NASA Tests Water Powered Spacecraft in Orbit
https://www.universetoday.com/143133/nasa-tests-water-powered-spacecraft-in-orbit/

Then picture them communicating, and using a water-powered thruster to approach each other. If you can do that, then you’re up to speed on one of the activities of NASA’s Small Spacecraft Technology Program (SSTP.) It’s all part of NASA’s effort to develop small spacecraft to serve their space exploration, science, space operations, and aeronautics endeavors.

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Tau.Neutrino said:

NASA Tests Water Powered Spacecraft in Orbit
https://www.universetoday.com/143133/nasa-tests-water-powered-spacecraft-in-orbit/

Then picture them communicating, and using a water-powered thruster to approach each other. If you can do that, then you’re up to speed on one of the activities of NASA’s Small Spacecraft Technology Program (SSTP.) It’s all part of NASA’s effort to develop small spacecraft to serve their space exploration, science, space operations, and aeronautics endeavors.

more…

So these things convert water to steam (using some unstated source of energy).

I’m not sure I’d call that “water power”.

These are solar powered thermal rockets, that use water as propellent.

dv said:

These are solar powered thermal rockets, that use water as propellent.

You don’t want mm to cm size ice blocks floating around among the satellites, could do a lot of damage on impact.

Steam is safer.