Yes, it is rocket science; although simplified here, it is adequately rich. The objective is to schedule thrust (e.g., change thrust with time) to maximize the altitude a rocket can achieve. You could have full thrust until the fuel burns out, and then let the rocket coast up until gravity pulls it back. But this plan makes the rocket go fast in the lower altitude where the air resistance is high and wastes energy. A better plan to minimize the impact of air resistance is to move slowly in the low altitudes and then full throttle to fast speed in...