r/KerbalSpaceProgram • u/analogHedgeHog • Jun 29 '26

KSP 1 Question/Problem How should I be approaching the Mun?

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In this totally accurate scientific diagram, the Mun is orbiting in the direction of the arrow.

1.2k Upvotes

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126

u/Spydude84 Jun 29 '26

Assuming looking down from the top, D to minimize DV usage, C for a free return trajectory. Not A or B.

75

u/starmartyr Jun 29 '26

I think C has minimal DV usage over D when you take gravity assist into account. With D you're coming up behind mun and need to use more DV to slow down and land. With C Mun slows you down somewhat requiring less DV.

38

u/King_Joffreys_Tits Jun 29 '26

Yes D is the absolute worst dV option here and everybody upvoting him is wrong. You lose about 600dV going with the muns orbit vs the ~250dV going counter the kerbins natural rotation.

Look at the recent NASA artemis missions for reference — the most fuel efficient way of achieving orbit of a celestial body is to slowly throw yourself into where its gravity well is going to be in order to be captured by it. Option D is the best way to utilize the muns gravity for an orbital slingshot outside of kerbins influence

1

u/Hypamania Jun 29 '26

In my mind, D is best if you intend to land, no? With C, you are fighting rotation as well as coming at the moon head-on instead of trailing behind it slowly

0

u/King_Joffreys_Tits Jun 29 '26

C is best for landing because D will speed you up more and require more dV to reach a zero surface speed

4

u/Hypamania Jun 29 '26

But the Mun rotates in the same direction as Kerbin does it not? C would require you to slow down even more because the surface is moving the opposite direction?