Thinking about the moon free return. It is that possible to doing a slingshot to slow you down? Surely that moon did not give you any I am not talk about aero sling. I saying is that use gravity to breaking.
If you arrive ahead of the moon, it should pull you back in a retrograde direction relative to Earth. You'll slow down before you start to accelerate toward the moon.
See picture 1: http://homepage.ntlworld.com/boolybooly/duna_slingshot01.jpg
Every diagram of a free-return trajectory that I've seen shows the vehicle moving ahead of the secondary body. (Note: The picture I included is not a free-rerurn)