Key Dates:
- 05.30.71: Launch (22:23:04 UT)
- 11.14.71: Arrival at Mars (00:18 UT)
- 10.27.72: End of Mission (22:32 UT)
- Status: Mission Complete
Mariner 9 Information:
Upon arrival at Mars, Mariner 9 discovered that the atmosphere was so dusty that the surface was obscured. Although this eventuality had been unexpected, it proved the case for studying a planet from orbit rather than just on a flyby mission. Mission controllers reprogrammed Mariner 9's computers from Earth to delay imaging of the surface for a couple of months until the dust settled.
After 349 days in orbit, Mariner 9 had transmitted 7,329 images, covering over 80% of Mars' surface. The images revealed river beds, craters, massive extinct volcanoes, canyons including Valles Marineris, a massive system of canyons over 4,000 kilometers [about 2,500 miles] long. The vast chasm is named in honor of the spacecraft. Mariner 9 also found evidence of wind and water erosion and deposition, weather fronts, fogs, and more. Mars' tiny moons, Phobos and Deimos, were also photographed. The findings from the Mariner 9 missions laid the groundwork for the Viking program.