A recently retired NASA engineer and some Department of Energy scientists and engineers jointly invented a lunar ascent vehicle that would use the Moon's water ice directly as rocket propellant. It would be able to transport an 18 wheeler (10 tons) from the moon's surface to an Earth transfer orbit, and return itself to the Moon.
 
 

At either the Arcitic or Antarctic poles of the moon, a water-extracting device could use the otherwise wasted heat from a small nuclear electric generator to warm the moon dirt (regolith) and its ice to just above the melting point of ice. The water would be distilled from the ice/soil mixture by heating it in a closed chamber, using the waste heat from thel nuclear reactor. The water vapor produced would be condensed and collected as liquid. The process is very similar to making "moonshine," a term for the back-woods distillation of whiskey. Then a nuclear-heated steam rocket would use the water in its tank, as propellant, and launch the ascent vehicle to a lunar escape orbit. The nuclear heater would be quite similar to the nuclear reactors used to power submarines for the United States Navy.

The ascent vehicle could haul people, food or supplies to and from the moon surface. The payload also could be water, transported back to low Earth orbit (LEO) where it could be electrolyzed to obtain propellant for space vehicles on their way to the Moon or elsewhere beyond LEO. Vehicles from Earth would only need to rise to a high orbit and rendezvous with the ascent vehicle.

The inventors named the vehicle a "zupmobile" because of their last names: Dr. Zuppero and Dr. Zupp. They designed it as a space truck to take payloads from the moon surface to low moon orbits.

This ascent vehicle could be especially inexpensive because it uses the water directly, as propellant in their steam rocket. Competing schemes would require complex, heavy and expensive water splitting electrolysis devices on the moon.

For each trip, the water mining system would warm about 100 tons of ice. This is as much moon ice as one could pack into 2 or 3 railroad cars (100 cubic yards of dirt).

The steam rocket moon shuttle would use about three times more water than the competing, chemical rocket moon shuttle. But the cost of making the chemical rocket fuels from water on the moon is about 1000 times greater than the steam rocket system.