Mariner 9 was the first spacecraft to orbit Mars.

    A dust storm that began on 22 September 1971 in the Noachis region eventually encircled the planet. When Mariner 9 arrived in November Olympus Mons and the three Tharsis volcanoes were the only features visible above the haze. By 30 December 1971 the orbit had been adjusted to have a periapsis of 1650 km and orbital period to 11:59:28 hr so that synchronous data transmissions could be made to the Goldstone 64-m DSN antenna. The dust storm had abated by then and the Mariner 9 spacecraft operated until 27 October 1972 when the attitude control gas was depleted.

    Basic Accomplishments

    Mariner 9 mapped 70% of the Martian surface and obtained views of Deimos and Phobos. It provided data to begin our understanding of temporal variability of the surface and atmosphere of the planet.

    For more information on the mission see the following links

    Available atmospheric data consists of: