Mariner 9 Anniversary/Landslides on Mars

November 13, 1971 is a red-letter date in the history of exploration. Thirty-one years ago today the American spacecraft, Mariner 9, became the first spacecraft to orbit another planet. Imagery from three previous flyby Mariner Missions (4, 6, and 7) indicated that Mars looked similar to the Earth's Moon (craters and plains). However, Mariner 9's eleven month mission mapped the whole planet with over 7,000 images. This mission rewrote the book on Mars by discovering channels, polar layered materials, enormous shield volcanoes, sand dunes, and an enormous canyon system. This canyon system, Valles Marineris, was named in honor of its discoverer. Therefore, in honor of Mariner 9, the THEMIS Team is releasing an image of a portion of Valles Marineris called Melas Chasma. Melas Chasma comprises the central portion of the Valles Marineris canyon system complex. A series of massive landslide deposists are visible on the canyon floor. The older (bottom-most) landslide deposit has longitudinal ridges which formed parallel to flow direction, while the younger slide deposits have concentric ridges. Dunes are also visible near the bottom of the image.