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Radar View of Layering near Mars' South Pole, Orbit 1334
Radar View of Layering near Mars' South Pole

A radargram from the Shallow Subsurface Radar instrument (SHARAD) on NASA's Mars Reconnaissance Orbiter reveals detailed structure in the polar layered deposits of Mars' south pole.

The horizontal scale of the radargram is distance along the orbiter's ground track, about 590 kilometers (370 miles) from about 75 degrees south latitude on the left to about 85 degrees south latitude at right. The vertical scale is time delay of radar signals reflected back to the spacecraft from the surface and subsurface. For reference, the blue double-headed arrow indicates a distance of about 1,500 meters (5,000 feet) between one of the deeper subsurface reflectors and ground level, based on an assumed velocity of the radar waves in the subsurface. The color scale varies from black for weak reflections to white for strong reflections.

Some of the subsurface reflectors can be traced for a distance of 100 kilometers (60 miles) or more. The layers are not all horizontal and the reflectors are not always parallel to one another. Some of this is due to variations in surface elevation, which produce differing velocity path lengths for different reflector depths. However, some of this behavior is due to spatial variations in the deposition and removal of material in the layered deposits, a result of the recent climate history of Mars.

The sounding radar collected the data presented here during orbit 1334 of the mission, on Nov. 8, 2006.

The Shallow Subsurface Radar was provided by the Italian Space Agency (ASI). Its operations are led by the University of Rome and its data are analyzed by a joint U.S.-Italian science team. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington.

Image Credit: NASA/JPL-Caltech/ASI/University of Rome/Washington University in St. Louis

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