Today on Discovery
Enterprise
we commemorate the forty-second
anniversary of Mariner 9’s exploration of the planet Mars. On November 14th,
1971 Mariner 9 became the first spacecraft to orbit another planet, narrowly beating
the Soviet space probes Mars 2 and Mars 3, which both arrived a month later.
In order to mark this auspicious occasion we present for your viewing pleasure a
NASA educational video from the early 1980's titled Mars: The Search Begins,
highlighting some of the important findings the 1971-1972 Mariner 9 mission to
Mars, featuring Dr. Carl Sagan and some of his colleagues who worked on the
mission. The findings from the Mariner 9 missions underpinned the later Viking
Lander program of which Carl Sagan played an active and vital role.
During the dust storm, four strange dark spots had been visible on the surface (three on this picture). As the storm subsided, it became clear that these were enormous craters, as much as 40 to 50 miles wide. What was most unusual about them was that each was perched atop the mountain. At JPL image team announced on December 1971 its surprising conclusion : They were volcanoes.
When Mariner 9 arrived at Mars on November 14th, 1971,
the entire surface of the planet was hidden by a planet-wide dust storm, the
largest storm ever observed.
The entire surface of the Mars was totally obscured,
and 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 begin until mid-January 1972.
However the first obscured images did give a hint of
the spectacular surface features that were soon to be revealed. These first
pictures showed three circular structures which were the first indication of
the existence of several huge high-altitude volcanoes of the Tharsis Bulge that
gradually became visible as the dust storm subsided.
Olympus Mons and a few other volcanoes in the Tharsis region stand high enough to reach
above the frequent Martian dust-storms recorded by telescopic observers as
early as the Nineteenth century.
The astronomer Patrick Moore points out that Schiaparelli (1835–1910)
"had found that his Nodus Gordis and Olympic Snow [Nix Olympica] were
almost the only features to be seen" during dust storms, and "guessed
correctly that they must be high"
After 349 days in orbit, Mariner 9 had transmitted
over seven thousand images, covering the entire of the Martian surface. These
images revealed a world of breathtaking geologic beauty showing evidence of a
Mars more conducive to life in the ancient past.
Mariner 9 revealed a world of ancient dried out 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 4,020 km long, evidence of wind and water erosion and
deposition, weather fronts, fogs, and more.
Valles Marineris,
The enormous Valles Marineris canyon system is named
after Mariner 9 in honour of its achievements.
Mars' small moons, Phobos and Deimos were also
photographed for the very first time. The findings from the Mariner 9 mission
underpinned the later Viking program and renewed interest in the exploration of
Mars.
Mariner 9’s mission of discovery finally ended after
the depletion its supply of attitude control gas and the spacecraft was turned
off on October 27th, 1972.
Now without further adieu we present Mars: The Search
Begins.
Mars: The Search Begins