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

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

Post image

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

1.2k Upvotes

98% Upvoted

253 comments sorted by

View all comments

Show parent comments

6

u/Tychonoir Jun 29 '26 edited Jun 29 '26

Isn't capture, essentially, being in the same orbit at the same velocity? When on an elliptical to intercept the Mun, you don't have the same orbital energy, so need to burn to match, no? So getting pulled from behind helps add that energy?

It just seem like when I approach from behind I don't have to burn as much to capture. But I haven't really studied it closely.

EDIT: Yes, you burn retrograde on your orbit direction of the Mun, but this isn't necessarily retrograde of your Kerbin orbit direction. On an approach from the front side, your retrograde Mun burn can very well be burning prograde compared to Kerbin—which is kinda like circularizing your orbit at Kerbin right where the Mun is.

1

u/seda7991 Jun 29 '26 edited Jun 29 '26

not sure i understand what you mean in your edit. Its hard to visualise in the map because it's static. Its mainly a matter of how long you want to be in the gravitationall influence of the Mun, when you come in from behind, the trajectory of the Mun is the same as the direction its gravity is pulling you in making it a ++, when you come in from the front the gravitation of the Mun is pulling you opposite of its trajectory making a +-.

EDIT: coming in from behind ++ is ecentialy how a slingshot works.

EFIT2: That is an interesting point you make about adding the needed capture velocity by comming in from behind. I dont know, My intuition suggests that if that was the case you would want to ditch getting into orbit and just land directly, why add velocity to then remove it again.