Viking 1

Viking 1 was the first of the two American spacecraft of NASA's Viking program, each made up of an orbiter and a lander, sent to Mars in 1975. It was launched on a Titan IIIE rocket with a Centaur upper stage on 20 August 1975, entered orbit around Mars on 19 June 1976, and set its lander down in western Chryse Planitia on 20 July 1976, after the first planned landing site proved too rough. It was the first truly successful Mars lander in history. The orbiter drew heavily on the Mariner spacecraft design and was completed by engineers at the Jet Propulsion Laboratory, while the lander was designed and built by contractors at Martin Marietta in Denver. The orbiter was shut down in 1980 when its attitude control gas ran low, and the lander worked on the surface for more than six years, until a faulty command in November 1982 ended contact.