Project Intrepidity- a Kerbalism Grand Tour (attempt)

[jimmymcgoochie]

I was going to go back to my RSS/RO/RP-1 career game (which I've been documenting here: https://forum.kerbalspaceprogram.com/index.php?/topic/198428-terranism-space-program/), but then I read some mission reports of people doing a Grand Tour in the stock Kerbol system with the added complications of Kerbalism- life support, part malfunctions, crew health, stress and radiation and more will put all sorts of constraints on the designs that a pure stock Grand Tour doesn't have to worry about. This being a difficult and complex challenge, I decided to jump in at the deep end with the difficulty set to hard, at least as far as Kerbalism is concerned, with only minor tweaks to the settings to reflect the fact that the 'plants' bonus doesn't seem to be working any more; most of the regular settings are left as they are, but I'm allowing reloads and reverts both to avoid game glitches and to give myself a chance at some practice runs for the trickier landings; landing on the Moon is easier than landing on Tylo due to the much higher gravity and orbital velocity.

While the mothership is entirely of my own design, I saw no need to reinvent the wheel when it came to the various landers I'd need to put boots on the ground on every planet and moon in the system, so I took a quick look on KerbalX and found a few promising designs: an Eve ascent vessel, a dinky SSTO that could be perfect for Laythe. A few minor upgrades were necessary- removing ISRU equipment, since Kerbalism does its own thing with that and makes it virtually useless as a result, adding radiation shielding and some backup parts in case something important fails and can't be replaced, and then adapting everything to be lugged around by a single huge craft, requiring some interesting uses of docking ports which should make the design a bit more modular, helping to shed dead weight when it's no longer needed.

By pure chance, the upper stage of the Eve ascent craft I found works brilliantly as a lander for pretty much everywhere else, with the obvious exceptions of Kerbin, Laythe and Tylo. With the addition of a single parachute on top for the Duna landing, it'll work fine for Moho, Gilly, Mun, Minmus, Duna, Ike, Dres, Vall, Bop, Pol and Eeloo. With a good descent stage, it'll do for getting back into orbit from the surface of Tylo too.

The single biggest problem with doing a Kerbalism Grand Tour is Jool. Specifically, the terrifyingly powerful and absolutely vast radiation belts that surround Jool and make its inner three moons incredibly dangerous to approach. The inner belt will mean instant death if you enter it, and extends out almost to Laythe's orbit; the outer belt is less lethal, but will still kill you if you don't have a lot of shielding, or even if you do and just stay there too long, and extends out beyond Tylo.

Those radiation belts are driven by solar output and the planet's magnetic field, so they're a bit lopsided as the solar wind pushes everything outwards- when it's closest to the sun, Tylo is right at the very edge of the outer belt and so will have a relatively low level of radiation, making that the best time to land; conversely Laythe's orbit comes dangerously close to the inner belt when it's being eclipsed by Jool and even Bop isn't necessarily safe when furthest from the sun. To survive getting to Vall and Laythe will require maximum radiation shielding, but this is heavy and reduces delta-V by a noticeable margin (though not by nearly as much as it does in RO/RP-1!). For this reason I plan to have three different variants of that 'lander' design: one with no shielding to land on Eve where any excess weight must be ruthlessly cut to stand a chance of escaping, which will also work for most other planets and moons; one with a little bit of shielding to land on Tylo, and probably Moho as well since it has a weird radiation belt going around its equator at low altitude that could be problematic; and one with maximum shielding to land on Vall, which I'll probably carry a second copy of in case of irreparable malfunctions before I get there.

So far I've spent four days worth of KSP-ing on this, purely doing design and testing work on the main ship, its propulsion systems and the various extra bits that will be needed for this undertaking.

A few screenshots of what I've been up to so far:

Spoiler alert- yes, yes we will...

It looked a bit like Kerbin rising over the Mun, then Jool showed up.

A night flight on Laythe with Jool hanging low over the horizon and Vall lurking at the very top of the image.

The Eve ascent craft was fine for the surface to orbit part, but had absolutely no ability to go from orbit to the surface in the first place. Quite a few attempts later I came up with the simple solution of "staple a bunch of big wings to the pointy end to keep it going heatshield first", which worked better than I was expecting and also means it has some semblance of control via the aerodynamic surfaces, which double as airbrakes too.

One parachute on top and some simple landing legs on the bottom are enough to make the second stage of the Eve ascent craft able to land on Duna too. This kind of reuse is going to be critical to keep the weight and parts count down on this mission. EVA construction will be put to use for this one, another reason to allow F5/F9 since it can be a bit unpredictable.

That's all for now, but I'll be posting updates to this when I have them and fully intend to complete this challenge.

Spoiler

Why "Intrepidity?" Well, it's a simile for Audacity

 

[king of nowhere]

hey, that's nice! i practically started a new fashion, and gave a new long term challenge for those people skilled enough to do practically everything in the stock game...

[jimmymcgoochie]

30 minutes ago, king of nowhere said:

hey, that's nice! i practically started a new fashion, and gave a new long term challenge for those people skilled enough to do practically everything in the stock game...

So this whole thing is your fault then? 

I’m trying to build a much smaller craft than your Dream Big, just to make the game run at something close to real speed for the several hours of burn time I’ll end up with 

[king of nowhere]

15 minutes ago, jimmymcgoochie said:

I’m trying to build a much smaller craft than your Dream Big, just to make the game run at something close to real speed for the several hours of burn time I’ll end up with 

well, you can definitely get away with something smaller. when i made the dream big, i had no idea exactly how bad would have been the various component breakdown. i only knew i'd need redundancies, and i decided to err on the side of exaggeration safety. you should definitely plan to have multiple copies of anything vital, but you don't need a dozen.

[Spaceman.Spiff]

18 minutes ago, jimmymcgoochie said:

much smaller craft

Will you be using mods other than Kerbalism?

[jimmymcgoochie]

3 minutes ago, Spaceman.Spiff said:

Will you be using mods other than Kerbalism?

I’m trying to do this without using parts mods, just what Kerbalism includes itself and what it does to the stock parts. DLCs are stock in my book so I’m using both of them and Restock just changed how the parts look rather than how they work so that’s fine, but so far the only part I’ve used outside of that so far is the 3.75m docking port from Restock+, and I can probably remove that since I now have a nice little launch rocket that can handle up to 2 kiloton payloads...

[jimmymcgoochie]

The Intrepidity is nearly complete:

On the top, the lower stages of the Eve lander; they're heavy and only have one purpose, so I'm aiming to go to Eve as soon as possible so I don't have to drag it around everywhere else.

Attached just below the top cupola, four lander craft- Mk1 pod, FL-T400 tank, Terrier engine, some gubbins to provide power and some more gubbins to dock them to other things at either end. One has no shielding to be used on Eve, where delta-V is critical and radiation is less of a concern; two have maximum shielding to go to Vall, there's a spare in case of critical part failures as Jool is pretty late on my list of destinations; and one has a little bit of shielding to land on Tylo, and possibly Moho too as it has a weird little radiation belt around its equator. They have ~2400m/s or so of delta-V each, depending on shielding levels, so will be more than adequate for landing anywhere else- I tested one on Duna and with a single parachute stuck to the top it landed with no issues and made it back to orbit with fuel to spare.

Below those, three boosters/space tugs- one of these will do the Tylo descent, another is a spare for that and the third will be used to throw landers around if necessary. There's a 1.25m>0.625m docking adapter on the fourth port where the Laythe plane will go, it can't be added on in the editor as it uses an inflatable airlock as its docking port, which has no front attachment node.

The central core consists of a Hitchhiker, lab module and a greenhouse which I'll use to produce extra food when close enough to the sun and then switch off when it starts drawing too much power. Plenty of interior volume for a crew of three, no problems with stress, all fully shielded plus three active shields and the radiation detox unit in the Hitchhiker should mean radiation isn't a problem either; that RDU will be getting used A LOT around Jool!

Below the crew section is a sort of service module, containing batteries, reaction wheels, food/water/oxygen for the crew to stay alive, nitrogen for pressurisation, hydrogen for the emergency fuel cells, many backup life support systems and lots of spare parts packed into a big cargo container. There are three active shields to protect against low level radiation, effective against up to 0.12rad/h which is much more than you'll get from the sun under normal circumstances, but will do almost nothing at all against the radiation belts of Kerbin, let alone Jool. Two enormous solar wings house a total of 44 Gigantor solar panels, with four more on the central module to provide power when the ship is under construction. Four Communotron 88-88 dishes- two on the body and one on each solar wing- cover long-distance communications.

Under that, the propulsion module- the central core has 16 NERVs and a single Wolfhound engine, with each of the eight radial boosters housing another eight NERVs and one Wolfhound apiece. Each radial booster has its own solar panels, RCS and reaction wheels, radiators, control core and a small relay dish to allow remote control, as well as a small docking port on the top which could be used to dock a lander or the Laythe plane to, to get them where they need to be- or back to the mothership.

Fully fuelled and including the Laythe plane, this thing is looking like it'll weigh close to 3500 tons; initially I thought I might be able to launch up to 400 tons at once meaning one propulsion module at a tine, however...

Things get a lot easier when you can launch over 1500 tons on a single rocket!

I tested it with four of the radial boosters for Intrepidity and it handled them with no trouble at all:

Unfortunately things didn't go so well when I started docking them together for orbital storage- one three were connected up the whole thing tore itself apart in seconds. That pesky Kraken...

I tried again, but launching most of the ship in a single go, minus fuel. Things were going well, right up until the boosters were due to separate; the game froze for over a minute, then...

A quick test flight of the Laythe plane I'll be using proved a) it's more than capable of getting down from an orbit higher than Bop's, aerobraking aggressively in Laythe's atmosphere to a direct descent, landing, flying back to orbit and then escaping Jool's radiation belts again, and b) that if I do all that, the pilot will inevitably die of radiation poisoning several days before escaping Jool's radiation belts.

It's a good thing I have some space tugs and maybe even one of the radial boosters to hurl stuff around much faster than the most efficient Hohmann transfer, between that and some good timing I might be able to dive through the belts, land, wait a while for the next escape window (radiation on Laythe's surface is very low, the atmosphere absorbs most of it somehow so it's relatively save down on the surface) and then burn like crazy to escape again.

Now, I could try launching this thing in many pieces and building it in orbit... Or I could install the KSTS mod to pre-record a flight of that mega-rocket carrying some ballast as payload mass, launch a space station with it, then use the space station as an orbital shipyard to build the Intrepidity in orbit instead, costing me nothing but time- nearly 300 days in fact- and saving me a lot of hassle with docking thousands of tons of spacecraft together with the frame rates chunking along like a slideshow due to the huge part count. I'm doing a Grand Tour with Kerbalism on hard settings, why would I want to complicate things any further than I already have?

The only problem with the KSTS route is that it sometimes goes a bit, er, wrong...

That was supposed to be the same Laythe SSTO shown in the image above, but somehow it got utterly mangled when it spawned in and I barely managed to deorbit it before putting a replacement in orbit and docking it to the station for safekeeping.

The first window to Eve is over a year away, so there's plenty of time to do some additional test flights to make sure everything works before I set off.

There's also time to select my three plucky Kerbonauts who will be making this fateful trip- rather than use Jeb, Bob, Bill and Val I'm going for three totally new Kerbals, one scientist to run the lab and two engineers to repair stuff and do EVA construction. No pilots- between probe cores and MechJeb I don't need them.

[jimmymcgoochie]

I just put Intrepidity through its paces in orbit, and oh dear...

2FPS at best, dropping to 1 at full power; 6 seconds of real time per 1 second of game time; at x4 time warp it actually becomes seconds per frame and still takes 3-4 real seconds per game second- and all this AFTER I stripped out a hundred or so parts by simplifying some of the secondary propulsion modules.

This isn't going to be workable, 4 minutes of game time took almost half an hour and the apoapsis was barely half way to the Mun by that point.

Solution 1: use some mods to cut down on part count- 5m fuel tanks carrying only liquid fuel would be particularly useful, supersized solar panels to generate loads of power would be good but could backfire due to part failures, even bipropellant (LF/Ox) multi-nozzle RCS thrusters would be helpful; but this would take away from the challenge of doing this as stock as possible- the stock system shouldn't need (m)any mods to do a Grand Tour even with Kerbalism.

Solution 2: increase physics warp rate considerably, hope everything doesn't disintegrate (which is pretty likely).

Solution 3: persistent thrust? Burn in the background so the vessel isn't loaded and the game doesn't chunk along at glacial pace, but not sure how that would work as I've never used it before.

Solution 4: go with it as it is, let MechJeb worry about throttling down once the burns are done and pay attention to other things while KSP runs in the background for a very, VERY long time.

Thoughts anyone?

[jimmymcgoochie]

Kraken montage:

In other news, persistent thrust turns out to work pretty well- it runs about 10x slower than it should, so at 10x time warp game time actually runs at real speed- but further experiments will be required before I know it'll do what I need it to do. I also think I know how to get to Laythe and back without radiation killing the poor chump who gets sent down there- using one of the space tugs (slash spare Tylo descent stage) as an expendable booster gives enough delta-V to crash down through the Jool Death Zone^TM and only take 48% radiation damage by the time they land on Laythe, with the spaceplane itself handling the return and with some decent timing making it back out again without reaching 100% radiation. Laythe's surface has just 1% of the radiation that you get in orbit so staying on the ground until the last possible moment will be key; having to wait for even half an orbit before the escape burn could be lethal.

I've also made some changes to Intrepidity's engines, swapping the Wolfhounds on the outer boosters for more NERVs- less thrust, but better efficiency and the way they're feeding fuel that's more important than outright thrust, I can break up the longer burns into bitesized chunks to avoid wasting fuel.

[king of nowhere]

it's a bit like watching my life from outside...

what's your part count? the Dream Big wasn't so bad, and it was 1300 part. My pc is a good laptop, but not excellent, and a fixed pc could get more powerful

wait, there is another trick. the game has some issue with ram usage, where it keeps accumulating it. you have to close and restart it regularly when using big ships. try that and see if it works

regarding the laythe plane, is it shielded? on a fast trajectory, a vehicle with shielded habitats should get around 10-15% radiation on its way to Laythe.

Edited May 15, 2021 by king of nowhere

[jimmymcgoochie]

@king of nowhere maximum shielding, to the extend that it makes the plane sink if it lands in the water, but I still get huge radiation issues going down to Laythe from a 100-125Mm orbit of Jool, the best I’ve ever done is 48% irradiation to the surface and I might be able to push back out again in the high nineties; shielding efficiency is worse with higher difficulty levels so this might explain the discrepancy.

I was at 1100 parts, trying to cut that down by trimming anything I don’t absolutely need to try and make the game (more) playable.

[king of nowhere]

2 hours ago, jimmymcgoochie said:

shielding efficiency is worse with higher difficulty levels so this might explain the discrepancy.

i missed the part about being at higher difficulty. yes, that triples the radiation. still, in my current run - at hard level - i managed to reach laythe at 30% radiation damage. i did have to make a burn directly towards the planet, though, spending a good 1000 m/s extra between accelerating and braking. when going through the death zone, even just saving a few minutes make a difference

Edited May 15, 2021 by king of nowhere

[jimmymcgoochie]

I’m at the stage of considering a direct approach from the Jool transfer, bombing down at interplanetary speeds with an expendable booster just to slow down to a survivable speed before tanking into the atmosphere. Relies a lot on very precise timing though, plus I’d also have to capture the main ship into a high Jool orbit at around the same time which could get messy... Vall should be a bit easier, but now I’ve also discovered that using even one unpressurised pod (Mk1 pod or cockpits) makes the entire ship unpressurised- even when their habitats are disabled; really ruins the stress score, but there’s nothing I can do to fix that.

Or is there? A little part hack here and there would do the job nicely methinks.

[jimmymcgoochie]

The almost-final design for Intrepidity, now featuring modified 3.75m fuel tanks containing 100% liquid fuel because the heavily clipped Mk3 fuselages caused many explosions whenever I tried to load it in after switching vessels.

Some minor tweaks were made after I took this image- the radiators and struts on the boosters were removed to save weight. I've ditched the lab and greenhouse idea and just gone for two Hitchhikers instead, which reduces weight but also dramatically reduces the space inside so it's a bit cramped for three crew- but just fine for two. Yup, I've changed the plan again- now I'm only sending two Kerbals on this mission. I've added some chemical plants for some added utility- turn waste into shielding, turn CO2 into O2 and shielding, electrolyse water to replenish the fuel cell fuel and turn ammonia and oxygen into nitrogen and water, though that last one won't be used much- and a pair of RA-100 relays have replaced the 88-88 dishes attached to the main body so that when the landers are out, er, landing, they can still communicate back home and be slightly less stressed as a result.

I reduced the shielding on the crew modules to half of maximum- a tactical risk, since the huge 5m fuel tank and the boosters will be a perfect sun shade to protect the crew from solar flares and the active shields will handle the rest. No entering into Jool's radiation belts, but then again I didn't plan to with this thing.

A few save hacks to remove all autostruts later and it was in orbit, not exploding, and the Laythe SSTO could join up to complete the assembly:

Oops... Not to worry, it's not like there are nearly a hundred nuclear rocket engines here or anything 

Assembly complete! Intrepidity is now ready to depart, all its resources fully topped up. All that's left is to send the crew up, plot the course for Eve and this grand adventure can finally get underway.

Those huge solar arms, though... They bother me a bit. 44 high-quality Gigantors plus the associated structural girders are adding a huge amount of dead weight which won't be needed until I go out to/beyond Dres, and are currently producing about 900EC per second which I just don't need right now. If I could, I'd leave them behind for the visits to the inner system and then pick them up again when needed, say around Duna; but that goes against the idea of the Grand Tour- one ship for everything, no splitting up and going in different directions because it's convenient. I can take some solace in the fact that that big, heavy Eve descent/ascent stage on the front will be getting dropped off at the first port of call, removing over 90 tons and a hundred or so parts from the equation.

Spoiler

Actually, now that I think about it, why am I using solar panels at all? They're colossal overkill in the inner system and by the time I get out to Jool and Eeloo they'll produce barely any power. RTGs could be the way to go, despite the radiation they emit and the 28 year half-life that will slowly decrease their power output. I'd need about 60 RTGs to produce enough power for Eeloo even after they'd lost half their output, and could attach them to the ends of really long booms to keep them away from the crew section. Those four panels on the core of the ship will be enough to power it anywhere inside of Duna even if one or two fail, then a big cluster of RTGs would provide the power further out with much less mass than those big solar panels and without the risk of part failures. There might be a refit in the near future!

 

[jimmymcgoochie]

One last "refit" (read: magic teleportation of a replacement craft into LKO and mysterious disappearance of the old, with a few gratuitous explosions thrown in for good measure) and Intrepidity is now nuclear-powered, with the four Gigantors on the main body able to handle all the power needs close to the sun and 48 RTGs to power it out to Eeloo.

All that was left to do was send up engineers Alice and Stephanie, top up all the tanks and plot a course for Eve.

The transfer to Eve wasn't particularly bad at about 1600m/s, but due to an appallingly bad TWR of just 0.16 that would take over 15 minutes of solid burn time- at under 1/5 real speed. Instead, I split the burn into a series of 200m/s chunks, each taking 2 minutes to complete, which cut the final burn time by half but also meant multiple engine starts and repeated trips through Kerbin's inner and outer radiation belts- 10% radiation damage before they've even gone past the Mun's orbit isn't a particularly auspicious start, but the radiation detox units in those Hitchhikers can heal them on the long trip out to Eve.

I ditched persistent thrust as I thought it might be messing up my trajectory during time warp with the engines off, but the replacement (better time warp) was no help at all- engaging any form of physics warp with something this big and with so many pieces tacked to the sides caused some alarming wobbles that could easily have torn the ship apart even with the relatively slow acceleration rate.

Five long burns (and a few real hours) later, Intrepidity is on its way to Eve to begin this Grand Tour. The intercept is mediocre at best, but I'll fix that later.

At this point it's too late to make any changes to the design, so if there's something missing that's mission critical then poor Alice and Stephanie are doomed; though with so many high quality parts, multiple redundant backups of all the life support systems, about a hundred repair kits and supplies enough for three Kerbals to last the entire trip rather than just two, they should be fine.

[jimmymcgoochie]

A small course correction half-way to Eve made for a nice low periapsis and a nice equatorial orbit. Capturing will take time, but I decided to save myself some fuel by leaving Intrepidity in a more elliptical orbit and just send the Eve lander down to the surface from there.

A bit of EVA construction was required, both to ready the lander and to fix a strange issue with one of the fuel hoses on the inner boosters- it had somehow clipped straight through the central tank and attached to the opposite side booster, causing uneven fuel draining which required TAC fuel balancer to fix; I took the opportunity to drain two of the outer boosters and ditch them to save weight, though this also undoes most of the TWR gained from burning the fuel to get here.

I only took engineers, but that's no reason not to try some EVA science:

Doing EVAs at really low frame rates is actually pretty difficult, since the poor Kerbal keeps trying to fix their heading but always overshoots; doing EVA construction even more so. I'll need to fix the settings so they don't keep trying to face camera forwards, and to separate 'rotate to camera' from 'go down' as both are bound to the control key.

Followed by a very slow and precise docking- those ladders have to line up or there'll be no flag planting (or a flag planted but no return):

Initial deorbiting with the SRBs:

I've tried many different aerobraking altitudes, but it seems the planet is in the worst position possible- the periapsis is about 30 degrees in the night side of Eve and almost everything from there to the opposite horizon is ocean of some kind. I think I'll wait until the opposite side of the planet moves into the light before attempting to land on land, as this rocket simply can't take off from water.

Amazing to think that it took several hours just to do this. I was hoping to actually land today, but it looks like that'll have to wait until tomorrow. On the bright side, that lander actually runs at full speed and after watching the 2FPS, 1/6 real time slideshow during the capture burn it's like playing a completely different game!

[king of nowhere]

2 hours ago, jimmymcgoochie said:

Doing EVAs at really low frame rates is actually pretty difficult, since the poor Kerbal keeps trying to fix their heading but always overshoots; doing EVA construction even more so. I'll need to fix the settings so they don't keep trying to face camera forwards, and to separate 'rotate to camera' from 'go down' as both are bound to the control key.

it shows you've not been running megaships for long enough.

I got used to low frame rate, and now i move easily in EVA with the lag. On the down side, when i don't have a huge ship to slow down the game, I have problems because the kerbals move and react too fast

(i'm actually overstating it; Bolt is nowhere near as laggy as the Dream Big, and I'm getting used to working in real time again. but still, i handle the jetpack better with a bit of lag)

[jimmymcgoochie]

7 hours ago, king of nowhere said:

it shows you've not been running megaships for long enough.

I got used to low frame rate, and now i move easily in EVA with the lag. On the down side, when i don't have a huge ship to slow down the game, I have problems because the kerbals move and react too fast

(i'm actually overstating it; Bolt is nowhere near as laggy as the Dream Big, and I'm getting used to working in real time again. but still, i handle the jetpack better with a bit of lag)

I’m sure there’s a Dark Knight Rises quote in there somewhere...

”Oh, you think lagginess is your ally. But you merely adopted the lag; I was born in it, moulded by it. I didn't see the framerates until I was already a man...”

[jimmymcgoochie]

After weeks of planning and testing, and several days of painfully slow progress for the mission itself. the first flags of this Grand Tour have finally been planted:

On Eve-

And following a brief pit stop to refuel, and swipe some food/water/oxygen pods from one of the nuclear boosters to extend the lander's duration from 5 days to over 200, on Gilly-

Following both landings, the Space Tug was deployed with a Docking Adapter to catch the lander and bring it back; in the case of the Gilly run, because the lander actually ran out of fuel during the rendezvous.

I tried a bunch of experiments over Eve and Gilly, but unfortunately I forgot that unlike in RO/RP-1, with 'stock' Kerbalism there's very limited data capacity on parts- only enough data capacity for a crew and EVA report from the surface of each body and one sample slot for the surface sample; Alice was very upset that her nice Eve rock (that she spent several minutes running around in a full spacesuit, in 1.7G, in nearly 400K temperatures, to collect) had been left behind, and Stephanie tried various EVA experiments on and around Gilly that ultimately had to be deleted to free up the storage space for the crew and EVA reports.

To resolve this issue, I've added an antenna to this particular lander (stolen from the Docking Adapter, which doesn't really need it) so it can transmit its data and theoretically get more science. Not that science really matters in this whole thing, but I want to see how much I can get with the limited selection of experiments I've brought with me.

Full album: https://imgur.com/a/rEJoO9p

The next Moho window is in 55 days and costs 5km/s delta-V in total, or I can wait another 120 days and save 500m/s; I might look into doing Eve->Eve->Moho trajectories to get a gravity assist of some sort to bring that number down, since I currently have about 13km/s in total left on the nuclear engines, though that's improved recently as I got rid of the heavy Eve descent/ascent stage. I'm a little bit worried by how much fuel I've used so far just going to one planet, but with Eve and Moho done it should get a lot easier from there.

[jimmymcgoochie]

I’ve been thinking...

The Eve lander/ascent system was nearly a hundred tons and a hundred parts, so I went there first to get rid of that weight and to deal with the most difficult landing first. Now that that’s over with, I have no less than five attached craft to deal with Jool- landers for Laythe, Vall and Tylo plus a descent stage for Tylo and I’ll need to sacrifice either the Space Tug or the backup Tylo descent stage, or possibly a nearly empty nuclear booster, to get to Laythe and back before radiation kills the crew; several are full of heavy shielding and all can be used then dumped, dramatically reducing the dead weight being hauled around the system.

Eve to Jool might be expensive, but I could try to use Eve and/or Kerbin for gravity assists to save some delta-V. Once at Jool, the biggest challenge is getting to Tylo- the descent stage is only for the descent, and likewise the ascent stage will only do the ascent, so I need something else to get them into low Tylo orbit; either I’ll need to use a Space Tug to tow them out there, then tow the ascent stage back to Intrepidity, or I could take a risk and send Intrepidity itself into Tylo orbit, timing it just right to get the minimum possible exposure to that deadly radiation belt- go in, capture, land and return within one orbit then leave within a second orbit.

The backup Tylo lander then takes the Vall lander to and from Vall, with some EVA construction surgery on the lander to dump any parts I can (fuel tank and engine mostly) to save weight; the landing stage can manage about 2700m/a with the Tylo lander, so I’m budgeting about 2400m/a with the heavier Vall version. If I have to, I’ll do the rendezvous back to Intrepidity with the Kerbal clinging to a ladder to gain more delta-V as I really want to have the Space Tug around for other planets, so I want the backup Tylo landing stage to come back from Vall to then fling the Laythe plane at Laythe.

Once I’ve done the inner moons of Jool, the rest of this Grand Tour should be a piece of cake 

[jimmymcgoochie]

Just doing the maths here and I don't think I'll make it to every planet and moon . The real issue is Moho, solely because it takes so much delta-V to get there- and to go from there to anywhere else- and its small SOI means long burns at high speed are particularly tricky. It takes about as much fuel to go from Eve to Moho as it does to go from Eve to Jool!

Eve to Jool is 4500m/s; call it 5000 after cosine losses from the very long burns (25 minutes for a single continuous burn) and any course corrections necessary to get into an orbit vaguely matching Laythe/Vall/Tylo.

Once in orbit around Jool, the landers for Laythe, Vall and Tylo can be used and ditched; that's one plane, one heavily shielded lander (or two, I have a spare in case of hardware failure) and a lightly shielded lander plus the Tylo descent stage plus its spare (to get the Laythe plane to Laythe as fast as possible); that's a lot of heavy stuff that I can get rid of. Add in all the extraneous parts I can get rid of from Intrepidity itself- an excessive quantity of vernor thrusters, struts and other spare parts that can be stapled to anything I'm not keeping before ditching it and I can easily boost the range with just the fuel in the main tanks to over 8000m/s; with that, I can hit Eeloo, Dres and Duna before returning to Kerbin and mopping up with the Mun and Minmus.

Not completing the whole Grand Tour would be disappointing, but it's my first try at any kind of Grand Tour, let alone with Kerbalism on hard difficulty. Landing on 13 out of 14 targets and coming back to Kerbin would be an accomplishment of its own, plus I can take any lessons learnt with this attempt to build the next ship even better.

[king of nowhere]

5 hours ago, jimmymcgoochie said:

Eve to Jool is 4500m/s; call it 5000 after cosine losses from the very long burns (25 minutes for a single continuous burn) and any course corrections necessary to get into an orbit vaguely matching Laythe/Vall/Tylo.

Once in orbit around Jool, the landers for Laythe, Vall and Tylo can be used and ditched; that's one plane, one heavily shielded lander (or two, I have a spare in case of hardware failure) and a lightly shielded lander plus the Tylo descent stage plus its spare (to get the Laythe plane to Laythe as fast as possible); that's a lot of heavy stuff that I can get rid of. Add in all the extraneous parts I can get rid of from Intrepidity itself- an excessive quantity of vernor thrusters, struts and other spare parts that can be stapled to anything I'm not keeping before ditching it and I can easily boost the range with just the fuel in the main tanks to over 8000m/s; with that, I can hit Eeloo, Dres and Duna before returning to Kerbin and mopping up with the Mun and Minmus.

I'm sure there are gravity assists to do Eve-Jool with less than 1000 m/s, plus whatever you need to get out of Eve's SoI.

As for Eeloo, there is a transfer window from Jool when you can do the trip with as little as 500 m/s. It's active between years 7 and 10. There isn't another such launch window for 40 more years afterwards, and it's the only chance you can ever get of getting to Eeloo cheaply, from anywhere. I generally set my schedule around it

Alternatively, if you reach Eeloo before the end of year 8, there is a nice window where you can get to Jool for less than 300 m/s. The problem is that getting to Eeloo is much more expensive than going to Jool, of course

[jimmymcgoochie]

Goodbye Eve...

...and hello Jool!

2 years of travel caused a few part failures- nothing mission critical was ruined, just a couple of redundant reaction wheels and one landing gear light on the Laythe plane, with a few other parts damaged but fixable.

By a stroke of pure, unadulterated luck, I can get an orbit around Jool that dances neatly around the radiation belts and provides a close approach to Tylo, when it's at the shallowest part of the outer belt and so will have minimal radiation, in less than one orbit.

That course correction has been done, now all it'll take is a small amount of fuel from one of the nuclear boosters (or the backup Tylo landing stage) to get into low Tylo orbit with the Tylo lander, land, return to orbit and then run away again before it gets too deep into the outer belt. Other moons will follow in due course.

Full album: https://imgur.com/a/C9mh0S1

Flag count so far: 2

Spoiler

Every time I make a save, I have to open it up and edit it to remove the magically regenerating autostruts on engine plates, otherwise all the nuclear engines will glitch into each other/the engine plates/fuel tanks and explode violently. Not particularly fun, so the next attempt I make I'll skip engine plates entirely and just stick the engines straight onto the fuel tanks.

 

Edited May 21, 2021 by jimmymcgoochie

[jimmymcgoochie]

Not one, but TWO landings today! And they're two of the most difficult landings of any Grand Tour, let alone with Kerbalism.

First, Tylo:

Unfortunately, Stephanie seems to have lost the picture of her planting the flag.

Spoiler

 

 Maybe this is the reason?

She didn't fall, but she was climbing the ladder sideways. I've never seen that before, but I did have trouble with the ladders here and on Eve as the hapless Kerbals decided to turn upside down whenever two ladders faced in different directions (ie one folded out upwards and the other downwards).

 

The return to orbit was nicely timed, requiring only a small rendezvous and speed-matching effort to return to the nuclear booster; good thing too, as it was very low on fuel.

No point waiting around here, the radiation will start building up as Tylo moves around Jool. The departure burn wasn't pretty, but it sent the craft out of Jool's radiation belts and into a holding orbit that would later turn out to be very convenient indeed!

Next up, Laythe. The backup Tylo landing stage was instead used to punt the Laythe plane over to the innermost moon, before becoming an impromptu heatshield to protect the plane's vulnerable shock cone on the nose. Lose that shock cone and there's no air for the jet, and no air for the jet means it's not going anywhere.

I originally wanted to recover that Tylo stage to Intrepidity, but it had no power generation so would run out of electricity long before getting back. Using it as ablator was the next best option.

Graphics glitches abounded for many of the attempts, with weird  frozen double images making it really hard to see where the plane was actually going:

But eventually, Stephanie landed safely on Laythe and remembered to take a picture with her flag:

Laythe's surface is survivable for short periods of time, so Stephanie waited a few days for an ideal escape window before heading back into orbit. Once in orbit there was a narrow window to do some EVA construction destruction to remove as much excess weight as possible- all the wings, the landing gear and that pesky shock cone were all lopped off and left orbiting Laythe while what's left of the "plane" escaped.

And "escape" is the right word for it- 94% radiation damage! One orbit of Laythe would have been enough to kill her.

Unfortunately, Stephanie is now stuck in a high and elliptical orbit of Jool. Her water supply runs out in 37 days; the only transfer to Intrepidity that could get her back before then would take her through the outer belt, which would kill her for sure. Looks like she's stuck...

Or is she?

Amazingly, the nuclear booster with Tylo lander on top was in the perfect position to make a quick transfer burn over to intercept the stricken "plane", a whole ten days before the supplies ran out. A bit of EVA construction malarkey with the big supply pods on that booster allowed Stephanie's craft to be fully restocked for a trip back to Intrepidity.

Except that it didn't, not quite. Going the long way will take 60 days, but the "plane" can only hold 45 days' water rations; the short route only takes about 15 days, but Stephanie can't take the radiation from going that way.

Solution? Swap crews. Alice took the Laythe plane back to Intrepidity, her comparatively low 60% radiation exposure making her able to take one last trip through the outer belt to get there sooner, while Stephanie took the long way round in the Tylo lander which had ample supplies for the job.

Alice arrived back at Intrepidity, docked the Laythe no-longer-a-plane and immediately went to the first radiation detox unit available, pausing only for mere seconds to rip some usable parts off the not-plane. After dumping all the resources back into Intrepditity, there's a bit of liquid fuel left on the former aircraft that could be useful to throw a lander at Bop or Pol before ditching it for good.

Full album: https://imgur.com/a/509AivX

Flag count so far: 4.

Spoiler

Persistent thrust is being a real pain, repeatedly interfering with engines even when it's supposed to be switched off and wasting a lot of ignitions in the process. I might uninstall it again and just accept some looooooong interplanetary transfer burns as a result.

 

Edited May 29, 2021 by jimmymcgoochie

[jimmymcgoochie]

Two more landings today.

First, Pol:

And with a quick pitstop to replenish the lander's fuel and supplies, it was on to Bop:

There was a bit of time to do some "science"...

Before returning to Intrepidity, docking the lander and then docking the nuclear booster too.

This allowed a quick bit of EVA construction to rip a load of unnecessary parts off- spare food/water/oxygen containers that were originally fitted to the boosters, a load of vernor RCS thrusters that are no longer needed, the large docking ports on Intrepidity's core propulsion stage and a bunch of spare parts all got the chop, as did the Laythe plane itself- after scrounging any usable parts and resources, it was sent off to float in orbit of Jool forever.

So far I've had one engine fail completely on Intrepidity, but sadly NERVs can't be EVA construction-ed so I couldn't replace it with a spare from the nuclear booster or the Laythe plane. It's a bit annoying, but I've serviced the rest and they're in good shape- plus with Persistent Thrust removed they don't blip the throttle many times per second and burn through all their ignitions when doing a simple burn.

Only Vall is left here; it'll be slightly easier to get to than Laythe and involve a bit less radiation, but I'm still waiting until both crew have 0% radiation damage before attempting the trip.

Full album: https://imgur.com/a/wVPYGF7

Flag count so far: 6.

Spoiler

The nuclear boosters originally held LF+Ox in the 3.75-2.5m adapter tanks, but I drained them and switched their contents mid-flight to avoid throwing the oxidiser away when I decoupled the boosters as I'd need it to refill the landers and Space Tugs; however this meant that there was no oxidiser for the RCS, so I had to use the Laythe plane's tanks to hold the oxidiser for that docking.