Munar Transfer

[Lar-E]

Is it possible to time a Munar transfer such that, upon entering the Mun's sphere of influence, it is not necessary to do a retrograde burn to avoid escaping the Mun's SOI?

[Superfluous J]

Unless you count crashing into the surface... no.

The way orbital mechanics works in a 2-body system (which is what you're in once you enter Mun's SOI) is, whatever speed you had at a certain height, you will ALWAYS have that speed every time you reach that height.

When you entered Mun's SOI, you were at a certain height at a certain non-zero speed. You're going to pass by Mun, head back to the edge of the SOI, and when you get there you're going to have the same height and therefore the same speed. Only this time, that speed's going to be going up instead of down and you'll leave Mun's SOI.

Edited December 25, 2013 by 5thHorseman
removed "altitude" and instead use "height" for (hopeful) added clarity

[zinfinion]

While you cant do what you want, you can manage an Apollo 8/10/11 figure-8 free return trajectory that spits you back into Kerbin's atmosphere and requires no thrust other than the initial TMI burn. It's a pain and a half to try to get it to work pulling and pushing on the node though.