Cold gas thruster
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A cold gas thruster is a propulsive device that uses pressurized inert gas as the reaction mass. The compressed gas is released through a propelling nozzle to generate a cold jet thrust.[1]
A cold gas thruster usually consists of simply a pressurized tank containing gas, a valve to control its release and a propelling nozzle, and plumbing connecting them. A very simple example would be the use of a handheld CO2 or nitrogen gas fire extinguisher while sitting down in a rolling office chair; motion is achieved by pointing the nozzle in the direction opposite of the desired movement and activating the extinguisher.
Because the gas is usually unheated, speed at the throat is low and very low performance is achieved; in a vacuum with nitrogen gas a specific impulse of 73 seconds can be achieved.[1] The maximum theoretical specific impulse for nitrogen gas is 76 seconds. In the simplest approximation, the specific impulse is modeled as proportional to the square root of the (absolute) gas temperature, so performance rises as the gas temperature is increased. A thruster in which the performance is increased by heating the gas by an electrical resistance is known as a resistojet.
Cold gas thrusters are mostly useful for vernier engines, and are employed chiefly for simplicity and reliability.
See also
- Mars Cube One is using cold gas thrusters
- Monopropellant rocket
- Quad - used cold gas thrusters
- Rocket engine
References
- ^ a b Assad Anis, "Cold Gas Propulsion System – An Ideal Choice for Remote Sensing Small Satellites", chapter 20, Remote Sensing - Advanced Techniques and Platforms, Boris Escalante (Ed.), ISBN 978-953-51-0652-4, InTech, doi:10.5772/37149. (Accessed 11 June 2015)
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