Project Intrepidity- a Kerbalism Grand Tour (attempt)

[jimmymcgoochie]

The final flight of the Nuclear Booster is at hand. While I designed the inner set of boosters to be able to operate independently to ferry stuff around, this one performed all the heavy lifting around Jool and orbited four of the five moons while the landings took place, making it an indispensable part of the mission.

The trip to Vall would require a lot of delta-V to be expended to make it survivable- Vall has most of the radiation you get in space around Laythe, without the shielding effect of the atmosphere or the ability to aerobrake. The Nuclear Booster alone didn't have the fuel left to make it there and back alone, so I brought along the Space Tug too; however the greater weight of the fuel-laden tug meant the burns to intercept and capture at Vall required some engines to be turned down or off:

In yet another case of unintended serendipity (read: pure luck), the Nuclear Booster ran out of fuel in a nice 110x20km orbit of Vall, allowing the lander to land quickly while the waiting Space Tug flew up to apoapsis at a fairly low speed. So low, in fact, that the lander was able to land, do the surface stuff and then take off again to rendezvous with it before it had completed a single orbit of Vall.

The return to Intrepidity was a bit dicey- 87% radiation exposure by the time the lander left Jool's outer belt (after burning to an escape trajectory around Jool before braking back into orbit once out of the Death Zone^TM) turned into 97% when the trajectory to return to Intrepidity crossed back through the tail end of that pesky outer belt. It took a lot of time to heal that damage away with the RDUs, and before I knew it two whole years had passed and it was time to head to Eeloo, or wait another 33 years for the next window from Jool.

One transfer burn and a long wait to reach interplanetary space later and Jool is but a small green speck in the distance, its moons even smaller specks orbiting around it...

All five moons of Jool were landed on, flags were planted and samples of their surfaces gathered, to go with those from Eve and Gilly. There's another 8km/s left in the Intrepidity's tanks, which will improve when the heavily shielded Vall lander (and backup) get ditched and some oxidiser gets burnt for the remaining landings on Eeloo, Dres, Duna, Ike, Mun and Minmus. Of those landings, Duna is probably the most difficult as it requires a parachute to work after spending many years in space getting irradiated and so on, as well as requiring the most delta-V and having the most gravity.

https://imgur.com/a/HpgKYg2

Flag count so far: 7.

Spoiler

I think there's a bug with EVA construction mode that causes inexplicable bright lights to start appearing when parts are added/removed. It can get pretty extreme after a long construction session:

 

[king of nowhere]

how are you doing at hardware maintenance? did you suffer many or few malfunctions?

[jimmymcgoochie]

22 minutes ago, king of nowhere said:

how are you doing at hardware maintenance? did you suffer many or few malfunctions?

One NERV failed on Intrepidity, but that's the only major thing that's broken and can't be repaired so far. There have been some failures on parts that have since been dropped- one of the reaction wheels on the Nuclear Booster went perma-kaput a couple of days ago and a few of the engines on the other dropped booster stages also failed, but nothing critically important has gone yet. Setting basically everything to high quality has undoubtedly helped, as has relying on RTGs for power as they can't fail.

I'm not entirely sure how the Kerbalism settings that increase MTBF after a failure on a similar part actually work, but with MTBFs of 31 years for pretty much everything I don't expect to have that many failures at all. The biggest risk is probably an engine failure on a lander, but now that I'm ditching the spare Vall lander I can keep its engine as a spare.

Edited May 25, 2021 by jimmymcgoochie

[jimmymcgoochie]

Three whole landings to report today!

Eeloo:

Glitchy flag decided to hover a hundred metres above the surface.

Followed by five years of travel to Duna, which caused quite a few part failures- mostly reaction wheels, which I think is a bit odd. There are plenty of spares and many of the failures were fixable, but it's still odd that I've had a total of one solar panel failure, one life support failure, one engine failure, no RCS failures and yet I've lost at least eight reaction wheels and many more had to be repaired.

The trajectory to Duna also seemed off- it took over 2500m/s and a 20 minute burn just to capture into an orbit that was just inside its SOI, which is a lot of fuel I could have used to get to Dres and then to Kerbin.

The Duna landing went exactly as planned, using the same lander that has so far landed on Pol, Bop, Eeloo and Eve and will also do the rest of the landings too.

Parachuting down to the surface. A small braking burn was required before touchdown but the landing 'legs' took the impact well.

With their job done, the spent parachutes were discarded, as was the ladder once it was time to leave, as were the struts and grip pads once the lander was heading back out of the atmosphere.

There was an Ike-clipse during the landing:

Followed by the closest close approach I've had yet- if I wasn't paying attention, the lander would have torpedoed Intrepidity right in the fuel tanks and it would have been game over.

A quick pit stop to replenish the fuel and supplies (and probably clean underwear for both crew!) and then Alice was off to Ike. Stephanie is currently confined to the ship, binge-watching box sets on the TV to try and stave off another stress breakdown; she's already vented some food and while Alice's stress levels go slowly down over time, Stephanie's are going inexorably up and she's nearly at 90%.

To Ike!

The lander was completely stable even with SAS off when Alice was inside it, but as soon as she got out it fell over. Strange.

The return trip was uneventful and Intrepidity is now ready to move on. Unfortunately I just missed the Dres window and the next one is another 2 1/2 years away. There's also the minor issue of fuel- I can't capture into Duna orbit and then get back to Kerbin with enough fuel to do any kind of braking burn. However, I do have an excess of oxidiser which I can use to my advantage: set a course for Dres but leave Intrepidity on a flyby course, then use the Space Tug to carry the lander to Dres ahead of Intrepidity's arrival, do the landing and then catch up with Intrepidity again as it flies by, then set course for Kerbin and dump all the remaining oxidiser reserves. I've also started dumping excess nitrogen and oxygen to lighten the craft further, and dropping any parts that I can afford to lose.

There are a number of changes that I'd make to Intrepidity based on what's happened so far: reaction wheels mounted individually so they can be removed if they break; putting the supplies etc. inside structural tubes instead of stacking them as part of the core structure; packing less of the resources I don't need or can replenish in flight- water, oxygen and definitely nitrogen- and adjusting the distribution of others, specifically oxidiser; and keeping the inventories as empty as possible with only a few repair kits and the bare minimum of spare parts.

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

Flag count so far: 10.

 

[jimmymcgoochie]

All that stuff about going everywhere bar Moho? Forget all of that...

Good news- I landed on Dres.

Bad news- I don't have a screenshot of it, so these will have to do:

This was by far the most Kerbal landing of this trip- Intrepidity did some braking at the edge of Dres' SOI, then the lander deployed with the Space Tug while Intrepidity braked some more; the Space Tug braked into orbit, the lander landed, then returned, met back up with the Space Tug and the two then burned to rendezvous with Intrepidity while the latter was bombing past Dres well above escape velocity. It wasn't pretty, and it wasted a lot of fuel, but it worked.

Worse news- I am now officially out of fuel. It took some spectacularly creative EVA construction shenanigans to throw away every last gram of unnecessary weight, followed by dumping large quantities of every resource bar liquid fuel overboard to make the ship lighter and eke out the delta-V so that Intrepidity can make it back to Kerbin. Even then it's a simple flyby that grazes the atmosphere, but I've saved just enough fuel so that Stephanie and Alice can jump into the Eve and Tylo landers, brake like crazy with the last dregs of propellant, re-enter (hopefully without burning up!) and then bail out of the landers to parachute down with their personal parachutes. Oh, and hopefully they'll be able to grab those precious surface samples when they jump, or a big part of the mission will be lost.

Full album: https://imgur.com/a/2QnPHZV

Flag count so far: 11, and it isn't going any higher than that.

Spoiler

I checked @king of nowhere's attempts and there's a lot of ship splitting and going in different directions going on, whereas I've been hauling the full weight of Intrepidity to each planet in a decidedly inefficient manner. My next attempt- because there will be a next attempt!- will no doubt do the same to save fuel and hopefully land on ALL the planets and moons.

 

[king of nowhere]

4 minutes ago, jimmymcgoochie said:

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I checked @king of nowhere's attempts and there's a lot of ship splitting and going in different directions going on, whereas I've been hauling the full weight of Intrepidity to each planet in a decidedly inefficient manner. My next attempt- because there will be a next attempt!- will no doubt do the same to save fuel and hopefully land on ALL the planets and moons.

 

on the other hand, it's not particularly elegant to split the ship too much. At some point it becomes just a bunch of separate missions that just happened to have a common start. In my first mission I did it because i couldn't manage otherwise (well, actually, with the experience I have now, I could have done it; I know the ship could have lasted 20 more years. But when the first stuff started breaking up, I sort of panicked and cut it short).

My current mission has the mothership orbit all planets - though it left behind the fuel tanks before going to Moho. And in the next mission, I will even attempt to land the mothership on most planets.

But every mission is a learning experience. Congratulations, and welcome to the world of big convoluted ships.

By the way, it took me three months, and roughly 300 in-game hours, to complete my tour. And now it's taking a couple months to complete my second mission. How did you manage in just a couple weeks?

[Single stage to ocean]

He probably did this before, but only started posting reports now, or he is really skilled.

[jimmymcgoochie]

One last burn to send us home:

Alice and Stephanie waved goodbye to their trusty ship, before burning all the remaining fuel to try and slow down before bombing into Kerbin's atmosphere at around 4km/s!

Then things got really weird. I stuck all the unnecessary parts (spare supply boxes etc) under the Eve lander's engine to try and take some heat during the hideously fast re-entry, and it worked. The first things to hit the atmosphere were some spare RCS thrusters, which quickly overheated and exploded. And exploded. And exploded. And exploded some more.

But no matter how many times they exploded, the parts just did. not. die. I think this is a bug with EVA construction?

Once the explosions had stopped and the (completely intact) craft was subsonic, Alice and Stephanie bailed out and parachuted to the surface. Stephanie made sure to grab the precious surface samples, but those added nearly 300kg so she was falling much faster than normal.

And somehow most of the lander stack survived too- there was more, but it toppled over when I loaded it in and some parts exploded then.

I can only get the credit for one landing it seems- those two landers between them landed on nine planets and moons.

After about 24 years of flight, Alice and Stephanie are back home. Both will be needing some serious medical attention to undo the effects of over two decades of microgravity, radiation exposure and severe stress.

And so this Grand Tour ends, without landing on Moho, Mun or Minmus, so it's a Baby Grand Tour? I could probably have made it to the Mun and Minmus if I skipped Dres (stupid fake planet ) but in the end a combination of less than ideal interplanetary transfers and bad design limited my delta-V too much.

Full album, with all the flags bar Eeloo which has disappeared (that flag was glitchy anyway): https://imgur.com/a/JcoPxcg

Five things I've learnt from this trip that'll be useful for the next one, because there will be a next one:

1. More fuel, less oxidiser. I ended up dumping thousands of units of oxidiser that weren't needed but running critically short on fuel. Bigger fuel tanks would definitely help, possibly with more asparagus-style staging and fewer engines to reduce the dry mass.
2. Keep things simple. Solar panels aren't needed at all, a cluster of 30 RTGs will power a ship that size for the duration of a Grand Tour and a single RTG per lander would be enough; radiators are dead weight, batteries are largely unnecessary with the continuous supply of power from RTGs, processing waste products into usable stuff (water recycling, solid oxide electrolysis to make CO2 into O2, turning waste into ammonia and then monopropellant) will make those resources last so much longer.
3. A nuclear space tug would be a great addition to the mission. The semi-intended Nuclear Booster worked an absolute treat around Jool and the Space Tug also proved its worth, so combining the two would be an obvious choice.
4. Better structural planning. Stacking all those supply tanks, batteries, shields and so on meant that if something broke it couldn't be discarded. There were some parts that I couldn't actually find inside the ship, the engine plates would repeatedly cause things to explode or get jumbled around if I didn't edit the save file every time before loading and the whole ship would wobble alarmingly any time I tried to rotate it. Those girder arms with the RTGs on the ends were also unnecessary; the RTGs could have been mounted on the core section to save quite a lot of weight and make it easier to dock too. Engine plates are bad- they have magic autostruts that keep regenerating every time a save is done- so I'll avoid those too.
5. Less redundancy and fewer spare parts. I threw away dozens of RCS thrusters, spare struts, a whole Hitchhiker's worth of repair kits and many other spare parts that were nothing more than dead weight, as well as the backup Vall lander that did absolutely nothing at all, the backup Tylo descent stage which I used to reach Laythe and the four big communications dishes were overkill; I could have done without the RA-100s and stuck with RA-15s to handle relaying duties.

Spoiler

22 minutes ago, Single stage to ocean said:

He probably did this before, but only started posting reports now, or he is really skilled.

Nope, this is my first Grand Tour of any kind. I've done a bit of a career with Kerbalism but only ever made it to Gilly for a while, and my RO/RP-1 career also uses Kerbalism but that's a very different setup. I must therefore agree with your second option- I am in fact really skilled  (yeah, right- most of it was pure luck!)

 

Edited May 29, 2021 by jimmymcgoochie

[jimmymcgoochie]

My next attempt has begun, follow it here: