On May 30, 1971, Mariner 9 robotic spacecraft was launched from LC-36B at Cape Canaveral Air Force Station, Florida on top of an Atlas SLV-3C Centaur-D rocket. It reached Mars on November 14 of the same year and became the first spacecraft to orbit Mars, and in general, another planet.
Today’s (May 30) story of what happened this day in Science, Technology, Astronomy, and Space Exploration history.
Mariner 9 (Also known as Mariner Mars ’71 / Mariner-I)
Mariner 8 (failed on launch on May 8, 1971) and Mariner 9 were the third and final pair of Mars missions in NASA’s Mariner series of the 1960s and early 1970s. Both spacecraft were designed to be the first Mars orbiters, marking a transition in our exploration of the red planet from flying by the planet to spending time in orbit around it.
Mariner 9 was launched successfully on May 30, 1971, and became the first artificial satellite of Mars when it arrived and went into orbit, where it functioned in Martian orbit for nearly a year. It narrowly beat the Soviet probes Mars 2 (launched May 19, 1971, inserted into Mars orbit on November 27) and Mars 3 (launched May 28, 1971, inserted into Mars orbit on December 2).
Mariner 9 complete its final transmission on October 27, 1972, after fter 349 days in orbit, well past its 90-day primary mission.
When Mariner 9 arrived at Mars on November 14, 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 of Mars was totally obscured. The spacecraft’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.
The Soviet Union’s Mars 2 and Mars 3 probes also arrived during the same dust storm but they were unable to adapt to the unexpected conditions. This severely limited the amount of data that they were able to collect.
Mariner 9 mapped 85 percent of the Martian surface and collected valuable information about Mars’ surface and atmosphere.
However, surface-obscured images did contribute to the collection of Mars science, including the 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. It also highlighted the importance of flexible mission software.
Mariner 9 continued to operate until October 27, 1972, well past its design life. While it was operational, the probe transmitted 7,329 images. Some of the most significant were:
- The first detailed views of Mons Olympus, the solar system’s largest volcano. Its height is 21.9 km (13.6 mi) above datum; 26 km (16 mi) local relief above plains (at least two and a half times the height of Mount Everest) and 374 miles (600 km) wide (nearly the size of the state of Arizona).
- Valles Marineris, a canyon system that dwarfs the Grand Canyon – it extends over 3,000 kilometers (1864 miles) long, spans as much as 600 kilometers (373 miles) across, and delves as much as 8 kilometers (5 miles) deep. That giant canyon system is named after Mariner 9 in honor of its achievements.
- Martian moons Phobos and Deimos.
Today, Mariner 9’s location is unknown. The spacecraft is either still orbiting Mars, has already burned up in the Martian atmosphere, or crashed into the surface of the red planet.
May 30 in Science, Technology, Astronomy, and Space Exploration history
- 1975: The European Space Agency (ESA) was founded.
- 1971: Mariner 9, the first spacecraft to orbit Mars was launched.
Sources
- Mariner 8 & 9 on the NASA Mars Exploration Program website
- Mariner 9 (Mariner I) on the NASA Jet Propulsion Laboratory website
- “Mariner 9: First Spacecraft to Orbit Mars” on Space.com
- Mariner 9 on Wikipedia
