[Cincinatus]

I agree -- fuel is the obvious commodity to do first. The Moon has copious oxygen (it's 40% oxygen by weight) and this can be extracted by any number of common, industrial methods. Even if there were no hydrogen there (although there is), oxygen is 4/5 of the mass of a hydrogen-oxygen rocket fuel load. The payback comes very quickly.

[Paleo Conservative]

I agree -- fuel is the obvious commodity to do first. The Moon has copious oxygen (it's 40% oxygen by weight) and this can be extracted by any number of common, industrial methods. Even if there were no hydrogen there (although there is), oxygen is 4/5 of the mass of a hydrogen-oxygen rocket fuel load. The payback comes very quickly.

The Moon has lots of aluminum oxide. Why not use solar power to separate it into oxygen and aluminum. Then build a rocket that uses powdered aluminum fuel with liquid oxygen oxidizer? That way you wouldn't need to use hydrogen.