Interplanetary Transport Network

[Wcmille]

I think I can get to Duna for a really small dV from 75km above Kerbin. Wondering what the smallest possible amount might be.

Here's the plan:

Create an elliptical orbit that just barely enters Mun's SOI. The timing will matter a lot. See below.

Enter Mun's SOI to establish an Elliptical orbit from Mun's SOI to low Mun Orbit. I think this will require very little fuel.

Wait a few days, so that the ellipse points in the best direction for Kerbin => Duna transfer.

Leave Mun orbit. The energy required will be very small, since the Ap is already MUns SOI. This should, or little extra required, to arrive at Duna.

The process could probably be applied to go anywhere, though you might need to use it to free-return to a planet and "Oberth" to reach farther distances.

 

[Corona688]

So you want to use the mun to change the angle you leave Kerbin's SOI?  That is an Oberth.  And the mun isn't large enough to give you much of one.

[HebaruSan]

Why not do the initial launch at the optimal moment, so the ellipse points in the best direction as soon as it's established? Then you would not even need to burn to capture, you could just cruise through Mun's SOI and on to Duna. This is called a gravity assist, and in the case of the Mun, it can net you about 80 m/s in the best case.

[The Aziz]

You need ~860m/s for a Mun transfer + somewhat more for capture, then even more for escape and trasfer to Duna.

For direct transfer from LKO, it's about 1100m/s overall.

[FlyingPete]

The Mun can be useful if it happens to be in the right place at the right time. Otherwise, it's not really worth the hassle. Far better to mine the Mun or Minmus, launch empty and fuel up there.

Sometimes Eve or Kerbin itself can be of use for a slingshot to elsewhere.

[Kerbal pancake]

the most efficient duna encounter i've ever gotten from kerbin is around 1080m/s. i dont thnik the mun will provide much help 

[zeta function]

I think the most efficient way to get there would be to launch into an elliptical orbit of kerbin that reaches the mun, use the mun for a gravity assist, and if that alone is not enough to get to duna, go to eve after that, and if that isn't enough, use kerbin for a gravity assist after eve. So a Mun-Eve-Earth path should get you to duna for <900m/s of delta-v (from LKO), with no TCMs.

Edited January 1, 2018 by zeta function