Jool 5 Complete! One launch, no mining or refueling!

[Duck McFuddle]

Completing this challenge has been a dream of mine since I started playing KSP back in ~2018. I've played KSP on and off since then, and amassed several hundred hours of playtime, but today I finally finished my first ever Jool 5 Mission. One launch, no mining, no refueling, completely vanilla! And to be clear, no cheats or anything either. I'm sure posts exactly like this are made every day here, but I am really proud of this accomplishment, so I'd like to make my own going in-depth on the whole mission.

I started thinking about doing this mission about a week ago. I had been coming back to the game and doing some things I'd never done before, like doing return missions to Tylo and Eeloo. At the time, my plan was really just to do a return mission to each celestial body, so I've truly explored the whole system. However, after visiting Pol and Bop, I started pondering the feasibility of a Jool 5 mission. I have distinct memories of fantasizing about doing the challenge years and years ago, and I even have the save files for one of those attempts. Although, I warn you, the lander designs are pretty... unconventional. This is a Tylo lander, apparently.

Spoiler

Anyway, I'm pretty sure my biggest KSP achievement back then was stranding a lander on Duna, so needless to say I was not exactly equipped to do a Jool 5 mission. Over the years since then, however, I've played KSP periodically, getting better and better each time I come back. And as I said, this time I felt ready to go for it, so I did!

When designing the craft, I took quite a lot of inspiration from Matt Lowne's Jool 5 video. This is most obvious in the Laythe spaceplane,  because I am terrible at making SSTOs. However, I still made the whole craft myself from scratch without downloading anything or whatever. Speaking of the Laythe spaceplane, this was by far the hardest thing for me. I tested this thing relentlessly, spending hours descending and ascending over and over again in a testing save file. It took several days and many, many iterations of the plane to get something that could a) land on Laythe, and b) limp back into orbit again. Even in the final version, it barely could make it to orbit and I actually had to fly the mothership down a bit to pick it up. I think I had too much liquid fuel, but I'm not totally sure.

The other lander to design would be for all the other moons, most notably Tylo. This was a piece of cake compared to the Laythe lander. I had already done a Tylo return without refueling, so I knew how to make it, and I didn't find it too difficult since I could use a lot of the same design elements (though I could only fit 4 side boosters instead of my previous 6). Nevertheless, I only had to make a couple changes while testing, and soon it was ready to go. After discarding the 4 side boosters via asparagus staging, the lander would be ready for use on the other vacuum moons (Vall, Pol and Bop).

My first attempt ran into some issues with parts blocking NERV thrust, but after getting that sorted, I was ready to go. However, the second attempt didn't get too far either. I was struggling a lot with getting into orbit around Laythe, since I wanted to be as efficient as possible and was trying to aerobrake a little. However, my craft was not set up for that at all, so I could barely enter the atmosphere, and my encounter was pretty bad too so I was using a ton of DeltaV to circularize. I eventually got there, but I was in a retrograde orbit, and still struggling to get my plane to orbit after landing. I only had about 4.6k DeltaV parked in Laythe orbit (even without the plane) and I didn't really trust myself to finish the journey with such limited fuel. So, I decided to start over, making some changes to the craft to allow for easy aerobraking.

Finally, we are at the important part of this post, the actual final mission. I launched 3 days ago, and this is what the craft looked like, rocket and mothership. In the VAB, the whole thing weighed in at 1300 tons, with 262 parts.

Spoiler

The rocket is pretty huge overkill, but I didn't feel like having to do a super efficient Kerbin launch, so I left it. In fact, almost all of the second stage is still full of fuel when we reach LKO, so I could use it as some nice high-TWR thrust for our first escape burn. As usual, I split the Jool transfer into a bunch of burns to be more efficient (and because the mothership has a TWR of 0.20). I wanted a nice Tylo gravity assist to save DeltaV, and they aren't super hard to get. However, the one I got here was amazing (by my standards at least), and with only a small adjustment it gave me a nice and curved Laythe encounter for an easy aerobrake.

Spoiler

I had the big inflatable heat shields at either end of the craft to aerobrake with. At first I had some flipping issues, but I got some advice from Reddit, and moved most of the mass to the front along with putting some wings on the back end. This fixed the issue for me. The aerobrake went smoothly, and I got lucky again here, because my first random guess at an altitude gave me a nearly perfect circular orbit with an Apoapsis of around 56 km (I think).

Spoiler

Now that I was here, I could continue with the hauntingly familiar task of landing and returning from Laythe. I had already developed a strategy to land on the correct land mass (be 1/4 of the planet back from where you want to land, burn down until your orbit line is as far ahead of that island as the distance between the two big equatorial islands, and go into the atmosphere at about 30 degrees with the plane). It's kind of a ridiculous method but it worked consistently for me. Anyway, I followed those directions and after a few quickloads made my first landing of the trip.

Spoiler

Now it was time to take off, which would prove to be much more difficult than the already challenging landing. I basically just did trial and error until I could barely get above the atmosphere and still be orbiting. The mothership was also in a somewhat inclined orbit, so I had to try and match that on the ascent. Eventually I got it, and we could collect all the science and move on to the next moon: Tylo.

Spoiler

After collecting the science, I detached the section of the ship that carried the plane, as well as the plane itself. Then it was time to make the journey over to Jool's largest moon. As expected, Tylo was pretty straightforward compared to Laythe - however, there were a few issues I ran into.

One of them you may be able to spot from the picture of the mothership earlier in this post. I moved a few engines up towards the front in order to prevent flipping while aerobraking, and made a very stupid mistake. Try and spot it.

The nuclear engines block the Tylo lander from getting out of its compartment! This was such a moronic error, and I was afraid I would have to start all over again. However! Bill Kerman was able to save the day, by using his engineer construction skills to move the mothership's docking port out of the way. This allowed the now undocked lander to just barely squeeze out. I later moved the docking port around to the front of the ship (since I had jettisoned the heat shield that used to be there). After that, the Tylo landing went pretty smoothly.

Spoiler

I'd like to mention that I think in the context of a Jool 5 mission, I think Laythe is way, way harder of a component than Tylo is. At least for me. I've heard a lot of people say Tylo is the most difficult moon, and maybe that's true as just a normal return mission, but within a Jool 5 mission Laythe is infinite more challenging. Both in designing a lander that works well for it, fitting it into the mothership, and then actually flying it down and back up again. 

Anyway, it was time for the Tylo ascent. Something weird happened here, and I'm not sure why - the craft just kept trying to tip over and fight my control. I had to use a lot of RCS throughout the whole ascent, which wasn't great, because I realized I didn't pack any extra monopropellant on the mothership besides the default stuff in the capsule. I would have to be more sparing with it from now on. Now that we had finished with the two hardest moons, I redocked with the mothership and headed over to Vall.

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After arriving at Vall, I turned the thrust limiter on my lander's aerospike engine down to 20 and left it like that for the rest of the mission. It seemed to mostly fix the weird flipping thing, and would just be more convenient on lower gravity bodies anyway.

The Vall landing was pretty standard, although I forgot to refuel one of the lander's fuel tanks which made the ascent way closer than it needed to be. I think I had to pick the lander up with the mothership again. I've always really liked Vall, I think it's a nice place to visit and isn't ridiculously challenging. 

Spoiler

Now we only have the two outermost moons left, Pol and Bop. I chose to do them in that order because I figured it would be a bit more efficient - because their orbits are inclined, I could just do one adjustment to match Pol and then another adjustment in the same direction to match Bop. This would prevent me from having to undo/go backwards on my Bop adjustment to match Pol.

Getting out to Pol was more trial and error, but I got pretty lucky and found a nice encounter fairly quickly. Pol is quite small, so the landing wasn't too hard, although I kept bouncing and tipping over when touching down. This was an issue on Bop too. I like visiting Pol a lot as well, it's got a cool design and the gnome hats are fun. 

Spoiler

So now it was time for the final landing, Bop. It's in a very inclined orbit, but I had quite a large excess of DeltaV by this point, so I didn't need to be too efficient about it. Just like Pol, it's nice and small, so the landing was easy and DeltaV wasn't an issue. 

Spoiler

And with that, we've landed on every moon in the Joolian system! I took some science from orbit around Jool since I realized I'd forgotten to do that earlier, and then it was time to do my burn back to Kerbin. I didn't need to bother getting into orbit or anything, since my command pod has a heat shield. I entered the atmosphere at nearly 5000 m/s, but heat shields are insanely powerful, so it was totally fine. Finally I splashed down in the ocean on Kerbin, home at last after a lengthy 7 years and 100 days!

Spoiler

Our final science gathered was almost 16,000! I only did science landed and in low orbit (or high orbit in the case of Jool), so I could have gotten much more. However, I didn't feel like doing science constantly, and I already cheat unlocked the whole tech tree before starting lol (don't worry, I've unlocked the tree legit before).

And that's the whole mission! I'm so happy to have done this, and I found it a really fun challenge. I hope this post can encourage people to do this themselves, if anyone wants advice or has questions I'd be happy to help any way I can (I'm not really a KSP super-expert though).

Congratulations and thanks if you read this whole thing, and good luck on your own missions!

Edited October 6, 2023 by Duck McFuddle

[Duck McFuddle]

Ok, just realized this section is actually for KSP2. My bad, it’s been a while since I used these forums,  I guess I just clicked the first “mission reports” I saw. Could a mod move this over? Or should I copy it and just delete this one? Thanks

[OJT]

I moved the thread, no worries
And congrats on completed mission! Jool 5 is no easy feat

[Duck McFuddle]

8 minutes ago, OJT said:

I moved the thread, no worries
And congrats on completed mission! Jool 5 is no easy feat

Thanks