Please visit my updated physics project here: https://scratch.mit.edu/projects/588966846/ A simple project that simulates 2D force vectors on an object. WASD and arrow keys to control various thrusters. There's no collision with the planet, all that's demonstrated is forces from the thrusters and the gravity between the spaceship and the planet. I'm not entirely sure the way the force is applied is entirely correct, someone would have to confirm it. What I believe to be the case is a force applied to a point that is not the center of mass can be separated into a force and a couple with the force being identical to the force applied at that point.
