Nothing new NASA experimented with nuclear rockets in the 1960’s at Nevada Test Range
Principle is simple use a nuclear reactor to heat working fluid to incredible temperatures and expel the superheated gases out the exhaust nozzle
Working fluid can be number of things,, liquid hydrogen, ammonia , methane , even water
The resultant ISP (amount of thrust produced by pound of propellants) is 2 to 3 times that of most powerful chemical rockets
As a creature that needs water to survive...I wonder how I would feel seeing it shoot out of the end of the rocket.
But seriously, liquids are pretty heavy. How would this differ from carrying liquid fuel and some oxidizer?
I am “assuming” they would look for water along the way (Water on the moon and Mars for example.” Refueling in a zero gravity environment would certainly be more efficient, I guess.