PBR water resistojets
A line of small thrusters that heat water into steam and vent it for thrust, sized from half a cubesat unit up to microsatellites.
Why it matters
Water is non-toxic, cheap and easy to load, which lowers cost and launch safety hurdles for small satellites that need to maneuver.
How the technology works
A resistojet uses electric heaters to vaporize water and push the vapor out a nozzle. Pale Blue sells PBR-10, PBR-20, PBR-30 and PBR-50 versions, from a 0.5U cubesat unit up to a 13.4 kg system for microsatellites, and lists several missions that have flown its water resistojets.
Sources
Updated Oct 22, 2026 · How we source facts · Suggest a correction