Teutooni's Grand Tour Landers

[Teutooni]

So I have finally decided to do it. The Grand Tour. Single launch from Kerbin orbit (assembly on orbit obviously), visit every landable body in the system and return - with crew and science! I will be attempting this without ISRU, as this is my last attempt at mastering the Tsiolkovsky rocket equation before moving on to ISRUs, fueling depots and permanent bases for good. The first and most important step is determining the route and landers. I have made prototype landers and a suggested route, and I am posting it here so you can give suggestions to improve them, or to get ideas for your own missions.

Mun and Minmus are done with the Ion Lander, detailed later.

The first interplanetary trip will be Eve, since it is close and requires the most massive lander. I need to get rid of that monster as soon as possible!

Here is my Eve Lander (craft file).

Weighs 40.6 tons, it is a 6-core asparagus using aerospikes. Tested using Hyperedit, rated for 500m landing altitude (did not test sea level). Requires a decent gravity turn to make it into orbit. Includes a small deorbit module that has 84 m/s delta-v. Starting orbit: anything it can survive heat-wise, or about 150 km circular.

From eve, it's logical to take the trip to Moho. Instead of bringing the whole mothership (MS), I modified my ion powered lander with extra fuel and engines to bring TWR up to be able to land on Moho. It will be taking the trip to Moho and back to Eve alone. Craft file.

Total mass: 6.8 tons with Moho tanks, 3.8 after it discards them on Moho. This configuration will also be the one landing on Mun and Minmus at the start, plus Ike later, with refueling aboard the MS. It will also serve as a tug, leaving the science package on the MS and tugging most landers to their rated starting orbits (10km for most without atmosphere).

Next stop Duna. Ike lander is the IonTug with science package, same as above. Duna lander (craft file).

Mass 3.3 tons. Needs to be put on aerobrake/suborbital trajectory by the ion tug. Should have plenty of delta-v for any lowish orbit.

Next up, Jool. Out here, solar panels don't provide enough power for landings, so I designed a quick reusable landing module, that will be used on Vall, Bop, Pol (maybe ion is enough for Pol?), Dres and Eeloo. Craft file.

Reuses the Ion lander's science package. Mass without the science package (as it is already accounted for in the Ion lander): 2.4 tons with minimal (24 units) monoprop. Total mass 3.4 tons again minimal (48) mono. Fuel tank mass 1.7 tons, needs to be considered on the MS design for refuels.

Laythe lander (craft file) will land on water, to simplify things. Also because it is a water moon.

Weighs 8.2 tons, with room to optimize the fuel amount (doesn't need it all).

And finally, Tylo lander (craft file).

Mass: 6.4 tons. As with most landings, needs to start from 10km orbit with full fuel. Returns to same orbit. The budget is tight, little room for errors.

From Jool the journey would go to Dres and Eeloo, but as those reuse the Vall/Bop/Pol lander they need no special attention.

Total Lander payload mass, counting 0.9 tons of xenon for each ion tug mission, and 1.7 tons of LFO for the far lander for each refuel: 79.9 tons. Neither the tug nor lander will need a full refuel for every mission, so there is some margin. Add 3.4 tons of monoprop, some crew, structural etc. and the entire payload should be less than 100 tons.

Tonnage summary:

Eve 40.6

Gilly + Moho 6.8

Duna 3.3+0.9(xe)

Ike 0.9(xe)

Laythe 8.2+0.9(xe)

Tylo 6.4+0.9(xe)

Vall,Bop,Pol 2.4 (initial) + 0.9(xe) + 2x(1.7+0.9(xe))

Dres,Eeloo 2x(1.7)

The reason I am not counting Mun and Minmus is because the refueling tank (0.9t xe) doesn't need to be moved at all and can be discarded immediately.

To sum up route:

- From LKO, take the ion lander and land on Mun and Minmus, rendezvous with MS back in LKO.

- Transfer to Eve, land and discard the 40-ton lander.

- Take the ion lander, land on Gilly, continue to Moho, get back to Eve and rendezvous.

- Transfer to Duna, land on it, take ion lander, transfer and land on Ike, rendezvous with MS on Duna orbit.

- Transfer to Jool. Order of landings depends on the orientation of the moons. Basically park the MS somewhere, take the tug and push the landers in position in turn, land and rendezvous with the tug, return to MS to refuel and pick up next lander. After Jool, dump the ion lander as it will be pretty useless at these distances.

- Transfer to Dres, land with the FarLander.

- Same with Eeloo.

- Back to Kerbin. At this point the only objective is to land back on Kerbin with the crew and science intact. Possibly with only minor course corrections and a heavy aerobrake.

I did test most of these, excluding Moho lander. Will need to run some tests on it as it only has ~1.1 TWR on Moho at arrival. It does have some monoprop though, so I'm thinking of constant altitude landing with monoprop assisted suicide burn at the end.

I have not yet attempted to design the mothership. It will probably be nukes with many stages, plus possibly an initial super-heavy chemical stage for the Kerbin->Eve transfer.

[sdj64]

Awesome! This really needs more attention since these are all very efficient designs. It's amazing that you were able to get full science capability in such small mass landers. One thing you might be able to do better is ditch the RCS and use a separate RCS tug to dock and undock, saving precious weight on your landers. I think I've got you beat on mass, but at the cost of not bringing a materials bay or goo down to the surface anywhere. We have the same plan for the mothership and order of the planets, too, except I might do Dres before Jool. How many parts are your landers all together?

On a side note, if you add a pressurized pod for the Moho transfer, you'll qualify for the Jool 5 challenge (shameless plug) since one of the rules is no seats for interplanetary transfers.

[Teutooni]

Thanks! I know sitting in an external seat for years is indeed kinda fishy. Actually, sitting in a tiny single seat pod would probably not be much better, realistically. I might redesign the Moho part at some point, since it happens early in the trip it might be reasonable to bring a dedicated lander, instead of slapping more fuel and engines on the sides of the tug.

The RCS tug is a great idea too. The reason the reusable landers have RCS is some landings actually need them for that little bit of extra TWR and delta-v to make landings on Moho/Vall/Mun even possible. I did the Moho landing, TWR was 1.00-1.02 with the ions, the RCS brought it up to ~1.1, which made the landing possible. I reckon redesigning most of the landers so they don't need RCS and to have a separate RCS tug would probably make total mass a little lower and be more convenient.

Regarding the Jool-5, does it matter if the interplanetary transfer in a seat does not actually involve any part of a normal Jool-5 mission?

[Foxster]

I did test most of these, excluding Moho lander. Will need to run some tests on it as it only has ~1.1 TWR on Moho at arrival. It does have some monoprop though, so I'm thinking of constant altitude landing with monoprop assisted suicide burn at the end.

I don't think that will work. Two big solar panels won't generate enough power for all those ion engines. You need 8.74 per engines and two panels will generate 48.8, so even in ideal conditions you will only be able to power 5 engines.

The TWR is too low but you will have burnt some fuel by arrival and it might have just enough.

I'd also find some way to ditch the RCS and swap out the pairs of docking ports for decouplers to save a lot of weight.

Do you really need to re-dock these craft? You can have a Kerbal EVA, grab the science from the capsule and take it to the mothership, discarding the lander then.

Edited October 16, 2015 by Foxster

[Teutooni]

Actually, a single solar panel at Moho will generate 100-125 energy per tick, depending on the phase of Moho's elliptical orbit. Should actually slap some more engines in there, the TWR is too low for comfort.

[Foxster]

Actually, a single solar panel at Moho will generate 100-125 energy per tick, depending on the phase of Moho's elliptical orbit..

Whoops, yes, I forgot the change to power output with distance from the sun now.

[Teutooni]

Do you really need to re-dock these craft? You can have a Kerbal EVA, grab the science from the capsule and take it to the mothership, discarding the lander then.

With current configuration most do need to dock with either the ion tug or the mothership, but you are both right. Redesigning to get rid of most RCS would probably be better.