Demo of a "Moon Lander", using two "helper" sprites to figure out where the ship is going to go during each "time step".
The relative location of the "Result" Sprite with respect to the Ship is used to represent the Ship's Velocity Vector. The "Pointer" Sprite is used to track the angle and velocity of the ship. (See comments in the scripts for a full explaination.)
In addition to "Thrust" (in the direction that the Ship is pointing) the Result sprite moves toward the Moon to represent the pull of the Moon's gravity. This pull is calculated as a constant divided by the square of the distance from the ship to the center of the moon.
Left/Right Arrows to Turn, Up Arrow for Thrust.