Word
Ion Propulsion
Propulsion that accelerates electrically charged particles to push a spacecraft in the opposite direction
Examples
Dawn used ion propulsion to reshape its orbit over long stretches of the journey.
An ion engine's efficient use of propellant does not mean it can lift a rocket from Earth's surface.
Origin
An ion is an atom or molecule carrying a net electric charge. In an ion thruster, electrical energy accelerates charged propellant out of the engine. The spacecraft gains momentum in the opposite direction, following the same conservation principle as other rockets.
How it connects
The term identifies the mechanism that trades high exhaust speed for gentle thrust.
This word appeared in A small push with time to work, the Involves connection for September 27, 2026, which asked: How can a gentle engine make a journey a powerful engine cannot easily afford?
Check yourself
Which process is ion propulsion?
Accelerate charged propellant electrically and eject it to produce thrust. Exactly. The engine gains momentum by expelling accelerated ions.
What the sources establish
Ion engines accelerate charged propellant and achieve high propellant efficiency with low thrust.
Sources
Dawn FAQ (NASA Science), Ion propulsion, low thrust, propellant economy, and electrical power
Dawn at Ceres Press Kit (NASA Jet Propulsion Laboratory), Ion propulsion system and Vesta-to-Ceres mission profile