ion propulsion

Syllable breakdown

Dictionary meaning

a form of spacecraft propulsion that generates thrust by electrically accelerating ions — charged atoms or molecules — to extremely high velocities and expelling them as a directed stream; ion thrusters produce very low thrust compared to chemical rockets but achieve specific impulse values — a measure of propellant efficiency — many times higher, meaning they extract far more thrust per kilogram of propellant; this makes ion propulsion highly efficient for long-duration missions where payload mass is precious and chemical propellant quantities would be prohibitive; ion propulsion was successfully demonstrated on NASA's Deep Space 1 mission in 1998 and has since been used on missions including Dawn, Hayabusa, and the European SMART-1 lunar mission; it is considered a leading technology for future crewed missions to Mars and beyond where the efficiency advantage compounds over multi-year transit times