The NASA Evolutionary Xenon Thruster project at Glenn Research Center aims to build an ion thruster about three times as powerful as the NSTAR used on Dawn and Deep Space 1. This week, NASA announced that one of its engines operated for 48,000 hours continuously. Continue reading for two videos and more information.

NEXT is a solar electric propulsion system where electricity from the spacecraft’s solar panels is used to power a a 7-kW class ion thruster. In this, particles of xenon gas are electrically charged and then accelerated to speeds up to 90,000 mph (145,000 km/h).

The thrust made by an ion engine is tiny compared to a chemical rocket, but its very high efficiency combined with its ability to fire for years on end means that it can build up astonishing speeds over time.