Electric propulsion (EP) is a broad category of thruster technologies that use electrical power to accelerate propellant to high exhaust velocities. Major variants include Hall-effect thrusters, gridded ion engines, pulsed plasma thrusters, and electrospray systems. EP systems are characterized by very high specific impulse (1,000-10,000+ seconds) but low thrust, making them ideal for long-duration missions where efficiency outweighs time constraints.
Electric propulsion has transformed the commercial satellite industry by enabling all-electric GEO satellites that trade longer orbit-raising times (months instead of days) for dramatic propellant mass savings. It is also the primary propulsion technology for mega-constellations, with thousands of Starlink and OneWeb satellites relying on EP for orbit maintenance and end-of-life deorbiting.