In Greek mythology, Prometheus was the Titan who stole fire from the gods and gave it to humanity. Arthur C. Clarke’s early novel “Prelude to Space” featured a nuclear powered ram jet for the first stage of a moon mission; it was called Prometheus as well. Last week NASA Administrator, Sean O’Keefe, announced a new Prometheus — a bold new nuclear space propulsion initiative that will do for spaceflight what fire did for humans of old.