Mariner 9 was the first spacecraft to orbit Mars and complete a global mapping mission.
NASA’s Mariner 9 entered orbit around Mars on 13 November 1971. It became the first spacecraft to orbit another planet, rather than simply flying past it. Its cameras were able to build a much broader picture of Mars as the spacecraft repeatedly circled the planet.
A global dust storm initially obscured much of the surface. As the storm subsided, Mariner 9 photographed volcanoes, canyons, channels, and both Martian moons. The mission revealed that Mars had a far more geologically diverse landscape than the limited Mariner 4 flyby images had suggested.
Mariner 9 operated until October 1972. It was later followed by the Soviet Mars 2 and Mars 3 orbiters and by NASA’s Viking orbiters. Mariner 9 is sometimes confused with Mars Global Surveyor, which arrived decades later and conducted a much longer, higher-resolution orbital survey.