Kerbal Space Program

I have found that if I EVA I get roughly 0.5m/s/s of thrust during my EVAs. I have been in a tight circular orbit around the mun and took an extended EVA to get EVA reports from biomes as I fly below 60Km. when I got back in the ship 5 min later I was no linger in orbit around the mun but on escape. one one hand it is nice that I have to work less about Fuel cost to get home, but it is frustrating that I need to make sure I need to keep getting back in and changing my orientation so I don't lose orbit