quick question--Jool tour

[birrhan]

I've seen a lot of Jool moon tour threads, but none that I recall have sent just 1 stock lander to all 5 moons in one trip--I've searched the forums, and found a couple of grand tours (using kethane) and a couple of multi-lander threads. Does anyone recall seeing any stories of 1 stock lander on all 5 moons in a single launch?

[-RanZ-]

if you can land on Tylo and get back to orbit that should work for any moon in the system. Tylo gravity is insane and there is no atmosphere so you would need a crap ton of delta V to do all the moons in 1 trip

[Tokay Gris]

Hm... so the way I read it, I need a lander that can pack about 6000 m/s and change? Plus a TWR high enough to lift again.

With refuelling, some parachutes... and a transfer vessel with enough fuel.... Hm.... can't wait for night shift to finish to try what I can cook up.

[birrhan]

if you can land on Tylo and get back to orbit that should work for any moon in the system. Tylo gravity is insane and there is no atmosphere so you would need a crap ton of delta V to do all the moons in 1 trip

Yeah, I've done it a couple of times--it was a beast.

The dv needed for descent and ascent from all moons is about 12,500 dv. Transiting b/w moons is another 8150 dv. I think the challenge is making the lander small enough that it can be moved and refueled by one transit/refueling vessel. Transiting, landing, and taking off from the other moons means you can't really stage the thing until Tylo. Oh, and I never fly less than 3 kerbals. Sending them solo brings the Space Madness, and if you're already at 2, why not 3? I like the added twist of mapping each moon, and bringing a rover too. There's a lot of ways to do it, I just wanted to know if it had been done before.

[-RanZ-]

not sure and unfortunately the forums were mostly nuked a few months back so any mission reports may be gone. Give it a try and report back and post screenshots!

[Spatzimaus]

I did it with a kethane-using vessel, but that really only made a difference on Tylo. Vall, Bop, and Pol are all low enough gravity that you won't spend much fuel on the landings and ascents, and Laythe's descent will use very little fuel if you've got wings and/or chutes. If you have something in orbit to refuel the lander for its transfer to the next body, the only real problems boil down to two things:

1> Enough delta-V and TWR to land on and take off from Tylo.

2> The ability to ascend on Laythe, as well as land on a good, stable point. Do NOT underestimate this one; if your design doesn't have wings, it's hard to pick a flat landing site, and the drag on ascent is not negligible. My Grand Tour had a horrible time ascending from Laythe, because it was just so hard to stay stable at the low speeds that the thick atmosphere required. (Well, Eve was worse, but that's hardly a shock.) It's for this reason that I design my spaceplanes to be capable of landing vertically, on their tails, in a vacuum; that way, I can make landers that can function on all the airless moons, as well as landing smoothly on Laythe, without having to maintain multiple designs. (The extra mass for jet engines and wings is fairly small.)

Now, that being said, you shouldn't be afraid to use the Kethane mod for this. Yes, it's a mod, which'd offend purists, but it's a mod that's currently standing in for the stock resource system which'll be added within the next couple major revisions. The upcoming system is going to be much more complex than what the mod includes, with a half-dozen raw resources to manage and an additional refined fuel type (nuclear), but the basic principles will still hold: you'll be able to land on Laythe, extract hydrogen and oxygen from the ocean water and/or from the rocks, make rocket fuel, and take off with a full tank. You won't need much raw resource storage, if you're refining on-site, so the only real questions with the upcoming system will boil down to the specifics of the refining equipment (like are the modules small enough to mount on a lander, or are they so big that only orbital stations will be able to actually make the fuel?). So in a few versions, a grand tour (or Jool tour, in this case) using only "stock" components is likely to be no different than doing it now using certain mods.

Also, upcoming versions are going to drastically change some relevant things, like the aerodynamics model used or the type of fuel nuclear engines consume. Some current stock designs will function VERY differently once those changes go in, so being wedded to a pure stock philosophy might cause you some serious problems down the road.

[RoboRay]

A Tylo-capable lander is ridiculous overkill for the other Julian moons, and also really difficult to do as a single-stage craft. My suggestion is to do a two-stage lander, with the upper stage able to operate independently to land on Laythe and return to orbit (meaning it can also handle all the smaller moons). Dock it to the "Tylo descent stage" whenever you're ready for that landing and jettison it on the way back up, when it's empty, returning to the interplanetary craft with just the upper section, which can then continue on to any of the smaller moons you haven't visited yet.

Edited May 31, 2013 by RoboRay

[Tada]

Only way how to do Laythe with style is an SSTO shuttle Some designs are so compact, that they don´t weight much more than equal lander.

[Epthelyn]

The best way to do Tylo is probably to abandon the idea of "one ship" and have a smaller lander which you can undock/uncouple in orbit. I'm not sure how that would work for getting it back up, since you'd need a fairly large and powerful lander to go down and up (roughly equivalent to the rocket you used to get into Kerbin orbit and then burn for Jool).

Laythe is another moon where a 'second' lander is ideal. If you can make a functional SSTO and attach it to a rocket and send it over to Jool, Laythe should be a lot easier.

The rest are low gravity and not much to worry about.

Alternatively, just use Kethane. Resources and refuelling are going to be a feature in KSP within the next few versions, so there's no point avoiding the inevitable and you might as well get some practice rather than trying to pull off something which is pretty much impossible