Chemical propulsion

Chemical propulsion uses the chemical reaction between a fuel and an oxidizer to generate heat that drives the expansion of a propellant in a rocket nozzle. The propellant is the product of the chemical reaction, for example water in the case of hydrogen and oxygen rocket engine.

A rocket engine is usually composed on an injection system, a reaction chamber and a nozzle. Most chemical rocket engines use pumps to feed the fuel and oxidizer into the reaction chamber, but pressure fed engines also are common, in particular for smaller thrusters.