Rocket

A rocket is a vehicle or device that obtains thrust by ejecting reaction mass at high speed. The propulsion follows Newton's third law: expelling propellant produces an opposite, accelerating force. Most rockets generate thrust by burning propellants to produce high-pressure, hot gases that exit through a nozzle.

Chemical rockets are the most common type and include solid rockets, liquid rockets, and hybrids. Solid rockets carry a propellant that acts as both fuel and oxidizer. Liquid rockets burn separate fuels and oxidizers in a combustion chamber. Hybrids mix solid fuel with a liquid or gaseous oxidizer. Other propulsion methods include electric propulsion (ion and Hall-effect thrusters), nuclear thermal propulsion, and solar sails.

Key components include the structural frame, propellant, propulsion system, payload, and guidance, navigation, and control systems. Most rockets have a nose cone, stabilizing fins or grid fins, thrust chambers or engines, and an avionics suite. Performance is described by thrust, specific impulse, and delta-v (change in velocity) for a mission.

Rockets have a long history, beginning with early gunpowder devices in medieval China and evolving through European use. The theoretical framework was developed by Konstantin Tsiolkovsky, and practical liquid-fueled rockets were built by Robert Goddard. In the 20th century rockets enabled space exploration and missiles; recent programs emphasize reusability.

Uses include space launches, satellite deployment, crewed missions, and research. Safety concerns include handling energetic propellants, explosive hazards, and debris.