Science Fair Project Encyclopedia
Pulsed plasma thruster
Pulsed plasma thrusters use an arc of electric current through a solid propellant (almost always teflon), to produce a quick and dependable burst of impulse. PPT's are great for attitude control, and for main propulsion on particularly small spacecraft (those in the hundred-kilogram or less category). However they are also one of the least efficient electric propulsion systems, with a thrust efficiency of less than 10%.
Pulsed plasma thrusters were the first electric propulsion system to be deployed in space, on the Soviet probes Zond-2 in 1964 and Zond-3 in 1965. Used as an experimental system for spacecraft orientation control, Soviet engineers subsequently returned to the use of high-pressure nitrogen jets.
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