Plasma propulsion

Article By:

Choueiri, Edgar Y. Electric Propulsion Laboratory, Engineering Quadrangle, Princeton University, Princeton, New Jersey.

Last reviewed:August 2020

DOI:https://doi.org/10.1036/1097-8542.525950

The imparting of thrust to a spacecraft through the acceleration of a plasma (ionized gas). A plasma can be accelerated by electrical means to exhaust velocities considerably higher than those attained by chemical rockets. The higher exhaust velocities (specific impulses) of plasma thrusters usually imply that, for a particular mission, the spacecraft would use less propellant than the amount required by conventional chemical rockets. This means that for the same amount of propellant a spacecraft propelled by a plasma rocket can increase in velocity over a set distance by an increment larger than that possible with a chemical propulsion system. An increasing number of near-Earth satellites have benefited from the propellant savings of plasma thrusters and rely on them for attitude control and station-keeping maneuvers. Generally, the larger the required velocity increment, the more beneficial is plasma propulsion compared to propulsion with rockets having lower exhaust velocities. Consequently, many ambitious missions—such as deep-space exploration including Moon tours and orbiters to outer planets, sample return missions, and heavy cargo and piloted missions—may be enabled by plasma propulsion. See also: Plasma (physics); Specific impulse

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