Viking landed on Mars 40 years ago

According to a press release by NASA's Langley Research Center, on July 20, 2016, NASA will celebrate the 40th anniversary of a major event in the history of interplanetary space travel and the exploration of the planets: the world's first successful soft landing of an operating planetary probe on the surface of Mars.

On that day 40 years ago, the Viking Lander 1 successfully soft-landed, on the surface of Mars. On Sept. 3, 1976, the Viking Lander 2 did the same. Both crafts arrived with complex payloads of scientific instruments to investigate the atmosphere and surface of the red planet. This included three biology experiments to search for extant life on...