How powerful is the rocket; how much thrust can the motor produce?
This is important because the rocket must be powerful enough to counteract Earth’s gravity, and get its payload (the stuff that the spacecraft is carrying) into orbit, or even out of orbit! • What is the power-to-weight ratio? This is important because the heavier the engine is, the harder it will be to get the spacecraft into space. However bigger (heavier) engines can be much stronger than small light ones. If you make a light enough spacecraft, it may not have enough thrust. So if a rocket is heavy, it must be strong, and if it is weak, it should be light. • What is the speed of the exhaust gases? The faster the exhaust gasses stream out, the more thrust, and thus the faster the ship goes forward. • How long can it run? The rocket has to get its payload to its destination against gravity. If the rocket runs out of oomph too quickly, the rocket may fall back to Earth or put its payload into a completely wrong orbit. No rocket design or kind of propellant will give the best answer to
