Moho Encounter

[Laxin10]

Hey guys, so I have built a rocket that has easily gone to and landed on laythe and eeloo (without even having to use a completely filled orange tank of fuel with a nuclear engine). I have landed on every planet except moho. I decided the other day that I was going to land on Moho, but every time I get an encounter with it, the burn time to get into an orbit is longer than the fuel I have available. (upwards of 40 minutes). I have tried to make mid course correction burns along the way to make a smoother encounter but in vain. I don't know if Moho is different in terms of sphere of influence than any other planet including Dres, or if its eliptical orbit is the thing throwing me off. I think it is not my rocket but rather my piloting that is keeping me from landing Jeb on moho. Any help on getting into Moho's orbit would be greatly appreciated, thanks.

Edited December 28, 2014 by Laxin10

[juanml82]

There are some guides about landing in Moho around. Some people argue aerobreaking on Eve before going to Moho is a good idea (although how to plan such a thing is beyond me - there might not be an Eve-Moho window when you reach Eve). Other idea, IIRC, is to launch when Kerbin is in one of the AN/DN nodes with Moho, even if there is no window. Since Moho orbits rather fast, you would get an intercept eventually and it will be cheaper, in terms of delta-v, than a regular hoffman transfer from Kerbin. Or you try to intercept Moho when Moho is near its Ap, so its orbital velocity will be slower.

But typically, a circularization burn will consume some 3,500-4,000 dv and you'll have about half an hour to accomplish it. If your interplanetary transfer stage is centered around an orange tank, I'd go with four nuclear engines. Otherwise you may end up with too little thrust to complete the burn in time. And when building your ship use KER or MJ to check how long it will take for your transfer stage to burn some 4,000 dv. If it's more than half an hour, you're in trouble.

Moho is the hardest body to orbit

[Superfluous J]

Yeah 1 with that much fuel, 1 nuke is hard to sit through. I'd go with at least 4.

If you've got KER or MechJeb installed, toss 4 nukes on it and note that your dV doesn't go down THAT much. If you've not got anything that tells you your dV, do the math or just trust me

[Aethon]

The lowest dv method to Moho I've used is Macollos' at around 5000m/s.

Put your ship in orbit (80ish km), set Moho as target, and pull a dummy maneuver node out until it shows Kerbin escape. This will show you the AN/DN to Moho. The first time Kerbin crosses Moho's AN ( Year 1, Earth day 21, hour 17) you want to burn a maneuver Kerbin retrograde, combined with an inclination change until your solar periapsis overlaps Mohos' solar periapsis, and your Moho relative inclination is 0. When you get to periapse, make a maneuver to lower your solar AP until you get a Moho encounter at periapse on your next orbit. The more you slow down here the better, as it will decrease your orbital injection burn.

Check post #8 in the first link, and post #17 and #18 in the second one:

http://forum.kerbalspaceprogram.com/threads/61478-Oh-bugger-Injection-burn-at-Moho

http://forum.kerbalspaceprogram.com/threads/26656-Delta-V-to-reach-Moho-orbit/page2?highlight=moho

The ship. System shuttle Argos (LVNs' and fuel on the prograde end) decouples after the Kerbin escape/solar periapse lowering burn and returns to Kerbin for an aerobrake/reuse. Hydra (retrograde end) continues to Moho. Note the inclination change.

Edited December 28, 2014 by Aethon

[Laxin10]

Thanks a lot, very appreciated