The Long way round to Moho

[MalfunctionM1Ke]

Hi Guys,

has anybody done this?

Fly out to Jool to swing by into a Moho Encounter?

How much dV would I need to bring myself into a Moho-Orbit that way?

I can only Imagine that I will travel inwards with insane Speeds.

Thanks for your heads up

[Kasuha]

I think you will not help it. The dv needed to brake will be even higher than braking from Kerbin and the ratio of Kerbin/Moho semimajor axis is not sufficient to make bielliptic transfer profitable. By gravity slingshot off Jool you'll only save small amount.

Use Eve slingshot instead, way better, way faster, recommended by nine of ten astronauts.

[Bacterius]

Use Eve slingshot instead, way better, way faster, recommended by nine of ten astronauts.

(the tenth astronaut missed his assist and burned up in the atmosphere)

[MalfunctionM1Ke]

Oh well, but it would be a nice trip for Fly-by's dont you think?

I think I will try that on my stream when I restart in .24

Thanks guys

[cantab]

If you want to enter Moho orbit, it's not going to help. You'll be going much faster when you encounter Moho, so your insertion burn will need to be enormous.

Playing around with the launch window planner, http://alexmoon.github.io/ksp/

Direct LKO-Moho, around day 68, takes ~1500 dV for the ejection, and 3500 for the insertion. (dV for Moho transfers varies a lot from window to window, because of Moho's elliptical orbit.)

LKO-Jool takes ~2000 dV for the ejection, we don't care about the insertion because we aren't entering orbit.

Jool-Moho, we don't care about the ejection because the gravity assist is doing that for us. Insertion, though, will need a whopping six thousand dV.

[Kasuha]

... we don't care about the insertion because we aren't entering orbit.

Jool-Moho, we don't care about the ejection because the gravity assist is doing that for us.

Not really. Gravity assist means you need ejection equal to insertion, or you must give the difference using your own engines.

To be able to do unpowered gravity assist to Moho, you need to intercept Jool with some extra speed (i.e. your interplanetary apoapsis must be above Jool trajectory) otherwise you cannot turn that to gravity assist to Moho.

[Alchemist]

The most energy efficient way to get to Moho is using Eve slingshot to get the same plane and periapsis at Moho's periapsis (fortunately, the major axis of Moho's orbit is close to Moho/Eve orbital plane intersection). This way you can get Moho orbit insertion with under 2 km/s of delta v. However for this to work for flight from Kerbin you either need to have periapsis of Kerbin-Eve trajectory halfway between Eve and Moho (and you'll need some angle anyway if you want to get your Moho tranfer in 1 slingshot) or burn additionally during the Eve slingshot.

I've once used double Eve slingshot to get to Moho from Dres (that was in a

, and I barely had idea if it will work with what fuel was there). It turned perfect Dres-Eve trajectory into perfect Eve-Moho, but the almost 180 degree turn around Eve couldn't be done in 1 encounter.

Anyway, if you want to directly approach Moho from up there (not a very good idea, given direct transfers from Kerbin to both Moho and Jool have similar delta v), align your periapsis with Moho's periapsis - that's the only way to get reasonable relative velocity