Achievements
Mariner 9 was the first spacecraft to orbit another planet. It carried an instrument payload similar to Mariner 6 and 7, but, because of the need for a larger propulsion system to control the spacecraft in Mars orbit, it weighed more than Mariners 6 and 7 combined.
When Mariner 9 arrived at Mars on 14 November 1971, planetary scientists were surprised to find the atmosphere was thick with "a planet-wide robe of dust, the largest storm ever observed." The surface was totally obscured. Mariner 9's computer was thus reprogrammed from Earth to delay imaging of the surface for a couple of months until the dust settled. The main surface imaging did not get underway until mid-January 1972. However, surface-obscured images did contribute to the collection of Mars science, including understanding of the existence of several huge high-altitude volcanoes of the Tharsis Bulge that gradually became visible as the dust storm abated. This unexpected situation made a strong case for the desirability of studying a planet from orbit rather than merely flying past.
After 349 days in orbit, Mariner 9 had transmitted 7,329 images, covering 100% of Mars' surface, whereas previous flyby missions had returned less than one thousand images covering only a small portion of the planetary surface.
The images revealed river beds, craters, massive extinct volcanoes (such as Olympus Mons, the largest known volcano in the Solar System), canyons (including the Valles Marineris, a system of canyons over about 2,500 miles (4,020 km) long), 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 underpinned the later Viking program.
The enormous Valles Marineris canyon system is named after Mariner 9 in honor of its achievements.
After depleting its supply of attitude control gas, the spacecraft was turned off on October 27, 1972.
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Famous quotes containing the word achievements:
“Our achievements speak for themselves. What we have to keep track of are our failures, discouragements, and doubts. We tend to forget the past difficulties, the many false starts, and the painful groping. We see our past achievements as the end result of a clean forward thrust, and our present difficulties as signs of decline and decay.”
—Eric Hoffer (1902–1983)