Jet Propulsion Laboratory (U.S.). Mariner Mars Orbiter '71 Spacecraft Design Team.

The Mariner Mars Orbiter Spacecraft Design Book describes the Mariner Mars Orbiter 1971 project from 1969 through 1971. When launched May 30, 1971, abroad an Atlas/Centaur SLV-3 launch vehicle, Mariner Mars Orbiter '71 became Mariner 9. Originally, Mariner 9 was schedule to have an identical companion, Mariner 8, but on May 8, 1971, 365 seconds after launch, Mariner 8's Centaur main engine shut down and the upper stage of the rocket, along with Mariner 8 fell into the Atlantic about 560 km north of Puerto Rico.

Mariner 9 was the first spacecraft to orbit another planet. Mariner 9 arrived in Mars' orbit on November 14, 1971 and began the most ambitious Mars exploration mission yet attempted. Mariner 9 combined the original mission objectives of both Mariner 8 (mapping 70% of the Martian surface) and Mariner 9 (a study of temporal changes in the Martian atmosphere and on the Martian surface). Mariner 9 carried sophisticated instrumentation similar to that of Mariner 6 and 7 (wide -and narrow-angle TV cameras, infrared radiometer, ultraviolet spectrometer, and infrared interferometer spectrometer). With this instrumentation a larger propulsion system was required for controlling the spacecraft during its time in Mars' orbit.

Imaging of the surface of Mars by Mariner 9 was delayed by a dust storm, which started on September 22, 1971. The storm quickly grew into one of the largest global storms ever observed on Mars. The storm abated through November and December and normal mapping operations began. By the end of 349 days in Mars' orbit, 7329 images (including images of Mars' two moons, Phobos and Deimos) had been relayed back to Earth and a total of 54 billion bits of data had been transmitted. Mariner 9 completely revolutionized our view of Mars and the information from this mission later served as the foundation for the Viking program.