I have a (very) small amount of physics code done and thought I should mock up the gui to work out what I would need to put in and what I will need out of the simulation.
You're about right. It's going to be called "Aerocapture" and it's about moving your craft into orbit using a planets atmosphere. It won't always be technically an aerocapture manoeuvre but the idea is still to be "caught" by the planets gravitational well.