A projectile driven by the reaction of gases produced by a fast-burning fuel. Unlike jet engines, which are also reaction engines, rockets carry their own oxygen supply to burn their fuel and do not require any surrounding atmosphere. For warfare, rocket heads carry an explosive device.

Rockets have been valued as fireworks since the middle ages, but their intensive development as a means of propulsion to high altitudes, carrying payloads, started only in the interwar years with the state-supported work in Germany (primarily by German-born US rocket engineer Wernher von Braun) and the work of US rocket pioneer Robert Hutchings Goddard. Being the only form of propulsion available that can function in a vacuum, rockets are essential to exploration in outer space. Multistage rockets have to be used, consisting of a number of rockets joined together.

Two main kinds of rocket are used: one burns liquid propellants, the other solid propellants. The fireworks rocket uses gunpowder as a solid propellant. The space shuttle's solid rocket boosters use a mixture of powdered aluminium in a synthetic rubber binder. Most rockets, however, have liquid propellants, which are more powerful and easier to control. Liquid hydrogen and kerosene are common fuels, while liquid oxygen is the most common oxygen provider, or oxidizer. One of the biggest rockets ever built, the Saturn V Moon rocket (see saturn rocket), was a three-stage design, standing 111 m high. It weighed more than 2 700 tonnes on the launch pad, developed a take-off thrust of some 3.4 million kg, and could place almost 140 tonnes into low Earth orbit. In the early 1990s, the most powerful rocket system was the Soviet Energiya, capable of placing 190 metric tonnes into low Earth orbit. The US space shuttle can only carry up to 29 metric tonnes of equipment into orbit.

https://www.nar.org Home page of the National Association of Rocketry, with reference materials, organizations, clubs, upcoming launches, contests, and more resources devoted to rocketry.