Moho > sigh

[Lohan2008]

Do I really have to make a journey to Moho ? I want to finish off the career tree BUT I find catching the little speeding ball a real CHORE, I never get the window right. Where position should Moho be at, if Kerbal is at 6 o'clock ?

Edited May 3, 2014 by Lohan2008

[Guest]

Oh my, Moho can be hard. Try doing your Moho transfer burn at either the Moho Ascending Node or Descending node. You can see the green AN and DN markers after you leave Kerbin SOI and you set Moho as target.

This thread might help, lot's of pictures : http://forum.kerbalspaceprogram.com/threads/36366-To-Moho-and-back

[Mitchz95]

Moho is a royal pain in the behind to intercept, and even if you manage to catch it you still have to burn yourself into orbit. Which takes a lot of delta-v.

[Taki117]

I remember there being a thread where the poster got to Moho with somewhere on the order of 5km/s dV.

[GoatRider]

You can finish off the career tree with Science!® from just Mun, Minmus, and Kerbin. So, no, you don't have to go there for that reason.

You have to go there for honor.

[tychochallenge]

download kerbal alarm clock, without it, its a pain in the crutch getting planetary encounters like those of Moho or Dres...

[cantab]

Play around with alexmoon's planner, http://alexmoon.github.io/ksp/ using the advanced options to tweak the time range to see the different encounters. The delta-V you need varies a lot between Moho windows due to its eccentric and inclined orbit. Moho's the hardest body in the game to get into orbit round, and it's not an easy place to land either being the second-largest airless body.

[Zeroignite]

I second Moho being the hardest body to get to. Once you stick it, it'll feel like an accomplishment.

Oh, and a heads-up: its SoI is tiny, so you better be fairly quick on that capture burn. I recommend setting an intercept periapsis as low as possible... I've done 5km before.

Which is, by the way, right properly terrifying.

[BudgetHedgehog]

I managed to land a probe on Moho once.

Once....

[Tokay Gris]

Do I really have to make a journey to Moho ? I want to finish off the career tree BUT ...

If finishing the career mode is your goal - namely, finishing the tech tree - you don't need Moho.

Heck, you don't even need to leave Kerbins SOI. There is enough science within Kerbins SOI to finish the tree. And most of it not hard to find. The only thing that is not that simple is a landing on one of Muns poles. The north one is a pain. And you need a little luck with the south one. IIRC, you need only one of them anyway. And you don't need it, really.

I just finished Mun and Minimus (there, the "slopes" are the problem. At least for me) and only random landings on Kerbin. And finished the tree with about 5000 (or so) left over.

[NecroBones]

I second Moho being the hardest body to get to. Once you stick it, it'll feel like an accomplishment.

.

This is so very true. Eve is one of the easiest to get to, but the hardest to return from the surface. Moho has the opposite problems. It takes a lot of dV to get there and back. For the round trip (not including what your lander will do), you really want to plan your interplanetary stages to permit at least 10km/s of dV. However much fuel you think you'll need... bring more.

The launch window calculators will routinely show that you need about 5km/s of dV each way. Again, not including what your lander does.

It's not so much that the rendezvous itself is hard to do, in terms of delta-V, but when that's combined with the relative speed that you'll have on arrival, and how long the burns have to be, it all adds up to a difficult mission.

When I sent a manned mission there, I clearly didn't have enough fuel for the return trip, even after stealing back as much fuel as I could from the lander. So I sent a rescue ship, which docked, and then stole as much fuel from the mission ship as it could while transferring my dude over. When the rescue ship arrived back in Kerbin's SOI, and got into an atmospheric entry trajectory, I had only 1% fuel remaining. The rescue ship barely succeeded, and all it had to do was pick up a guy and bring him home, and got a free partial refueling at Moho. I was stunned.

[godefroi]

I sent Jeb to Moho once. I ended up sending not one but two refueling missions there in order to get enough dV together to make the return trip.

Also, as others have said, mind your TWR on arrival, as the SoI is small, and very efficient low-TWR transfer stages might not be able to get you captured.

[Red Iron Crown]

I second Moho being the hardest body to get to. Once you stick it, it'll feel like an accomplishment.

Oh, and a heads-up: its SoI is tiny, so you better be fairly quick on that capture burn. I recommend setting an intercept periapsis as low as possible... I've done 5km before.

Which is, by the way, right properly terrifying.

Quoted for truth, both about the difficulty and the capture burn. I once went to Moho via ion power (before 0.23.5's super ions), once arriving in its SOI I sailed right through the SOI with the ions burning retro the whole way. It's a double whammy, a tiny SOI and you arrive with a ton of velocity to scrub off.

[Kasuha]

Do I really have to make a journey to Moho ? I want to finish off the career tree

No. You don't need to go to Moho to finish career tree. You don't even have to leave Kerbin SOI to finish the tech tree. Unless you made it yourself harder via some mods.

Where position should Moho be at, if Kerbal is at 6 o'clock ?

Don't mind the position, eject opposite to Moho's periapsis (which happens to be its inclination point as well), and reduce your periapsis to just touch Moho's orbit. Then at that periapsis, brake a little to meet Moho at exactly that point the next time you will be there. It's not exactly fastest, but it's reasonably fast thanks to Moho's short orbital period, and you'll do it in less dv than what calculators will tell you.

[Lohan2008]

Thanks a lot rocket folk ! Yes, I am a Kerbal deleter ;(

[Tokay Gris]

Don't mind the position, eject opposite to Moho's periapsis (which happens to be its inclination point as well), and reduce your periapsis to just touch Moho's orbit. Then at that periapsis, brake a little to meet Moho at exactly that point the next time you will be there. It's not exactly fastest, but it's reasonably fast thanks to Moho's short orbital period, and you'll do it in less dv than what calculators will tell you.

Lets see if I understood this:

So, you leave Kerbin opposite Mohos perigee. So to speak, when Kerbol is between Kerbin and Mohos periapsis. Right?

Then, you make your periapsis the same as Mohos. Then, you change your apoapsis that you meet Moho next time around.

Why not Mohos apoapsis? Should work as well, shouldn't it? And at that point, Moho is closer. Shouldn't that also mean less delta-V?

[Rus-Evo]

I'm doing my first Moho mission now. I have a dread feeling that training and testing the equipment on the Mun was dumb, as Moho seems to have higher gravity.

So all I can say is "Moho-SIGH"........

[LethalDose]

So, I've only sent a probe to Moho and I haven't attempted a return mission, but I got there on my first try, which I attribute to not approaching Moho directly. My flight profile included the following maneuvers:

1. Escape Kerbin
   
2. Adjust orbital inclination to match Moho
   
3. Drop orbital periapsis to lie on or very near Moho's orbit
   
4. At periapsis, burn retrograde to adjust your orbital period so you catch Moho on your vessel's next orbit
   
5. Burn at Moho periapsis, as would normally would to make orbit
   

For me, the trick was step 4, which is really no different than trying to rendezvous with another vessel in orbit. This really only works well with Moho because it's orbital period is so short.

Anyway, this method worked really well for my probe. I think overall, my rocket had ~ 14k of dV (I think), and I made orbit with 2k dV to spare. Hope that helps.

Edit: I wanted to add that there isn't a launch window for this method. Being in the correct phase with Moho is dealt with in step 4.

Edited May 3, 2014 by LethalDose
No launch window