A NASA Mars mission which was launched on 4 December 1996 and arrived at the planet on 4 July 1997. The main objective was to test a low-cost means of sending a spacecraft and a surface rover vehicle to land on the martian surface. It carried a 10-kg 22-lb miniature rover, named Sojourner, equipped to measure the elemental composition of the surface rocks and soil and take images around the landing site in Ares Vallis. In a new technique, the lander’s impact was cushioned by airbags, which bounced several times before coming to rest. The performance of both the lander and the rover exceeded expectations and they were able to continue operating beyond the minimum target of 7 martian days sols originally envisaged. Panoramic views of the landscape were returned and Sojourner successfully travelled on expeditions covering about 80 metres. Instruments on the lander monitored atmospheric conditions at the surface. Measurements of the martian atmosphere also were made during the parachute descent. After arrival at Mars, the lander base station was renamed the Sagan Memorial Station in honour of the American planetary scientist, Carl Sagan, who died in 1997.