Editing Propulsion (section)

===Space===
[[Image:Shuttle Main Engine Test Firing.jpg|thumb|left|A remote camera captures a close-up view of a [[Space Shuttle main engine]] during a test firing at the [[John C. Stennis Space Center]] in [[Hancock County, Mississippi]]]]
{{main|Spacecraft propulsion}}

Spacecraft propulsion is any method used to accelerate [[spacecraft]] and artificial [[satellite]]s. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the back/rear of the vehicle at very high speed through a [[rocket engine nozzle|supersonic de Laval nozzle]]. This sort of [[engine]] is called a [[rocket engine]].

All current spacecraft use chemical rockets ([[bipropellant rocket|bipropellant]] or [[solid rocket|solid-fuel]]) for launch, though some (such as the [[Pegasus rocket]] and [[SpaceShipOne]]) have used [[air-breathing engine]]s on their [[Multistage rocket|first stage]]. Most satellites have simple reliable chemical thrusters (often [[monopropellant rocket]]s) or [[resistojet rocket]]s for [[orbital station-keeping]] and some use [[momentum wheel]]s for [[Spacecraft attitude control|attitude control]]. Soviet bloc satellites have used [[Electrically powered spacecraft propulsion|electric propulsion]] for decades, and newer Western geo-orbiting spacecraft are starting to use them for north–south stationkeeping and orbit raising. Interplanetary vehicles mostly use chemical rockets as well, although a few have used [[ion thruster]]s and [[Hall-effect thruster]]s (two different types of electric propulsion) to great success.
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