Guys! I'm preparing a small course on gravitation, planets, satellites and stuff for my university and planning to use KSP for demonstrations (i know some physics is bogus, mostly spheres of influence but whatever) and I got some questions. I know some of you know this trade a lot since you've helped me a lot pre-forum crash. 1) Apollo shot free-return trajectories. Those trajectories look like an "8". The 8 is seen from what coordinate system? Was it truly an 8? Was the lunar orbit retrograde then? 2)oberth effect: does it work reversely? i.e.: If I have to retroburn, will it be most efficient at higher, lower speeds, or it's the same? 3)Why is the apoapsis the most efficient place to burn to lower periapsis and, reversely, the periapsis the best place to raise apoapsis? Oberth effect/reverse oberth effect? Does burning raise/lower every point but the current, but the opposite point raises/lower more? Why? Thanks!
