing some EVA construction can't fix. Goes to EVA construction, moves, the docking port, the ship explodes - well, nothing a reload and some EVA construction can't fix.

Docking Spider on the newly moved docking port

By the way, look how misaligned are those wheels. One even got broken. How did it happen? Last time I used Spider, it was on Mercury

Now Cylinder will move to Titan. From there, Nitrogenie in a Bottle will land on Titan, and since it's there it will also grab some nitrogen. The inner moons cannot be reached with a crew because of the radiations, but I will send Clamp with Fat Man to do unmanned landings.

The route for Titan. Nothing special there, except to show it takes 700 m/s from Iapetus to the bigger moon

Here the alignment bug turned my spaceplane into a Picasso painting. Just the occasional hiccup

Because of Iapetus inclination, Cylinder reaches Titan with a high inclination. I want to be in a nice equatorial orbit for practical reasons, so I aerobrake into an elliptic orbit, then change inclination. It takes 240 m/s. Then I go back aerobraking to a circular orbit. I considered staying in an elliptic orbit, but I do have all the fuel I need to make up for it, and I just like being able to launch at the time of my choosing for once.

The plane change to get equatorial

Unleashing Nitrogenie in a Bottle

Cylinder raises periapsis to stop aerobraking, while Nitrogenie prepares for a final plunge into the atmosphere

Nitrogenie in a bottle flying down to Titan

Those brown spots appear to stand still over the monitor, while the rest of the terrain flows underneath. Maybe they are supposed to represent clouds or something, but the practical effect is poor; I did try to wipe my monitor, mistaking them for spots of dirt over it.

Status of the propellers as I start flying

Bad news from the propellers. Despite all the care taken, they are bent somewhat. With them standing still it's not evident, but the centrifugal force makes them pull outward. Still, they are not so badly bent that Nitrogenie in a Bottle won't fly; I guess as long as they work, I can't complain too much.

After a long descent, approaching landing

The two KAL controllers are one for propeller angle, and one for maximum rounds per minute. I did found out that in the denser atmospheres, being able to control that improves performance. No, I don't know how or why, I just know that if I fiddle with that control, I can increase propeller thrust (which is shown as negative drag in the aerodinamic window).

Landing not exactly as planned

Ah, that's partially my fault. I didn't test the actual landing, because landing on a dense atmosphere, low gravity world, how difficult can it be? The engines on Nitrogenie are very long and very low on the ground, if the landing is just a bit rough, they will hit the ground when the plane bounces.

Still, I say only partially my fault, because Titan itself is not helping.

See the wheel going underground

There's some kind of ground bug with Titan, making landing a lot more difficult. It took me a lot of trial and error, but eventually I did manage to land with Nitrogenie in one piece.

Nitrogenie in a Bottle, safely landed

But more bugs are looming

The yellow message reads "Can't get out of the vehicle away from the surface of Kerbin. You need an upgrade of the astronaut complex". It's a well-known bug (#10 according to the updated list) . Though I did start the game by loading, it shouldn't manifest. Anyway, to revert it I have to save, then close the game, then reopen the game. I did just so - for once, with only a small plane in physical range, I didn't have to worry about loading time - and Nitrogenie in a Bottle just exploded on reload.

Yeah, still the ground bug. When reloaded, it suddenly realizes the plane is clipped into the ground.

In the end, I can't reload the game - or change vessel - when I have the plane on the ground. Would be ok, I don't need to change vessel, except that another bug manifested: the game suddenly thinks Cylinder has no electricity, its nuclear reactors stopped working (Bug 22 according to the updated list). To fix that, I just need to load Cylinder into physical range. Except that then I can't go back to Nitrogenie, or it will get broken by the ground bug.

I solved it by cheating the plane into orbit, then changing ship, then going back to the plane and cheating it back on land. That's what I have to do in this game.

After landing and planting a flag, I spent a few days to get nitrogen. Nitrogenie in a Bottle has a bunch of chemical plants turning nitrogen from the atmosphere of Titan, plus water and oxidizer that it carries down from orbit, into monopropellant, which I use to make nitrogen on A'Twin. The whole process lasts seven days; I cut it a bit short because the plane run out of food

Before leaving Titan. Also, the picture looks nice with the sun

I got 4.5 tons of monopropellant, equivalent to 35 years of consumption. Nitrogenie in a Bottle does not use much fuel, so it can make multiple trips. But I'll save that for later, before leaving Saturn for good. For now, a single load suffices. You may notice I have exactly 0 food left, what about safety? Well, how long can a kerbal survive without food? Several days? Indeed, seems safe enough to me. I know the pilots won't kill me for it, as I picked them through a careful testing to determine who were the most stable and less likely to engage in rash actions.

Damn, I come across as such a bad boss. Nitrogenie has very limited fuel supplies because, except for a first trip to plant a flag, it's supposed to go unmanned.

Time to take off, facing a new problem: the plane is not rolling on the ground. Still because of the ground bug, the wheels - which sunk into the terrain - are now making lots of drag, keeping the plane from reaching takeoff speed. I brilliantly solved that issue by closing the wheels, then extending them again; this gave Nitrogenie a jolt upwards so that it floated for a few seconds. Those seconds were enough to pick up speed and fly.

Before going back to orbit, I want to splahs land on a lake I noticed nearby.

Flying over Titan

Going towards the lake

I have to say, Nitrogenie in a Bottle flies really well, extremely stable. It may be my best plane as far as manueverability in the air goes.

Preparing for water landing

Sinking into the lake!

Yes, Titan's lake are made of hydrocarbons, they have low density. However, the fuel tanks of Nitrogenie in a Bottle are also full of hydrocarbons. Plus there are many empty tanks, and the crew cabin which is full of air. It definitely should float under any realistic physical engine. Anyway, since the propellers don't work underwater, I had to reload the game and give up on this. Finally it's time to leave this place.

In the dense low atmosphere, Nitrogenie can fly up easily. It could probably fly straight up too

Picking up elevation, it can achieve top speed as the air is still dense enough for the propellers, but drag is reduced

Even with 0.25 atmospheres of pressure, Nitrogenie keeps going up, just a bit slower

As the atmosphere gets thinner, Nitrogenie is forced to a more level flight, a slower ascent. It still keeps going up, though

By this point, I could already activate the rockets, they are close enough to peak efficiency. By the way, the left window is wrong on thrust. I had to separate the three rockets, for some reason if I keep them together they don't show deltaV correctly, so the shown TWR (RSP in the italian interface) refers to two engines, not three.

With one twentieth of Earth pressure, Nitrogenie keeps going up, but it's struggling ever more

By now there's not much incentive to keep ascending on propellers, so I finally start the rocket-assisted ascent

If I was a serious flier I'd test with various ascent profiles, but really, Nitrogenie works well enough. Especially since no engines broke, this machine is very overpowered for Titan; it's supposed to make it to orbit with two engines and asymmetrical thrust, this is really a piece of cake. Anyway, the gains between an optimal ascent profile and a passable ascent profile are minimal. Unlike my previous planes, I gave its wings 0 angle of attack so that it would fly better under rocket power.

In the high atmosphere, it has... negative drag?

Negative drag is how the game shows thrust generated by propellers, but the propellers are safely locked inside the cargo bays. I also made sure to remember to deactivate and lock them to avoid damage in the vacuum. Anyway, I can confirm that if I shut down the engines, the plane decelerates, apoapsis and periapsis values go down. So drag is behaving normally, it's just the interface that's bugged.

Man, I'll have to add a lot more lines to that bug compilation after this.

En route to orbit

Nitrogenie will make it to orbit with almost 1 km/s left. So much extra fuel for multiple reasons; I tested it with over one more ton of monopropellant, I tested activating rockets at 50 km instead of 56, and I tested with two rockets. So I basically got a lot of extra safety there. Speakng of safety, my kerbals have skipped several meals by now, but they are only at 10% hunger, they will be fine.

Nice pic of servicing the engines after the flight

By the way, the three reaction wheels are supposed to be easily replaced by EVA construction, but I now see the lateral ones are clipping inside the wings. Also, to change them I need to detach the engines, and then I have to put them back in place, and for that I must first fit them with a clamp-o-tron that I'll have to salvage from one of the extra docking ports. I hope I won't need them fixed, else it would require some major restructuring - and I'm not sure the game would let me do all that.

About to rejoin Cylinder, still plenty of time before starvation

Nitrogenie in a Bottle reunited with the mothership

After this, I immediately shut down ammonia production on my ships. Yes, I have unlimited nitrogen as long as I stay around Saturn, but getting it is annoying enough, I'd rather save it as much as possible.

And that's it for this part of the exploration. This chapter has run long enough already, the remaining moons will get another chapter.

Part malfunction has reduced steadily over the past few decades - something I assume is caused by the "encourage redundancy" option, but really, the practical rate of malfunction is always completely off from what it should be. So, even if this chapter covered some 13 years, I got only a handful of malfunctions, none of which was critical. I still need to fix the nuclear reactors regularly, though I shifted the schedule from once every year to once every 18 months.

Bugs compilation updated

Spoiler

The more I write bugs down, the more I realize there are other bugs that I'm so used to dealing with, I don't even remember them anymore. Now I numbered them for ease of reference. Problem and Solution

1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

4) Propellers start twisting around. No worry, it fixes once you stop time warping

5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

10) I can't make manuever nodes or go eva, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: Click on the time warp arrow instead of using dot and comma

13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

17) Crew hatch registered as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

20) Upon starting the game, clicking on the VAB does not work (old, but I forgot to mention it previously). Clicking on the icon on the bottom left corner of the screen still works

21) Sometimes elements of the HUD change size (started during the Mercury mission, I forgot to mention previously). It doesn't affect the game, and seem to revert spontaneously

22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason (old, but I forgot to mention). Load Cylinder into physical range and they restart

23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced (NEW). Reload when it happens, and it will get fixed

24) The ground on Titan has all sort of glitches and malfunctions (NEW). Be extra careful during landing, cheat the vessel in orbit before leaving it, jump to start flying. See 7.3 for more details

25) Negative aerodinamic drag displayed on the user interface (NEW). Drag is still behaving normally, it's only the display that's bugged

Edited January 28, 2023 by king of nowhere

[king of nowhere]

Part 8: The lord of the rings: a stroll inside Chernobyl's reactor

The extreme radiation make the inner Saturn moons unapproachable by a crewed ship. Fat Man and Clamp perform unmanned landings.

This time Saturn is properly spectacular

8.1) Ranting on realism and radiations (recognizing routing with a rooster results in reverse)

Spoiler

Saturn has the strongest radiations in the game. Actually, the inner belt of Jupiter is slightly stronger, but there are no moons inside. Instead, Saturn's main belt is so big, it encompasses five of its seven moons.

The Saturn radiation belt. Here the ship is experienceing 60 rad/h, but it grows to 150 going in

This radiation belt makes crewed landings impossible. Even inside a shielded ship, the crew would die in three hours, give or take.

But, I already had a similar situation in the previous grand tour, and that time I did manage to land anyway.

Yes, but the radiation belt was much smaller; even then, it took 8 km/s and the crew got to 90% radiation. This time I don't have the same chance. In rss trips take three times more deltaV and three times longer, so if I attempted that, it would require 24 km/s - an impossibility - and it would still take 9 hours, which would kill my crew three times over. Plus, just compare how big this belt is compared to the diminutive belt of Sarnus. In the above image you can see approaching Rhea, the outermost moon, it will still take over 30 hours since entering the belt. I can reduce that time with a high energy transfer, yes, but can I reduce that time to 90 minutes - leaving another 90 minutes to escape? No, and that's just for the outermost moon.

I knew in advance of this, and I had two options: make unmanned landings, or go in the option and increase shielding efficiency to 100% (from its default 90%), which would entirely negate radiations inside a shielded ship. I asked @Stamp20, who's keeper of the grand tour challenge, what he thought was best for the purpose of a grand tour, and he told me to go unmanned. Which I'm kinda happy with, because it's the most challenging option.

By the way, if you look at habitat radiation in the picture, it reports zero. That's because radiations are glitched and storms still affect the ship during time warp, even though they should not (Bug #13). Stopping time warp and limiting to x1000 during a storm fixes the problem, but it's a real bother in a long mission, so I fight it by just setting shielding to 100%. A'Twin is shielding its crew perfectly anyway, and those few radiations that pass are covered by the radiation detox units. But for a trip inside a radiation belt, where it's actually relevant, I reactivate normal radiation shielding.

Before we go on, I want to complain - for a mod that makes a point of introducing "realism", to the point of making calculations on how much solar energy you get from a certain solar panel and how does that equate to performing certain chemical reactions - of how utterly irrealistic that huge death zone is. Nope. That's not how it works.

I can't find hard data on how lethal those radiations are. There are a dozen different ways to measure radiations, and I'm not enough of an expert. I did find a piece of hard data that the Van Allen belts would give a dangerous dose to a human in a few weeks, in an unshielded ship. Which is already a lot less lethal than this game make them, because in this mod you can survive a couple of days (Earth days, not Kerbin days) with maximum shielding.

I can't find data on Saturn, I said, except that the wikipedia article says they are "relatively weak". How does that compare with the Van Allen belts? I don't know. What I do know is that the radiations in this game are frying my electronic equipment incredibly fast. Every single new piece of hardware I brought inside the death zone was broken in a few weeks. Every old piece of hardware survived, because there is a weird bug where the longer time passes, the less malfunctions I get (Bug #15, the only one actually working in my favor. Mostly), but default is malfunction in weeks.

So, if that was even remotely realistic, how did we get to send the Cassini probe spending a decade around Saturn without breaking anything? Rubbish. I use the kerbalism mod for the additional challenge and not for extra realism, though, so that's fine. I can still rant about it.

Speaking of ranting and realism, here we are on Enceladus - a literal ball of ice - at the south pole, where there are known active geysers, and we're not finding any water. Great!

8.2 Rhea and Dione: easy starts

Spoiler

I start preparation for the trip by refueling Clamp and Fat Man. Here I get struck by yet another new bug: I can't transfer fuel to Clamp!

This image shows that fuel transfer is indeed allowed through the docking ports, but the game refuses it

I had a similar bug on the DREAM BIG, where half of the ship got isolated as far as fuel transfer was concerned. How do I get out of this one?

By grabbing Clamp on a claw

Grabbing Clamp on the claw of a Service Probe solves the issue. I deactivate fuel transfer rules for the occasion - doing that still resulted in no fuel transfer through the bugged docking port, but it can be transferred through a claw.

Fat Man and CLamp, ready to go

I can barely start, thrust is all asymmetrical. I blame the new docking port on Clamp, before discovering that Fat Man still has the rockets set for different levels of thrust from that time around Mercury when it had to compensate for a broken engine.

That was easily fixed, but I also realize a bunch of mistakes I was making, so I go back and fix them all.

First: I am on an unmanned mission. Fat Man only has 2 antennas, only one truly long range. That's because it was supposed to have a crew, so a broken antenna would not be a big deal. It can also be repaired. Well, now Fat Man won't have an antenna, and it can't be repaired, and it's going to take lots of radiation damage. So I opened the spare parts drawer and took out two brand new big antennas.

Fitting Fat Man with more antennas

Second: the asymmetrical docking port on Clamp is a real nuisance. I move it back to its original position. If it makes problems for a crew, well, right now I don't have a crew, and in the future I can take that out again.

Fitting back the old docking port on Clamp

Here I discover that the old docking port I placed asymmetrically got thoroughly bugged. It can't be removed by EVA construction, no matter how many docking tricks I pull out to ensure it's not a root part. And if I try to crash it somewhere, it crashes the game (it will be bug #26).

I'll have to keep it, Clamp will work just fine with 50 kg of unnecessary mass.

Then I also realize I will have an additional problem: engine maintenance. Without it, engines have a limited duration. A high quality Nerv rocket is rated for 53 minutes of ignition, but I know from painful experience that once the remaining time goes below 25 minutes, the engine may break spontaneously. With full tanks, Fat Man has enough for over 50 minutes of burn, but I can't actually use the engines so long without risking them. So, I unload part of the fuel. Now I have the 30 minutes ignition I know to be safe.

And I also take the chance to unload all the monopropellant. I can't dump the food, though, because I don't have anywhere else to put it, and it takes forever to regenerate.

Trajectory to Rhea

Time to leave for Rhea. Those trajectories are complicated by Titan having high inclination compared to the inner moons - which are all close to the plane of the rings. Fixing the inclination mid-course is very expensive, almost 1000 m/s. Fixing it in the capture burn is also expensive, because those small moons have negligible Oberth effect. The best way to fix the inclination, then, is to do so at the start. Leaving Titan at the planar node (in this case ascending), and adding a normal component. By combining the plane change with the ejection from Titan, I can take advantage of Pitagora's theorem to save fuel.

At periapsis I will miss Rhea, of course, but a retrograde burn will change orbital time enough to meet it in the near future. In this case, I spend 950 m/s to leave Titan, 355 m/s at Saturn periapsis, and 1000 m/s for capture. Once more, I repeat: making the capture burn at Rhea, or burning retrograde at Saturn periapsis, it makes almost no difference, because Rhea is so small, it has negligible Oberth effect to take advantage of.

Just one day in the death zone, the first component breaks

Here we have a reaction wheel breaking up after one day in the death zone (it's not critical, it can be fixed).

I had inspected it before, it was sound.

Radiations are also deadly for the ship, though it can withstand them far longer than a human. I must spend as little time as possible around here. Some stuff will break, well, I have plenty of spares.

Rhea

Clamp prepares for landing

Radiations and engine maintenance are a problem, but those moons are really small, once there there's really no challenge in landing... wait a moment, they are calling me from the control center... what do you mean, we lost signal?

Clamp about to crash on Rhea without signal

Oh, right, I'm running an unmanned mission, I do have to actually pay attention to signal. Fat Man has an antenna strong enough to reach Earth, so least concern there. It only lose ssignal when passing behind a planet; and even then, there's a chance it can pick up Cylinder or Trypophobia.

Clamp is a lot harder. It can't pick up Earth, and the relay antenna on Fat Man does not allow it to be controlled remotely from Cylinder - not unless Cylinder itself has a Earth connection. And since all those ships are orbiting moons, and spent 50% of the time covered from any point of view, the chances that each one of them will be aligned properly get increasingly small the more links are required for signal.

Either way, at this point Clamp can only be controlled from Cylinder. Trypophobia, on Iapetus, is too far for its weak antennas to pick up the signal. Or so I thought; except that the next mission Clamp was picking up Trypophobia perfectly, and it wasn't picking up Cylinder. And then I switched vessel to Cylinder, and then returned to Clamp, and then Clamp was picking up Cylinder again, and so I realize I got yet another bug! (#27)

I could solve this in many ways. I could send up the two Wings probes in polar orbits, to help relay the signal - I gave them relay antennas exactly for one such occasion. I could prepare an accurate time table of the orbits and visibility of each vessel. Or I could just go by trial and error and reload when it goes wrong. Yeah, the first two look like they involve a lot of work - the boring kind of work, not the rewarding kind. Let's just go by chance.

Landed on Rhea. A boring, featureless moon completely undistinguishable from a dozen others, except for the status panel on the upper right

And returning to Fat Man

Docking was made awkward by Clamp being out of control at the time, so I had to manuever Fat Man around it.

Ok, Rhea done. I've got a bunch of fuel left, so I can go to Dione.

Route to Dione

As the two moons have virtually identical inclination, I can go for a normal Hohmann transfer this time. 500 m/s to leave Rhea, 750 for capture at Dione. It will leave me with 3000 m/s to return.

Dione. The rings should look great now that I'm close, but I'm in the same plane, so they are barely visible as one pixel thin

If nothing else, this green color is striking

Landed. Dione is slightly smaller than Rhea, not a challenge for a high power lander

Returning to Titan. It takes 2000 m/s to get an intercept

It also took 300 m/s to syncronize orbit to meet it at the next passage. I could have done it more cheaply by waiting a few more orbits, but I want to minimize time spent in the death zone.

One of the new antennas is killed by the radiations

Oh, well. It was itself a spare.

As we established, aerobraking at Titan is perfectly safe coming from the inner moons, or from anywhere around Saturn in general.

Perfect aerobraking, leaving the plane change manuever to be performed at apoapsis

Reunited with Cylinder

This was hard on the engines. As you can see from the action windows, the nerv rockets have only 2 ignition left, out of over 40 when new. 23 minutes of ignition left, which is already in the danger zone - that starts at 25 minutes left. The smaller engines on Clamp have 4 ignitions left.

Of course, now those vessels are in the loving hands of good mechanics that will fix everything. Before sending them out again.

8.3) Mimas: as bad as Mercury

Spoiler

Ok, the first two moons were relatively easy, let's see if I can get the remaining three in a single mission. Let's check solutions for the innermost, Mimas, and see how much it is to get there... wait, what?

First rough attempt at a Mimas transfer. Just to give an idea of the cost

2 km/s to leave Titan, before even plane change is accounted for, plus 4 km/s to circularize and you're not even done???

Alas, yeah. There's nothing to be done; Mimas is a very internal moon, very close to Saturn itself. And Saturn is still a giant planet. Stuff close to it move very fast. Mimas will be extremely expensive, for the same reason Mercury is expensive.

But it's ok, it would actually be very cheap to get there by bouncing around the moons by gravity assists. Sure, they are small moons, small assists, but with multiple passages maybe...

Attempt at getting a gravity assist from Rhea. The red trajectory is the outcome

Rhea is the biggest of the inner moons, and the most promising. If I can use it in the same way I used Venus to get to Mercury...

Well, the image speaks for itself. The red line would be the outbound trajectory. It's barely changed! That gravity assist was worth less than 100 m/s.

But ok, I can make multiple passages, change the orbit slightly every time, until I get where I want.

No, no I can't. For two reasons: first, it would take an ungodly amount of time, time spent in the death zone, the ship is very unlikely to survive. Second, it would take lots of correction manuevers, and the engines have limited ignitions, so the ship would definitely not survive.

I also tried a bunch of other ideas, mostly involving pivoting around Rhea, or getting a Titan's gravity assist to equalize inclination. None works. Rhea is way too small to provide much Oberth effect, and barring that, there's nothing better than an Hohmann transfer. As for orbital inclination, paying it while leaving Titan can be done with a few hundred m/s, everywhere else it's a lot more expensive.

Refined manuever for Mimas. 6.5 km/s to get there

So this leaves me with this trajectory. 2 km/s to leave Titan, fixing inclination in the process. And a staggering 4.5 km/s in intercept speed. Because this is a symmetric operation, raising again Saturn apoapsis to leave Mimas would cost another 4.5 km/s to reach Titan. Once at Titan, aerobraking takes care of the capture, and while I'd like to have enough fuel for a rendez-vous, I can always send a shuttle to recover the ship. But this is moot, because Fat Man won't get back to Titan. The required combined cost is 11 km/s - plus correction manuevers, plus cosine losses - and the taxi can squeeze at most 10.5 km/s out of its tanks.

But it's ok, I can still make this work. Just like Fat Man was used to extend Cylinder's range when it had to orbit Mercury, so now Cylinder can be used to extend Fat Man's range to reach Mimas. Specifically, Cylinder can provide the 2 km/s Titan ejection burn, and stay in a transfer orbit from which it could get captured by Titan again. Fat Man, in turn, would "only" have to pay the 4.5 km/s for apoapsis lowering/raising, for a total of 9 km/s, within its capabilities.

There's still the problem of the engine life. Getting so much deltaV requires filling Fat Man to the brim, which give 50 minutes burn. And the atomic rockets can only burn safely for 30 minutes, though they still have an additional 20 minutes before they are basically guaranteed to break. To which my answer is, screw this. I can't do anything about it. I will have to take the risk. If nothing else, it shouldn't be too bad; out of 24 engines on Cylinder, only a few of them break up if I keep them running longer. Fat Man has six engines, maybe one will break, or two, but the ship can go on.

And if they cannot be fixed, there are still two more spare small atomic rockets for Fat Man, plus in the worst case scenario I can cannibalize the engines out of Nitrogenie in a Bottle, which doesn't need to be used often.

It's risky, but I have literally exhausted every other option. Ok, I suppose if this goes poorly I can try to pay some of those 9 km/s with Cylinder, relieve Fat Man's engines of some additional stress. But in any case, I have to push my machinery to the limit.

Of course, I can't send crewed Cylinder down in the death zone, so first thing I have to put the crew to safety. Once more, the Dolphins are there to back me up.

It starts with a Service Probe

The Service Probe grabs Nitrogenie in a Bottle

And the second Service Probe docks with the first. Now it has an exposed claw

I am doing this because I want to leave behind a single ship, for easier/cheaper rendez-vous. And I've got to stick together both Dolphins and Nitrogenie, and all those ships only have one docking port, and I needed to create an additional grabbing point.

Sure, I could have moved a docking port by EVA construction, but after what's happened to poor Clamp, I'd rather not do it if I have an alternative.

Dolphin 3, with a crew of three, leaves Cylinder

Those are Ikea Dolphins, some assembly required. Peretto installs the RTGs and the antenna. Both are normally kept in storage to protect them from aging

And after some manuevering, which gives a good excuse for some tech/scenery porn...

...goes to get grabbed by the claw on Nitrogenie

But for now, only one. Because Cylinder itself needs some engine maintenance.

Here Cylinder raising apoapsis, its engines have 34 minutes left

Cylinder's engines just so happen to have 35 minutes of ignition available. New, they have 53 minutes. At 30 minutes I can run maintenance on them. At 25 minutes they risk blowing up. Cylinder will need a 2 km/s burn, which would take a good 15 minutes, plus whatever manuever to return to Titan, and this will put its engines squarely in the "blow up" phase.

But I can solve this. I keep a crew in Cylinder and perform an apoapsis raising manuever first. Those 600 m/s will be enough to push the engines past the check-up time, so I will be able to service them and renew their time. Then the last Dolphin will leave, and Cylinder will keep going unmanned.

Maintenance on the engines. Titan is too far from Saturn for a truly spectacular view, but at least its inclination lets one see the rings as something more than a thin slice

Dolphin 2 leaves Cylinder

And after some orbital manuevers, goes back to the Nitrogenie/Dolphin assembly

It costed some additional xenon, but xenon is produced in small amounts by the nuclear reactors. I can't do anything too crazy with it, but for those limited manuevers it's basically free.

Fat Man leaves Cylinder. It's nominally got 9.4 km/s, but the number will increase a bit as Clamp uses up its own fuel

Saturn getting closer

Finally Saturn looks good! Also, with some magnification you can appreciate one of the moons in the upper left part of the image

Lowering apoapsis. Also, great view on the rings

18.7 km/s of orbital speed. Yes, it really isn't strange that manuevering here is so expensive.

This image to appreciate how diminutive is the sphere of influence of Mimas; less than 200 km above the surface

At Mimas

Mimas has an interesting surface. I want to try to land in that canyon. Flying over the Herscel crater, but it's too big to make out from this low orbit

Capture burn, and an excuse to show some more scenery

Landing in the aforementioned canyon

By the way, after the communication problems in the previous mission, I opened again the spare parts drawer and took out a HG-5 antenna for Clamp. Now it's in contact most of the time.

The canyon!

Driving in the canyon

Being an interesting feature, I wanted to drive a bit inside. Of course, given the extremely low gravity, one can't do much actual driving. One picks up some speed, and then starts to bounce around. I miss having a pilot for the IVA views.

Even though Clamp only takes a tiny amount of fuel to land, I loaded it to the brim because I want to use its engines to push Fat Man. Every second I take off of the poor taxi's own rockets is valuable.

Using Clamp's engines to push Fat Man

Leaving Mimas, with a great view of Saturn

And now, the rest of the return trip

After draining all the fuel on Clamp, Fat Man still needs 4.2 km/s to get a Titan intercept - plus whatever it will take afterwards to syncronize with Titan's passage. It's got well over 5 km/s, no worry there - though the 2 km/s gained by using Cylinder for the Titan ejection were decisive. But the engines only have 20 minutes left. They are already in the phase when they could break at any time, but after that timer runs out, they will break almost for sure (there actually is some chance they keep working, but the probabily of damage increases exponentially).

Leaving Mimas. I'm already out of its sphere of influence

Well, surprisingly, all went well and no engine gave up. Perhaps only the bigger Nerv3 have that problem, because they have a greater tendency to overheat. Anyway, good to know for the remaining two moons.

Meanwhile, the original plan was to grab Fat Man with Cylinder again, but I now realized trying to get a rendez-vous in those conditions is highly impractical. Both vessels can aerobrake at Titan, so let's just have everyone get there on its own.

Cylinder's manuever to syncronize orbit with Titan

At 1150 m/s it was very, very expensive. However, I am into some sort of resonance where I keep staying away from Titan for a long time. And raising periapsis is very expensive when periapsis is so low. Raising apoapsis would be problematic, though in retrospect it was probably better.

Anyway, the choice was to spend 1 km/s, and return to Titan in 10 days, or spend 100 m/s, but spend 150 days in this orbit encroaching the death zone. All the while getting radiation damage, all the while the crew on the Dolphins would get stressed by the limited space and lack of amenities. After a quick check to make sure there is enough fuel, and considering that I have to take a long refueling pause and wait a Jupiter transfer window anyway after this, I took the expensive option without hesitation.

Now both Fat Man and Cylinder will return to Titan a few hours from each other.

Fat Man returns to Titan

Still 3 and a half minutes of ignition, it will make it. The planned 40 m/s are for the plane change.

Cylinder returns to Titan

This manuever was a bit less accurate, periapsis was lower than optimal and it resulted in a relatively low apoapsis, forcing a more expensive plane change. Not enough to reload and do it better, though.

Cylinder is diving in the atmosphere nose-first to avoid burning some ablator off the shields of the Dolphins. Except right now it doesn't have any Dolphin docked, so it could have totally used the retrograde orientation, but whatever, not enough of a difference.

Cylinder reaches the crew

End of the trip for Cylinder. At 28 minutes of remaining burn, it got dangerously close to exhausting its engines - though Fat Man's proved reliable to the end, Cylinder's bigger nervs did prove they can explode mid-burn already several times.

Fuel is more than adequate to resupply Fat Man for the last two moons and return to Iapetus.

Returning the Dolphins to their places

Returning Nitrogenie in a Bottle in its place

Fat Man arrives

Finally also Fat Man arrives; it reached Titan first, but it aerobrake in a higher apoapsis, and it took longer to rendez-vous. It's got 2 minutes left of ignition.

Fixing everything

This time there were no victims to the death zone, but both vessels got a thorough inspection afterwards.

Mimas was the most difficult moon, the others are feasible. I have to see if I can land there without having to use Cylinder again, though, as it would lack the fuel for another similar trip.

8.4) Unremarkable Tethys, beautiful Encelado

Spoiler

Transfer between two close moons is cheap, and I want to try to do both Tethys and Encelado at once. I start with Tethys, because it should be cheaper this way - I get a faster Titan intercept on return, which I get to aerobrake away, so I'm probably saving more fuel.

To Tethys, part 1: leaving Titan

By now I'm tired of describing those manuevers, they are always the same. 1600 m/s to leave.

To Tethys, part 2: encounter and capture

And 3 km/s for capture. Apparently, each moon costs approximately 750 m/s more than the previous one.

The additional antenna strapped to Clamp breaks

The additional powerful antenna I gave to Clamp breaks, so I'll have to perform those landings with the same limitations as the first ones. Ok, it's just slightly more annoying.

At Tethys

Another moon passing in front of Saturn

Landing

Landed on Tethys. And another passage of a moon

Tethys is yet another flat featureless barren rock, I have no incentive to stay and I leave immediately for Enceladus.

It takes 1000 m/s to reach Enceladus. And from there, it should be 4 km/s to Titan

5300 m/s may not be enough to cover it, but deltaV will go up once Clamp uses up its fuel. The trip is feasible.

Approaching Enceladus

Arrived there. Still 14 and a half minutes of burn

This is somewhat worrying. I have enough fuel to burn for 15 and a half minutes, but I only have 14 and a half minutes of burn on the engines. Meaning some fuel will be wasted, and I'll have less deltaV.

An unusual landing

This time I want to land near the south pole. It's where they found active geysers, and the terrain also looks different. Those moons are small enough, even a radical change of inclination isn't a big deal.

Flying over the south pole

I suppose the blue lines represent the cracks from which the geysers erupt

Wow

This is one of the most beautiful places ever! I want to drive around. I'll post some pictures. It totally makes up for the rings being a bit of a disappointment.

Taken in real light. Still looks good, but you miss the violet stripes

Another pic in real light. Despite the lower color appreciation, there is a certain something to it

Leaving the south pole

Who stole Saturn's rings? Also, update on remaining ignitions

Alas, going polar required more corrections. With those few ignitions left, I started deactivating engines in pairs, to last longer. I managed to dock to Fat Man with 1 ignition left, which will be used to burn off the remaining oxidizer.

Engine status upon docking Fat Man

Manuever to Titan; it's 3900 m/s

Fat Man makes it back to Titan with 800 m/s, but it's only got 1 minute of ignition time, meaning it won't get to use half of its fuel

Close to Cylinder, but only 18 seconds left of ignition

Successful rendez-vous, 2 seconds left!

From there, an engineer came by EVA to repair those poor engines.

In a worst case scenario, I could have sent an engineer with a Dolphin to rendez-vous with Fat Man anywhere around Titan.

8.5) Isru, return and other burocracy

Spoiler

I'm almost ready to wrap up Saturn exploration. Still, a few things left. First, getting more nitrogen. I said I was going to wait until I left Saturn for good. Then I realized how much of a nuisance it is to get to Titan just for the nitrogen, and I changed idea. With some luck, I'll never need to get new nitrogen again, and I can avoid a trip.

Nitrogenie in a bottle, back on Titan surface

This time unmanned, to avoid food and water problems. Though in retrospect, I could have sent in a lone pilot to plant a flag.

By the way, I figured out why landing was so hard. The ground bug prevents the wheels from rolling on the ground, so when they touch down, they behave like they were a rigid part. And this jolts the plane big time.

Nine days later, with 5 tons of new nitrogen

On the plus side, I discovered that I can still drag Nitrogenie across the ground if I set the propellers just right to have enough power. This makes taking off a lot easier.

Ready to take off

Since Nitrogenie is unmanned, I must be careful about control in the long ascent.

The plane has no antennas, because it's never intended to be far from Cylinder. This refueling only makes sense if Cylinder is in orbit, since Nitrogenie doesn't have the fuel to go anywhere on its own. So, as soon as Cylinder shows up over the horizon and I get control of the plane, I take off.

I speculated whether Nitrogenie could fly vertically. Yes, it can

Why a wing is generating lift downward, instead, is a mystery for the ages. Though later it gets fixed; I guess that's the source of the spinning bug (#23).

This time I start using the rockets earlier, around 54 km, because if I spent too long flying, Cylinder may pass over the horizon and lose contact. The ascent was also less efficient, an angle too low that caused too much drag. Still, Nitrogenie has almost 1 km/s more than it needs, it managed orbit without problems despite additional costs.

And now, suddenly Nitrogenie is without contact! For no reason!

I already established that probe control is bugged and it sometimes causes a probe to not see a communication line. And this bug can easily be fixed just by changing vessel. Except that here I cannot do it, because I am in an atmosphere. Only thing left to do was going in the options and deactivating communication requirements.

Now it's back to Iapetus to rejoin Trypophobia and get more fuel. The manuevers involved are routine enough, I won't describe them.

Cylinder status before leaving Titan. Nitrogen is replenished, and fuel is adequate

Possibly the last shoot of Saturn from this close

Rejoining with Trypophobia, at Iapetus

Once more, the twin modules of A'Twin slide into each other in a well-oiled mechanism.

And by "well-oiled", I actually mean "they generally get stuck at some point, and it takes some careful rocket push to get Trypophobia to slide in to the end". So, it's less like a smooth mechanism, and more like hammering the two parts in place. With the hammer in question being 6000 kN of rocket thrust.

As I was manuevering Spider back to its customary place, it felt particularly sluggish. Curious, I set to examine it, and I could not find any mention of the reaction wheel on the crew cabin of the detachable Hartman rover.

Lack of reaction wheel on Spider; confrontation between two identical pods

On the right, another identical crew pod (the one of Clamp), showing reaction wheels settings as first thing. On the left, Spider's own pod does not have any mention of such reaction wheels. Except that in the reliability, it says it's nominal. On the other hand, it says the life support is broken, but there is still the life support shown as running. So maybe it's a bug and what actually broke is the reaction wheel, but it's wrongly displaying the life support. Who knows? Well, as long as it works. And so we have bug #28.

Last second, low altitude suicide burn

But I run out of oxidizer, and I had to complete it with nuclear engines

I wanted to land somewhere where Saturn would be visible on the horizon, but I lowered periapsis too much; then I went long before starting the burn. Fortunately, Iapetus gravity is low enough that the nuclear rockets were adequate.

Landing

Status upon landing

Ultimately, it's been almost one year since Cylinder left for Titan. All missions were small, but there were a lot of them, and time did add up.

Disaster! Another fission reactor broke!

That's the third broken reactor. This is troubling. First, I already lost three of those. They break up so easily! I can lose one more before losing efficiency, and five more before it really gets bad, but this mission can easily span another couple of centuries, I may actually have a reliability problem here. Good thing I was careful to bring extra nuclear power, and I can at least afford to go down to 4 reactors - from the original 12.

Most troubling, though, is that I had inspected that reactor only six months before the accident, and found it sound. Which means that even yearly check-ups may not be enough. But I'm not going to run them more often, it's a huge nuisance. I'l just have to hope.

A few years later...

Refueling is still not complete. However, this looks like a Jupiter transfer window to me.

Actually, I discovered I was already in a Jupiter transfer window while I was exploring Titan. But now Jupiter is a lot closer. This looks the end of the transfer window, so I better hurry up and catch it, or I'll have to wait at least another decade.

8.6) Bonus: how do the rings of Saturn look from up close

Spoiler

I didn't get a chance to send anything passing through the rings; it was too expensive, and too irradiated. But I was curious. So I cheated a small probe in place. Here's what it saw.

Saturn rings, seen from a probe cheated in place for purely viewing purposes

Bugs compilation updated

Spoiler

A numbered list is so convenient to refer to bugs quickly. This list keeps growing. Problem and Solution

1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

4) Propellers start twisting around. No worry, it fixes once you stop time warping

5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

10) I can't make manuever nodes or go eva, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: save before exiting time warp

13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

17) Crew hatch registered as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

20) Upon starting the game, clicking on the VAB does not work. Clicking on the icon on the bottom left corner of the screen still works

21) Sometimes elements of the HUD change size. It doesn't affect the game, and seem to revert spontaneously

22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason. Load Cylinder into physical range and they restart

23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced. Reload when it happens, and it will get fixed

24) The ground on Titan has all sort of glitches and malfunctions. Be extra careful during landing, cheat the vessel in orbit before leaving it, jump to start flying. See 7.3 for more details

25) Negative aerodinamic drag displayed on the user interface. Drag is still behaving normally, it's only the display that's bugged

26) The docking port on Clamp has all kinds of problems, does not allow fuel transfer, can't be removed (NEW). I stuck another docking port there, and I can grab Clamp with a claw if needed

27) Sometimes there is no signal for probe control even though there should be (NEW). Switch to the vessel that's not being seen, then back to the probe

28) Crew pod of Hartman rover has a broken life support and a functional wheel, but it instead appears to have a working life support and a broken wheel (NEW). Nothing I can do about it; but it still works

Broken parts recap

Spoiler

I want to keep track of how much stuff I break, and how much it's affecting the mission, so I prepared a list

Life support

1 life support broken on a Dolphin. I've got five more redundant pieces on it.

1 and only life support broken on Hartman. Sucks, I can't take extended trips, but the rover has enough air to conduct landing operations safely.

Nuclear power

3 Excalibur reactor broken.  They are redundant. There are 12, and up to 4 can be lost before mining is slowed down. Still, there is concern here that they are breaking up fast. (+1 NEW)

Reaction wheels

2 large reaction wheels broken. I've still got 88 working.

1 medium reaction wheels broken on Clamp. I've got 8 or 9 spare ones in storage.

Engines

2 big nerv broken. I've got 1 more spare. Afterwards, the ship can work with less than the full complement.

1 big wolfhound broken. I had a spare. Afterwards, the ship can work with less than the full complement.

1 small nerv broken. I've got 2 more spares.

Communication

1 RA-100 dish broken. I've got 5 more redundant pieces. After that, I still have more non-relay antennas.

1 HG-5 antenna broken. I've got 1 more spare. After that, the mission can still use normal non-relay antennas.

1 Communotron 88-88 antenna broken. It was itself a spare part, and I have more spares, as well as redundant antennas. (NEW)

Others

1 radiator panel broken. I had 12 redundant. They should be needed to vent heat from the nuclear reactors, but they are not actually needed anyway.

Low-quality parts

A landing light broken on Nitrogenie in a Bottle. Irrelevant, I don't need them.

Life support on Trypophobia's gravity ring broken. Irrelevant, the same function is included in the greenhouses.

1 Converter broken. Irrelevant, converter is the stock isru functionality that I'm not using. I need the chemical plant functionality, and that one is still working perfectly.
Outdated

2 reaction wheels broken on Milly. Now Milly has done its job.

1 dart engine broken on the Mars Descent Stage. Now it's a pile of debris on Mars.

Discounting the low quality and outdated parts, that's 16 critical malfunctions so far.

Edited February 8, 2023 by king of nowhere

[king of nowhere]

Part 8.X SPINOFF: Nothing is impossible with enough mass to orbit

One can get infinite deltaV with an infinitely big rocket, provided one has infinite patience

The unmanned landings on Saturn  left me missing something. I calculated that it would be possible to move safely in the inner Saturn system with 10000 tons of radiation shields. I decided to make a spinoff challenge to do just that: safe manned landings on the inner moons.

or this purpose I designed and assembled Ringrazer, a 200k tons ship - 30 times bigger than A'Twin.

The outlook looked good. However, after one month of building up massive stuff, realizing it was going to take a lot more time, I grew tired with the effort. But it would have been possible.

This spinoff is not part of the grand tour mission.

Ringrazer in all its illogic glory. It doesn't give much of a sense of scale, until you look at the tiny bit on the left and realize those are Mk3 parts

Spinoff.1) What would it take?

Spoiler

What would it take to actually fly safely amid Saturn's rings? One 2.75 tons (high quality) radiation shield removes 0.04 rad/h. For a 150 rad/h radiation belt, 3750 shields would be required. The total mass is 10 thousand tons. Plus it would require nuclear reactors to power them, and of course a living deck and everything else a ship needs, but all that's negligible in the face of 10000 tons of radiation shields.

The DREAM BIG carried 350 tons of shields, and it was already bothersome. Here we're talking 30 times more. But it can be done and I want to do it.

The main limitaton I face is that I can't send up much more than 1000 tons in a single launch, else the launcher becomes too overengineered and crashes the game. But I can design a modular ship to assemble in orbit.

Then I'll need lots of fuel. Since I appear to be a masochist, I decided as an additional challenge I'll only use chemical engines. No, actually, hear me out on that. A'Twin requires 24 Nerv3. I can't make bigger nuclear engines, else they overheat and explode. I won't reduce heat output, that feels like cheating. So if I want to power up this preposterous ship, I'd need 700 nuclear engines. My pc is going to commit seppuku if I try. And even if it works, I don't want to think of the moment those engines need maintenance and I have to send an EVA engineer to service all of them.

Part count is a real bummer. To keep it as low as possible, I'll use cougar engines, the most powerful vacuum engine of any reasonable mod. And of course I'll have a bigger modded radiation shield, that I can make myself by resizing the old one and changing some numbers in the config files. Then I got another mod for bigger reaction wheels. All in all, I managed to keep part count around 1000.

So, this is the first part. It has 14 oversized shields, one 30-tons nuclear reactor (which alone is enough to power four of those modules), some fuel, and 6 lateral docking ports for the drop tanks. The engines behind are for docking, they get jettisoned to make room for the rest of the ship. Dry mass is around 1200 tons, which is the limit of what I can launch - it required a 50k tons launcher, further beating my previous record when launching Trypophobia. And all this with less than 50 parts.

The core module of Ringrazer

Then I need a crew module. With 10000 tons of mass already taken, I can go big without worry, any mass I'll add is just negligible compared to everything else.

Ringrazer crew pod, here seen as it detaches from its launcher

To show that the radiation belt of Saturn is totally safe and not dangerous at all, I decided to carry 10 tourists. There are some greenhouses because plants improve morale, but I'm not using large scale isru this time. Not convenient. Instead, I packed enough food for 30 years.

I did make a point to not include radiation shielding in the crew module. It won't be required, because there will be no radiation danger.

The tip of the command module can be detached and doubles as reentry pod, when the trip will be over.

I even included a cupola on a robotic arm that can look backwards to admire the ship

Docking the first two parts of Ringrazer

Then I took a shortcut. Those are all very ponderous parts, they take a long time loading, they lag a lot, they are hard to dock. And I'd need hundreds of launches to send all in orbit. I'm not so crazy as to try that - I already did assemble the Navis Sideralis Neanderthalensis with over 100 launches for my caveman career, and it took months, and at least those parts didn't lag.

No, for this challenge I send one piece in orbit to show that it can be launched, and then I bring the rest up with alt-f12 to save time.

Next step is the king of nowhere style Elcano: land the rover, drive 500 m with it. Then declare "this shows that it could circumnavigate the whole planet, if I kept doing this, but I'm saving time" and leave.

Yeah, well, that's another matter. This challenge isn't entirely serious anyway.

So next step is the drop tank: I use two 1000-ton tanks in a line.

The drop tank, minus the bottom part needed to manuever and docking, that will be jettisoned

It can bring to orbit over 500 tons of fuel. I settled for 200000 tons of rocket as target, though it turned out I was too optimistic and I needed even more fuel.

Then I need an engine block. 48 cougars, I don't dare to put more because I fear structural stability. This ship is too big for struts, they can only be deployed up to a certain lenght, and autostruts have limits. And 7 wolfhound 3, because cougars are limited to 2 ignitions. Basically, I'm using the equivalent of 21 regular wolfhounds as an rcs system.

The engine block, about to be docked to the rest of Ringrazer

Somewhere along the way I decided it would be a good idea to mine oxidizer on the spot. I'm not using full isru capacity like A'Twin has, because it would require way too many parts and mass. But if liquid fuel is hard to get, oxidizer can be obtained cheaply and easily from water, so I brought an excess of liquid fuel and I'll land on some of the smaller moons to get the oxidizer to burn it. landing on those moons is very cheap, so it will save mass.

The lander moving between the drop tanks

A test landing on Mimas

The landing worked, if with the loss of some engines. You can see Val standing on one of the engines on the left, to give a scale of this absurd ship

Finally, I needed a lander. I'm not going to land massive Ringrazer everywhere. Without any special requirement, I opted for something fun and panoramic.

Ringrazer's lander

The cupola and lights grant a great view. The single wheel isn't even powered, but the rcs system is designed to move around in low gravity. Basically, you accelerate with the rcs and bounce around on the wheel, moving with little fuel. I tested it, it's effective for the environment and quite fun.

It docks with a claw because I forgot to think of a small docking port and felt too lazy for eva construction.

Spinoff.2) Massive launchers galore

Spoiler

"Don't work harder, work smarter" is a motto that really can't be applied here. I need all that mass to orbit, then I need proportionally big launchers.

The launcher for the core module with shields

I went past my previous mass record of 40k tons by simply using bigger tanks. The limitation for crashing the pc is the number of engines, and if I keep that equal while adding tanks I'll be less efficient, but I still gain something.

The engines in action

Of course, such a launcher won't work at the first try. Here someting explodes during staging

And here too much gravity drag results in the rocket running out of fuel while missing 50 m/s to orbit

Here I kept an ascent profile too low, and a shield burned up in the atmosphere

The crew module is a lot smaller, surely it will be easier. Aerodinamics is bad, but it won't be a problem, right?

Right?

The problem here wasn't even strutting. Strutting alone didn't help. The problem is that on such a long, narrow ship some vibrations of the tip are unavoidable, no matter how well strutted. And the rocket is controlled from the tip, so the tip shifts slightly because of aerodinamic pressure, and the SAS system perceives a deviation in trajectory of the whole rocket, and tries to steer back. This, of course, besides sending the rocket ouf of trajectory, generates more vibrations, which shake the tip worse, which the SAS will try to fix by harsher manuevers...

The proper fix was to include a probe core in the middle of the launcher, and set to control from there.

Of course, stuff keeps exploding

But I discovered that, between the vector's high gimbal and those large boosters making up most of the rocket's mass, the launcher keeps flying straight even in this condition

Until I can drop a couple boosters and restore symmetry

No, I couldn't drop those boosters immediately. I lost one and I still had enough fuel to orbit, but discarding two more without sucking up their fuel would have lost too much deltaV.

The crew module jettisons the manuever engines before getting docked

And this is the drop tank launcher. Part of it, at least

When launching something that big, the main problem becomes keeping it stable on the launchpad without it eploding under its own weight. There are at least 400 launch stabilizers in that part count. This time I experimented with using a wider design - 4-fold symmetry instead of 6-fold - including more mammoths, because if the problem is the number of engines, maybe this will let me go bigger.

This design was strongly influenced by the discovery that I can clip the launch stabilizers without anything crashing. Keeping that long, straight tower of a drop tank in place would have been impossible otherwise.

Usual stuff, no need for special caption

The grey mess over the navisphere is the launch stabilizers

This rocket had a problem of too few engines on the upper stages, lowering thrust ad efficiency. I was forced to keep some spent boosters to mitigate it

The mammoth engine falling on the left of the rocket is a bug

Here seen better. It can't be a debris from the rocket, at it comes from higher up

Very weird bug there. At regular intervals, mammoths and pieces of launch stabilizers would drop from the sky. I had this problem with all my launchers bigger than 51k tons; of course, since I only tried two of those, I'm not sure how general it is.

And this is... no, this is just a genuine RUD. Detaching that inner layer of mammoths is tricky

But I tried again, and eventually made it. That midair explosion is part of the bug, the engine and launch stabilizer colliding as they fell

This worked, and as per the rules of this silly challenge, I didn't need to launch more. One drop tank, to show that it can be done. Sure, it went up half empty, but that just means that to fill the 60 drop tanks of Ringrazer I'd need 120 launches.

But I wanted to try. All those rockets were inefficient for low twr. The problem is that I would soon start dropping engines, which instead I needed. I wondered, could I make a new rocket design? One that will let me drop fuel tanks without dropping engines?

Yes, yes I can

Well, this is far from the first time I try to launch a rocket with the engines on top.

This launcher is even bigger than the previous ones, at 58k tons. I was able to use only mammoths, thus reducing the number of engines; but this time the limitation is how much stress the engine "arms" can take, and how many launch stabilizers I need. TWR is abysmally low, but I will get to drop spent tanks, so it doesn't matter. Really, the first couple of tanks only lifts me to 30 m/s before running out, but I lose absolutely nothing by putting them, and I gain 30 m/s.

I devised an extremely complex launch sequence to keep twr around 2. There are several dozen stages.

Dropping the first tanks, all goes smoothly. TWR goes up, leading to more efficiency

Enough tanks discarded, I start dropping engines too

And here the vacuum engines are also ignited. Those are needed not for efficiency, but because they have high allowed ignitions; you can't manuever without

This rocket was doing great, until this happened

I think it was a bug. If the thrust from the rocket had been too big for the girders to which the engines were attached, then the rocket should have exploded at liftoff. Or at maxQ. Here I was already well past maxQ, and I already dropped several lines of engines, reducing thrust and mechanical stress.

Still, for once I'll not complain, because that rocket should have never, ever flown anyway under any realistic simulation.

It also gave the most spectacular RUDs on the launchpad

I would have liked to make that model work, but it kept disassembling on the launchpad. And it looks like it's bugs. Sometimes I'd make a small, insignificant change, and the stable rocket would explode, and I'd spend hours trying to get it on the launchpad in one piece again. It felt too much random, so I lost interest.

After all this, I didn't even bother with a launcher for the engine block. That was only 500 tons, if I could launch 1200 tons then the engine block would be no problem, and that's it.

Next for the Elcano king of nowhere style: if this rover did drive 500 meters on Mun - and it has therefore shown it can complete a Mun Elcano - then it also can drive on Minmus. So there, this rover completed a Minmus Elcano without even bothering going there.

Spinoff.3) You must wear a old man's hat to drive this

Spoiler

After all this, I have Ringrazer assembled in orbit and I must get it to Saturn.

Leaving Earth gravity costs a bit more than 3 km/s. Reaching Saturn costs 6 km/s. Once at Saturn, I can use aerogravity assists from Titan and land on Rhea with maybe 2 km/s.

Well, I don't have the 6 km/s to reach Saturn. Those tanks of liquid fuel I'm carrying will greatly extend my range once I'm there and I can refuel on oxidizer (and I will need them, because going from one moon to the other is over 1 km/s, for four more moons, and then I'll have to return), but right now they are an additonal 30000 tons of dead weight that I must carry to Saturn. So the plan is to go as far as Mars, and use gravity assists.

Starting now, reaching Mars in 7 years. This unconventional trajectory is convenient for having more intercept speed when passing near Mars; it will allow reaching Jupiter

Here the planned first gravity assist

So with that first gravity assist I can raise aphelion by 60 million kilometers. I can eject in a resonant orbit, and incrementally raise aphelion to Jupiter. Once at Jupiter, a gravity assist to Saturn is easy.

That will require time. Well. Including food for 100 years is a lot cheaper than adding even just another line of drop tanks.

Despite the spectacular power of the engines, burning 30 tons of fuel every second, Ringrazer is extremely sluggish. Like, it's got a twr around 0.05. I would have used more engines, but I worried about structural stability. I'm already happy the rockets are not tearing themselves apart.

The first drop tanks are dropped

By a design flaw, they collide with the engines. But Ringrazer is so sluggish, the impact is low speed, and nothing breaks

Even for those tanks that are further from the engines, throttling down is enough to avoid damage.

Ok, 8 minutes of thrust, 200 m/s gained. I only have to do this... 19 times....

And of course, there is engine maintenance.

Here Bill is flying besides one of the nuclear reactors

Just going to the engine is slow, this ship is over 200 meters long.

A jungle of engines. All must be fixed

This is a lot worse than the engines on A'Twin. One thing that helps a lot in maintenance is a path. A clear track that you can follow, and you encounter everything you need. For A'Twin, you just move in circle around the outer rim of the ships, the nuclear engines are all there. Then you move inside, and you move in a smaller circle for the high thrust engines. It's easy. But Ringrazer doesn't have such a trail to follow. It's very easy to forget an engine.

And of course there is the lag. Ringrazer has as many parts as A'Twin. Most of them are simpler, plain fuel tanks, so it lags a bit less. But not by much.

Bill barely visible in the middle of the image, to give a scale of how big Ringrazer is

And the small space left between the shields. It's big enough for Bill to fly through

The engine maintenance is a major nuisance, so I look to cheat for it. This isn't an official or serious challenge, after all.

I wanted to change the number of allowed ignitions by editing the save file. However, the save file didn't have such number; that's in the engine configuration, which I don't dare to touch. However, the save file does have the number and time of previous ignitions, which is subtracted from the maximum value to give the actual value. Will the game accept a negative number?

Yes, it did. Now I have 1000 ignitions

It took a few aftenoons of slowly raising apoapsis. Here all the discarded drop tanks

However, as I said, that's not enough drop tanks. Ringrazer has enough fuel to reach Saturn, but it won't land anywhere.

So I send more drop tanks.

This time not bothering with a launcher

I spent half an hour to make the first docking. Ringrazer, despite its huge torque power, takes many minutes to change direction. The drop tanks are moderately more manueverable. I also gave them some massive rcs power, but it's still hugely inadequate for a 40000 ton ensemble. And before I could complete docking, one of the drop tanks snapped in two.

That was the last straw. Half an hour for a failed docking, that I have to restart. I have to conduct 40-odd more similar dockings, which will take weeks. Then I need to spend more afternoons raising apoapsis. Then I have an ungodly amount of gravity assists from Mars. Then I reach Saturn, and have to make all the landings. It would take months.

And that's not a problem alone. My missions take months. But my missions are technically challenging; this one isn't. Ringrazer can really do the job. It's not difficult. The only problem is time, because everything is so slow.

So I abandoned this mission. Maybe I will pick it back up one day, maybe I won't.

In any case, I have demonstrated that it is possible to land on the inner moons of Saturn, with enough resources. However, of all those resources, the ones I missed was patience.

And now, back to the real mission.

Edited November 24, 2022 by king of nowhere

[SkyFall2489]

On 8/10/2022 at 8:46 AM, king of nowhere said:

Part 8.X SPINOFF: Nothing is impossible with enough mass to orbit

One can get infinite deltaV with an infinitely big rocket, provided one has infinite patience

The unmanned landings on Saturn  left me missing something. I calculated that it would be possible to move safely in the inner Saturn system with 10000 tons of radiation shields. I decided to make a spinoff challenge to do just that: safe manned landings on the inner moons.

or this purpose I designed and assembled Ringrazer, a 200k tons ship - 30 times bigger than A'Twin.

The outlook looked good. However, after one month of building up massive stuff, realizing it was going to take a lot more time, I grew tired with the effort. But it would have been possible.

This spinoff is not part of the grand tour mission.

Ringrazer in all its illogic glory. It doesn't give much of a sense of scale, until you look at the tiny bit on the left and realize those are Mk3 parts

Spinoff.1) What would it take?

  Hide contents

What would it take to actually fly safely amid Saturn's rings? One 2.75 tons (high quality) radiation shield removes 0.04 rad/h. For a 150 rad/h radiation belt, 3750 shields would be required. The total mass is 10 thousand tons. Plus it would require nuclear reactors to power them, and of course a living deck and everything else a ship needs, but all that's negligible in the face of 10000 tons of radiation shields.

The DREAM BIG carried 350 tons of shields, and it was already bothersome. Here we're talking 30 times more. But it can be done and I want to do it.

The main limitaton I face is that I can't send up much more than 1000 tons in a single launch, else the launcher becomes too overengineered and crashes the game. But I can design a modular ship to assemble in orbit.

Then I'll need lots of fuel. Since I appear to be a masochist, I decided as an additional challenge I'll only use chemical engines. No, actually, hear me out on that. A'Twin requires 24 Nerv3. I can't make bigger nuclear engines, else they overheat and explode. I won't reduce heat output, that feels like cheating. So if I want to power up this preposterous ship, I'd need 700 nuclear engines. My pc is going to commit seppuku if I try. And even if it works, I don't want to think of the moment those engines need maintenance and I have to send an EVA engineer to service all of them.

Part count is a real bummer. To keep it as low as possible, I'll use cougar engines, the most powerful vacuum engine of any reasonable mod. And of course I'll have a bigger modded radiation shield, that I can make myself by resizing the old one and changing some numbers in the config files. Then I got another mod for bigger reaction wheels. All in all, I managed to keep part count around 1000.

So, this is the first part. It has 14 oversized shields, one 30-tons nuclear reactor (which alone is enough to power four of those modules), some fuel, and 6 lateral docking ports for the drop tanks. The engines behind are for docking, they get jettisoned to make room for the rest of the ship. Dry mass is around 1200 tons, which is the limit of what I can launch - it required a 50k tons launcher, further beating my previous record when launching Trypophobia. And all this with less than 50 parts.

The core module of Ringrazer

Then I need a crew module. With 10000 tons of mass already taken, I can go big without worry, any mass I'll add is just negligible compared to everything else.

Ringrazer crew pod, here seen as it detaches from its launcher

To show that the radiation belt of Saturn is totally safe and not dangerous at all, I decided to carry 10 tourists. There are some greenhouses because plants improve morale, but I'm not using large scale isru this time. Not convenient. Instead, I packed enough food for 30 years.

I did make a point to not include radiation shielding in the crew module. It won't be required, because there will be no radiation danger.

The tip of the command module can be detached and doubles as reentry pod, when the trip will be over.

I even included a cupola on a robotic arm that can look backwards to admire the ship

Docking the first two parts of Ringrazer

Then I took a shortcut. Those are all very ponderous parts, they take a long time loading, they lag a lot, they are hard to dock. And I'd need hundreds of launches to send all in orbit. I'm not so crazy as to try that - I already did assemble the Navis Sideralis Neanderthalensis with over 100 launches for my caveman career, and it took months, and at least those parts didn't lag.

No, for this challenge I send one piece in orbit to show that it can be launched, and then I bring the rest up with alt-f12 to save time.

Next step is the king of nowhere style Elcano: land the rover, drive 500 m with it. Then declare "this shows that it could circumnavigate the whole planet, if I kept doing this, but I'm saving time" and leave.

Yeah, well, that's another matter. This challenge isn't entirely serious anyway.

So next step is the drop tank: I use two 1000-ton tanks in a line.

The drop tank, minus the bottom part needed to manuever and docking, that will be jettisoned

It can bring to orbit over 500 tons of fuel. I settled for 200000 tons of rocket as target, though it turned out I was too optimistic and I needed even more fuel.

Then I need an engine block. 48 cougars, I don't dare to put more because I fear structural stability. This ship is too big for struts, they can only be deployed up to a certain lenght, and autostruts have limits. And 7 wolfhound 3, because cougars are limited to 2 ignitions. Basically, I'm using the equivalent of 21 regular wolfhounds as an rcs system.

The engine block, about to be docked to the rest of Ringrazer

Somewhere along the way I decided it would be a good idea to mine oxidizer on the spot. I'm not using full isru capacity like A'Twin has, because it would require way too many parts and mass. But if liquid fuel is hard to get, oxidizer can be obtained cheaply and easily from water, so I brought an excess of liquid fuel and I'll land on some of the smaller moons to get the oxidizer to burn it. landing on those moons is very cheap, so it will save mass.

The lander moving between the drop tanks

A test landing on Mimas

The landing worked, if with the loss of some engines. You can see Val standing on one of the engines on the left, to give a scale of this absurd ship

Finally, I needed a lander. I'm not going to land massive Ringrazer everywhere. Without any special requirement, I opted for something fun and panoramic.

Ringrazer's lander

The cupola and lights grant a great view. The single wheel isn't even powered, but the rcs system is designed to move around in low gravity. Basically, you accelerate with the rcs and bounce around on the wheel, moving with little fuel. I tested it, it's effective for the environment and quite fun.

It docks with a claw because I forgot to think of a small docking port and felt too lazy for eva construction.

Spinoff.2) Massive launchers galore

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"Don't work harder, work smarter" is a motto that really can't be applied here. I need all that mass to orbit, then I need proportionally big launchers.

The launcher for the core module with shields

I went past my previous mass record of 40k tons by simply using bigger tanks. The limitation for crashing the pc is the number of engines, and if I keep that equal while adding tanks I'll be less efficient, but I still gain something.

The engines in action

Of course, such a launcher won't work at the first try. Here someting explodes during staging

And here too much gravity drag results in the rocket running out of fuel while missing 50 m/s to orbit

Here I kept an ascent profile too low, and a shield burned up in the atmosphere

The crew module is a lot smaller, surely it will be easier. Aerodinamics is bad, but it won't be a problem, right?

Right?

The problem here wasn't even strutting. Strutting alone didn't help. The problem is that on such a long, narrow ship some vibrations of the tip are unavoidable, no matter how well strutted. And the rocket is controlled from the tip, so the tip shifts slightly because of aerodinamic pressure, and the SAS system perceives a deviation in trajectory of the whole rocket, and tries to steer back. This, of course, besides sending the rocket ouf of trajectory, generates more vibrations, which shake the tip worse, which the SAS will try to fix by harsher manuevers...

The proper fix was to include a probe core in the middle of the launcher, and set to control from there.

Of course, stuff keeps exploding

But I discovered that, between the vector's high gimbal and those large boosters making up most of the rocket's mass, it keeps flying straight even in this condition

Until I can drop a couple boosters and restore symmetry

No, I couldn't drop those boosters immediately. I lost one and I still had enough fuel to orbit, but discarding two more without sucking up their fuel would have lost too much deltaV.

The crew module jettisons the manuever engines before getting docked

And this is the drop tank launcher. Part of it, at least

When launching something that big, the main problem becomes keeping it stable on the launchpad without it eploding under its own weight. There are at least 400 launch stabilizers in that part count. This time I experimented with using a wider design - 4-fold symmetry instead of 6-fold - including more mammoths, because if the problem is the number of engines, maybe this will let me go bigger.

This design was strongly influenced by the discovery that I can clip the launch stabilizers without anything crashing. Keeping that long, straight tower of a drop tank in place would have been impossible otherwise.

Usual stuff, no need for special caption

The grey mess over the navisphere is the launch stabilizers

This rocket had a problem of too few engines on the upper stages, lowering thrust ad efficiency. I was forced to keep some spent boosters to mitigate it

The mammoth engine falling on the left of the rocket is a bug

Here seen better. It can't be a debris from the rocket, at it comes from higher up

Very weird bug there. At regular intervals, mammoths and pieces of launch stabilizers would drop from the sky. I had this problem with all my launchers bigger than 51k tons; of course, since I only tried two of those, I'm not sure how general it is.

And this is... no, this is just a genuine RUD. Detaching that inner layer of mammoths is tricky

But I tried again, and eventually made it. That midair explosion is part of the bug, the engine and launch stabilizer colliding as they fell

This worked, and as per the rules of this silly challenge, I didn't need to launch more. One drop tank, to show that it can be done. Sure, it went up half empty, but that just means that to fill the 60 drop tanks of Ringrazer I'd need 120 launches.

But I wanted to try. All those rockets were inefficient for low twr. The problem is that I would soon start dropping engines, which instead I needed. I wondered, could I make a new rocket design? One that will let me drop fuel tanks without dropping engines?

Yes, yes I can

Well, this is far from the first time I try to launch a rocket with the engines on top.

This rocket is even bigger than the previous ones, at 58k tons. I was able to use only mammoths, thus reducing the number of engines; but this time the limitation is how much stress the engine "arms" can take, and how many launch stabilizers I need. TWR is abysmally low, but I will get to drop spent tanks, so it doesn't matter. Really, the first couple of tanks only lifts me to 30 m/s before running out, but I lose absolutely nothing by putting them, and I gain 30 m/s.

I devised an extremely complex launch sequence to keep twr around 2. There are several dozen stages.

Dropping the first tanks, all goes smoothly. TWR goes up, leading to more efficiency

Enough tanks discarded, I start dropping engines too

And here the vacuum engines are also ignited. Those are needed not for efficiency, but because they have high allowed ignitions; you can't manuever without

This rocket was doing great, until this happened

I think it was a bug. If the thrust from the rocket had been too big for the girders to which the engines were attached, then the rocket should have exploded at liftoff. Or at maxQ. Here I was already well past maxQ, and I already dropped several lines of engines, reducing thrust and mechanical stress.

Still, for once I'll not complain, because that rocket should have never, ever flown anyway under any realistic simulation.

It also gave the most spectacular RUDs on the launchpad

I would have liked to make that model work, but it kept disassembling on the launchpad. And it looks like it's bugs. Sometimes I'd make a small, insignificant change, and the stable rocket would explode, and I'd spend hours trying to get it on the launchpad in one piece again. It felt too much random, so I lost interest.

After all this, I didn't even bother with a launcher for the engine block. That was only 500 tons, if I could launch 1200 tons then the engine block would be no problem, and that's it.

Next for the Elcano king of nowhere style: if this rover did drive 500 meters on Mun - and it has therefore shown it can complete a Mun Elcano - then it also can drive on Minmus. So there, this rover completed a Minmus Elcano without even bothering going there.

Spinoff.3) You must wear a old man's hat to drive this

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After all this, I have Ringrazer assembled in orbit and I must get it to Saturn.

Leaving Earth gravity costs a bit more than 3 km/s. Reaching Saturn costs 6 km/s. Once at Saturn, I can use aerogravity assists from Titan and land on Rhea with maybe 2 km/s.

Well, I don't have the 6 km/s to reach Saturn. Those tanks of liquid fuel I'm carrying will greatly extend my range once I'm there and I can refuel on oxidizer (and I will need them, because going from one moon to the other is over 1 km/s, for four more moons, and then I'll have to return), but right now they are an additonal 30000 tons of dead weight that I must carry to Saturn. So the plan is to go as far as Mars, and use gravity assists.

Starting now, reaching Mars in 7 years. This unconventional trajectory is convenient for having more intercept speed when passing near Mars; it will allow reaching Jupiter

Here the planned first gravity assist

So with that first gravity assist I can raise aphelion by 60 million kilometers. I can eject in a resonant orbit, and incrementally raise aphelion to Jupiter. Once at Jupiter, a gravity assist to Saturn is easy.

That will require time. Well. Including food for 100 years is a lot cheaper than adding even just another line of drop tanks.

Despite the spectacular power of the engines, burning 30 tons of fuel every second, Ringrazer is extremely sluggish. Like, it's got a twr around 0.05. I would have used more engines, but I worried about structural stability. I'm already happy the rockts are not tearing themselves apart.

The first drop tanks are dropped

By a design flaw, they collide with the engines. But Ringrazer is so sluggish, the impact is low speed, and nothing breaks

Even for those tanks that are further from the engines, throttling down is enough to avoid damage.

Ok, 8 minutes of thrust, 200 m/s gained. I only have to do this... 19 times....

And of course, there is engine maintenance.

Here Bill is flying besides one of the nuclear reactors

Just going to the engine is slow, this ship is over 200 meters long.

A jungle of engines. All must be fixed

This is a lot worse than the engines on A'Twin. One thing that helps a lot in maintenance is a path. A clear track that you can follow, and you encounter everything you need. For A'Twin, you just move in circle around the outer rim of the ships, the nuclear engines are all there. Then you move inside, and you move in a smaller circle for the high thrust engines. It's easy. But Ringrazer doesn't have such a trail to follow. It's very easy to forget an engine.

And of course there is the bug. Ringrazer has as many parts as A'Twin. Most of them are simpler, plain fuel tanks, so it lags a bit less. But not by much.

Bill barely visible in the middle of the image, to give a scale of how big Ringrazer is

And the small space left between the shields. It's big enough for Bill to fly through

The engine maintenance is a major nuisance, so I look to cheat for it. This isn't an official or serious challenge, after all.

I wanted to change the number of allowed ignitions by editing the save file. However, the save file didn't have such number; that's in the engine configuration, which I don't dare to touch. However, the save file does have the number and time of previous ignitions, which is subtracted from the maximum value to give the actual value. Will the game accept a negative number?

Yes, it did. Now I have 1000 ignitions

It took a few aftenoons of slowly raising apoapsis. Here all the discarded drop tanks

However, as I said, that's not enough drop tanks. Ringrazer has enough fuel to reach Saturn, but it won't land anywhere.

So I send more drop tanks.

This time not bothering with a launcher

I spent half an hour to make the first docking. Ringrazer, despite its huge torque power, takes many minutes to change direction. The drop tanks are moderately more manueverable. I also gave them some massive rcs power, but it's still hugely inadequate for a 40000 ton ensemble. And before I could complete docking, one of the drop tanks snapped in two.

That was the last straw. Half an hour for a failed docking, that I have to restart. I have to conduct 40-odd more similar dockings, which will take weeks. Then I need to spend more afternoons raising apoapsis. Then I have an ungodly amount of gravity assists from Mars. Then I reach Saturn, and have to make all the landings. It would take months.

And that's not a problem alone. My missions take months. But my missions are technically challenging; this one isn't. Ringrazer can really do the job. It's not difficult. The only problem is time, because everything is so slow.

So I abandoned this mission. Maybe I will pick it back up one day, maybe I won't.

In any case, I have demonstrated that it is possible to land on the inner moons of Saturn, with enough resources. However, of all those resources, the ones I missed was patience.

And now, back to the real mission.

My laptop is already starting to smoke just displaying this

[king of nowhere]

Part 9: Make Jupiter small again: the conquest of Io

The Cylinder module goes to Jupiter. In this first part, Spider lands on the innermost moon Io.

A combintion of high deltaV requirements and radiations turn this into the most difficult landing so far. Stunts I had to pull in this chapter include, but are not limited to: 30 gravity assists, the creation of an entirely new and unplanned vehicle configuration, a 12-hours burn with ion engines, Bill reaching 90% radiation damage twice, recovering a vehicle drifting in the void with fuel exhausted. It took over two years of game time.

Flag planting with bug 29: the sun shines through Jupiter

9.1) Going to Jupiter

Spoiler

I finished last chapter in what looked like a transfer window to Jupiter. At it turns out, it wasn't. It's already too late, and I have to spend a lot more deltaV to make this transfer. On the other hand, this transfer is going to be cheap (at least for rss standards); both giant planets provide a lot of Obert effect for ejection and capture. And since Jupiter's moons are too big to land A'Twin, I'm only sending Cylinder, which has over 10 km/s available. So I can totally make the trip right now, while waiting the next transfer window would require many years, with malfunction risk. So, I go now.

Leaving Iapetus, leaving behind a broken nuclear reactor [actually it's not broken, but see bug 18 and its solution]

Even though the rings would look better from up close, a saturnrise is always beautiful

Splitting A'Twin

This time, Cylinder will only carry Fat Man and Spider, while Clamp and Nitrogenie in a bottle will stay with Trypophobia. Jupiter has dozens of moons, but this mod only has the major four, and they all require Spider.

I loaded the maximum amount of oxidizer on Cylinder for this mission, because Spider will need to be refueled three times. Indeed, I did pick the amount of oxidizer carried by Cylinder specifically for this mission.

The route to Jupiter

And the ejection burn seen from Japetus

Being late compared to the optimal transfer, I have to dip periapsis lower than I'd like. It will result in a high intercept speed, but I'm counting on Jupiter's massive Oberth effect and gravity assists from the moons to minimize that. Compared to all my previous transfers, this is still a pittance.

Ten years passed, with regular maintenance works. Two parts broke.

What's better than a saturnrise? A saturnrise through a maze of complex machinery!

A reaction wheel broke on Nitrogenie in a bottle

That's quite annoying, swapping that wheel for a good one will require grabbing the engine with a Service Probe, detaching it, removing the docking port, changing the wheel, putting the docking port back, get a new docking port to fit on the engine, and dock the engine in place. I can't do it right now because all the service probes are with Cylinder. All reaction wheels on Nitrogenie in a bottle started aging a lot faster (bug 15), and I'm now inspecting them every time I inspect the reactors. But besides the nuisance of those wheels being hard to change, it's not a big deal because I have at least a half dozen spares.

A life support broke on Fat Man

The red highlight makes the cupola look ugly, but aside from that, this is of least concern; there are five other redundant life support systems on that vessel.

Ten years are quite the long time to spend in space, but A'Twin's life support stockpiles are designed for 60 years, so I have all the time I need. You may notice I didn't even carry a full load of water; I judged that 45 years worth of water would be absolutely safe.

Besides regular maintenance, I have to plan the intercept for a gravity capture. Here I had a bad surprise: I can't do that. Maybe it's the angle of my trajectory, maybe the extreme intercept speed that only let me stay in those moons' SoI for a few minutes, but I'm getting really bad outcomes from every gravity assists I make. At most I can save 200 m/s, which is not enough for capture.

I would like to use multiple moons for a gravity capture. But unfortunately, my plane change still left me with some inclination over the moons, so I can make one flyby depending on where I cross the equatorial plane. I don't even have a recording of the plane change, but judging from fuel levels on Cylinder it looks like I only spent 180 m/s on it, so it wasn't a matching of planes to get 0 inclination, I just pushed the planar node to meet Jupiter. With how expensive plane changes are in rss, it was probably the best choice, even if I now have to rocket brake.

Planned Jupiter insertion

I took an assist from Ganymede, as it's the biggest of the moons. A minor saving is better than nothing. I also lowered Jupiter periapsis as much as possible while staying clear of the death zone; Cylinder will still pass through the outer radiation belt, but for a short enough time to be survivable. Finally, after 500 m/s to get captured, I spend an additional 200 m/s to lower apoapsis a bit and end up in a 100-day orbit. It's still a high enough apoapsis to leave Jupiter cheaply, but short enough that I will be able to get rendez-vous with Fat Man in a reasonable time.

Closing in on Ganymede

Capture burn

Finally, after capture, I use a second Ganymede gravity assist to fix inclination. And this time, the moon does it job and gets me equatorial in one swift flyby.

The gravity assist to change inclination, matching the equatorial plane

It would have been very inconvenient to have to make plane changes every time I'd send Fat Man for a landing. The four moons are not all exactly on the same plane, but close enough, with inclination differences no bigger than 0.5° between each other.

Cylinder parked in its final orbit, status. Also highlighted the extent of the radiation belt

Having parked Cylinder in an orbit crossing the moons, I make sure it's not going to have any unplanned collision in the next few years. Then I prepare for landings. I pick Io first because it's going to be the most difficult, and if something has to go wrong or I can't manage, I'd rather know it immediately.

9.2) False starts

Spoiler

There are two problems in going to Io: radiations and deltaV.

For radiations, Cylinder passed through the belt, at Io's level, and the crew got around 50% irradiation. This was a very fast passage, coming from a high apoapsis, an actual rendez-vous with the planet at lower speeds would take longer and have more exposure. Still, there should be enough time to land, but nothing to spare.

As for deltaV, an intercept from the current orbit would cost 5300 m/s. Factor in cosine losses for low thrust and circularizing, we're looking at over 6 km/s. Fat Man has that kind of deltaV while carrying Spider. But it wouldn't have any fuel left to leave Io afterwards. So I must reduce this cost to no more than 3.5 km/s, by taking gravity assists. All the while avoiding the radiation belt, which extends as far as Ganymede.

Of course I could also try to lower Cylinder's trajectory, but I'd rather not to. 6.7 km/s looks like a lot, but four trips of Fat Man in its heaviest configuration will already eat one third of that fuel. And then once at Saturn I'll need another 1.5 km/s to return to Iapetus. And I checked, from Ganymede's orbit it takes 4 km/s to leave Jupiter. So no, I can't do anything too crazy with Cylinder. I could lower apoapsis for 500 m/s, but that's nowhere near enough to help here. So, gravity assists for Fat Man will be.

First gravity assist, using Ganymede to lower apoapsis

Of course the first thing to do is to raise periapsis out of the radiation belt. It will be a tight run to land on Io without getting killed, I can't hope to make it if I start with an already irradiated crew. And so 600 m/s are gone already.

The moons of Jupiter are big, but not that big. They give a significant assist, but I can't exactly pivot around them and change orbit entirely. I can get a limited deltaV from each flyby, So I eject in resonant orbits, to get multiple flybys. Here, after the first in 50 days, I already planned a second 40 days later.

P.S. the 9.3 km/s indication is wrong; it assumes Fat Man can burn all its liquid fuel, but some of that fuel will be used by Spider too.

P.P.S. The life support supplies window underestimates the duration of water because it's not accounting for recycling. O the down side, I had bug 11 strike and stop water recycling, further jeopardizing the mission.

Nice view of Jupiter with Europa and Io passing in front; Ganymede is the big one, shortly before the flyby

More spectacle from the moons

Second Ganymede flyby, with resonance for a third one

Nice, we are gradually lowering apoapsis.

Unfortunately, because of Ganymede's position and how gravity assists work, we are also lowering periapsis. And now we start getting inside the irradiated area. There's no way to avoid it; the radiation belt is too big, if I lower my orbit gradually I will have to spend too much time inside, if I don't lower my orbit gradually I don't have enough fuel to return. This attempt is doomed.

Still, before giving up I have another plan. Because I do have a vessel capable of reaching Io fast, pulling the 7 km/s required: the sturdy, dependable Dolphin, always there to save my missions when I need that extra deltaV and life support. Projected as escape pods, they were never used for an emergency escape, but they were used multiple times as impromptu fast crew transports. Wonderful ships.

So the new plan is this: Fat Man will go unmanned. It will enter the radiation belt, and take all the gravity assists it must take, and orbit Io. Then a Dolphin will carry the crew to Io, very fast, and rendez-vous with Fat Man. Manned landing follows. Then I hope I have enough fuel and healt left for a fast return; because Dolphin won't have enough fuel to also carry the crew back on a fast trajectory.

Let's get to work on this.

9.3) Fat Man takes the slow route (including a special insert with ALL the 21 flybys)

Spoiler

First, some preparatory work. I send Wings A into a polar orbit to act as communicaton relay

Let's recap some gravity assist theory.

When you make a flyby, you get a direction change, equivalent to a manuever. Just like with any manuever, the effects are greater on the opposite side of the orbit. The entity of this change depends on how massive the body is, how close you can get, and how fast you're going. The main caveat is that you leave the body with the same speed you arrived, only in a different direction.

The moons of Jupiter are large enough that I can get a reasonable push out of them; not at all like Rhea, whose push was so tiny it would have required hundreds of passages to get anywhere. On the other hand, they are also small enough that I can't get too crazy. Especially because in my first passages I'm moving vey fast compared to the moons, and therefore my flybys are less effective. I need many flybys, and for that I make sure to get ejected in resonant orbits, where my orbital time is an exact multiple of the moon's orbital time, so I meet it again in the same place.

So I start by using Io to slow down. Io is very close to my periapsis, so by getting assists from it, most of the effect is on apoapsis. And then there is some lowering of periapsis, to keep the speed relative to Io constant. So I lower apoapsis using Io, and I lower periapsis slightly in the process.

Actually, for the first few assists I saw fit to use Ganymede

I'm not sure anymore why I used Ganymede at first. Maybe because it's bigger, so I was hoping to squeeze more from it. Maybe I wasn't yet sure on my strategy. It's certainly adequate while I have this very high apoapsis, but soon I was getting too much effect on periapsis and I had to switch to Io to keep lowering.

When periapsis gets too low, I look for an assist from Callisto, the outermost moon; being closer to apoapsis, it has a greater effect on periapsis. So by using Callisto to speed up, I mostly raise periapsis, keeping it around Io, with a minor effect on apoapsis. The net result of slowing down at Io and speeding up at Callisto was to lower apoapsis; when I saw I was getting apoapsis down while keeping periapsis level, I knew I was on the right track.

All this was achieved with very small manuevers. I made sure, at every flyby, to be ejected in the right orbit to ensure another flyby afterwards. Tiny discrepancies due to rounding errors could often be fixed with manuevers of less tha 1 m/s. I made them with one single engine at 1% power for maximum precision. This also spread the many ignitions across all six engines of Fat Man, so that none was used too often. Sometimes I had to change plane a bit, but I was careful to always be ejected equatorially, and only had to correct slight imprecisions. As plane changes are expensive, those tiny ones were in the 10-20 m/s range.

After a while, I lowered apoapsis lower than Callisto. I kept using Io to lower apoapsis, but I started using Ganymede to raise periapsis. Until I managed to drop apoapsis lower even than Ganymede, and so I started using Europa.

Eventually, even Europa became apoapsis and I could gain nothing more. Ok, maybe I could have, but it was getting increasingly difficult, and I already achieved my goal.

And so it was that, spending between around 100 m/s in correction manuevers and with the engines still in working order, I brought Fat Man to the point of needing only 1500 m/s to orbit and circularize at Io. From the first manuever at 99:70 to the last at 100:23 almost an year passed. It took afternoons of painstakingly managing trajectories, but it was worth the effort.

The final flyby, and the manuever for capture

This trasfer is cheap enough to leave Fat Man with most of its fuel. The deltaV will be further stretched as Spider burns its own fuel.

Radiations can be a problem for electronics, but they were a minor issue. For once, this is 15 times weaker than the Saturn radiation belt. More important, even though it took almost one year to get there, the radiaton belt expires between Europa and Ganymede. So I only crossed it near periapsis. And by orbital laws you spend more time near apoapsis, which is free of radiations. When the crew arrived, the routine inspection found everything in working order, with only slight signs of aging on a couple of parts.

Approaching Io for the final time. I'll be covered from Earth and Cylinder, luckily Wings was able to act as relay and enable the manuever

Also, new bug (#29): the sun is shining through Jupiter. It's just a visual glitch, without any impact on the game.

In low Io orbit

Fat Man circularized at Io while only spending 37% of its fuel (after detracting what's allotted for Spider). It will be vital to try and get away from here.

Now, for the gritty details, all the gravity assists recounted. I already doubt anyone reads my reports, someone reading all the flybys is even more unlikely, but what the hell, for the sake of completion I put them. I do hate when people write mission reports where they do difficult things and they don't explain how they did them, I'd rather err on the other side.

9.3.1) Special insert with ALL the 21 flybys

Spoiler

Flyby 1: Ganymede, -37 days, so it will be at 99:111. Lowers orbit. Exits in a 6:1 resonant orbit for a new Ganymede flyby, at -80 days. Orbit is still high, therefore slow. It probably would have been more efficient if I used Io from the beginning.

Taken just after flyby 1. Flyby 2, Ganymede, -42 days, hence 99:154. Keeps lowering orbit. Sets up new 4:1 resonance for another encounter at -71 days, 99:182.

After flyby 2. Flyby 3, Ganymede, -28 days at 99:183. Ejects in 3:1 resonant orbit for a new flyby at -49 days.

After flyby 3. Flyby 4, Ganymede, -21 days at 99:204. Orbit is too low now for Ganymede to be efficient at lowering it, so I switch to Io - with the simple trick of matching the orbital time to pass in the same location at the same time. Io will be encountered at -37 days.

After flyby 4. Flyby 5, Io, -16 days so 99:221. Keeps lowering orbit and eject in a resonant 7:1 orbit, for a new encounter at -28 days.

After flyby 5. Flyby 6, Io, -12 days at 99:233. Keeps lowering, and ejects with a 6:1 resonance for another flyby.

After flyby 6. Flyby 7, Io, -10 days at 99:244. More lowering, ejection in a 5:1 resonant orbit for a new encounter at -19 days. So long as I keep lowering, keep finding convenient resonances and stay out of the inner radiation belt, I keep going.

Why did I apparently gain 100 m/s since the previous manuever?

After flyby 7. Flyby 8, Io, -8 days at 99:253. Periapsis is getting too low, I must raise if by using Callisto at 36 days. The flyby of Europa at -9 days is an accident; I wanted to reach Callisto, and found Europa on the way, and I was able to incorporate it into the trajectory. It still counts, though, as flyby 9, Europa, 99:254. Mostly tries to minimize the impact of this flyby on the way to Callisto.

After flyby 9. Flyby 10, Callisto, -26 days at 99:280. Raise periapsis and exits in a 1:1 resonance for a new encounter at -43 days. I can't doubt it's a 1:1 resonance because I see the orbital times, but how can it be when the periapsis is so low and apoapsis is only slightly higher baffles me.

After flyby 10. Flyby 11, Callisto, -16 days at 99:297. Raises periapsis some more, and hits Io again sortly after periapsis at -18 days. This is the point where I saw I restored periapsis where I wanted it while moving apoapsis, and I felt confident I was going in the right direction.

Shortly before flyby 11, but refining it to prepare already for a second subsequent Io flyby, at -13 days.

After flyby 11. Flyby 12, Io, -1 day at 99:299. Lowers orbit. It does not eject in a resonant orbit, but it meets Io in a different part of its orbit (red circle, on the left side) in -10 days.

After flyby 12. Flyby 13, Io, -8 days at 99:308. Lowers orbit. Here I couldn't find a nice clean resonance, changing orbit is harder as Fat Man gets closer to Jupiter. But I did manage an 11:3 resonance, which is still lower than a 4:1 and meets Io 20 days later. Second encounter not highlighted because bug 16 manifested again.

After flyby 13. Flyby 14, Io, -11 days at 99:327.  Keeps lowering orbit. Once more, ejection is not in a resonant orbit because it meets Io in a different place (purple circle for the first flyby, cyan for the second) at -17 days.

After flyby 14. Flyby 15, Io, -5 days at 99:333. Lowers orbit, but also sets up an encounter with Ganymede at -10 days.

After flyby 15. Flyby 16, Ganymede, -5 days at 99:339. Raise periapsis. There is no planned manuever next, because by now getting to Io is cheap enough that it can be done with Fat Man fuel budget. I almost did it. Then I realized, with all the problems I'm having, and with a crew coming in and needing to leave the radiation belt asap, I really should conserve every drop of fuel I can. Wise choice.

After flyby 16. Flyby 17, Io, -30 days at 100:05. As I left the previous flyby without a carefully arranged resonance, I had to struggle to find a new flyby without spending much fuel. It costed some more time.

After flyby 17. Flyby 18, Io, -8 days at 100:14. Keeps lowering, and ejects in a 2:1 resonance for a new encounter at -12 days.

After flyby 18. Flyby 19, Io, -3 days at 100:17. Ejects in a 2:3 resonance, once more invisible because of bug 16.

After flyby 19. Flyby 20, Io, -5 days at 100:23. Basically tries to find a way to Europa to raise periapsis one last time, but it resulted in an expensive plane change manuever. Maybe raising periapsis by rocket burn would have been cheaper overall.

After flyby 20. Flyby 21, Europa, -2 days at 100:24. Raises periapsis just enough for a perfect Hohmann transfer.

This was the last gravity assist; from here, I used 1500 m/s to circularize on Io.

This pic was already shown

Now, I cold have been even more efficient. I can no longer use Europa, and I long believed that you cannot reduce your intercept cost without using other bodies. But I recently learned, thanks to @Lt_Duckweed, that if I take an assist from Io to lower apoapsis, well, of course it also lower periapsis keeping the same intercept speed on Io. But! At this point I can raise periapsis with rockets, and the cost of doing that is less than what I gain in reduced intercept. So it's possible I could have saved some more. Then again, I tried doing just that, and it would have costed 700 m/s to reset periapsis, and that 1500 m/s intercept includes 600 m/s apoapsis lowering that cannot be avoided, so at best I could save less tha 200 m/s.

Also, I just learned it's spelled maneuver, not manuever like I always did. Well, I'll probably forget about this detail soon.

9.4) Dolphin 2 takes the expensive route

Spoiler

Dolphin 2 leaving its place

And preparing for the journey. Once again, this game cannot make estimates on water supply

A Dolphin pod totally has the deltaV to pull of this mission. On the downside, it has a different problem: thrust. It needs to pull more than 6 km/s - because that planned manuever assumes Oberth effect, which Dolphin won't be able to use - with two ion engines. A quick calculation of thrust against mass shows that the manuever should take 6 hours. I wish it was that easy; the two advanced RTGs can only power the engines up to one third of their maximum thrust, so we're actually looking at something like 18 hours.

A real ion powered ship would lower orbit gradually, but this is not an option here. I can't allow the crew to run multiple time through the death zone. Similarly, I can't circularize at the height of Ganymede and then plunge; On a neat Hohmann transfer, Dolphin would spend too long inside the radiation belt.

Starting the engines 11 hours before approach, using the navisphere to set the direction

The idea is to use the navisphere to keep my direction towards the target. Something akin to what I did in the DREAM BIG mission, chapter 10.3, a rendez-vous at 3 km/s.

This time, however, it's a lot worse. First, this time I need twice the deltaV. Second, back then I had a solar-powered Dolphin, and it was close enough to the sun to thrust at 100%. I also had more deltaV. So the first attempt failed miserably. I couldn't even keep a straight direction towards Io.

Io already passed periapsis, and Dolphin is too far behind to reach it

I didn't even try another go. It's clear I need a different approach. And besides, those manuevers really take hours; I could speed them up with the persistent thrust mod, but the last time I did it, it broke my ship (Bolt mission, part 3.2, aptly called "feeding Nail to the kraken"), so I'd rather not risk it.

So, first thing, I refurbished Dolphin. A Dolphin has 2 RTGs, because I want to keep them light, compact, and relatively cheap. It's also enough for their intended use, i.e. making one single big manuever in solar orbit to get back to Earth. But in this case, I can salvage the RTGs of Dolphin 1. And with only 300 kg, I doubled my thrust.

The refurbished Dolphin, with 4 RTGs

Also, last time I forgot a bunch of spare parts that I was conveniently storing in the hitchhicker container (A'Tuin had special containers for spare parts, but then I realized the hitchhickers have plenty of storage space, so I'm using those). By removing those parts, as well as the parachutes that Dolphins have equipped by default, I could gain some deltaV despite the additional RTG mass.

The second change was in the planning. Instead of aiming for an intercept, I'll aim to pass in front of Io. This way, when I gradually slow down, it will result in an actual intercept. I tried this approach, going for different distances, and failed. I need to be more accurate. I've seen a mod that splits an ion burn into dozens of smaller burns, maybe I'll go look for it? Then I realized I can actually do this manually.

I split the injection burn into two smaller manuevers so that it would more accurately simulate the actual burn

I actually tried splitting it into 10 different burns at first. Problem is, I have to move each manuever manually every time, since the game ties them to the global clock. It was unmanageable. Two manuevers, each lasting 4-5 hours, the second manuever is 2 hours before closer approach, the first is 4 hours before the second. Turns out, this was accurate enough and I could reach Io.

Also, I keep spelling maneuver wrong. I'm too used to typing manuever.

Injection at Io. Actually, this pic comes from a failed attempt where I was going too fast, but it's a good pic nonetheless

Entering Io's SoI, slow enough to be able to stop. Bill got 29% radiation by now. For some reason, he's taking more damage than the rest of the crew

Flying over Io's volcanic plains

In orbit. Now I must rendez-vous with Fat Man, and I must be quick for the radiations

I found a rendez-vous in 4 hours, but the maneuvers required were too long, I tried and failed to make it. I tried multiple high energy rendez-vous, Dolphin has the deltaV to make them, but it lacks the thrust.

Then I decided to just run an experiment to figure out how much time I have left exactly, and it turns out Bill will die from radiations in 24 hours. This is significantly longer than I thought, so I could afford to make an easier rendez-vous in 6 hours instead of 4.

Rendez-vous with Fat Man, status

Dolphin did an awesome job bringing the crew to this point with limited irradiation. Its xenon supply, though, is now exhausted, and it will take many mining stops to renew it. So now I have to land, and then I'll have to hope Fat Man has enough fuel to bring everything back safely.

9.5) Exploring Io

Spoiler

I barely started Spider's engine, that one of them broke.

Spider broke an engine

It's all ok, the hardware is planned for it. Spider is perfectly capable of landing with 4 engines. It could probably make it even with 2. And I have spares back on Cylinder.

I keep expecting those landings to be harder than they are. They require 2000 m/s, so they make me think of Tylo, but those are no Tyo landings; the deltaV is high because the real solar system is bigger, but the gravity is still low, Moon-like.

Flying over an alien landscape. Yeah, well, that's kinda the point of the whole game

Descent, with four engines

Landing. Those lava flows look highly irregular, but it's just visual, the terrain is rendered as smooth

Planting the flag

Some IVA view. Also, this time with the deltaV display on, showing there is a lot of extra

Now, despite the radiation clock ticking, I have to wait 2 hours before leaving. That's the time it takes Fat Man to complete an orbit and return over Spider. So I decide to detach the Hartman rover for a ride, a 50 km round trip to visit a nearby biome.

By the way, the wheel misalignment problem that I noticed in 7.3? As soon as I fixed the broken wheel, all the other wheels realigned themselves perfectly.

The land is very smooth, allowing high speeds and jumps

I wanted to take an IVA picture wih both the flag and Jupiter

I had to push the rover with reaction wheels to make it

I just discovered what you see by internal overlay and looking from behind

Leaving Io

Docked with Fat Man again. I took the time to remove the broken engine along the way

9.6) More false starts

Spoiler

The deltaV counter in the last image is accurate. Fat Man, owing to a much reduced payload, now has 6800 m/s. Those would be enough to return to Cylinder, if the orbits were aligned properly. Which, of course, they aren't.

An indication of the time it takes to leave the death zone

I had 24 hours of survivability when Dolphin reached Io. I spent 6 for rendez-vous with Fat Man, and 2 to land, leaving 16 hours. Which is more or less the time it takes to exit the radiation belt, according to the pic above. Ok, near the edge the radiation level decreases, so the crew is actually safe, but there isn't any time to lose. I must launch right now. I can at most wait one orbit.

Leaving Io

To escape radiations I must raise apoapsis at least as far as Ganymede. This already eats up 2700 m/s, leaving me with 4 km/s, which is still good. However, to avoid falling inside the radiation belt again, I now also must raise periapsis. And this costs another 2.5 km/s. Now I have 1.5 km/s, which aren't all that much in rss. No, I can't get any kind of gravity assists. Europa is also in the radiation belt, and Ganymede is on the wrong side of the orbit. To get a Ganymede encounter I'd have to raise apoapsis way too much, and meet the moon on the descending part of the orbit. And then I'd be too fast for any kind of gravity assist or manuever to change my path significantly, and plunge back inside the death zone.

So, I have to spend 5 km/s raising my orbit, leaving 1.8 km/s to return with gravity assists? Looks doable. But it gets worse.

Because if I circularize at Ganymede's level, then I am going very slow compared to Ganymede, and I can't get any sizeable gravity assist. In order to reach Callisto, I'd need another 1000 m/s. Leaving me with basically no fuel.

My best attempt to circumvent the problem

In the above pic, I try to solve this problem by raising apoapsis above Ganymede, and keeping periapsis slightly below; this way, I'd stll have a large difference in velocity, which would let me make gravity assists. Didn't work, it's still too low and Bill died for radiations.

Once more, I need another way. So I figured I could replicate what worked in the outbound trip: put the crew in a small vessel with lots of deltaV, on a high energy trajectory. Put all the heavy cargo in a slow, cheap trajectory wit plenty of gravity assists.

Splitting Fat Man, Spider and Dolphin

Fat Man, basic configuration, will get all the fuel and carry the crew to safety

Indeed, there was enough fuel left that Fat Man - in its basic configuration, without the extra tank - can get filled completely. This way, it has 10 km/s of deltaV, which should be enough to overcome the obstacles I had.

And the rest of the cargo: Dolphin, Spider, and the extra tank of Fat Man

The remaining stuff that got left behind to make Fat Man lighter is Spider, Dolphin and the extra bit of Fat Man. Sounds like some mythological chimera, and I will call it such. The smidgen of fuel left is enough for 2500 m/s. Not much, but with 1100 m/s I can get to Europa, and from there start the gravity dance. And even if I can't get back to Cylinder, I can surely park Chimera in a convenient enough orbit where Fat Man - after being refueled - can come to rescue it.

9.7) Fat Man takes the expensive route back

Spoiler

Fat Man starts immediately with a 2700 m/s burn to get its apoapsis level with Ganymede, just like I was doing in the previous failed attempts. This time, though, Fat Man has an additonal 3 km/s to use, and it makes all the difference. Indeed, without even looking for gravity assists, I find a way to return to Cylinder.

Fat Man rendez-vous with Cylinder

A 5200 m/s burn raises apoapsis far away from Jupiter, and close enough to Cylinder's trajectory. As we know, near apoapsis ships are moving slowly, and you can get away with strange trajectories involving lots of radial changes without spending much. In this case it means 800 m/s, because this is still rss. There's still 1 km/s left.

There's still an additonal complication. Cylinder is passing through the death zone at every periapsis, and the crew takes roughly 50% radiation damage. That damage is healed as the ship moves slowly to apoapsis, because the ship design included one radiation decontaminaton unit (RDU) for each crewmember, and it's always on. However, the crew of Fat Man is heavily irradiated (Bill at 86%, Etdania and Monbrio around 75%, because for whatever reason Bill keeps taking more radiation damage). And the rendez-vous will happen after apoapsis. There isn't enough time to heal the crew before Cylinder plunges again into the death zone, killing them. Attempts to put the rendez-vous before apoapsis were way too expensive.

The solution was to alter slightly the trajectory to have the rendez-vous one orbit later. While I don't like leaving the crew for 80 additional days on Fat Man, where they do get stressed from the lack of space, in this time the lone RDU of Fat Man will heal each crewmember in turn, just enough that they will survive.

The altered trajectory; this time rendez-vous is in 133 days

What can I say, I'm just glad I gave Fat Man supplies for one year.

133 days later...

Fat Man rejoins Cylinder

All kerbals on board are below 50% radiation damage, which I determined was enough to save them. Indeed, Bill rose again to 88% during periapsis passage through the death zone, but then he fully recovered. Stress rose to 20%, not ideal, it will take a few years in front of the TV to heal that. Meanwhile, I can expect a couple stress breakdown; A'Twin is fully capable of dealing with those.

9.8) Spider-Dolphin takes the slow route back (including a special insert with ALL the 9 flybys)

Spoiler

Long story short; I sent Chimera to Europa in a Hohmann trajectory. I used Europa's gravity assists to raise orbit to Ganymede, then to Callisto. Then I used the last flyby to hurl the ship on a rendez-vous trajectory. Rendez-vous speed was high, more than Chimera had left, so it just passed close to Cylinder at 500 m/s. At this point, Fat Man went to rendez-vous with Chimera and bring it back.

9.8.1) Special insert with ALL the 9 flybys

Spoiler

Flyby 1, Europa, -1 day at 100:81. Raises orbit, ejects into a 3:4 resonance to prepare another flyby 10 days later, marked as -12 days.

Chimera ejects from Io with this manuever, uses 1100 m/s and a 24 m/s plane change.

After flyby 1. Flyby 2, Europa, -10 days at 100:91. Does not eject into a resonance, it meets Europa at a different part of its orbit: flyby 2 is the yellow one in the lower part of the screen, while flyby 3 will be the cyan one in the upper part.

After flyby 2. Flyby 3, Europa, -4 days at 100:96. Ejects into the red orbit, in 4:3 resonance. It will meet Europa again in at -18 days.

After flyby 3. Flyby 4, Europa, -14 days at 100:111. Chimera doesn't have enough energy to raise orbit all the way to Ganymede, so it gets helped by a small 87 m/s push while passing at Europa's apoapsis. This will be enough to reach Ganymede at -28 days.

Just before flyby 4. Flyby 5, Ganymede, -14 days at 100:125. Flyby 4 and its periapsis prograde burn still hasn't been done, but I don't have a proper screenshot of flyby 5 otherwise.

The flyby 5 is the green one at the bottom of the screen. It does not eject into a resonant orbit (yellow dotted orbit), it will instead meet Ganymede at a different part of its orbit 38 days later, the -52 days purple encounter on the upper right of the image. The red dotted orbit is the planned trajectory after the subsequent flyby, but that is still to plan.

Includes a 74 m/s plane change. This sequence is going less smoothly than the previous one.

Just after flyby 5. Flyby 6, Ganymede, -35 days at 100:160. Raises orbit enough for a Callisto encounter at -79 days. Chimera will run a full circle of the purple orbit before meeting the external moon.

Shortly after flyby 6. Flyby 7, Callisto, -42 days at 100:205. Ejects into a 3:2 resonance to meet again Callisto 50 days later, at -92 days.

In the meantime between flybys 7 and 8, Fat Man reunites with Cylinder.

Many days after flyby 7. Flyby 8, Callisto, -37 days at 100:255. Ejects from the ochra circlet into the green orbit with the red maneuver. The red maneuver, 158 m/s, is an attempt to align the point of encounter to Cylinder's periapsis, in an attempt to have a resulting orbit more similar and a lesser intercept speed. Will meet again Callisto at -88 days, in the location of the cyan circlet.

I could surely save some more fuel with more flybys, but by now Chimera can safely rejoin Cylinder, and the fuel saved would be negligible for the overall fuel budget, and those orbits are starting to take quite a bunch of time, and I'm just tired. So the next flyby is the last one.

The special insert closes here because the final trajectory is important.

Just after flyby 8. Flyby 9, Callisto, -51 days at 100:306.  Final flyby, ejects into a high orbit (purple) that will result in a close approach with Cylinder. Chimera has only 1300 m/s, while the intercept speed is 1800 m/s, but once the craft is close to Cylinder and relatively slow, I can grab it with Fat Man.

Chimera runs out of fuel

Here I used all the fuel on Chimera to slow down compared to Cylinder - minus a smidgen to facilitate docking. Remaining speed is 450 m/s. Now I send Fat Man to grab Chimera.

Fat Man leaves. I left its tanks mostly empty to save mass; it needs 1000 m/s, even including that it will grab extra mass it won't need much fuel

It carries a second pilot because Dolphins don't have probe cores, they need manual piloting. No, I never ever considered a situation where I could have one unmanned. Just like I never imagined I'd use the bottom half of Fat Man as a secondary taxi. Good thing at least Spider had a probe core to control Chimera.

Fat Man gets reunited with its extra tank

All aboard Cylinder, safely

At this point I dismantled all the refurbishing I did on Dolphin 2, I put back the parachutes in its container, and I replaced the broken engine on Spider. And I finally decided to raise Cylinder's periapsis, I'll lose a bit of fuel but I won't get a radiation sickness warning at every periapsis. The RDUs can heal it, but irradiating my whole crew to near death every 80 days just feels wrong.

With this most difficult moon cleared, the rest of the Jupiter system should be explored without too many problems.

Bugs compilation updated

Spoiler

A numbered list is so convenient to refer to bugs quickly. This list keeps growing. Problem and Solution

1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

4) Propellers start twisting around. No worry, it fixes once you stop time warping

5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

10) I can't plan manuevers or go EVA, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: save before exiting time warp

13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

17) Crew hatch registered as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

20) Upon starting the game, clicking on the VAB does not work. Clicking on the icon on the bottom left corner of the screen still works

21) Sometimes elements of the HUD change size. It doesn't affect the game, and seem to revert spontaneously

22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason. Load Cylinder into physical range and they restart

23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced. Reload when it happens, and it will get fixed

24) The ground on Titan has all sort of glitches and malfunctions. Be extra careful during landing, cheat the vessel in orbit before leaving it, jump to start flying. See 7.3 for more details

25) Negative aerodinamic drag displayed on the user interface. Drag is still behaving normally, it's only the display that's bugged

26) The docking port on Clamp has all kinds of problems, does not allow fuel transfer, can't be removed. I stuck another docking port there, and I can grab Clamp with a claw if needed

27) Sometimes there is no signal for probe control even though there should be. Switch to the vessel that's not being seen, then back to the probe

28) Crew pod of Hartman rover has a broken life support and a functional wheel, but it instead appears to have a working life support and a broken wheel. Nothing I can do about it; but it still works

29) The sun shines through Jupiter's body as if it was part of the sky (NEW). It's just an harmless visual glitch

Broken parts recap

Spoiler

I want to keep track of how much stuff I break, and how much it's affecting the mission, so I prepared a list

Life support

1 life support broken on Dolphin 1. I've got five more redundant pieces on it.

1 and only life support broken on Hartman. Sucks, I can't take extended trips, but the rover has enough air to conduct landing operations safely.

1 life support broken on Fat Man. I've got five more redundant pieces on it. (NEW)

Nuclear power

3 Excalibur reactors broken.  They are redundant. There are 12, and up to 4 can be lost before mining is slowed down. Still, there is concern here that they are breaking up fast.

Reaction wheels

2 large reaction wheels broken. I've still got 88 working.

1 medium reaction wheel broken on Clamp. I've got 8 or 9 spare ones in storage.

1 medium reaction wheel broken on Nitrogenie in a bottle. I've still got a half dozen in storage. (NEW)

Engines

2 big nerv broken. I've got 1 more spare. Afterwards, the ship can work with less than the full complement.

1 big wolfhound broken. I had a spare. Afterwards, the ship can work with less than the full complement.

1 small nerv broken. I've got 2 more spares.

1 cheetah broken. I've got 2 more spares. (NEW)

Communication

1 RA-100 dish broken. I've got 5 more redundant pieces. After that, I still have more non-relay antennas.

1 HG-5 antenna broken. I've got 1 more spare. After that, the mission can still use normal non-relay antennas.

1 Communotron 88-88 antenna broken. It was itself a spare part, and I have more spares, as well as redundant antennas.

Others

1 radiator panel broken. I had 12 redundant. They should be needed to vent heat from the nuclear reactors, but they are not actually needed anyway.

Low-quality parts

A landing light broken on Nitrogenie in a Bottle. Irrelevant, I don't need them.

Life support on Trypophobia's gravity ring broken. Irrelevant, the same function is included in the greenhouses.

1 Converter broken. Irrelevant, converter is the stock isru functionality that I'm not using. I need the chemical plant functionality, and that one is still working perfectly.
Outdated

2 reaction wheels broken on Milly. Now Milly has done its job.

1 dart engine broken on the Mars Descent Stage. Now it's a pile of debris on Mars.

Discounting the low quality and outdated parts, that's 19 critical malfunctions so far.

Edited February 13, 2023 by king of nowhere

[king of nowhere]

Part 10: Make Jupiter small again: the other moons

After Io, the remaining three moons do not present particular problems. Cylinder then returns to refuel on Iapetus.

10.1) More Europa

Spoiler

With Fat Man's fuel budget it may be possible to make a direct trip to Europa, just barely. But I'd rather not risk it and take a few assists from Ganymede first.

Route to Europa, part 1

In this first part, Fat Man goes for a Ganymede flyby, with an additional burn at Ganymede's periapsis (312 m/s, in 37 days). This is to immediately reduce the orbital time, because more time spent on Fat Man means more stress for the crew. It results in the dotted blue trajectory, resonant for another Ganymede flyby in 64 days.

Route to Europa, part 2

This second pic is between the first and second Ganymede flybys. It refines the second flyby (-28 days) into a resonant orbit (purple) for a third flyby (-42 days).

Route to Europa, part 3 and final

Before the third flyby. Now there's not much left to be gained - especially since further assists would risk running into the radiation belt - and enough fuel was saved for safety.

After one last apoapsis reducton, a periapsis lowering (red, 399 m/s) lowers periapsis at the level of Europa, resulting in 1600 m/s intercept speed.

Meanwhile, I also recover Wings A. I don't need a relay anymore, and the probe needs a good check up after two years in space

Europa looking great with its surface patterns

Up close, the irregularity of the surface becomes more apparent

Europa is one of the landings I was most eager to performs. They say the surface must be very interesting, a chaos of ice chunks. They expect penitentes tens of meters tall. Will I even find some even surface to land on?

Yeah, of course

I already established, surface features is not this mod's strong point. I did drive some tens of kilometers, but without much passion. In stock, every body has a unique feeling driving a rover on it; even with the outer planet mod, many planets have a distinctive surface. In rss, they all feel the same.

Upon returning to the lander, I find it howering midair, alongside the flag

That's an old, well-known issue. I don't even think I should add it to the bug list.

Wait, why not? I could still have Spider crash in some way for it. So, welcome bug #30

Returning to Cylinder

The return trip requires almost 5 km/s between ejection from Europa and intercept speed, but thanks to the fuel saved with the Ganymede assists, Fat Man has that deltaV. Radiation damage is low, as Europa is on the outer edge of the radiation belt. It will cap at 50%. I'm short on water because of bug #11, the water recycling plants produce also ammonia, they were told to dump it, but they glitched and stopped working. At this point I remembered to reset them, and they started working again and there's more than enough water for the rest of the trip.

One last pic of Europa

10.2) Ganymede and Callisto

Spoiler

The last two moons were unremarkable. There was no need of gravity assists or anything. Which is just fine, because the crew is starting to get to 20% stress levels from all the time spent in cramped Fat Man, and it will take years for it to go down to 0.

Trajectory to Ganymede

Landing on Ganymede

Return to Cylinder

Route for Callisto

Landed on Callisto

Back to Cylinder

All back, landings are done. Time for status

Cylinder has 4750 m/s left - a bit more after I dump the remaining oxidizer. Which is a lot more than it should have been because of a bug I've noticed since 5.1, but never wrote down: apparently, when I reload the game the central tank of Cylinder gets filled with new oxidizer. Even though I dumped it previously. And this is BAD; Cylinder has nuclear engines, it does not need any oxidizer save that required by the landers. Any more oxidizer is just wasted mass. Ok, I can dump it again, but if I reload the game and forget to empty that tank before a maneuver, I end up wasting fuel.

10.3) Iapetus the convenient

Spoiler

It took another year and a half to complete the landings. Almost four years spent around Jupiter. Now it's time to leave, but the proposition is complicated by unfavorable alignment.

Cylinder is on a convenient elliptic orbit to leave Juputer cheaply. It can only reasonably burn at periapsis, else it would take many km/s to leave. But this limits the time window when I can burn to exit with a higher solar apoapsis, and that time is not when Saturn is conveniently aligned for a transfer.

The transfer problem illustrated. It would take a much higher apoapsis to let Saturn overtake, and 30 years

Thirty years are probably within the limits of my life support, but it's a lot of time I'd rather save. I actually spent a couple hours studying gravity assists to try and exit Jupiter with a different angle. Followed by driving some rovers for my Elcano challenges and picking up a whole new challenge, because after Io I am fed up with more gravity assists.

Then I cursed myself for a fool. I can just eject from Jupiter with minimum speed, and then raise aphelion in solar orbit at the convenient time. Sure, I'll lose all the Oberth effect from Jupiter, but this far from the Sun it won't be too expensive, and Cylinder has plenty of deltaV.

Planned return to Saturn

So here's the plan. 450 m/s to leave Jupiter in solar orbit (and I actually plan to save some of that by gravity assist), then 1500 m/s to make a Hohmann transfer to Saturn. I could have gotten away with 1300 m/s, but it would have taken 2 years longer. Time is malfunctions.

Speaking of malfunctions, I keep going back to Trypophobia to service the reactors

Exiting Jupiter with a Ganymede flyby. The gravity assist alone does not suffice, hence a 200 m/s burn at periapsis

The crew is still stressed years later, and they had some breakdowns. None of them dangerous; here they dumped electric charge

Speaking of malfunctions, I had many of them, but all noncritical; got quite a lucky streak here.

Approach to Saturn

Once more, Titan is perfect for aerobraking. This time, having spent some extra fuel for a faster transfer, I'm coming somewhat faster than I was during the first Saturn capture. But then, Cylinder only needs 1.5 km/s to return to Iapetus - which can go as low as 1 km/s in an emergency - so I can afford to use some fuel to slow down first if necessary.

Approaching Titan. The rings of Saturn look better than I remembered

I try first with a 240 km periapsis, because it worked very well the previous time

Yep, it worked again. Cylinder was going faster, but the nuclear reactors on Trypophobia are more heat sensitive, Cylinder alone can aerobrake harder.

Now I have to repeat the manuever and remember to pull back the antennas first, though. Also, dismantle the heat shields on the Dolphins and store them somewhere safe, to avoid wasting ablator.

Trajectory to Iapetus

With all this fuel left, going to Iapetus is easy. Forget all the gravity assists I had to take the first time. 450 m/s burn lowers apoapsis to Iapetus level, then 180 m/s burn changes orbital time enough to ensure an encounter on the next passage. Which is in 80 days, well, Iapetus has a slow orbit, I couldn't get there any faster. Less than 800 m/s intercept speed.

And so once more I have to try and dock the two subunits

As much as I align them perfectly before docking, there's always some drifting. I started to consider wheter installing an RCS system on Trypophobia - and stowing it away in a container after use to avoid malfunctions - would have been better after all. But this time, for the first time ever, the docking worked immediately.

Year 114. A'Twin reunited again after 28 years, status

Landing on Iapetus

Iapetus is known for having two emispheres with starkly contrasting colors. Here I'm at the boundary line, and the color does not gradually fade. No, you just get spots of different colors.

Landed

Another bug! Where are all those uraninite harvesters coming from?

I got another bug here (#32). Apparently, all my drills are also uranium drills now. Technically it's an advantage, except that uranium mining is already as fast as it needs to be. And I fear all those additional drilling functions may increase lag. For sure, they make it harder to use the automated functions.

I checked back some saves, but after discovering that this bug has exhisted for at least several days now, I decided to just keep playing. And hope it won't cause any worse issue.

Just a nice pic of running maintenance

Year 118: refueling completed

It took less than four years to refill the tanks. And this time I wanted them full to the brim, because I'm about to try what could be an even harder target than Io: a high inclination asteroid.

Bugs compilation updated

Spoiler

A numbered list is so convenient to refer to bugs quickly. This list keeps growing. Problem and Solution

1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

4) Propellers start twisting around. No worry, it fixes once you stop time warping

5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

10) I can't make manuever nodes or go eva, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: save before exiting time warp

13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

17) Crew hatch registered as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

20) Upon starting the game, clicking on the VAB does not work. Clicking on the icon on the bottom left corner of the screen still works

21) Sometimes elements of the HUD change size. It doesn't affect the game, and seem to revert spontaneously

22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason. Load Cylinder into physical range and they restart

23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced. Reload when it happens, and it will get fixed

24) The ground on Titan has all sort of glitches and malfunctions. Be extra careful during landing, cheat the vessel in orbit before leaving it, jump to start flying. See 7.3 for more details

25) Negative aerodinamic drag displayed on the user interface. Drag is still behaving normally, it's only the display that's bugged

26) The docking port on Clamp has all kinds of problems, does not allow fuel transfer, can't be removed. I stuck another docking port there, and I can grab Clamp with a claw if needed

27) Sometimes there is no signal for probe control even though there should be. Switch to the vessel that's not being seen, then back to the probe

28) Crew pod of Hartman rover has a broken life support and a functional wheel, but it instead appears to have a working life support and a broken wheel. Nothing I can do about it; but it still works

29) The sun shines through Jupiter's body as if it was part of the sky. It's just an harmless visual glitch

30) An object on the surface coming into physical range may be loaded tens of meters above it (OLD stock bug, but NEW in this mission). Hope nothing explodes. Reload if necessary

31) Cylinder's central tanks gets refilled on (useless) oxidizer upon reloading; see 10.2 (first noticed in 5.1, but didn't write it here before). Dump the dead weight again

32) All mining drills suddenly manifested a new uranium drilling function (NEW). Can't revert it, but they still work normally; it seems harmless

Edited November 30, 2022 by king of nowhere

[king of nowhere]

Part 11: Closest thing we've got to a comet

I wanted to include a comet in the grand tour. Since the game is not spawning any comet (new bug #33), I went for the closest approximation available: an asteroid in a highly inclined, elliptical orbit.

The target is very challenging, but the Cylinder/Fat Man combo is up to the task.

If the game is not spawning comets, I'll at least pick a large asteroid

11.1) Preliminary work

Spoiler

After my previous OPM grand tour, I decided to include an asteroid and a comet as destinations in every grand tour. I can easily skip asteroids, because getting a near-Earth one is very easy. Comets are challenging targets, and I definitely want to get one.

Throughout this mission, I kept track of unidentified objects, thanks to the infrared telescope on Wings B. But the game never spawned a comet, likely due to a mod malfunction. However, it did spawn several large asteroids in comet-like orbits, and lacking a real comet I'm going to one of those.

With an inclination of 45 degrees over Earth, asteroid NZK-022 is impossible to reach without a gravity assist from Jupiter.

Asteroid NZK-022, its orbit shown compared to Jupiter

From this perspective, the inclination can be better appreciated

Getting such a high inclination requires arriving to Jupiter with high speed. A simple Hohmann transfer won't do. So I'll have to spend at least 4 km/s for the Jupiter transfer. Then, in the most favorable scenario, I can match inclination and periapsis; but a rendez-vous with the asteroid will still require lowering apoapsis and a radial change, for at least 3 km/s. And then getting back to a Jupiter encounter will require just as much. And from Jupiter I get back to Saturn, and I can use Titan to aerobrake some, but I still need to have some fuel left. And so it looks like the 11 km/s of Cylinder cannot suffice, even under the most favorable conditions.

However, I can extend my deltaV by using Fat Man, just like I did with Mercury. I can make a high speed flyby of the asteroid with Cylinder, and have Fat Man pay the 3 km/s to slow down to the asteroid, and other 3 km/s to return to Cylinder - which is still in a Jupiter intercept trajectory - afterwards.

This is the plan. I lift off from Iapetus and start simulating trajectories.

Leaving Iapetus, once more

Not without some hiccups. It is not rare that A'Twin undergoes a spontaneous RUD, but this time the debris cloud was quite spectacular

I had a half dozen tracked asteroid in interesting orbits. I picked up NZK-022 for a very practical reason: by starting immediately, I could get an intercept to Jupiter very close to its ascending node. For the other asteroids, I'd have to wait a more favorable alignment, and I didn't want to wait.

Time is going to be another important factor for this mission. Cylinder has supplies for 60 years. With the orbital times involved, I may need all of them. For this reason, I wait until a few days before the Iapetus ejection to separate the two A'Twin subunits.

Obligatory rearranging of the various shuttles while splitting the ship

Trypophobia module, ready to land back on Iapetus

I initially wanted to use some fuel from Trypophobia to further boost Cylinder's orbit, but I realized the mining module can barely land on its own already. It doesn't have much fuel to push a fully loaded, very heavy Cylinder. Indeed, after a few calculations I even had to transfer a few tons of fuel back from Cylinder. Trypophobia barely has enough fuel to land.

I picked the crew by leaving behind kerbals that were most active during the Jupiter campaign. Except poor Jeb, who should have participated, but was left behind for a shuffling mistake.

Cylinder module, ready to chase a comet

Cylinder is full to the brim with supplies. I loaded all the water and fuel I could get. I even carried Nitrogenie in a Bottle in this mission, solely because it has a 3 tons water tank. I figured a couple extra years worth of water were more valuable than a couple dozen m/s I'm losing for the extra mass. Of course, no oxidizer because no lander is involved. The bit of oxidizer left in the tanks is caused by bug #31.

Landing Trypophobia back to Iapetus

In its status screenshot, if one took the time to run the deltaV calculations (the gauge on the left is inaccurate, as it often is for large complex ships) it looked like Trypophobia didn't have enough fuel to land. But that's because it was still burdened with extra supplied it ended up not needing. Here I dumped all the water and the uranium, down to the last ton.

Landed, by the thinnest margin

The poor Trypophobia barely had a couple seconds of ignition left when it touched the ground.

11.2) Outbound trip

Spoiler

It takes 5 km/s to reach Jupiter with the current alignment - already a fair bit more than I planned. It's not in a good position to reach from Saturn, it requires dipping perihelion all the way to Venus orbit. But at least it will give me enough excess speed over Jupiter to exit in the direction I want.

Option 1 for leaving Saturn: direct ejection from Iapetus

I considered doing some tricks to get a Titan gravity assist. According to the picture below, it could have saved some 400 m/s roughly.

Option 2 for leaving Saturn: Titan gravity assist

In this scenario, an 840 m/s burn at Iapetus would lower Saturn periapsis to the edge of the death zone, where a 175 m/s burn would syncronize the orbit for a future Titan flyby, By making a burn at Titan periapsis, I can save some fuel from gravity assist and extra Oberth effect.

I didn't take that path. Not sure why, it's been almost one month ago. Possibly because it would take 90 days t get to Titan, and that may affect getting to Jupiter at the right time for the ascending node of the "comet". Or maybe because it involved a long burn at periapsis, which would surely have suffered from cosine losses.

To avoid cosine losses, I instead opted for a small burn to exit Iapetus, followed by a big burn in Saturn orbit. It was the most precise option.

How I actually left Saturn: big burn in Saturn orbit, no worry about cosine effects

Still wasn't that easy. For such a long burn, I had to stop and service the engines twice. And then I had to do it over because I missed slightly the proper timing to Jupiter, missing the ascending node.

Full trajectory to the "comet"

As the picture shows, I'm leaving Saturn with a very low perihelion, reaching inside Venus orbit, to catch up with Jupiter. In this picture the big burn to leave Saturn is split into two smaller burns, because I was still exploring ways to try and make it cheaper. Anyway, after one more correction maneuver in 4 years, Cylinder will meet Jupiter in six and a half year. It will pass slightly outside of the orbit of Callisto, the outer moon, so no radiation problems there.

This gravity assist will change Cylinder's inclination, flinging it on the purple orbit. That orbit has a lower periapsis than the "comet", because if I matched periapsis exactly I wouldn't get a rendez-vous. Orbital timings aren't conveniently aligned, and I had to exit on a more elliptical orbit to compensate. However, meeting the "comet" in those conditions - crossing its orbit instead of touching it Hohman style - would have resulted in too much intercept speed, roughly 8 km/s (see the next image). I can tolerate 4 km/s intercept speed, maybe 5, because Fat Man must pay that twice. So, another maneuver is planned close to aphelion (not at exact aphelion, I can move it around a bit to refine the orbital time) to raise perihelion at the proper time to touch the "comet". It results in an intercept speed of 3 km/s, and an encounter after 20 years, for a total cost of 6 km/s.

This trajectory leaves 40 years and 4.5 km/s to find a way back to Saturn.

What happens if I try to save fuel by skipping the periapsis raising: 8 km/s intercept speed, too much. And if I exit from Jupiter with higher perihelion, I miss the "comet" by weeks

This time, luck is not with me; I soon start breaking up stuff, and a lot of those are critical malfunctions. It's very hard to keep a regular repair schedule on a multi-decade mission, on two different ships with very long loading time.

Malfunction: lost the reaction wheel on Nitrogenie in a Bottle

That's annoying because it cannot be replaced; still, I did include lots of reaction wheels in the back specifically to have extra torque. I really hope I won't have to actually try a Titan ascent with two asymmetric engines, though.

Malfunction: lost a life support unit on Dolphin 2

Now Dolphin 2, like its sister ship Dolphin 1, is down to five working life support units. Still no concern.

Malfunction: another big fission reactor

Ouch! This one is starting to hurt. Up until this point, all the ore I was mining on Iapetus (which has 9% ore concentration) was processed to extract CO₂. Now Trypophobia won't have enough power to process the ore faster than it is mined, so ISRU will be a bit slower.

Still, considering that I'm entering the part of the mission where I face multi-decades travel times, spending one or two years more on Iapetus is not a big deal. Fast mining was a lot more important while I was in the inner system, and I had transfer windows to take.

Jupiter is reached without further accidents

I already lost three parts in six years, one of them a precious reactor. Did you want even more accidents?

There are still a dozen more years to reach the "comet", so there is time for more accidents.

Malfunction: an antenna on Wings A

Ok, I still have a handful of replacements for those. But I'm waiting to install one because as long as I keep it in storage, it can't get broken.

Malfunction: life support failed on Nitrogenie in a Bottle

While I would have preferred to keep it functional, Nitrogenie is not supposed to carry a crew except on its very first landing, which it already performed. So, no harm done.

By now I'm starting to get close to the "comet".

Two years from the target, status

So far Cylinder has traveled 17 years, and it used up 25.4 tons of water. An average of 1.5 tons per year, almost exactly. So there's still water for 45 years. The ship still got 5.5 km/s of deltaV, though it will have to spend some fuel to move Fat Man shortly.

You may notice intercept speed is 400 m/s higher than it was supposed to be in the trajectory shown earlier. Planned trajectories are not followed exactly; there are small approximations made when burning, and then course corrections, and then I have to plan the trajectory again and it won't be exactly the same. In this case it resulted in a pretty large difference, luckily a few more tons of fuel used up by Fat Man mean absolutely nothing to Cylinder's greater fuel budget.

There is still time for one more malfunction: a life support system on one of Cylinder's own crew pods

Six broken parts in 18 years worth of traveling. But, due to bug #15, only some parts are getting degraded at a fast rate. And with this piece, all of them are either critically broken, or reversibly broken and I'm not going to fix them so they can't get broken again. So the bleeding should slow down now.

And no, that last part is not an issue either. Not only Cylinder has a bunch of redundant life support, it's supposed to work entirely on the life supports of its Dolphin pods.

11.3) Encounter

Spoiler

We're finally arrived at the "comet". Half an hour before the close approach, I detach Fat Man and start slowing down.

Shortly before the encounter

Fat Man leaves, burns retrograde to the comet

The burn takes some time because of the low thrust, but it presents no problems.

The "comet" is big, an F class object. It was somewhat funny to see it appear suddenly as it entered physical range and occupy a large part of the sky.

Close to the "comet"

Rudatte takes a sample. And sinks into the "comet", the ground glitching. Nah, that doesn't even deserve a mention in the bug list

Rudatte returns to Fat Man... but he can't hold the sample!

Aww, crap. Fat Man doesn't have a storage space for samples. It's supposed to carry around landers, and those landers have sample storage aplenty, so the problem never came up before.

No, no way I came this far, went through so much hardship to get this "comet" and I'll just give up on keeping the sample. Though the mission doesn't require it, I am going to keep the sample if I have to return to Cylinder with Rudatte hanging from the ladder.

Yep, I have to. Rudatte hanging from the ladder with her precious sample

Return to Cylinder, of course, is performed by setting it as target - it's now leaving at 3300 m/s - and burning enough to make up for that speed difference. Then burn some more to get closer.

I still got more problems, though, or this part wouldn't deserve a subchapter of its own. Because after using the engines so much, they need servicing. Here I discover another problem: out of eva propellant!

Toboono (engineer) is out of EVA propellant

Monopropellant is used for EVA, and I never refilled the storage on Fat Man. There were 3 units left, and Rudatte took them when it went out. The first kerbal going out always takes as much monoprop as it can get.

Luckily, having also a pilot on board left me with a solution. First I also sent out Monbrio. He took the sample from Rudatte, because EVA kerbals can swap samples with each other. Then I sent Rudatte inside, thus restocking Fat Man monoprop supplies. Then I sent Tobono inside, and outside again, and this time he had monopropellant and he could go fix the engines.

The trip towards Cylinder

Meanwhile, even though the stop at the "comet" was short, Cylinder was moving away at 3 km/s, and it's at 7000 km by now. After equalizing speed I spent another 500 m/s to return fast, but it's still going to take a few hours. An EVA kerbal only has air for 2 hours, but this limitation can easily be overcome by sending out a new kerbal, with fresh air supplies, to take the sample while the other kerbal goes back inside. And so it was that I rendez-vous with Cylinder five hours later.

Still with Rudatte hanging from the ladder! The precious sample was saved

11.4) Return to Iapetus base

Spoiler

Now it's time to look for a way back to Saturn.

Actually, I started looking and simulating trajectories already, which is why some of the screenshots below are dated year 135 while I met the "comet" in year 137.

As it turn out, I have many different viable trajectories.

Trajectory 1 to return to Saturn

This trajectory uses a 1600 m/s burn to reach Jupiter in 20 years. Yes, it's a long time; the burn raised aphelion. By making those burns close, but not exactly on aphelion, I can slightly change aphelion, and thus change how much time I'll spend in this orbit and ensure I'll get a Jupiter encounter. Which is why I have so many options. Anyway, (after the purple course correction) Jupiter will eject Cylinder on the plane of Saturn. Saturn will still be lagging way behind, so Cylinder must be ejected on a higher apoapsis, to lose time and let the planet overtake it. It results in an intercept in 33 years. While the intercept is not ideal, we're far enough from the Sun that it's unlikely to result in too much intercept speed. And Cylinder will still have almost 4 km/s that can be used to help before aerobraking.

This is a very safe and cheap trajectory. But it is slow, and time is malfunctions. So I keep looking to see if I can find some way to use my remaining fuel to save time.

Trajectory 2 to return to Saturn

This is a very extreme trajectory; it skips the Jupiter flyby entirely, simply raising aphelion enough to reach Saturn in 25 years. The high inclination, unfortunately, results in 12 km/s intercept speed. Further refining of the trajectory lowered it to 5 km/s (meeting Titan in the right part of the orbit makes a lot of difference, as does adding 1000 m/s of normal component to that 3 km/s burn), but it's still too much, considering that I will be out of fuel to slow down.

Trajectory 3 to return to Saturn

Trajectory 3 lowers aphelion with a 1450 m/s burn immediately, resulting in a Jupiter encounter in 10 years. From there, a direct trajectory to Saturn exhists - and it reaches the gas giant in only 23 years.

Unfortunately, it has a high inclination. Cylinder will be coming to Jupiter very fast, it wll also leave very fast, which means I either get into a solar escape trajectory, or I get a high inclination.

Trajectory 3, seen from the side to better appreciate inclination

Still, this will result in a 5 km/s intercept on Titan, just like trajectory 2. But this time Cylinder will still have over 3 km/s, which it can use to reduce intercept speed. I know from the previous missions that the highest safe intercept speed on Titan is 3 km/s, which means I can spend 2 km/s to slow down, aerobrake at Titan, and still have 1 km/s left to reach Iapetus.

Trajectory 3, detail of the Jupiter encounter

This trajectory will make a 90° plane change at Jupiter, it will have to pass very closely. But it misses the greater death zone just enough to be safe.

I later realized I could have done even better. My problem is that I must leave Jupiter as fast as I'm coming to it, and I'm leaving at high inclination to "burn off" some of that excess speed. However, once close to Jupiter - thanks to the titanic Oberth effect of the gas giant - it only takes 800 m/s to get captured. Meaning that I can use my engines to reduce that excess intercept speed, and get on a milder trajectory with less than 800 m/s.

It would have been very hard to plan, though, because of the way maneuver nodes work. Any change in the nodes leading to Jupiter would have moved the Jupiter periapsis node away from periapsis, leading to a very difficult planning.

As I said before, all the parts that were getting the most aging already broke, so for the next 9 years I got no malfunctions.

The south pole of Jupiter. Io is still too far to be seen

Periapsis, over Jupiter's north pole

I could have taken the chance to send Fat Man to skim the upper atmosphere, and maybe from this polar trajectory a crew could even have survived. But without a dedicated spaceplane like Arrowhead, I'm no longer motivated to skim the atmosphere of the gas giants. Some of them now are completely unaccessible because of the radiations, and the others are way too big to enter atmospheric flight anyway. With those premises, touching the upper atmosphere feels kinda pointless.

Trypophobia leaves Iapetus, preparing to meet Cylinder

Cylinder reaches Saturn after 14 more years of space travel, without any further accidents

Good thing I haven't had an outbreak of bug#22 ever since leaving the inner solar system, or those long Cylinder travels would take a lot longer.

And it prepares to slow down before Titan aerobraking; it's still got 3500 m/s

By the way, rocket braking before entering the atmosphere changes periapsis; I was ready to find the best trajectory by trial and error, but at the first pass I discovered that I'm actually coming fast enough, and I'm braking close enough to the moon, that periapsis changes only by a handful of kilometers. This pic is from the first failed attempt, showing a 430 km periapsis (way too high to brake enough). Second time I went again for 240 km periapsis and it worked fine.

Entering Titan atmosphere at 6 km/s. A bit faster than the last time, but I still have a few minutes to slow down

I forgot to take screenshots from inside the atmosphere, but I spent another 600 m/s to brake, so I was actually slower than I was when returning from the moons of Jupiter in 10.3.

After aerobraking

I came out of Titan's dense atmosphere with an apoapsis slightly higher than Iapetus. I could have reloaded and tried a few km lower Titan periapsis, but this is good enough.

Trajectory to reach Iapetus

This trajectory first requires to raise apoapsis. Yes, it is expensive, but if I lower apoapsis I won't get a close encounter with Iapetus for, like, 200 days at least. And by now Cylinder is relatively light, so I don't save much fuel. So this first apoapsis raising brings me to the purple apoapsis; the rest of the trajectory is invisible (should I add this to the bug list? Only if it repeats). That high apoapsis make me lose enough time that when I come back to periapsis, I can lower apoapsis to Iapetus level (362 m/s) and get an intercept.

Still trajectory to reach Iapetus, this time also including intercept deltaV

Intercept deltaV of 1200 m/s. I barely have enough fuel for it.

As I said, I could have taken a cheaper, but longer trajectory if I was starved for fuel.

Malfunction: an engine exploded during the Iapetus capture burn

It's ok, I still had a third spare engine to replace the broken one.

Meeting Trypophobia

Cylinder has been away for 43 years. It had a bunch of malfunctions, but it handled the extended trip like a pro. Water level is very low in the last screenshot because I dumped some leftover water to save fuel.

The docking dance ofthe landers is repeated, moving them to the top of Cylinder

A Service probe is used to grab the last spare engine to replace the broken one

Finally, Trypophobia and Cylinder are docked

Cylinder is running on fumes, but Trypophobia got full while it waited. And now that there aren't anymore 4000 tons of fuel to lift to orbit, it doesn't have any deltaV shortage.

And A'Twin lands on Iapetus, using only nuclear propulsion

In retrospect, A'Twin didn't even need chemical engines. After I gave up landing on the Moon because it was too expensive, the bigger place I can land on is Triton. Which doesn't have any water because "rational resources" mod is anything but rational. After that, the biggest moon where A'Twin can land is Titania, a moon of Uranus, which is only slightly bigger than Iapetus itself. And it has a surface gravity of 0.033 g. A bunch of nuclear engines would have been totally sufficient to land in such low gravity, and it would have given Trypophobia a much better deltaV on its own, and it would have made logists easier - I still carry a spare cougar that I'm unlikely to ever use.

Well, the current setup I used was good enough.

With 8 reactors left A'Twin should produce 24000 electricity, but it's limited to 18000

Damnit. Bug 18 is still striking. I have two more reactors that should work but are nonfunctional. Since those breakages are correlated to the reactors becoming broken and getting repaired, from now on whenever I have a non-critical malfunction on a nuclear reactor, I will reload the game and prevent the malfunction. Maybe this way I'll stop losing reactors to bugs, and will lose them only to aging.

For now, I have to further reduce the conversion rate. It's still reasonably good even with six reactors. Actually, on both Titania and Pluto the ore concentration is low enough that six reactors are enough.

A couple of nice pics taken during a maintenance trip

I liked the way the "window" opened up to a glimpse of the ship's complicated interior

Year 166, refueling done

Previously it took 3 and a half years to refuel on Iapetus, now it took five years with broken up reactors. Hopefully it won't be a problem.

Next I'll be moving to the outer solar system. DeltaV requirements are low, but travel times are getting high, and transfer windows are rare. But so far it looks like I'm lucky: Uranus is in a good position to reach from Saturn, and afterwards I'll leave Uranus with a transfer window to Neptune.

Pluto is on the opposite side. Can't pretend too much. I already have ideas, but it will likely take a few more months before I can implement them. This update was slow in coming, my real life got busier lately.

Bugs compilation updated

Spoiler

A numbered list is so convenient to refer to bugs quickly. This list keeps growing. Problem and Solution

1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

4) Propellers start twisting around. No worry, it fixes once you stop time warping

5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

10) I can't plan maneuvers or go EVA, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: save before exiting time warp

13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

17) Crew hatch registered as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

20) Upon starting the game, clicking on the VAB does not work. Clicking on the icon on the bottom left corner of the screen still works

21) Sometimes elements of the HUD change size. It doesn't affect the game, and seem to revert spontaneously

22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason. Load Cylinder into physical range and they restart

23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced. Reload when it happens, and it will get fixed

24) The ground on Titan has all sort of glitches and malfunctions. Be extra careful during landing, cheat the vessel in orbit before leaving it, jump to start flying. See 7.3 for more details

25) Negative aerodinamic drag displayed on the user interface. Drag is still behaving normally, it's only the display that's bugged

26) The docking port on Clamp has all kinds of problems, does not allow fuel transfer, can't be removed. I stuck another docking port there, and I can grab Clamp with a claw if needed

27) Sometimes there is no signal for probe control even though there should be. Switch to the vessel that's not being seen, then back to the probe

28) Crew pod of Hartman rover has a broken life support and a functional wheel, but it instead appears to have a working life support and a broken wheel. Nothing I can do about it; but it still works

29) The sun shines through Jupiter's body as if it was part of the sky. It's just an harmless visual glitch

30) An object on the surface coming into physical range may be loaded tens of meters above it. Hope nothing explodes. Reload if necessary

31) Cylinder's central tanks gets refilled on (useless) oxidizer upon reloading; see 10.2. Dump the dead weight again

32) All mining drills suddenly manifested a new uranium drilling function. Can't revert it, but they still work normally; it seems harmless

33) The game is not spawning comets (always been active, but only became relevant now). For the comet landing, pick a large asteroid in an inclined, eccentric orbit and pretend it's a comet

Broken parts recap

Spoiler

I want to keep track of how much stuff I break, and how much it's affecting the mission, so I prepared a list

Life support

1 life support broken on Dolphin 1. I've got five more redundant pieces on it.

1 life support broken on Dolphin 2. I've got five more redundant pieces on it. (NEW)

1 life support broken on Cylinder. It's a redundant piece of a redundant piece. Least concern. (NEW)

1 and only life support broken on Hartman. Sucks, I can't take extended trips, but the rover has enough air to conduct landing operations safely.

1 life support broken on Fat Man. I've got five more redundant pieces on it.

1 and only life support broken on Nitrogenie in a Bottle. No problem, it's not supposed to carry a crew any longer. (NEW)

Nuclear power

4 Excalibur reactors broken. Up to 4 can be lost before mining is slowed down - though it is already slowed by bug #18. There is concern here that they are breaking up fast. (+1 NEW)

Reaction wheels

2 large reaction wheels broken. I've still got 88 working.

1 medium reaction wheel broken on Clamp. I've got a half dozen spare ones in storage.

1 medium reaction wheel broken on Nitrogenie in a Bottle. I've still got a half dozen spare ones in storage.

reaction wheel on the crew pod broken on Nitrogenie in a Bottle. Can't be replaced, but the other three wheels should be enough to keep the plane stable even if I break a lateral engine. (NEW)

Engines

3 big nervs broken. I had three spare ones. If more engines are broken, the ship can work with less than the full complement. (+1 NEW)

1 big wolfhound broken. I had a spare. Afterwards, the ship can work with less than the full complement.

1 small nerv broken on Fat Man. I've got 2 more spares, then I can start cannibalizing Nitrogenie in a Bottle.

1 cheetah broken on Spider. I've got 2 more spares.

Communication

1 RA-100 dish broken. I've got 5 more redundant pieces. After that, I still have more non-relay antennas.

1 HG-5 antenna broken on Wings B. I've got 1 more spare. After that, the mission can still use normal non-relay antennas.

1 Communotron 88-88 antenna broken on Fat Man. It was itself a spare part, and I have more spares, as well as redundant antennas.

1 Communotron 88-88 antenna broken on Wings A. I've got a few more spares; then I can cannibalize antennas from Trypophobia if really needed. (NEW)

Others

1 radiator panel broken. I had 12 redundant. They should be needed to vent heat from the nuclear reactors, but they are not actually needed anyway.

Low-quality parts

A landing light broken on Nitrogenie in a Bottle. Irrelevant, I don't need them.

Life support on Trypophobia's gravity ring broken. Irrelevant, it only does pressure control and the same function is included in the greenhouses.

1 Converter broken. Irrelevant, converter is the stock isru functionality that I'm not using. I need the chemical plant functionality, and that one is still working perfectly.

Outdated

2 reaction wheels broken on Milly. Now Milly has done its job.

1 dart engine broken on the Mars Descent Stage. Now it's a pile of debris on Mars.

Discounting the low quality and outdated parts, that's 26 critical malfunctions so far.

Edited November 30, 2022 by king of nowhere

[king of nowhere]

Part 12: Outward to the lopsided planet

A'Twin moves outward to Uranus, sends a lander to the moons and refuels there.

Refueling on Titania, admiring a passage of Ariel and Umbriel over Uranus

12.1) Make sure you fill up your nitrogen stock before leaving Saturn

Spoiler

I'm about to leave Iapetus base for good. Goodbye, best refueling spot in the whole solar system.

But before I leave Saturn, I have to stop at Titan to stockpile on nitrogen - as there's no other practical source of it anywhere else.

And this means I have to fix the Nitrogenie in a Bottle first.

Sending out an engineer

Tobono must first recover a spare docking port; those used to host the non-reusable landers, and are now redundant

To reach the broken wheel, the engine must be removed. A Service Probe grabs it, and it is released from its docking port

With the engine out of the way, Tobono can remove the docking port and finally the broken wheel. A new wheel was brough out of storage

The new wheel is placed, the docking port is restored. The spare docking port was put on the engine, so that it can be docked back in its place

The Service Probe proceeds with the docking. The cramped location and off-center push made this docking very difficult

Overall it took over one hour - because I was subject to A'Twin's full lag during all the time. Definitely not something I want to do again.

Meanwhile, I'm heading for Titan. Since Iapetus has a relatively large inclination, I'm arriving on a polar orbit. I have considered many ways to fix that, but they all cost fuel, which I want to spare. So my plan is to park A'Twin in a polar orbit, then use Fat Man to carry Nitrogenie in a Bottle up and down to Titan. Then, when it's time to leave, eject into a resonant orbit and get a gravity assist from Titan to get pointed in the right direction.

Releasing Fat Man and Nitrogenie in a Bottle, around Titan

For greater practicality, I'm using Nitrogenie's thrusters to help

I already described the process of mining nitrogen from Titan and converting it into monopropellant in subchapter 7.3, and to a lesser extent in 8.5, so I won't make this already overly long report even longer by repetition. I'll just highlight the usual assortment of bugs.

A manifestation of bug #2. Fortunately, it tends to revert on restarting the game

The left wheel is also suffering from bug #2, but not too badly; I should still be able to land

The propellers are twisted out of their way; that's a problem with the stock game that's not even in the list; anyway, they still work, and if the push is asymmetrical, it is not noticeable

A'Twin is missing some 3000 units of monopropellant (12 tons), and Nitrogenie can make 1300 units on each trip. I would need three trips. However, after two trips I made some calculations. I only miss 400 units of monopropellant, what I have is enough for 220 years, I would only gain 12 years. And I have a pretty good estimate of how much time I'll need, and I can always return to Saturn in a pinch. So I skip the third trip and move immediately for Uranus.

12.2) En route to where?

Spoiler

Finding a trajectory to Uranus would be easy, except that I'm stuck in an eccentric polar orbit around Titan, and I have first to find a way to fix that without wasting too much fuel. Even that would not be too hard, except for all the lag. It took me a while, with a lot of trial and error, but that's what I managed.

Trajectory to leave Saturn, zoomed in on Titan

Trajectory to leave Saturn, zoomed out

First I leave wih a 400 m/s burn at periapsis. This sends A'Twin into a higher Saturn orbit (green) with a 2:1 resonance, meeting Titan again. There, by carefully aligning the incoming trajectry, I can make a 1070 m/s burn, get a good Oberth effect from Titan, and exit equatorial and in the right direction. And I actually did a pretty good job: I simulated starting from an equatorial circular orbit around Titan, and (even accounting for 600 m/s of apoapsis raising for not starting elliptic) I couldn't find a cheaper trajectory.

Trajectory for Uranus

I'm put into a high energy trajectory leading to Uranus in 20 years. Yes, it's not a Hohmann transfer; I'm now too far from the Sun, and those are too slow. I am spending fuel to save time. I would spend even more, except that the moons of Uranus are inclined by nearly 90 degrees over the ecliptic, it will be extra expensive to reach them; and afterwards I have to land on Titania, the biggest of the lot. I miss Iapetus already.

I am in a bit of a time crunch. Right now, Neptune is in a good position to reach from Uranus, and it will stay there for a few more decades. But there are no refueling opportunities on Neptune, so I will send Cylinder and it will also have to come back to Uranus. And all that will take at least 60 years. And after 60 years, Pluto will be properly aligned to reach from Uranus. It would be very convenient if I could catch such a transfer window.

20 years for Uranus, 10 years for refueling, 20 years for Neptune, 20 years to return to Neptune, 10 more years for refueling, we're at 80 years already. And that's bad. I'm missing my transfer window opportunity; and Uranus has an orbital time of 80 years, it would take too long to wait for the next one. I'd have to return to Saturn and wait only 30 years for a transfer opportunity, and then Pluto would be farther away.

So it looks like I'm losing this opportunity! I have to find a way to save time. Maybe I can skip the 10 years for refueling. I start concocting a crazy plan.

If I approach Uranus, then I split A'Twin... Then I give all the water to Cylinder, which uses a gravity assist from Uranus to reach Neptune. While Trypophobia lands and refuels. But Trypophobia has low deltaV, and I didn't load much oxydizer for its chemical engines. But I can circumvent that! I load its fuel tanks with all the liquid fuel, then I use the nuclear engines on Fat Man for maneuvering Trypophobia. This way, I should stretch its fuel to 3 km/s, which probably are enough to land. Maybe. And meanwhile, there should be enough fuel for 5-6 km/s on Cylinder, and it will be already on its way to Neptune... I went as far as plotting this.

Trajectory if I wanted to turn the Uranus approach into a gravity assist for Neptune

Well, it probably wouldn't have worked. First, 3 km/s look like a lot when I'm already in an intercept trajectory; but there is the capture from a high energy transfer, and then the plane change because the moons have high inclinations, and finally Titania is relatively big. It probably wouldn't have sufficed. Then there is the matter of Cylinder; it would have to spend 1 km/s to capture around Neptune, and then to return to Uranus on a high energy trajectory, and then to capture and reach Titania. Hard to do when starting with half fuel.

But what definitely closes the question is the water level A'Twin has got 100 tons right now, because I was planning a 20 years journey and I brought water for 50 years, it seemed safe. But now, by the time I'll reach Uranus I'll be down to 55 tons. I give all that to Cylinder, it will have 40 years worth of life support. By the time it will reach Neptune, it will have 7 years left. So, not a chance.

It probably wouldn't have worked anyway.

On the plus side, by plotting the calculated positions of Uranus and Pluto in 60 years, I see that I underestimated a bit the time it would take to enter the transfer window to Pluto. So, 80 years is still a good time to launch, that's my next target. Otherwise, I'd have probably skipped Neptune to reach the more difficult Pluto.

Now that I decided to stay at Uranus, it's time to plot the course correction for the arrival.

Trajectory for Uranus insertion. No puns, please

Trajectory for Uranus insertion (no puns please) seen sideways

Bad news here, I tried to get some way to minimize inclination, or at least to have a planar node at apoapsis to get a cheap plane change. There isn't any. As the second picture shows, I'm coming 90 degrees up from the plane of the moons, and there's no way around it. Even with all my effort, I still have a 45° inclination to pay for. So I first get captured around Uranus for 408 m/s, then I make a plane change for 1000 m/s.

Trajectory to reach Titania

From there, with a couple of minor corrections, I am already in an optimal trajectory for capture on Titania. It requires some more 850 m/s.

Considering another 700 m/s to land on Titania, I'd have needed nearly 4 km/s from Uranus encounter to landing. So, an improvised nuclear-powered Trypophobia would likely not have worked. I could have tried getting gravity assists from the moons, but they are all too small to be effective.

Twenty years of traveling passed without any major accident. Quite lucky here. I got three malfunctions on the nuclear reactors, plus a bunch of other unimportant parts, but none was critical. Furthermore, because of bug #15 (I am sooo happy I made a list for quick reference) most of the spaceship stopped aging almost completely. I long since gave up checking the main reaction wheels, the chemical plants, the mining drills, and none of them malfunctioned in over a century. There were only a few parts that were aging regularly, and now - except the main reactors - they all broke. I am not fixing them, so now I only have the reactors to check. This is actually a life saver, because at this point in the challenge, where I have to take very long trips with nothing to do but fix stuff under heavy lag, having to run full maintenance every time would be maddening. Having to run a dozen reactor maintenances before arriving anywhere is already annoying enough.

The three reaction wheels on Nitrogenie in a Bottle are among the pieces that were aging regularly. Now they are all yellow; delightful!

Arriving at Uranus. I really like the color

12.3) Moons of a midsummer night

Spoiler

Before arriving at Titania, I send out Clamp to land on the moons.

By previous experience, those ice giants are really convenient environments to travel. They have enough Oberth effect to be good for gravity assists and cheap captures, but they are also small enough that moving between the moons is reasonably cheap. No more crazy desperate stunts like I had to pull for Io and Mimas. In fact, I'm planning to get all the three innermost moons in one go, despite the radiation belt. I'd go for the fourth too, but Clamp doesn't have enough fuel to land on all of them without refueling.

Preparing Fat Man with Clamp. By the way, if you look closely you see a small speck on Uranus; that's Miranda, the innermost and smallest moon

Separating Fat Man's trajectory from A'Twin, I use Titania for a gravity assist, and I use its Oberth effect to lower Uranus apoapsis. This saves 400 m/s

Then first trajectory for Umbriel. 900 m/s total. Umbriel is just inside the radiation belt for half of the time

That radiation belt is slightly more than one third as deadly as that of Jupiter, so a crew can spend several days inside in relative safety. From the picture above, it looks like Fat Man could try to syncronize to reach Umbriel when it's in a safe area, but the radiation belt actually rotates very fast, several times per day, I can't plan too much around it.

By the way, all the moons of Uranus are named after literary characters from Shakespeare or Pope, hence the chapter title.

Umbriel

Still Umbriel

Unfortunately, at this point bug #17 manifested again: I can't get my crew out of Clamp. But I want to plant a flag and collect a sample, so...

Somebody has to make the landings stuck on a ladder. This time it's Etdania

Etdania still holding tightly to the ladder as Clamp brakes

Flag on Umbriel

Next is Ariel. Ariel is not properly aligned for a Hohmann transfer, but I am still inside a radiation belt, so I pick a high energy transfer to get there in 2 days. It's significantly more expensive, but still well within Fat Man capabilities.

By the way, I'm starting with the external moons because they are bigger. This way I get to use up Clamp's fuel sooner, leaving more deltaV for a lighter Fat Man.

Trajectory to Ariel

Ariel. 34% radiation damage so far

Ariel, and Uranus

Once more, somebody has to travel in third class. More like fourth class. Tenth class?

Planting flag... wait, where is the flag?

Here it is, 300 meters above ground. And now the game crashed

NEW BUG #34: on some moons of Uranus, planting a flag can result in the flag hundreds of meters above the ground. Selecting the flag may then crash the game. Reloading generally works at ensuring the flag gets planted correctly.

Back to orbit, I was lucky to find Miranda in a perfect position for a transfer. As we're moving closer to Uranus, the costs of maneuvers are getting bigger and bigger, having to get to Miranda in a high energy trajectory would have been problematic.

Trajectory to Miranda. Spending two days in the radiation belt netted 38% exposure, I should be safe

Uranus is beautiful, isn't it? Not sure if the distant moon is Ariel or Miranda

Miranda. It's got quite a peculiar shape

Interesting terrain. Great sky. I don't miss Neidon

Landing. This time it's Jeb staying outside. I left him on Iapetus for both the Jupiter and "comet" mission, so now I'm landing him on all the moons

I picked a landing spot specifically to get this view of the sky

I happened to land on a sort of plateau, just in front of a big ravine

Mimas looks perfectly flat, with strange massifs jutting out of the plains. Probably the real one doesn't look like this

Here I'm returning to orbit

To be faster, I am chasing Fat Man on a high energy trajectory, something I can only do because the gravity is very low (orbital speed 100 m/s). Clamp is in hyperbolic trajectory, and occasionally burning downward to approximate a circular trajectory.

Wait a minute, I made a bit of research and discovered that Miranda is renowned for having the biggest cliff of the solar sistem, Verona Rupes, over 10 km high. I missed the chance to land there, and with the radiations I'm not going to try, but I will sneak a peek with alt-f12.

Bonus: a sight of Verona Rupes. I had to take it with Clamp in midair, because the bottom was below 0 altitude, which causes funny visual glitches

Return trajectory to Titania

To return I burn prograde until I'm level with Titania, then burn immediately to raise periapsis out of the radiations. It will take a few orbits to catch up with Titania, but it's safer this way. Irradiation will top at 73%. The 294 m/s maneuver is a plane change, Miranda has a different inclination from the other moons.

Getting a rendez-vous with A'Twin in a polar orbit wasn't trivial, but Fat Man will still have 2 km/s, so I'm cutting the report short by skipping that part.

Fat Man rejoins A'Twin for refueling. Docking in that position was quite complicated

Now out to Oberon. It's very cheap. If I had enough fuel in the lander, I could have gone there directly

To reach Oberon, I made a small push to exit Titania, and raised apoapsis from there. I was into a polar orbit misaligned with the plane of the moons, this was just easier. I got some slight complication when, along the way, I stumbled again on Titania. But I was moving very slowly compared to the moon, so I got a very small speed change from that encounter.

Oberon! The north pole terrain glitch must be really impressive if it can be seen from this up high

And this is Titania passing over Saturn, seen from the cupola on Fat Man

Which reminds me, I've never shown internal visuals from Fat Man's cupola. That's why it's blocked by a water tank and docking port. I wish I could find a practical way to avoid blocking the view

Flag on Oberon. Without bug, this time

Once more I forgot to land on interesting terrain, and once more I fix with alt-f12. This is the north pole. The small speck in the middle is Clamp being swallowed. Impressive

Going back to Titania

12.4) SSllooww... rreeffuueelliinngg... oonn... TTiittaanniiaa...

Spoiler

There are only two Uranus moons outside of the radiation belt: Titania and Oberon. Of them, only Titania has water (obligatory rant on how irrealistic that is), on a single biome - Messina Chasmata.

Preparing to land

The eponymous chasm

I had to repeat the landing halfway because I realized too late I forgot to drain the oxidizer (bug #31), so I consumed extra fuel. It seems like half the times I make some major maneuver, I have to reload it because I forget goddamn bug #31. But in this case it saved me an engine, because the first time I landed I broke a nerv and the second time I didn't.

Landing. Though I used chemical engines for a while, now I'm just using nuclear engines for finer control

Bug #34 shows up again. At least it hasn't crashed the game

Messina Chasmata is the only place with water, and nicely it also has uraninite. On the downside it has very low ore concentration, just 3%. So the drills are drilling slooooooowly, and refueling will take a looooooong time. Being down at 50% electrical power is not an issue here.

A screen showing the speed of fuel mining. On Iapetus it was 664, at least before I started losing reactors

Ariel passing in front of Uranus while Peretto is runnig maintenance on the reactors

It took 11 years to refuel, even though I already had a 20% of fuel left upon landing. But I won't try to cut it short, because I've done some quick estimate of what it will take to get to Neptune and back, and I'll need all the fuel I can get.

No accidents in those 11 years either. Two more reactors breaking reversibly, despite me being very regular with maintenance checks. Well, so far so good, 33 years spent without breaking anything.

Status at the end of refueling

Now I'm ready to send Cylinder to Neptune. Though I seriously doubt I'll be able to make the round trip in 40 years. And I need 10 more years for refueling anyway.  I would really, really like to leave for Pluto in 40 years, because I will be passing on the planar node, allowing to fix inclination as part of the ejection burn. I am seriously evaluating the pros and cons of waiting 40 years for a Pluto window, and the main con is "I'll go crazy if I spend 40 more years doing nothing".

I'm confident I can tackle Neptune, but Pluto may yet turn out to be the greatest challenge in this mission.

Bugs compilation updated

Spoiler

A numbered list is so convenient to refer to bugs quickly. This list keeps growing. Problem and Solution

1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

4) Propellers start twisting around. No worry, it fixes once you stop time warping

5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

10) I can't plan maneuvers or go EVA, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: save before exiting time warp

13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

17) Crew hatch registered as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

20) Upon starting the game, clicking on the VAB does not work. Clicking on the icon on the bottom left corner of the screen still works

21) Sometimes elements of the HUD change size. It doesn't affect the game, and seem to revert spontaneously

22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason. Load Cylinder into physical range and they restart

23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced. Reload when it happens, and it will get fixed

24) The ground on Titan has all sort of glitches and malfunctions. Be extra careful during landing, cheat the vessel in orbit before leaving it, jump to start flying. See 7.3 for more details

25) Negative aerodinamic drag displayed on the user interface. Drag is still behaving normally, it's only the display that's bugged

26) The docking port on Clamp has all kinds of problems, does not allow fuel transfer, can't be removed. I stuck another docking port there, and I can grab Clamp with a claw if needed

27) Sometimes there is no signal for probe control even though there should be. Switch to the vessel that's not being seen, then back to the probe

28) Crew pod of Hartman rover has a broken life support and a functional wheel, but it instead appears to have a working life support and a broken wheel. Nothing I can do about it; but it still works

29) The sun shines through Jupiter's body as if it was part of the sky. It's just an harmless visual glitch

30) An object on the surface coming into physical range may be loaded tens of meters above it. Hope nothing explodes. Reload if necessary

31) Cylinder's central tanks gets refilled on (useless) oxidizer upon reloading; see 10.2. Dump the dead weight again

32) All mining drills suddenly manifested a new uranium drilling function. Can't revert it, but they still work normally; it seems harmless

33) The game is not spawning comets. For the comet landing, pick a large asteroid in an inclined, eccentric orbit and pretend it's a comet

34) Flags are planted hundreds of meters in the air. Sometimes this crashes the game (NEW). Just reload if it happens

Edited November 30, 2022 by king of nowhere

[king of nowhere]

Part 13: Deep Blue Dot

Cylinder goes to a Neptune flyby, drops Clamp on Triton, returns to Uranus for refueling.

Two more nuclear reactors are broken, putting strain on the long term energy supply of the mission.

Triton with Neptune in background

13.1) How the heck do I eject from this place???

Spoiler

I barely have time to lift off from Titania before one of the wolfhounds on Trypophobia goes kaboom!

Trypophobia, now with four wolfhounds active

I already used up the one spare wolfhound I did carry, but Trypophobia can still work with 4 wolfhounds if I shut down its opposite for symmetry.

Now I have to split up A'Twin. Neptune only has one moon - Triton - rendered in this mod, and for some weird reason Triton only has 3 biomes; north pole, south pole, and "flatlands" covering everything else. And none of those 3 biomes had water.

While transfering fuel from the various tanks - I want to remove all oxidizer from Cylinder, and leave Trypophobia with the proper amount of liquid fuel - I noticed another issue. I select all fuel tanks and tell them to drain into a central one to maintain a symmetrical balance of fuel, but despite that fuel is being moved faster from some tanks. Despite those tanks being perfectly identical. Oh, well. List updated with Bug #35.

Bug #35: all fuel tanks started equal, and they were told to drain simultaneously; still one tank is a lot more full than the others

To minimize the impact on the center of mass, I have to fix things up manually. I barely went to Titania's orbit, and I already have a critical malfunction and a new bug; what more could possibly go wrong?

Next is splitting up the ship

Once more, A'Twin is separated into its two modules

And here we have old bug #9 manifesting. Good thing I'm keeping track of part count

I carry to Neptune Clamp and Fat Man, but I do leave behind the additional tank of Fat Man because I won't need it.

Cylinder, ready to go. Even though I need many high energy transfers, 10 km/s should really suffice

Trypophobia, staying behind. I left it with baely enough fuel to land again

Wow, it feels so weird to have the game displaying accurate deltaV figures for both pieces of my mothership!

Now I've got to find an efficient way to leave Uranus. The moons being rotated by 90 degrees makes leaving very difficult. I am using the movement of Titania around its orbit as part of the maneuver, something equivalet to a normal burn, while I had to include strong normal and radial components to exit in the direction I wanted - which was not aligned with the plane of the moons at all.

Maneuver to leave Titania for a Neptune intercept

Same maneuver, zoomed out

Same maneuver, zoomed in, I am basically stopping my orbit and going in a completely different direction

Neptune is too close to Uranus for a proper Hohmann, but such a trajectory would have been too slow in any case. A close Neptune suits my needs. I could have spent more fuel for faster transfer, my choice was a compromise between saving time and saving fuel.

Leaving Titania, Cylinder broke another engine

That one is my fault, I got distracted and didn't perform the engine checkup when remaining burn time went below 30 minutes. As a result, when it became lower than 25 minutes an engine broke.

I'm out of spare engines, but the ship had 24; I shut down its symmetrical - which I can now use as another spare - and I only lost 8% of maximum thrust.

13.2) Free return trajectory is not for free

Spoiler

I want to try something new: a free return trajectory. In theory, I could use a gravity assist from Neptune to return to Uranus. Since I only have to visit one moon, I can drop Fat Man and have it catch Cylinder back. I could not plan for this before leaving Uranus because you can't set a planet as target while you're orbiting it.

Turns out, I could use a free return trajectory - if Neptune was a black hole of equivalent mass.

The free return trajectory would require a huge change at Neptune, which would require passing below the surface

The best I can get: I use a gravity assist, but I've still got to pay 2500 m/s to exit Neptune in the proper direction

After some simulations, I went for it. This not-so-free return sends me on an Uranus intercept - and a cheap one at that - for 2500 m/s. Getting captured around Triton, on the other hand, would cost 2600 m/s; more, after cosine losses are factored in (notice: Triton has a thin atmosphere, but it's not enough for aerocapture; I tested it). And then returning from Triton to Uranus would cost more than 2 km/s. So I'm still saving a lot of fuel.

Full trajectory from leaving Uranus to returning

Side view to gauge my chances at Pluto later

Once more, I could go faster by spending more fuel, and Cylinder will have 5 km/s left. But there's no need to hurry; the best time to launch for Pluto is close to the planar node, and - considering that Uranus orbit is 84 years - the current trajectory would return 15 to 20 years before that time; factor in 10 years for refueling, I'll still have to wait a bit.

Now I have to pass 15 years, doing periodic maintenance trips for the fusion reactors - the only parts of the ship that are still aging.

Trypophobia lands back on Titania

Trypophobia breaks a nuclear reactor

Case in point. Seven reactors left out of 12. Because of bug #18, I reverted this malfunction and dropped one of the nonfunctional reactors instead. Then I went on a few more years. Then I had to move to Cylinder because, due to bug #11, I can't run water electrolysis remotely. Then I reloaded Trypophobia, as I need to service the reactors every year. As soon as loaded, the ship broke apart. Loading previous saves also broke the ship. It turns out the save file had clipped the discarded reactor inside the ship, causing the two to collide as soon as they were loaded. Fortunately I was able to delete the offending debris manually by editing the save file, so I didn't have to reload many years of gameplay. And it wasn't even technically a bug.

13.3) On Neptune

Spoiler

200 days from Neptune, I detach Fat Man with Clamp to set it for a Triton intercept. I also accelerated it a little bit to make sure there would be no overlapping of the Triton capture burn with the Neptune periapsis burn of Cylinder. I could have waited more, but the burn would have been more expensive, and I still wasn't sure how much I would need to return to Cylinder afterwards.

Fat Man departing from Cylinder

And finding a trajectory for Triton

Triton orbits retrograde from any other moon, but when it's the only moon modeled by this mod, it doesn't really make any difference. Intercept speed is high because I'm coming from a high energy trajectory, but Fat Man has lots of deltaV.

Neptune and Triton. I like the dark blue hue

More Neptune and Triton

An attempt at aerocapture, hopefully tried because Fat Man is so draggy. Even a few km above the ground, pressure is very low, drag is tiny. DeltaV gained is 30 m/s

So I had to suck it up and use the rockets all the way

I still took a periapsis as low as possible, less than 1 km above ground as you can see from the picture. Negligible savings by aerobraking are bettern than no savings at all.

Triton's surface

Clamp about to land. Or to crash down, because I'm still delaying engine use in the hope of getting some measure of aerobraking

But bug 17 is still active, and the crew can't leave to plant a flag or collect a sample. So I had to reload and land with a kerbal on the ladder.  I was worried about the atmosphere, though. Why would I be? Have I not yet understood that Triton's atmosphere is just for show? Even close to the ground, Adai could let go of the ladder and fly around with the jetpack, the air only providing the barest modicum of resistance.

Flag planted. I really do like the lighting on the surface, though Enceladus was better

The same scene, in natural light. I still make a point to check how things would look without light amplification from time to time

As I liked Triton's surface, I tried to drive around. But after a few meters, the wheels suddenly lost grip. They were spinning, but the rover was immobile. Bug #36. I already met this bug in my previous OPM grand tour (on the moons of Neidon, Neptune's analogue), seems related. Triton's surface also has some weird behaviour similar to Titan's - you can see the wheels sinking into the ground - so I updated bug #24. I wonder if a rover on Titan would similarly fail to function.

I took a picture of the bug to show, but the wheels spinning don't show in the still image, so there's no point. Anyway, I just gave up on trying to drive on Triton and resolved to GTFO as soon as possible from this bug-riddled place.

Meanwhile, Cylinder makes its first burn at Neptune periapsis

Now Fat Man has to catch Cylinder. First thing, it has to wait a few days because Triton is in the wrong part of the orbit. Then, since the game will never give me a close approach between two ships in escape trajectories, I set up some maneuver nodes at intervals for Cylinder to have a marker for where it would be at a certain time. Then I made similar markers for Fat Man. Then I tried to make a maneuver that would overlap two such markers.

Fat Man has 6 km/s, and 2 km/s would suffice for a return trajectory to Uranus, so I am not worried about fuel availability.

Finding an intercept with Cylinder. The two maneuver nodes are both in roughly 19 days, showing that the two ships will be close after that time

Here I refined the trajectory, the two nodes are perfectly overlapping

Of course, "perfectly overlapping" is purely visual here, and it will still mean tens of thousands of kilometers at close approach. But it something I can work with. Once I am close enough to Cylinder, I can start to burn to ensure that my prograde marker stays firmly over the target marker.

Burning to push the prograde marker over the target marker. Actually it's the retrograde marker over the anti-target, but it's the same principle

Reunited with Cylinder

Those 200 days spent in Fat Man brought the crew to 30% stress, but the only outcome of this was a nervous breakdown resulting in a reversible damage.

13.4) Return to Titania, now with 50% more plane change

Spoiler

Now it's 22 more years of doing nothing but waiting, going EVA to fix the reactors, make more ammonia, wait, fix reactors, make ammonia, wait, make nitrogen, make oxygen, make CO₂, wait, wait, wait. Why do I even play those kind of missions?

Year 216: another nuclear reactor fails

Now I'm down to 6. I can lose another couple before it really starts to hurt. How many reactors will be left once I reach Pluto? Only time will tell.

A nice picture taken while performing maintenance. But do notice the empty holes where engines and reactors used to be

No more accidents in the next 20 years, now I have to plan for Uranus insertion (no puns, please).

Which is going to be even more annoying than the previous time, because the moons plane is rotated even worse and I can't get any better than 60 degrees inclination. Why did I ever landed on Uranus in the first place? Iapetus was such a nice place for refueling, and whatever extra fuel I'd have to spend to go from Saturn to Uranus orbit is more than compensated by not having to deal with this inclination and being able to aerobrake at Titan.

Oh, because using Uranus this way takes less time and gives me a chance to be ready to launch for Pluto in a transfer window. Damnit!

Anyway, fixing that much inclination is going to cost a fortune, and there's no way around it. Spending a fortune is the best solution, the alternative being spending more fuel than I've got.

Trajectory to reach Titania

My approach is thus: first, 200 m/s close to Uranus to get captured in an elliptic orbit. I could have saved some fuel by being captured in an even higher orbit, but I don't want to waste too much time either. Then 580 m/s at apoapsis to get a high orbit. This orbit is high enough that I can make a 60 degrees plane change for "only" 1762 m/s. It also lowers periapsis to touch Titania's orbit. At this point there's a small correction burn of 12 m/s, and finally a 450 m/s capture burn on Titania.

All in all I'm spending almost 3 km/s for this. But it's well within Cylinder's capabilities.

Uranus periapsis

Rendez-vous with Trypophobia

Moving the shuttles around to prepare for joining the twins. Fat Man additional tank has no probe core, so I'm docking it in this peculiar way. I now realize I could have used a Service Probe

Also featured using Fat Man's engines as an impromptu RCS

Cylinder and Trypophobia docking, seen from inside a nearby Spider. A view I was still missing

Descent on Titania

Landing with only nuclear engines. Not for precision, but because I've been careless and run out of oxidizer too early

Landed back on Titania in year 237, 38 years after departing. Now I am looking to roughly a decade of refueling.

By the way, another bug (#37): this time I set up to use all my CO₂, so that there is none in storage. But as soon as I stop time warp, some CO₂ and ore appear. This is another benign bug, gifting me stuff. And unlike bug #31, this one gives me some actually useful resources, and not some dead weight I must remember to dump every time (btw, I forgot it in the whole Titania approach phase). But the amount of resources is too small to make any meaningful difference, especially since I only stop time warp a couple times per year (once for reactor maintenance, once to make new ammonia).

Reaction wheel broken on Nitrogenie in a Bottle

That reaction wheel was one of the few pieces still aging; I was leaving it reversibly broken so I wouldn't have to worry about it, but I had to fix it to dock Nitrogenie (thinking back, I could have grabbed it with a Service Probe), else it was completely out of control. Then I ignored it; just not worth the effort. I was hoping it would get reversibly broken again, but I still have a bunch of spare reaction wheel in case I ever need to stop at Titan and make new nitrogen.

Crawling through tunnels - or, well, flying up narrow vertical ducts - during maintenance

Status after 11 years of refueling

Position of Uranus and the planar node with Pluto

Pluto could be very tricky. It's very small, so I won't get any Oberth effect for capture; we're easily talking several km/s intercept speed. Add several km/s of ejection burn, especially with the crappy alignment of Uranus moons, and it will be expensive, but still feasible. However, Pluto itself is fairly large, requiring roughly 1 km/s to land on - hence why I'm carrying lots of oxidizer. But wait, can't I just land on smaller Charon instead? No, because Charon has no water anywhere (insert more ranting against the mod)(EDIT: actually Charon has water everywhere, but my spreadsheet was confusing and I misread it. Yes, I took notes in the form of abbreviations and symbols and then I forgot what they meant. Feel free to laugh at me. /EDIT). A'Twin as whole has roughly 8 km/s, and it's got to spend 600 m/s just to reach Titania's orbit; I should still have enough, especially factoring in the very long life support.

Oh, and just to be even more annoying Charon has uranium, which is lacking on Pluto; so I have to carry all the uranium, land on Pluto, make fuel with the uranium I have - I'll go somewhere above half tanks - then take off, land on Charon, fill up on uranium again, land on Pluto, finish refueling, leave.

But no point worrying before starting a simulation. A'Twin is as prepared as it could possibly be for this trip. I've got all the resources I can keep, I can spend 60 years in space. I even have a ship much lighter than it was at start, thanks to dropping well over 100 tons of broken hardware. I reached Mercury, I conquered Io, I managed a landing on Mimas, I don't expect Pluto to be any worse.

Electricity may be a problem in the future. I will surely have enough reactors to keep going at Pluto, but afterwards I'll probably need an additional stop on the way back, I doubt a direct Pluto-Earth trajectory will be feasible. I'll have to stop either at Iaptus or at Phobos, and I worry in what state my reactors will be by then.

Bugs compilation updated

Spoiler

A numbered list is so convenient to refer to bugs quickly. This list keeps growing. Problem and Solution

1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

4) Propellers start twisting around. No worry, it fixes once you stop time warping

5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

10) I can't plan maneuvers or go EVA, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: save before exiting time warp

13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

17) Crew hatch registers as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

20) Upon starting the game, clicking on the VAB does not work. Clicking on the icon on the bottom left corner of the screen still works

21) Sometimes elements of the HUD change size. It doesn't affect the game, and seem to revert spontaneously

22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason. Load Cylinder into physical range and they restart

23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced. Reload when it happens, and it will get fixed

24) The ground on Titan (UPDATED: and a few other planets) has all sort of glitches and malfunctions. Complex. See 7.3 for more details

25) Negative aerodinamic drag displayed on the user interface. Drag is still behaving normally, it's only the display that's bugged

26) The docking port on Clamp has all kinds of problems, does not allow fuel transfer, can't be removed. I stuck another docking port there, and I can grab Clamp with a claw if needed

27) Sometimes there is no signal for probe control even though there should be. Switch to the vessel that's not being seen, then back to the probe

28) Crew pod of Hartman rover has a broken life support and a functional wheel, but it instead appears to have a working life support and a broken wheel. Nothing I can do about it; but it still works

29) The sun shines through Jupiter's body as if it was part of the sky. It's just an harmless visual glitch

30) An object on the surface coming into physical range may be loaded tens of meters above it. Hope nothing explodes. Reload if necessary

31) Cylinder's central tanks gets refilled on (useless) oxidizer upon reloading; see 10.2. Dump the dead weight again

32) All mining drills suddenly manifested a new uranium drilling function. Can't revert it, but they still work normally; it seems harmless

33) The game is not spawning comets. For the comet landing, pick a large asteroid in an inclined, eccentric orbit and pretend it's a comet

34) Flags are planted hundreds of meters in the air. Sometimes this crashes the game. Just reload if it happens

35) Fuel transfer is asymmetrical even when it should be symmetrical (NEW). Manually fix to ensure even distribution of fuel

36) Wheels do not work on Triton (NEW). Driving a rover can be skipped

37) Resources can appear from nothing when exiting time warp (old, but wasn't in the list). It's benign, and those resources are not enough to make a significant difference     

Broken parts compilation

Spoiler

I want to keep track of how much stuff I break, and how much it's affecting the mission, so I prepared a list

Life support

1 life support broken on Dolphin 1. I've got five more redundant pieces on it.

1 life support broken on Dolphin 2. I've got five more redundant pieces on it.

1 life support broken on Cylinder. It's a redundant piece of a redundant piece. Least concern.

1 and only life support broken on Hartman. Sucks, I can't take extended trips, but the rover has enough air to conduct landing operations safely.

1 life support broken on Fat Man. I've got five more redundant pieces on it.

1 and only life support broken on Nitrogenie in a Bottle. No problem, it's not supposed to carry a crew any longer.

Nuclear power

6 Excalibur reactors broken. Up to 4 can be lost before mining is slowed down - though it is already slowed by bug #18. There is concern here that they are breaking up fast. (+2 NEW)

Reaction wheels

2 large reaction wheels broken. I've still got 88 working.

1 medium reaction wheel broken on Clamp. I've got a half dozen spare ones in storage.

2 medium reaction wheel broken on Nitrogenie in a Bottle. I've still got a half dozen spare ones in storage. (+1 NEW)

reaction wheel on the crew pod broken on Nitrogenie in a Bottle. Can't be replaced, but the other three wheels should be enough to keep the plane stable even if I break a lateral engine.

Engines

4 big nervs broken. I had three spare ones. Now the ship is working with 22 engines out of the original 24. (+1 NEW)

2 big wolfhound broken. I had a spare. Now the ship is working with 4 engines out of the original 6. (+1 NEW)

1 small nerv broken on Fat Man. I've got 2 more spares, then I can start cannibalizing Nitrogenie in a Bottle.

1 cheetah broken on Spider. I've got 2 more spares.

Communication

1 RA-100 dish broken. I've got 5 more redundant pieces. After that, I still have more non-relay antennas.

1 HG-5 antenna broken on Wings B. I've got 1 more spare. After that, the mission can still use normal non-relay antennas.

1 Communotron 88-88 antenna broken on Fat Man. It was itself a spare part, and I have more spares, as well as redundant antennas.

1 Communotron 88-88 antenna broken on Wings A. I've got a few more spares; then I can cannibalize antennas from Trypophobia if really needed.

Others

1 radiator panel broken. I had 12 redundant. They should be needed to vent heat from the nuclear reactors, but they are not actually needed anyway.

Drills

Drills never got broken, even though I stopped checking them 200 years ago. Bug #15 working in my favor.

Chemical plants

Chemical plants  never got broken, even though I stopped checking them 200 years ago. Bug #15 working in my favor.

Low-quality parts

A landing light broken on Nitrogenie in a Bottle. Irrelevant, I don't need them.

Life support on Trypophobia's gravity ring broken. Irrelevant, it only does pressure control and the same function is included in the greenhouses.

1 Converter broken. Irrelevant, converter is the stock isru functionality that I'm not using. I need the chemical plant functionality, and that one is still working perfectly.

Outdated

2 reaction wheels broken on Milly. Now Milly has done its job.

1 dart engine broken on the Mars Descent Stage. Now it's a pile of debris on Mars.

Discounting the low quality and outdated parts, that's 31 critical malfunctions so far.

Edited February 27, 2023 by king of nowhere

[king of nowhere]

Part 14: Making fuel in hell

A'Twin goes to the binary system of Pluto and Charon, named after gods of the underworld.

The names prove accurate, because the bugs involved in refueling were staggering.

Pluto and Charon seen from the cupola

14.1) Going to Pluto is easy, leaving Uranus is hard

Spoiler

Picking a trajectory for Pluto turns out to not be too hard. Or, well, the main difference with my near disaster on Plock in the OPM grand tour is that back at the time, I was required to be able to return without refueling; this time, I know I can refuel on Pluto and I plan for it.

A proper Hohmann transfer would take over a century, but there are pretty cheap trajectories also for lesser durations.

A low energy transfer to Pluto, requiring little more than 3 km/s (mostly to leave Uranus gravity) but 70 years

Seventy years are within A'Twin's life support capability, barely. Still, I have 8 km/s and as usual I try to save time. For the same reason I am launching immediately instead of waiting 7-10 years to pass exactly on the planar node, even though that would be cheaper.

Turns out, the main difficulty is actually leaving Uranus. Not only the moons rotate shifted by 90 degrees compared to the ecliptic but right now their plane is also pointed in the completely wrong direction. Imagine that the plane of the ecliptic is the xy plane, and to reach Pluto I must make a burn in y direction; the moons of Uranus are rotating in the xz plane, so I can't ever use their momentum to gain speed in the y direction.

Another major difficulty is that sometimes I make an additional maneuver node for a correction maneuver, just to see a close approach to Pluto, and when I don't need it anymore, I can't delete it. Clicking on the X on map view does nothing, clicling on the X on the box in the bottom left of the screen crashes the game. I add it to the list as bug #38, though it's been plaguing this mission on occasions for a while. I learned that the best way to deal with it is to leave the maneuver node, but reset it to 0 m/s so it won't interfere with whatever new trajectory I'm planning.

Ultimately, I decided to just leave Uranus and make the burn in interplanetary space. It's less frustrating this way.

Trajectory to Pluto

So I'll end up paying 1140 m/s to exit Uranus' sphere of influence, then 2200 m/s evenly spread between normal and prograde at the planar node ten years later to match inclination and get away from the sun, arriving at Pluto 40 years later with 2 km/s intercept speed. Total cost is 5 km/s; fully fueled, A'Twin has between 7 and 8 km/s depending on the order of use of nuclear and chemical engines, leaving 1 km/s to land on Pluto and 1 km/s for any emergency.

If I had saved more out of the fuel budget, I'd have used it to get a faster trip.

Forty years in space. Requiring yearly maintenance on the reactors. The later part of this mission is a real slog. Having to fix the ship is not a big deal in the inner solar system, where you plan trajectories, land somewhere, and in the middle of it all you perform maintenance once and it's all part of the fun. Here I do nothing but maintenance. At least I can thank bug #15 for not having to service the rest of the ship too.

I'm trying to get pictures of A'Twin from unusual directions, for the sake of novelty

By the way, one of the remaining six reactors was also struck by bug 15, and doesn't need upkeep anymore. But I'd rather keep more than a single working reactor.

This time forty years - 38 plus three and a half months, to be accurate - go smoothly. No malfunctions, not even fixable ones.

Arriving at Pluto, still with half my water available. Also with half the nitrogen (stored as monopropellant), that was last restocked 120 years ago

Now, I said that I had to land on Pluto - despite being bigger and heavier and having no uranium - because Charon had no water. Well, I was wrong. I annotated ore availability in a confusing way, and then I misread it later. Turns out, Charon has water in every single biome. I looked it better, and found a tiny biome near the equator with high concentrations of all the three resources I need. Yay!

New trajectory for Charon

So I'll get captured in a trans-Charon injection orbit. I also dumped most of the oxidizer that I planned for landing in higher gravity, and most of the uranium that I planned because Pluto has no uranium.

Servicing the engines around Pluto

14.2) Forever a planet in our hearts

Spoiler

A'Twin will spend 3 days in its current elliptic orbit waiting to meet Charon; a perfect time to send Clamp to land on Pluto. Clamp's deltaV is also barely enough to land and return from its current orbit without needing Fat Man.

By mission procedure I should not send Clamp alone in case of life support malfunction, but what the hell, it's been almost 300 years, what are the odds that a malfunction will happen in the next 3 days?

Bug #17 is still active, so Rudatte must still take the rough ride

Landed

At this point, since I have 3 days to pass anyway, I decide to drive around a little bit. Actually I was surprised that I could drive at all, Pluto is very similar to Triton, including an identical atmosphere, and I worried it had the same terrain bug (#36). Everything is fine as long as I go straight, but while braking I lost control and tumbled around. Having the two reaction wheels broken make the rover sluggish, and I can't send out Peretto to fix them. The rover survived, but the front docking port hit hard and exploded.

That docking port was the one struck by bug #26, and I would have removed it if I could. So, it's actually a good outcome! I did try to explode the offending docking port in the past, since I could not remove it manually, but it resulted in crashing the game.

Clamp without the frontal docking port

No, this did not magically fix also bug #17. On the plus side, I shouldn't need Clamp ever again.

Back to orbit

Return to A'Twin, with very tight fuel budget

Now, I may have been very optimistic on the cost of this landing, or perhaps I was wasteful. But I need a 206 m/s burn followed by a 99 m/s intercept, for a total of 305 m/s, and I have 307. I already optimized as well as I can.

Clamp rejoining A'Twin, which is below the sun in this picture

And the same in natural light; A'Twin is actually more visible, due to being backlit and shilouetted. The surface is still lit well enough

About to dock, with 1 m/s left. That was close

Ok, if I had run out of fuel I could always move A'Twin, not a big deal.

New bug #39! Those colored lines have been appearing on and off when I moved past the orbit of Neptune, but this is the first time I get to take a pic

Bug #39 had me worried, but it looks like a harmless visual glitch. At least, it disappears as randomly as it appears, and the game keep working.

Speaking of bugs, this whole mission is always on the verge of crashing. Whenever I open the debug console, I see this.

The debug console; I have no idea what any of that means, but all that red can't be a good sign

I haven't included that as a bug in the list because it's more of a notification of bugs.

Anyway, without further excitement I reached Charon.

14.3) I'm Charon, and I'll ferry you to hell

Spoiler

The place I'm supposed to land in is called Butler Mons, though it looks more like a crater. It's quite small, but still big enough to be easy to pinpoint.

The landing zone, and status in orbit. Still plenty of fuel left. I dumped most of the water because it's useless mass now, and I'll find new one soon

Landing. It's been a while since I last used this inner perspective

In fact, I tried to land using only the inner perspective, and I ended up falling on a side.

The landing zone is almost underneath Pluto

Landed

Now refueling operations can start, bugs allowing. I already see bad signs.

Charon has a terrain bug. See how deeply the landing struts sink into the ground

This looks like bug#24, the game being confused on where exactly the "ground" is.

And I expect this to also glitch with whether a drill is properly inserted into the ground, leading to bug #7.

Indeed, here's bug #7

And just to add, on Charon there's a high chance that A'Twin will randomly explode. Like this

I realize I don't have any specific entry for "ship explodes when loading the game", but I guess it can be considered a more extreme case of bug #2 or #9, with the detached/mangled parts clipping into each other and starting explosions. It's normally rare, but on Charon it's been happening roughly half the times.

Some of those explosions were quite spectacular, like the one in this sequence

Went to service the reactors, took the chance to plant a flag

By the way, science experiments when I fly around the ship with the jetpack report as "space high". This mountain/crater isn't high at all; I wonder where space low is on this moon.

Ore concentration is above 9%, like on Iapetus. I mine ore very fast, the limitation to how quickly I can refuel is the process to extract carbon from the ore; it's very energy intensive, and I only have 6 nuclear reactors left.

A screen to detail isru speed

I managed to use my available electrical power to the fullest; the reactors are producing 18350 electricity/second, when their very maximum is 18360 (3000 each for the six big reactors, and 60 each for the small reactors on Cylinder). I am making 4900 liquid fuel at *1000000 time warp - it was less than 2000 on Titania. Earlier on Iapetus I got at high as 7000, but I had more working reactors back then.

So, if on Titania I refueled in 11 years, I should do it in slightly more than four years on Charon. Except that bug #7 is in full swing, and A'Twin spends more time failing to mine than it spends working correctly.

Just a good picture of the landed mothership with Pluto in background

One year passed, it's time to again service the reactors; of course I wouldn't even mention this routine operation except that something is about to happen.

New bug #40! Peretto explodes in midair!

While gently flying mid-air, the game suddenly decided Peretto had sunk on the ground, making him explode in a cloud of smoke. This is troubling, because I need to service those reactors.

I tried reloading, the bug kept happening in the same way. I tried moving Peretto to the cupola and send him out from there, the bug kept happening. I tried to reload back a couple saves, the bug kept happening.

Also, reloading made the ship explode again

But hey, at least Peretto could make it to the ground this time!

Since Peretto was able to land, maybe this save is not afflicted by bug #40? I reloaded again, this time the ship did not explode, but Peretto did.

I thought maybe the responsible was ground tether (a function I just discovered to stop a ship from sliding on the ground, because I was having the same issue I had on Vesta back in 6.4), but it made no difference.

Having exhausted other options, I did resort to extreme means. I used alt-f12 to move A'Twin in orbit. There I serviced the reactors, without any ground problem. Then I alt-f12 the ship back in place; I actually managed to "teleport" it within 150 meters of the original flag.

Nine years later, refueling is done. Status before leaving

What? You were expecting some more bugs? Wasn't that enough?

Remember, it should have taken less than 5 years without bug #7; but despite all, it's still been faster than on Titania. And nothing broke.

The grand tour is almost done. Now I need to return to Earth. I can make the trip in a reasonable time, but I will have a high intercept speed. So my plan involves going for Mars first, to refuel on Phobos... Wait, if I have enough fuel to capture on Mars, shouldn't I have enough also for capture on Earth, with greater Oberth effect compensating for higher orbital speed?

Yes, but I still miss two landings. I landed on the Moon twice, but both times I had to restart the mission. In this save continuity, I never did, so I will have one last mission for Spider. And I never went to a near-Earth asteroid, which together with a comet is part of my extended grand tour objectives; I can visit one along the way between Mars and Earth.

I don't expect any more significant problems. I should be done in 50 years at most.

Bugs compilation updated

Spoiler

A numbered list is so convenient to refer to bugs quickly. This list keeps growing. Problem and Solution

1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

4) Propellers start twisting around. No worry, it fixes once you stop time warping

5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

10) I can't plan maneuvers or go EVA, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: save before exiting time warp

13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

17) Crew hatch registers as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

20) Upon starting the game, clicking on the VAB does not work. Clicking on the icon on the bottom left corner of the screen still works

21) Sometimes elements of the HUD change size. It doesn't affect the game, and seem to revert spontaneously

22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason. Load Cylinder into physical range and they restart

23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced. Reload when it happens, and it will get fixed

24) The ground on Titan and a few other bodies has all sort of glitches and malfunctions. Complex. See 7.3 for more details

25) Negative aerodinamic drag displayed on the user interface. Drag is still behaving normally, it's only the display that's bugged

26) The docking port on Clamp has all kinds of problems, does not allow fuel transfer, can't be removed. I stuck another docking port there, and I can grab Clamp with a claw if needed

27) Sometimes there is no signal for probe control even though there should be. Switch to the vessel that's not being seen, then back to the probe

28) Crew pod of Hartman rover has a broken life support and a functional wheel, but it instead appears to have a working life support and a broken wheel. Nothing I can do about it; but it still works

29) The sun shines through Jupiter's body as if it was part of the sky. It's just an harmless visual glitch

30) An object on the surface coming into physical range may be loaded tens of meters above it. Hope nothing explodes. Reload if necessary

31) Cylinder's central tanks gets refilled on (useless) oxidizer upon reloading; see 10.2. Dump the dead weight again

32) All mining drills suddenly manifested a new uranium drilling function. Can't revert it, but they still work normally; it seems harmless

33) The game is not spawning comets. For the comet landing, pick a large asteroid in an inclined, eccentric orbit and pretend it's a comet

34) Flags are planted hundreds of meters in the air. Sometimes this crashes the game. Just reload if it happens

35) Fuel transfer is asymmetrical even when it should be symmetrical. Manually fix to ensure even distribution of fuel

36) Wheels do not work on Triton. Driving a rover can be skipped

37) Resources can appear from nothing when exiting time warp. It's benign, and those resources are not enough to make a significant difference     

38) Sometimes trying to delete a maneuver node crashes the game (old, but wasn't in the list). Reset the offending node to 0 m/s instead of deleting

39) Strange semicircles of color appear randomly on the screen (NEW). It seems to be a harmless visual glitch

40) On Charon, an EVA kerbal can explode in midair, ostensibly for hitting the ground (NEW). Alt-f12 the ship in orbit. Go EVA to service the reactors. Alt-f12 the ship back in its place

Edited June 5, 2023 by king of nowhere

[king of nowhere]

Part 15: A'Twin's longest trip

A'Twin returns to the inner system in a 50-years long trip. Arrives at Phobos and refuels there.

Life support for the long trip holds perfectly. Two more reactors break, reaching a critical point, but by now they've done their job.

Here A'Twin is taking a gravity assist from Jupiter

15.1) Leaving Charon

Spoiler

Charon is small and has low gravity, so it's easy to leave it.

Or at least, it should be. Here I'm crashing onto a crater edge

And here A'Twin collapsed to pieces spontaneously

Yes, aside from a couple small accidents, orbiting Charon is easy.

A couple of new perspectives...

... I got while servicing the engines

Now A'Twin must reach the inner system. I still have to land on the Moon, and I have to land on a near-Earth asteroid, so I need to reach the inner system with fuel. This requires a refueling, and Phobos is the only place I have there. I still have enough hydrazine stockpiled that I won't need to stop at Saturn to get more.

The first step to get back is a Jupiter gravity assist, of course.

Trajectory to inner system, part 1

I could have gone to Jupiter with less fuel, but I sacrificed some 600 m/s to save 10 years. A'Twin has about 8 km/s in this setting, so I can afford it.

In this trajectory I'm aiming for a Venus flyby, to take some gravity assists and then go to Earth. But I changed my mind later.

Trajectory to the inner system, side view

Unfortunately, I made a major mistake here. I ejected from Charon from an equatorial orbit; however, because of how rss uses all the planets being inclined as a way to simulate axial tilt, a Charon equatorial orbit is not equatorial for the interplanetary purposes. I ended up with a high inclination, and I didn't notice it while looking only from above.

Which is not a big deal as far as the transfer, Jupiter can take care of it. But I spent more fuel than I should have. If I had included a normal component to the ejection burn to eject into Pluto's orbital plane, I would have saved 500 m/s. Well, I can't get everything perfect in the first try. And if what I get is good enough, I won't reload.

Leaving Charon was also a bit hard, because the burn is long and, as shown here, it would make me crash on the planet. I had to start later, take some extra cosine losses. Not a big deal

Some nice pics taken while servicing the engines again

I never took a picture of an EVA kerbal from inside this specific cupola before

Still more nice views

Goodbye, Pluto

15.2) The long, long way

Spoiler

Now that I performed the big ejection burn, it's time to refine the Jupiter flyby. I finally decide at this time to go for Phobos and refuel. I want to park A'Twin in Earth orbit with still enough fuel to leave again, because I like to think it could be refurbished and used for more missions.

To reach Phobos, the best way is to get gravity assists from Earth to reduce solar apoapsis at Mars level. This will give me the cheapest possible Mars injection burn.

Trajectory part 2: from Jupiter to a Earth-touching perihelion

This just required a small change in the path leading to Jupiter. I could not lower aphelion further, but it's all right; it was more important to reduce inclination as much as possible. I will spend some fuel to syncronize orbit for a later Earth flyby.

New bug #41!

Welcome to the latest bug! Whenever I tried to time warp, I got that error message and the game reduced time warp to x1000. It was basically impossible to warp more than that, which is not good for a multi-decade mission. It got fixed by restarting the game.

Year 319: another reactor gone

I actually hadn't broken a reactor in a long, long time. Last one was in year 216, more than a century before. The reason for that is that I accidentally found a very stable loop.

At some point I decided, I really didn't want to have yet another EVA to service reactors, so I decided to make an experiment: one year already passed since last inspection, I decided to wait another year, while allowing a reload in case something broke. Basically I said, let's see if the reactors can go two years without breaking, if they don't I'll reload and keep making inspections every year. And the rectors held for the second year, and after I went to service them, all of them needed servicing. Which is very important, because when I service a reactor, its malfunction clock is reset. So at this point all my remaining reactors were shiny new, and I repeated the experiment and once more two years passed with no malfunctions, and once more all reactors needed servicing afterwards. And so I entered into this stable loop where I'd refurbush all reactors every two years.

Lately, the loop broke. Not because a reactor got broken, but because a reactor didn't get broken. So its malfunction clock was not reset, and it broke half an year later.

It's ok. I only need to refuel once more, then I can just let all those remaining reactors collapse.

Jupiter flyby went fine, A'Twin had to pass in the outer radiation belt shortly, but it was still well out of the inner radiation belt. Afterwards, it's time to refine trajectory for Earth.

Trajectory part 3: from Jupiter to the first Earth flyby

At perihelion A'Twin will need a 118 m/s burn to reduce its orbital time and get to a Earth flyby 9 years later - aphelion still over 1 billion . Aphelion is too high to lower to Mars level in one go, so I'll have to lower aphelion to 600 million kilometers first, ejecting into a resonant orbit to return to Earth 4 years later - here shown as the close approach in 13 years, will need one more correction maneuver to finalize.

I also checked if direct Mars injection was possible, but deltaV required was 5000 m/s. A'Twin has roughly 4 km/s at this point.

I wanted to see if I could squeeze a kerbal between the fuel tanks on the bottom of A'Twin

Actually possible, but easier to move on the outside

Crew died for no reason during time warp. This is one of the applications of bug #12

First Earth flyby, over Australia

Trajectory part 4, after first Earth flyby

Just a small correction maneuver will send A'Twin en route for a second Earth flyby in 4 years. This second flyby will lower aphelion to the level of Mars. A later 118 m/s maneuver will take care of the remaining inclination.

Second Earth flyby; by coincidence, still over Australia

Trajectory part 5, after second Earth flyby to Mars flyby

At aphelion, A'Twin makes a 1160 m/s burn to raise perihelion and change orbital time, to syncronize with the passage of Mars slightly less than 4 years later, resulting in an intercept of 900 m/s. I could have done it more cheaply by waiting many more years, but I have more than enough deltaV for it.

Year 340: another reactor gets broken

I'm down to four now, which I considered the minimum number to keep going. But soon I'll refuel for the last time.

Actually I'm down to 3, consider there's a yellow reactor there which I didn't bother to fix; I'm pretty sure it will be struck by bug #18 and be forever nonfunctional. The thing is, Phobos has very low ore concentration, three reactors are enough - even two may suffice. And by now I'm getting bored of interminable trips and just want to end faster.

Arrival at Mars

Previous estimate of 900 m/s intercept was based on a higher periapsis; with a low periapsis I can get as little as 550 m/s, and I may be able to squeeze some aerobraking from the atmosphere too - actually, I did. The problem is to find the right altitude to aerobrake enough for capture, but not too much. I have a high inclination over Phobos, which I must compensate for at apoapsis. I want to stay with a high apoapsis so that the plane change will be cheaper. This required some trial and error for the right altitude.

A moment of aerobraking. Surprisingly, I can leave the radiators out to increase drag and they won't break

I determined that to survive the atmosphere, I need to enter at less than 5 km/s. So I need to provide 300 m/s with the rockets, and the rest is provided by the air. I used an altitude of roughly 60 km to stay in a high orbit.

Keeping a high apoapsis, I can fix inclination with just 30 m/s

Afterwards, a few aerobraking passages to lower apoapsis to the level of Phobos. I've done this maneuver a few times already in the past.

Along the way, I found Phobos passing in front of Mars

Apoapsis lowered by aerobraking, periapsis is raised for a Phobos capture. Total cost slightly less than 600 m/s

At Phobos

After 47 years, A'Twin landed again. It's still got over 50 tons of water left. This ship life support is huge.

15.3) Annoying Phobos

Spoiler

I had forgotten how annoying landing on Phobos can be. The low gravity really can get in the way. The first time I ended on a ravine and I spent over an hour sliding down. I almost went out of the biome. Luckily I have the ground tether function - I still don't know if it was always there, or if it's caused by one of my many mods.

First landing, sliding down an incline

Finally stopped, though some drills are not in the ground and this will slow refueling

IVA view

Now, you may not remember from the early part of the challenge, but Phobos has no uranium and water together. So I have to gather up uranium, then make a suborbital hop, get fuel from the water biome until I run out of uranium, and if I still need fuel I need to hop again to the uranium biome and repeat. I had 20 tons of uranium, about half of my maximum stock, and with that I could make 900 tons of fuel, in addition to the 500 I already had left. Now I have to make the first jump to get uranium.

The suborbital jump. At least on Phobos it's very cheap. I did all of it just by the small thrust I get from dumping excess water. Then I realized I could have used that water to make more fuel

Soaring over Phobos

Landed again. This time easily, on a flat ledge

Bug #8, is that you? It's been so long, I've been missing you! No, not at all

And some 80 days later, I am ready to jump back

In the past one single jump was enough, but back then I had all my reactors, and they hold additional uranium. Discarding them means I have to go back and forth multiple times, as my maximum uranium stockpile is significantly smaller.

Jumping back to highlands, the water biome

Again, I found a flat ledge to land on

Five years later, I'm again out of uranium

I probably have enough fuel already, but no sense ruining a perfectly successful mission by haste, let's finish the job.

By the way, I have always full ammonia now because I turned Haber process always on. I lose the ammonia recycling from waste water, so I consume around 20% more nitrogen this way, but I have more than enough. It's just more convenient to not have to stop and make new ammonia every year.

Landing again to make uranium. This time I stopped with half my drill in the air

And again back to highlands. This time once more on a ravine

Just planting another flag. And showing how tilted the ship is by comparison

Finally, after 11 years, A'Twin is refueled. Despite using only 3 reactors

I'm ready to leave for the final two objectives: a near-Earth asteroid, and the Moon. Soon it will be over. I don't expect any difficulty.

Bugs compilation updated

Spoiler

A numbered list is so convenient to refer to bugs quickly. This list keeps growing. Problem and Solution

1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

4) Propellers start twisting around. No worry, it fixes once you stop time warping

5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

10) I can't plan maneuvers or go EVA, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: save before exiting time warp

13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

17) Crew hatch registers as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

20) Upon starting the game, clicking on the VAB does not work. Clicking on the icon on the bottom left corner of the screen still works

21) Sometimes elements of the HUD change size. It doesn't affect the game, and seem to revert spontaneously

22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason. Load Cylinder into physical range and they restart

23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced. Reload when it happens, and it will get fixed

24) The ground on Titan and a few other bodies has all sort of glitches and malfunctions. Complex. See 7.3 for more details

25) Negative aerodinamic drag displayed on the user interface. Drag is still behaving normally, it's only the display that's bugged

26) The docking port on Clamp has all kinds of problems, does not allow fuel transfer, can't be removed. I stuck another docking port there, and I can grab Clamp with a claw if needed

27) Sometimes there is no signal for probe control even though there should be. Switch to the vessel that's not being seen, then back to the probe

28) Crew pod of Hartman rover has a broken life support and a functional wheel, but it instead appears to have a working life support and a broken wheel. Nothing I can do about it; but it still works

29) The sun shines through Jupiter's body as if it was part of the sky. It's just an harmless visual glitch

30) An object on the surface coming into physical range may be loaded tens of meters above it. Hope nothing explodes. Reload if necessary

31) Cylinder's central tanks gets refilled on (useless) oxidizer upon reloading; see 10.2. Dump the dead weight again

32) All mining drills suddenly manifested a new uranium drilling function. Can't revert it, but they still work normally; it seems harmless

33) The game is not spawning comets. For the comet landing, pick a large asteroid in an inclined, eccentric orbit and pretend it's a comet

34) Flags are planted hundreds of meters in the air. Sometimes this crashes the game. Just reload if it happens

35) Fuel transfer is asymmetrical even when it should be symmetrical. Manually fix to ensure even distribution of fuel

36) Wheels do not work on Triton. Driving a rover can be skipped

37) Resources can appear from nothing when exiting time warp. It's benign, and those resources are not enough to make a significant difference     

38) Sometimes trying to delete a maneuver node crashes the game. Reset the offending node to 0 m/s instead of deleting

39) Strange semicircles of color appear randomly on the screen. It seems to be a harmless visual glitch

40) On Charon, an EVA kerbal can explode in midair, ostensibly for hitting the ground. Alt-f12 the ship in orbit. Go EVA to service the reactors. Alt-f12 the ship back in its place

41) An error message stops time warp (see 15.2) (NEW). Restarting the game fixed it

Broken parts recap

Spoiler

I want to keep track of how much stuff I break, and how much it's affecting the mission, so I prepared a list

Life support

1 life support broken on Dolphin 1. I've got five more redundant pieces on it.

1 life support broken on Dolphin 2. I've got five more redundant pieces on it.

1 life support broken on Cylinder. It's a redundant piece of a redundant piece. Least concern.

1 and only life support broken on Hartman. Sucks, I can't take extended trips, but the rover has enough air to conduct landing operations safely.

1 life support broken on Fat Man. I've got five more redundant pieces on it.

1 and only life support broken on Nitrogenie in a Bottle. No problem, it's not supposed to carry a crew any longer.

Nuclear power

8 Excalibur reactors broken. This is stretching A'Twin's resilience; but they lasted long enough to reach the end. (+2 NEW)

Reaction wheels

2 large reaction wheels broken. I've still got 88 working.

1 medium reaction wheel broken on Clamp. I've got a half dozen spare ones in storage.

2 medium reaction wheel broken on Nitrogenie in a Bottle. I've still got a half dozen spare ones in storage.

reaction wheel on the crew pod broken on Nitrogenie in a Bottle. Can't be replaced, but the other three wheels should be enough to keep the plane stable even if I break a lateral engine.

Engines

4 big nervs broken. I had three spare ones. Now the ship is working with 22 engines out of the original 24.

2 big wolfhound broken. I had a spare. Now the ship is working with 4 engines out of the original 6.

1 small nerv broken on Fat Man. I've got 2 more spares, then I can start cannibalizing Nitrogenie in a Bottle.

1 cheetah broken on Spider. I've got 2 more spares.

Communication

1 RA-100 dish broken. I've got 5 more redundant pieces. After that, I still have more non-relay antennas.

1 HG-5 antenna broken on Wings B. I've got 1 more spare. After that, the mission can still use normal non-relay antennas.

1 Communotron 88-88 antenna broken on Fat Man. It was itself a spare part, and I have more spares, as well as redundant antennas.

1 Communotron 88-88 antenna broken on Wings A. I've got a few more spares; then I can cannibalize antennas from Trypophobia if really needed.

Others

1 radiator panel broken. I had 12 redundant. They should be needed to vent heat from the nuclear reactors, but they are not actually needed anyway.

Drills

Drills never got broken, even though I stopped checking them 200 years ago. Bug #15 working in my favor.

Chemical plants

Chemical plants  never got broken, even though I stopped checking them 200 years ago. Bug #15 working in my favor.

Low-quality parts

A landing light broken on Nitrogenie in a Bottle. Irrelevant, I don't need them.

Life support on Trypophobia's gravity ring broken. Irrelevant, it only does pressure control and the same function is included in the greenhouses.

1 Converter broken. Irrelevant, converter is the stock isru functionality that I'm not using. I need the chemical plant functionality, and that one is still working perfectly.

Outdated

2 reaction wheels broken on Milly. Now Milly has done its job.

1 dart engine broken on the Mars Descent Stage. Now it's a pile of debris on Mars.

Discounting the low quality and outdated parts, that's 33 critical malfunctions so far.

Edited June 5, 2023 by king of nowhere

[king of nowhere]

Part 16: For every beginning there is an ending

A'Twin visits a couple of near-Earth asteroids before getting parked in Moon's orbit. The crew is returned to Earth, completing the mission.

Splashing down near the Mauritius

16.1) It's not the size of the asteroid that matters

Spoiler

I still have two targets remaining for this grand tour. One is the Moon; I went there twice at the beginning of the mission, but both times I had to reload because A'Twin had some critical flaw. The third time I just wanted to jump straight to testing A'Twin in interplanetary travel, and it was the time that the mothership worked, leaving lunar exploration for later. The second target is a near-Earth asteroid, because I forgot about it.

I was uncertain whether to aim for a big asteroid or for a small one, so I decided I'd go for both. I'd find a small asteroid, grab it, then carry it back to Earth, and I'd also meet with an I class asteroid to see how big they are.

Leaving Phobos

Aiming for the first asteroid

I waited the planar node to eject complanar with the asteroid, since pure plane changes are too expensive in the inner system. So far I'm matching perihelion, I'll get a rendez-vous by properly changing aphelion.

A'Twin doesn't carry any oxidizer except the one required to land Spider. And the one made by bug#31, that I sometimes forget to vent before a maneuver. All in all, I have roughly 8 km/s available.

Leaving Mars

I had a new bug (#42) while there: I left A'Twin burning prograde in background, and after a few minutes it was pointing radial instead. I have no idea how or why it happened, anyway I had to reload. And then I had to periodically check and remake the maneuver. This is not an issue of the orbit moving, A'Twin is in a high Mars orbit with a 6-hours time.

And getting an intercept for the asteroid

Intercept speed will be high. I initially considered having a rendez-vous with the whole A'Twin - I do have the fuel for it - but moving to another asteroid later would be expensive. So I set for a fast intercept and using Fat Man for the task. Like I did catching a "comet" in chapter 11.3.

This is an A-class asteroid, so I move a claw on Fat Man to grab it

Fat Man leaves A'Twin

I already described the rendez-vous procedure in 11.3, and it's not all that different from a normal rendez-vous except for the higher speed. Fat Man has plenty of deltaV.

Here's the asteroid. It looks a bit big for an A class, maybe I'm closer than I look like?

Is that even supposed to be an A-Class asteroid at all?

Yes, I checked the tracking station. This is supposedly an A-Class. It's a lot bigger than anything else I've seen.

I'm certainly not going to move it, but I still want to grab it. I'm moving very slow, let's speed it up with a 2x time warp... Activating 2x time warp sped up time a lot more than it was supposed to, resulting in the ship crashing into the asteroid almost immediately. Bug #43.

Trying to grab the asteroid

Fat Man sinks for several meters below the surface, but it can't ever grab the asteroid. Bug #44. I don't know if it's a bug with asteroids and my mods, or if it's the claw that's malfunctioning after I moved it with EVA construction.

Anyway, I'd grab a sample and leave, except that I realize now that Fat Man cannot store samples. See 11.3, I had the same problem there. This time I do not want to face a long trip with somebody hanging from the ladder, so I just reloaded to grab a crew pod with sample storage capability. And this signals the end of drama for the time being.

I grab the Hartman rover, because it's by far the lightest option I have

Again at the asteroid

Leaving the asteroid after taking samples

Docking back on A'Twin

Now the second asteroid, an I class. If the A-Class was that big, will the I-Class be bigger than its physical range?

Reaching the new asteroid. Timing an encounter was just a matter of a slight change of aphelion. Intercept speed is higher because there is some radial component to add

New part failure! A life support unit on a Dolphin

This time, aging is not responsible. Nothing is aging anymore, see bug #15. And after leaving Phobos, I stopped maintaining the fusion reactors, they all became reversibly broken by now - wow, I forgot how relaxing it is to not have to worry about part maintenance. No, I got a nervous breakdown because Etdania got to 33% stress. How did it happen? He's in a hitchhicker container, TV is on... Bug #45, I guess. I don't know if it's because I'm using the higher level of time warp, or because I left Etdania with Peretto and Jeb inside the same crew pod (Peretto and Jeb are fine, by the way). Whatever the reason, after this event Etdania stress started to reduce.

Nothing else worthy of note until rendez-vous with the next asteroid.

It's always funny to rendez-vous with a large asteroid. It does not show until you enter in physical range. And since it's big, when it does show it seem to appear randomly as a giant object in the middle of the sky.

One second before, nothing to see...

One second later. Was that giant piece of rock supposed to be always there?

Approaching the asteroid at 470 m from its center, which shows it has a radius less than 470 m. Smaller than the previous one. Bug #46

I got one more bug on the close approach, in that the marker signaled a certain close approach, but by that time the ship and asteroid were still getting close to each other, and the real close approach was later, and not shown. Close approaches do have some issues, but I never recorded it. Bug #47. Wow! I got a lot of bugs on this part.

I also tracked how much fuel I'd spend compared to intercept speed, and I discovered that the inefficiency coming from burning close - but not exactly on - retrograde is very small. Less than 1% of the total fuel budget for the intercept.

And that's enough asteroid samples. Now on the final target.

16.2) We choose to go to the Moon in this decade because we couldn't be bothered to do it earlier

Spoiler

To reach Earth in the most favorable way, I combine a small change of aphelion, a small plane change and a raising or perihelion.

Trajectory for Earth intercept. A'Twin has slightly more than 5 km/s left

I have to choose whether to aim directly for the Moon, or to get captured in low Earth and then go to the Moon. The first one will lose much Oberth effect on the capture burn, but it will save the Earth-Moon intercept deltaV.

Direct Moon injection: 1240 m/s to achieve low orbit

Earth injection; capture is cheaper, but overall it's slightly more expensive. Having to change plane to match the Moon's inclination makes the difference

Direct Moon injection it is, then.

Arriving near Earth

And getting captured in a stable orbit

And that's it. A'Twin's final burn of its engines. A'Twin's resting place.

I picked this orbit carefully. Even though I won't be using A'Twin ever again, I like to imagine that it can still be used. It's still in good shape, only needing some serious refurbishing on its main nuclear reactors.

And I placed it there, around the Moon, because it's still got enough deltaV to return to Phobos and start a new cycle. I didn't finish circularization to keep enough fuel for that.

Now I have to land. Spider has enough fuel to make it even though the orbit is slightly elliptic.

Spider coming to land on the Moon

Beautiful desolation

About to land

I have to say, the metallic sheen on the surface looked great on Enceladus and other icy moons, but it made sense there. On the Moon? Not so much.

Landed

And since I was there, I did drive some 40 km to get a second biome. Nothing to report there

Returning to A'Twin was uneventful.

16.3) Organ music for the returning heroes!

Spoiler

At this point I only need to return the crew to Earth.

I could use the Dolphins, they are made for that specific reason. But I like to imagine that A'Twin is ready for more missions, and I'd hate to use the Dolphins, which are still in good shape. So I decided to launch a new vehicle for the purpose. I'm not sure about the rules; the Jool 5 specifically allows that, not sure about the grand tour but the rules are flexible enough. It's not like I couldn't land my crew with the Dolphins if I wanted.

So I decide on a lightweight vehicle with just command seats. 3 tons of dry mass to land 9 kerbals.

The Organ return vehicle, with its launcher

I called it Organ, like the musical instruments, from the thin lines of drop tanks on the last stage looking like organ pipes.

Second boosters separated. I made a point to only use stock parts for Organ, so a rhino engine instead of the cougar. The cougar is better, but the rhino looks much cooler

Fourth stage has 4 darts and a cheetah for gimbaling

Final stage detached

4178 m/s are not enough to reach A'Twin and return, so I added a couple boosters and launched again. But it's not really relevant, I could have saved the hassle.

I also took a bunch of pics to show trajectories, but I realized a rendez-vous in lunar orbit is easy enough that it doesn't require explanations.

Dropping some pipes from the Organ

By the time it reached A'Twin, it could have been renamed Mushroom

Now loading the crew. This is the last time I'll be using this most capable mothership of mine.

I won't ever build something as wonderful. And this is not like the DREAM BIG, where I went back to the drawing board and made a better ship. No, this time I decided I'm done with huge lag and neverending EVAs to service aging parts. I may do other missions, even big ones, but I'm not going to try big ship + breakable parts together. A'Twin is really the last of its kind.

So, nostalgia moment.

Loading the first crewmember, with Earth in background

Loading a second, with Organ barely visible

Organ seen in IVA from the main cupola

The great shot of A'Twin, the Moon, Organ... This has just become one of my favourite screenshots ever

This dude will exit from the top, just to provide a different perspective

Final IVA; everyone is on board, except the dude in the cupola

Unfortunately, even with the additional set of boosters, 950 m/s are not enough to return to Earth from the current orbit.

But wait, no need to reload all the way. A'Twin still has a bit of fuel left on Spider. I can stick a docking port on Organ and refuel it.

Refueling Organ. Bill is still in EVA, he'll put the docking port back after it's not needed anymore

A smidgen of fuel for a 50-ton ship is more than enough to gain 1 km/s on a 3-tons ship. And this is why adding boosters to gain some 500 m/s once in orbit didn't really make any difference.

Had I been out of oxidizer, I could have made tens of tons more from the water on board. I could also have used the one that keeps getting replenished from bug #31, but taking advantage of a bug like that would be cheating.

Organ leaving. Goodbye, A'Twin! My most capable mothership ever

what? Why my crew is dieing?

I provided oxygen and food for 10 days, while 3 would be needed for the return. As for CO₂, I figured EVA suits have chemical filters, and I had no idea kerbalism was actually tracking those, or how long they'd last. This is 15 hours after leaving. But I did some experimenting, and the time passing before kerbals on the seats start dieing for CO₂ poisoning does not seem fixed.

So, when I said that Milly the Venus ascent vehicle could stay in orbit a few days if needed, I was wrong. Good thing I got a rendez-vous real fast.

Anyway, not wanting to lose all the time by reloading back to Organ launch, I find an easier solution: just send Fat Man with Organ. Fat Man has plenty of scrubbers to clean the air.

Organ being towed by Fat Man

I have to keep the crew on the external seats, though, because there are not enough internal seats.

Clean air is no longer an issue. The impossibility to change diapers still is, though.

A few hours before Earth, Organ is detached. Fat Man will skim the atmosphere, Organ will make a burn to lower periapsis

By the way, Organ has a second engine for emergencies, under the first, in case the first malfunctions. I found no other place to mention it.

Jettisoning the engine and other paraphernalia, only the reentry pod remains

20 g are hard on the crew, but they are safe

Splashed down

And this concludes the grand tour. 367 real Earth years, equivalent to more than 1000 kerbal years. All this time running maintenance to the ship. Fighting lag. Fighting bugs. Taking forever. My first saved game file for a test is on 12 march, so this mission took 9 months and a half of gaming.

A unique achievement, I doubt anyone else will have the patience to repeat it in the same conditions.

Final bug compilation

Spoiler

A numbered list is so convenient to refer to bugs quickly. This list keeps growing. Problem and Solution

1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

4) Propellers start twisting around. No worry, it fixes once you stop time warping

5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

10) I can't plan maneuvers or go EVA, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: save before exiting time warp

13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

17) Crew hatch registers as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

20) Upon starting the game, clicking on the VAB does not work. Clicking on the icon on the bottom left corner of the screen still works

21) Sometimes elements of the HUD change size. It doesn't affect the game, and seem to revert spontaneously

22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason. Load Cylinder into physical range and they restart

23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced. Reload when it happens, and it will get fixed

24) The ground on Titan and a few other bodies has all sort of glitches and malfunctions. Complex. See 7.3 for more details

25) Negative aerodinamic drag displayed on the user interface. Drag is still behaving normally, it's only the display that's bugged

26) The docking port on Clamp has all kinds of problems, does not allow fuel transfer, can't be removed. I stuck another docking port there, and I can grab Clamp with a claw if needed

27) Sometimes there is no signal for probe control even though there should be. Switch to the vessel that's not being seen, then back to the probe

28) Crew pod of Hartman rover has a broken life support and a functional wheel, but it instead appears to have a working life support and a broken wheel. Nothing I can do about it; but it still works

29) The sun shines through Jupiter's body as if it was part of the sky. It's just an harmless visual glitch

30) An object on the surface coming into physical range may be loaded tens of meters above it. Hope nothing explodes. Reload if necessary

31) Cylinder's central tanks gets refilled on (useless) oxidizer upon reloading; see 10.2. Dump the dead weight again

32) All mining drills suddenly manifested a new uranium drilling function. Can't revert it, but they still work normally; it seems harmless

33) The game is not spawning comets. For the comet landing, pick a large asteroid in an inclined, eccentric orbit and pretend it's a comet

34) Flags are planted hundreds of meters in the air. Sometimes this crashes the game. Just reload if it happens

35) Fuel transfer is asymmetrical even when it should be symmetrical. Manually fix to ensure even distribution of fuel

36) Wheels do not work on Triton. Driving a rover can be skipped

37) Resources can appear from nothing when exiting time warp. It's benign, and those resources are not enough to make a significant difference     

38) Sometimes trying to delete a maneuver node crashes the game. Reset the offending node to 0 m/s instead of deleting

39) Strange semicircles of color appear randomly on the screen. It seems to be a harmless visual glitch

40) On Charon, an EVA kerbal can explode in midair, ostensibly for hitting the ground. Alt-f12 the ship in orbit. Go EVA to service the reactors. Alt-f12 the ship back in its place

41) An error message stops time warp (see 15.2). Restarting the game fixed it

42) After a while, a prograde maneuver starts pointing the ship radially (NEW). When the maneuver marker is not pointing where it should, delete the maneuver node and create a new one

43) Using time warp near an asteroid has nefarious consequences (NEW). Do not use time warp near an asteroid

44) Can't grab an asteroid with the claw (NEW). Do not grab an asteroid

45) Etdania got stressed even though he should not have (NEW). No idea, but it didn't happen anymore. See 16.1

46) Asteroids do not have the size they are supposed to have (NEW). Nothing to be done, but it does not create problems with the mission

47) Close approach markers are not accurate (old, but wasn't in the list). Trust the navball over the map view

I recorded and catalogued 47 different bugs. Some mostly harmless, some mission-critical. Some specific to a certain location, some general. Wow. At times, it felt more difficult than navigating the solar system. At least, when navigating the solar system I can rely on physical laws behaving like they are supposed to do.

Too bad I didn't got 2 more bugs. 49, 7², could have been a nice number for ominous quotes. "Thou shalt be struck by bugs not seven times, but seven times seven"

Final broken parts recap

Spoiler

Life support

1 life support broken on Dolphin 1. I've got five more redundant pieces on it.

2 life support broken on Dolphin 2. I've got four more redundant pieces on it. (+1 NEW)

1 life support broken on Cylinder. It's a redundant piece of a redundant piece. Least concern.

1 and only life support broken on Hartman. Sucks, I can't take extended trips, but the rover has enough air to conduct landing operations safely.

1 life support broken on Fat Man. I've got five more redundant pieces on it.

1 and only life support broken on Nitrogenie in a Bottle. No problem, it's not supposed to carry a crew any longer.

Nuclear power

8 Excalibur reactors broken. This is stretching A'Twin's resilience; but they lasted long enough to reach the end.

Reaction wheels

2 large reaction wheels broken. I've still got 88 working.

1 medium reaction wheel broken on Clamp. I've got a half dozen spare ones in storage.

2 medium reaction wheel broken on Nitrogenie in a Bottle. I've still got a half dozen spare ones in storage.

reaction wheel on the crew pod broken on Nitrogenie in a Bottle. Can't be replaced, but the other three wheels should be enough to keep the plane stable even if I break a lateral engine.

Engines

4 big nervs broken. I had three spare ones. Now the ship is working with 22 engines out of the original 24.

2 big wolfhound broken. I had a spare. Now the ship is working with 4 engines out of the original 6.

1 small nerv broken on Fat Man. I've got 2 more spares, then I can start cannibalizing Nitrogenie in a Bottle.

1 cheetah broken on Spider. I've got 2 more spares.

Communication

1 RA-100 dish broken. I've got 5 more redundant pieces. After that, I still have more non-relay antennas.

1 HG-5 antenna broken on Wings B. I've got 1 more spare. After that, the mission can still use normal non-relay antennas.

1 Communotron 88-88 antenna broken on Fat Man. It was itself a spare part, and I have more spares, as well as redundant antennas.

1 Communotron 88-88 antenna broken on Wings A. I've got a few more spares; then I can cannibalize antennas from Trypophobia if really needed.

Others

1 radiator panel broken. I had 12 redundant. They should be needed to vent heat from the nuclear reactors, but they are not actually needed anyway.

Drills

Drills never got broken, even though I stopped checking them 300 years ago. Bug #15 working in my favor.

Chemical plants

Chemical plants  never got broken, even though I stopped checking them 300 years ago. Bug #15 working in my favor.

Low-quality parts

A landing light broken on Nitrogenie in a Bottle. Irrelevant, I don't need them.

Life support on Trypophobia's gravity ring broken. Irrelevant, it only does pressure control and the same function is included in the greenhouses.

1 Converter broken. Irrelevant, converter is the stock isru functionality that I'm not using. I need the chemical plant functionality, and that one is still working perfectly.

Outdated

2 reaction wheels broken on Milly. Now Milly has done its job.

1 dart engine broken on the Mars Descent Stage. Now it's a pile of debris on Mars.

Discounting the low quality and outdated parts, A'Twin suffered 34 critical malfunctions.

The malfunction count was severely skewed by bug #15. Still, A'Twin showed that it could have tanked upwards to 100 broken parts before being severely affected.

17) Aftermath: no more kerbalism?

Spoiler

This is the last mission of this kind that I'll run.

First, with the conquer of the real solar system I really run out of ways to increase the difficulty. I'm thinking of trying whirligig world, other players spoke well of it, but it can't be harder, can it?

Second, I really can't improve the mothership anymore. Not significantly. Unlike in all my previous missions, where I always had moments of "this could have been better if I had made things differently", this time I never had one such moment. The ship is the best that can be done with the mods I use, or close enough.

But most important, I have done enough maintenance. I don't want to spend hours and hours flying around a massive ship at high lag, running around all the nuclear reactors.

I also feel like I have conquered kerbalism. For the first time, all the denizens of kerbalism were controlled. I never had to almost scrap the mission because of issues with life support or stuff.

Parts breaking was not a problem. I brought lots of spares, and it worked. Parts breakage was countered by additional mass. In fact, I'm thinking running future missions with no parts breakage, and adding some ballast to simulate spare parts. Same result, less lag, less nuisances.

Solar storms have not been an issue for a long time.

Stress was solved, by selecting the crew and having a luxury ship.

Isru was solved, it requires nuclear reactors and very heavy converters.

Life support was basically solved, I never had a shortage of anything. By carrying 200 tons of resources I got 60+ years worth of life support for 9 crewmembers.

Radiation belts still constrain trajectories, but nothing can be done there.

So I really could play stock, carry a big ballast to simulate all the spare parts and life support resources and chemical plants, roll a dice for where I'm allowed to refuel, and it would be functionally identical to using kerbalism. And 90% faster.

Still, playing just stock would feel wrong now. Not having to worry about food and stuff feels like cheating.

I could deactivate part breakage and keep everything else, that would still allow a huge part reduction.

Well, I'll see. I have a few ideas of stuff to try. As soon as I have again enough free time in my life.

Edited June 5, 2023 by king of nowhere

[Stamp20]

8 hours ago, king of nowhere said:

So I decided to launch a new vehicle for the purpose. I'm not sure about the rules; the Jool 5 specifically allows that, not sure about the grand tour but the rules are flexible enough.

Separate crew return vehicles are allowed.

[SkyFall2489]

I'm pretty sure the ground tether thing is from USI tools, a dependency of most of the USI/MKS mods. Sometimes, I have USI tools alone installed just for this feture, it's really helpful at preventing landed bases from being kraken'd.