The $10 million Ansari X Prize competition, which so spectacularly spurred the development of commercial space flight, ended last year; but now, NASA's Exploration Systems Mission Directorate has jumped into the game of offering prizes for technology innovation. So far, three Centennial Challenges have been announced. Brant Sponberg is the program's manager.

You've just announced the latest competition -- lunar oxygen?
It's called Moon ROx -- Moon Regolith Oxygen Challenge. Contestants have eight hours to produce five kilograms of oxygen from lunar soil. We know how to do it, but we need to get the efficiencies to the point where it's practical.