Ion thruster

An ion thruster is a form of electric propulsion used for spacecraft propulsion that creates thrust by accelerating ions with electricity. The term is strictly used to refer to gridded electrostatic ion thrusters, but may often more loosely be applied to all electric propulsion systems that accelerate plasma, since plasma consists of many ions.

Ion thrusters are categorized by how they accelerate the ions, using either electrostatic or electromagnetic force. Electrostatic ion thrusters use the Coulomb force and accelerate the ions in the direction of the electric field. Electromagnetic ion thrusters use the Lorentz force to accelerate the ions. In either case, when an ion passes through an electrostatic grid engine, the potential difference of the electric field converts to the ion's kinetic energy.

Ion thrusters have an input power spanning 1–7 kilowatts, exhaust velocity 20–50 kilometers per second, thrust 25–250 millinewtons and efficiency 65–80%.

The Deep Space 1 spacecraft, powered by an ion thruster, changed velocity by 4300 m/s while consuming less than 74 kilograms of xenon. The Dawn spacecraft broke the record, reaching 10,000 m/s.