How would you calculate centrifugal force?

[Yerst]

Hey!
I have a spaceship flying around a planet with gravitation.
The spaceship should be able to find a stable orbit using the centrifugal force.
The gravitation is no problem, but i'm not sure about the centrifugal force.
Would it be better using a physics engine (e.g. JBullet) or trying doing that manually?
If manually, could you give me some advices how i should start?

[EgonOlsen]

I don't think that you need a physics engine for this. It shouldn't be too hard to calculate this yourself. At least i remember that i did such things in school 25 years ago, so it can't be that hard... I'm not even sure if a physics engine is a good idea for this special case, because i somehow doubt that you'll get a stable system with that.