Launching and landing a 32 kerbal Mun colony in one shot?

[lewisd]

I've build an interesting colony that I'm trying to get to mun. I'm using stock parts, other than MechJeb2 to help fly this thing. (I don't consider it cheating, since even the Apollo missions were flown by computer.)

I have a small 2.5m rocket in the middle, surrounded by 8x symmetry long trusses, with a hitchhiker storage container on the end of each. There's a bunch of other anciliary stuff, batteries, lights, solar panels, SAS modules. This rocket+colony, on it's own, should be able to get from munar orbit to the surface, in one piece, according to MechJeb2's calculations. The total passenger compliment is 32.

The design of the rocket part of it is a bit odd, I think, but functional. It has a single engine, but is 2 stage. The single engine is in the middle, with a small fuel tank on top of it. Each of the hitchhiker pods has a small fuel tank on top fo them too. That's the final stage. Then, on top of the middle engine's fuel tank, I have a stack separator, and a large fuel tank. Ringing the large fuel tank are a few of the solid fuel seperator motors. The idea is, the fuel from the top tank gets used first, during deorbit and initial deceleration for landing. Once it's dry, it's ejected *upwards* (and to the side somewhat, since a few seperator engines are sideways) and the remainder of the colony ship lands gently on the surface of the mun.

The trick is, of course, getting this monstrosity into munar orbit. And I'm determined to do it in one gigantic launch, rather than launching space tugs, or refueling ships, or anything practical like that

I've been learning that asparagus staging, while useful, may not be the way to go for this. It takes an awful lot of power to get this thing aloft, somewhere around 8 mainsails on my first stage, to lift the colony and the stages in between. With asparagus, it would be losing an engine each time it dumped an empty tank, and even starting with 13 engines, it just doesn't get high enough before that happens, and the loss of the engines means there isn't enough thrust to keep climbing.

The way I've attempted to build it is this:

Under the colony lander engine, I've stacked an orange tank, with a mainsail on the bottom. Around that, in 4x symmetry with radial decouplers, are the same, orange tank with mainsail under it. That's my center 5 engines.

Then, under each of the hitchhiker pods is another orange tank and mainsail, so that's another 8 engines.

That on it's own launches fine, would even less than half the engines, but doesn't have nearly enough delta-v for orbit.

So I did basically the same thing again underneath. However, this one needs around 8 of the engines going to be able to climb, and if I run the 8 outer ones, then when they run out and I eject them, I'm not high enough for the 5 remaining engines to keep me climbing. I've stuck 3x8 booster rockets outside the 8 tanks, to fire along with the first 8 engines, but it still doesn't get me high enough to continue the climb with 5 engines.

At this point, with all the struts needed to keep things in one piece, my ship is over 800 parts, and my fancy new gaming rig is running KSP at around 4 FPS, but with MechJeb doing the flying, the framerate doesn't matter quite so much. Once I start ejecting stages, I'm sure it'll improve a lot.

Anyway, I'm wondering if anyone's succeeded in getting something this size to the Mun in one shot, using stock parts? (other than MechJeb, as previously mentioned)

Any suggestions for approaches to redesigning the ship? I'll try to post some pictures, and maybe the .craft, later.

Edited September 16, 2013 by lewisd

[Captain Sierra]

Pictures are worth a thousand words. F1 to screenshot, grab that, upload to Flickr, Imgur, Imageshack, etc. Post here in . Post a few of them and we can give you all the answers you so desire.

[Diazo]

While I'm not sure it is viable without pictures, my first though is to simply 2 stack the orange tanks.

Would require a lot of struts I suspect, but with the Hitchhiker cans hanging off as you've done them, you don't have the slim center piece asparagus staging is typically built around.

D.

[SkyRender]

If you want something absurdly complicated and strut-heavy that will get absurd payloads into orbit, talk to Whackjob. He's the master of that sort of thing. As for me, well...

I prefer more elegant, compact solutions. This one is a bit finnicky and has about a 5% margin of error on its fuel, but it will get you to the surface of the Mun if you fly her right. It won't get you BACK from the surface, but that would defeat the purpose of a base anyway, right?

[lewisd]

Pictures are worth a thousand words. F1 to screenshot, grab that, upload to Flickr, Imgur, Imageshack, etc. Post here in . Post a few of them and we can give you all the answers you so desire.

Yeah, I have a few screenshots already, but they're on my desktop machine, at home. I'm at work now, posting here on a "coffee break". I'll post them next time I'm at that computer.

[Temstar]

I've been learning that asparagus staging, while useful, may not be the way to go for this. It takes an awful lot of power to get this thing aloft, somewhere around 8 mainsails on my first stage, to lift the colony and the stages in between. With asparagus, it would be losing an engine each time it dumped an empty tank, and even starting with 13 engines, it just doesn't get high enough before that happens, and the loss of the engines means there isn't enough thrust to keep climbing.

Surely not? It's just a matter of figuring out what the payload weighs and then building an appropriately sized asparagus staging rocket underneath:

Here we have the launch of a 110 ton, 132 Kerbal space colony into LKO.

Here we have the launch of a 160ton, 16 Kerbal Mun surface propellant depot into LKO.

After being lofted into LKO by its booster rocket, the depot then fires up its own engines for trans-Munar injection and landing. Final mass on the Mun is around 100 tons I think.

Several more launches later...

So yes it's certainly possible. Any launcher that can put payload into LKO should be able to deliver about 60% of its LKO rated payload capacity to the surface of the Mun, as long as the payload is able to complete at least the final landing under its own power.

For the above two, you can find the launch vehicles here: http://forum.kerbalspaceprogram.com/showthread.php/33381-0-20-2-Zenith-rocket-family-%28modernised-for-0-20-x-with-perfect-subassembly%29

[lewisd]

Wow! That's a very impressive mun base. I'll definitely checkout that Zenith set, looks interesting. Thanks

[lewisd]

Success!

I got my 32 Kerbal colony to the Mun.

The colony itself is 80 tons wet, which includes 3100m/s delta-v, and has a TWR on the Mun of 5.0. The stage that gets it from LKO to orbit around the Mun is another 50 tons, so I needed to launch 130 tons to LKO. I ended up using the Supernova launcher from the Zenith launch vehicle set, which I can't recommend enough. With a 160 ton payload capacity, I didn't need to add the boosters, in the end, but I wanted to save as much delta-v in my colony as I could, for a bit of munar exploration.

Notice, however, that the colony has wheels too. It's able to maintain a pretty steady 18m/s on the surface of the Mun, while remaining very stable. I leave SAS on though, because sometimes it catches a bit of air from munar terrain, and keeping it level as it's flying is essential for landing in one piece.

I used MechJeb2 for the launch, all orbital maneuvers, and the landing, targeting coordinates quite close to my first-touchdown flag on the Mun. After landing, I did a bit of roving to go find the flag, then I got the whole colony out for a group photo.

(There seems to be a bug of some kind, the nosecone didn't go away when the previous stage decoupled. I tried editing the persistance file to remove it, but somehow doing that rotated my whole colony 90 degrees, leaving it embedded in the surface of the mun. Glad I made a backup first.)

Pretty happy with how that mission went.