A gas-dynamic control system is one where the path of an object in flight is controlled by either the generation or redirection of gas flow out of an orifice rather than with the traditional movable control surfaces. There are two major types of gas-dynamic control: thrust vectoring and control jets.

Thrust vectoring

Thrust vectoring

Thrust vectoring, also thrust vector control or TVC, is the ability of an aircraft, rocket or other vehicle to manipulate the direction of the thrust from its engine or motor in order to control the attitude or angular velocity of the vehicle....

involves redirecting part or all of the same gas outflow that is used to generate thrust for maneuvering. Either vanes that are placed in the gas flow jet are moved, redirecting it, or else there is a nozzle around the gas jet which can be tilted in one axis (1D thrust vectoring) or two axes (2D thrust vectoring) in order to direct the gas jet.

Control jets are small orifices in the top/bottom and/or sides of the object to be controlled, through which gas can be ejected. This gas may be tapped from the main engine or generated separately from compressed gas in bottles or by burning fuel. If mounted in the front of the vehicle, a gas jet blowing out the left of the nose will push the nose, and therefore the object, to the right. If mounted behind the center of gravity of the object the opposite effect will occur - a gas jet on the left side will turn the object to the left. Varying the amount of gas exiting the jet will control the amount of force and therefore the rate of turn.

Gas-dynamic control systems are typically found on high-altitude jet aircraft

Jet aircraft

A jet aircraft is an aircraft propelled by jet engines. Jet aircraft generally fly much faster than propeller-powered aircraft and at higher altitudes – as high as . At these altitudes, jet engines achieve maximum efficiency over long distances. The engines in propeller-powered aircraft...

 (such as the Sukhoi Su-35

Sukhoi Su-35

The Sukhoi Su-35 is a single-seat, twin-engined supermaneuverability multirole fighter. It is a derivative of the Su-27 'Flanker', and was initially known as the Su-27M. More than a dozen of these were built with some used by the Russian Knights aerobatic demonstration team...

, F-22 Raptor

F-22 Raptor

The Lockheed Martin/Boeing F-22 Raptor is a single-seat, twin-engine fifth-generation supermaneuverable fighter aircraft that uses stealth technology. It was designed primarily as an air superiority fighter, but has additional capabilities that include ground attack, electronic warfare, and signals...

 and X-15), spacecraft

Spacecraft

A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....

 (such as the Space Shuttle

Space Shuttle

The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...

), ballistic missile

Ballistic missile

A ballistic missile is a missile that follows a sub-orbital ballistic flightpath with the objective of delivering one or more warheads to a predetermined target. The missile is only guided during the relatively brief initial powered phase of flight and its course is subsequently governed by the...

s, air-to-air missile

Air-to-air missile

An air-to-air missile is a missile fired from an aircraft for the purpose of destroying another aircraft. AAMs are typically powered by one or more rocket motors, usually solid fuelled but sometimes liquid fuelled...

s (such as the Vympel R-73

Vympel R-73

The Vympel R-73 developed by Vympel machine-building design bureau, is the most modern Russian short-range air-to-air missile.-Development:...

 (AA-11) and surface-to-air missiles (such as the S-400 "Triumf" (SA-20) and 9K332 "Tor" (SA-15)).