PASADENA, Calif. (AP) - Northrop Grumman Space Technology has been selected to help NASA design a nuclear-powered spacecraft to orbit and explore three moons of Jupiter that may have oceans beneath their icy surfaces. The $400 million contract with the Redondo Beach, Calif.-based unit of Northrop Grumman covers work through mid-2008, NASA's Jet Propulsion Laboratory said Monday. The Prometheus Jupiter Icy Moons Orbiter spacecraft will be designed to explore Callisto, Ganymede and Europa sometime in the next decade, after launching in 2012 or later. Scientists want to know what the big moons are made of, their history and whether the...