Mariner 9 global survey

Mariner 9 · 1971 CE – 1972 CE · Mars

Mariner 9 global survey — Mariner 9 · 1971 CE – 1972 CE · Mars — Recorded expedition route · schematic map

Enter orbit and map the surface of Mars, taking on the mapping planned for the lost Mariner 8 as well as its own study of changes over time.

Historical context

Mariner 4 had left a picture of a cratered, Moon-like planet, and the two flybys of 1969, Mariners 6 and 7, had not changed it. Mariner 9, by NASA's record the first spacecraft to orbit another planet, waited out a global dust storm and then mapped the whole surface, which turned out to include volcanoes far larger than any on Earth, a canyon system thousands of kilometres long and dry channels. Its maps were used to plan the Viking flights.

The voyage, step by step

  1. Arrival into a storm

    14 November 1971

    Mariner 9 reached orbit on 14 November 1971, Universal Time, to find the entire planet hidden under a global dust storm.

  2. Hellas under the dust

    1971 CE

    The great southern basin, beside Noachis where the storm had broken out in September, stayed featureless for weeks.

  3. Two small moons

    1971 CE

    While the dust settled the orbiter turned its cameras on Phobos and Deimos, and resolved them for the first time as battered, irregular rocks.

  4. A canyon four thousand kilometres long

    1972 CE

    As the air cleared, a gash appeared along the equator deep enough to swallow the Alps and long enough to cross the United States.

  5. The labyrinth of night

    1972 CE

    West of the canyons the ground broke into a maze of intersecting troughs, cracked open where the Tharsis bulge had lifted the crust.

  6. The largest volcano known

    1972 CE

    One of the four dark spots that had risen above the dust turned out to be a shield volcano, now measured at about twenty-two kilometres high and six hundred across.

  7. The layered cap

    27 October 1972

    In the north the cameras found terraces of ice and dust stacked in fine layers, a climate record written into the pole.

Outcome

7,329 pictures, the first complete map of Mars, and the discovery of its great volcanoes, canyons and dry channels.

Mariner 9

First spacecraft to orbit another planet, by NASA's record, and the first to map the whole of Mars.

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Sources

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