When the Mars Observer spacecraft disappeared into the cold void of space nine years ago, it broke Bill Feldman’s heart. Feldman, 62, a Los Alamos National Laboratory scientist, had worked since 1984 to develop an instrument for the spacecraft called a neutron spectrometer. There was no room to fit the instrument, which is smaller than a shoe box and weighs about 8 pounds, on subsequent missions to the planet until the Mars Odyssey spacecraft. It took nearly a decade, but Feldman finally got a second chance with Odyssey, which was launched in early 2001 and successfully reached orbit in October. A few months ago, the instrument returned some surprising results – including showing that hydrogen, which many think indicates water, is more abundant on Mars than previously believed.