Rockets and Missiles

The term rocket refers both to a non-air-breathing jet engine and to any vehicle it propels. Rocket fuels may be either solid or liquid. In the former case, the rocket is commonly known as a rocket engine, while in the latter case, it is usually called a rocket motor.

A missile is an unmanned vehicle propelled through space, usually carrying some type of explosive intended to do harm to an enemy. A missile, like a rocket, usually carries its own means of propulsion. It may also carry its own guidance system or, alternatively, it may be guided by a ground-based command center.

Rockets have two primary functions. First, they are used to carry out research on Earth's atmosphere, other parts of the solar system, and outer space. Rockets designed to carry instruments no farther than the upper levels of the atmosphere are known as sounding rockets. Those designed to lift spacecraft into orbit or into outer space are known as boosters or as carrier vehicles.

The second function of rockets is as components of missiles. A large fraction of the research and development on modern rocketry systems has been carried out by and/or under the supervision of the military services.