Mars Pathfinder was a United States spacecraft that transmitted images and other data from the surface of Mars for nearly three months in 1997. On July 4, 1997, Pathfinder "bounced-down" on the Ares Vallis flood plain of Mars. It "bounced" because part of its mission was to test a new landing system that used parachutes and air bags rather than the traditional rockets. Just before landing, the air bags inflated to completely enclose the spacecraft. This cushioning enabled Pathfinder to land in a rocky, boulder-filled valley that would have been impossible for a conventional spacecraft.