NASA decided Monday not to include a rocket-powered airplane built by scientists at the Langley Research Center in its next Mars Scout mission, possibly because of concerns over risk factors following the Columbia shuttle disaster. The unmanned ARES plane, short for Aerial Regional-scale Environmental Survey, would have been the first plane to fly on another planet. The plane was designed to fold up inside an aeroshell for the flight to Mars, then unfold and fly over the planet's surface for about 310 miles, studying air, magnetism and geology. The mission would have launched in 2007. Instead, NASA chose the Phoenix...