NASA's Top Science, Exploration and Discovery Stories of 2008

NASA landed on Mars, photographed distant worlds, added to the International Space Station, took part in a lunar science mission with India and made major progress toward returning astronauts to the moon as the agency celebrated its 50th birthday in 2008. Here on Earth, NASA researchers recorded the continued decline of Arctic sea ice, won awards for aviation breakthroughs, discovered the cause of storms that brighten the Northern Lights and helped create state-of-the-art swimsuits worn by Olympic gold medalists. Here are ten of the top accomplishments of America's space agency in its golden anniversary year.