Image: ALLSTAR NETWORK
Above a certain altitude the atmospheric density diminishes and jet propulsion is only possible for rocket engines that carry their own oxygen. Rocket motors use either solid or liquid fuels. Solid rockets are the oldest types, and their bodies contain the combustion chamber and the solid fuel mixed with oxidizer. When the fuel is ignited the gaseous products of combustion are accelerated through the nozzle to produce thrust. In liquid rockets, the fuel and oxygen are stored in separate tanks and fed at controlled rates to the combustion chamber.