Mariner 9 was a NASAspacecraft. It was the ninth spacecraft in the Mariner programme. It was sent to study and orbit the planetMars. It was the first spacecraft to orbit another planet. Mariner 9 was launched on May 30, 1971 from Cape Canaveral Air Force Station.[1] Mariner 9 reached Mars on November 13, 1971, after a ~170 day flight. The spacecraft was sent to map 70 % of the surface of Mars and to study the temperature changes of the Martian atmosphere and surface. When it arrived, a dust storm hid the surface of Mars. After a few months the dust settled and Mariner 9 discovered the Valles Marineris.