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How much delta-v to Moho?


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I am currently building my first attempt at a return mission from Moho, however I have a few questions about the mission,

- How much delta-v to go to Moho

- How much delta-v from launch

- Any techniques or things to help on top of that

I really do not want to get there and not be able to get an encounter or not be able to enter orbit, if you could help me out or answer a few of these question that would help me alot. On top of this, referring back to the tips, if there are any, how would I begin to complete them? Thanks

 

 

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Delta-v to Moho can vary by large amounts depending on technique and when you depart and whether or not you use gravity assists from Eve or even Moho itself. My personal advice is forget about conventional launch windows and time your departure so that you can do a retrograde burn where Moho's orbit is at it's highest altitude relative to the Sun. Burn until there is a close approach, then time warp to this close approach and complete the capture burn. Yes the transit time is longer, but it makes for a fairly simple approach, and is reasonably efficient.

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A lot of players think Eeloo is the hardest place to go to in KSP, because it is so far away. This is not true. Moho requires more dV, and vastly more precision. Moho is the hardest destination to reach in KSP.

That's why many people opt for the "depart Kerbin at Moho's apoapsis" strategy. It will not get you an encounter right away, but it will put you into a solar orbit from which you can get an encounter in a second step fairly easily, and it requires around 5 km/s dV if you do it well.

The classic Hohmann transfer is still possible, but you'll want to budget at least 6 km/s dV for it. That's ~5.2 km/s one way, i.e. from low Kerbin orbit to low Moho orbit, plus a decent safety margin because the precision required is so high that on your first try you'll definitely end up needing more than you planned spending. The way back costs roughly that much again, though it's much easier to fly, so you don't need that big of a safety margin.

Edited by Streetwind
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Some other things to bear in mind.

Moho has a significant orbital inclination with respect to Kerbin, big enough that you'll have to deal with it in some fashion. There are various strategies for this... just be aware that the simplistic "do a normal/antinormal burn at the AN/DN" approach that you may be used to (e.g. en route to Minmus) is going to be an expensive burn. One approach that can work is to launch when Kerbin is located at the AN/DN.

ISRU can really save your bacon by allowing you to fill up before your return journey. Just be prepared for the fact that Moho is a lot heftier than the Mun and needs considerably more dV to land and take off.

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If you opt for direct transfer (inclination change method does not matter) you should also pack a decent TWR for capture burn, not some puny LV-N. Trajectory to Moho is a long fall in Kerbol gravity well, you will arrive pretty fast. Forget about having hours for lowering PE and executing breaking burn, and even if you had time, excess energy make adjustments incredibly costly. You should set up PE on route (this is gonna be fun with decay bug raging) and avoid radial/planar burns until captured.

Other way is to just forget about direct transfer, do transfer to circular orbit somewhat higher then Moho and transfer from there. It is obviously less efficient, but you don't have to care about TWR and use most efficient engines which offset it somewhat. Also its easier to plan gravity assist from Eve and get most of it.
 

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