PIA09222: Bright Lower Echo in Radargram of South Polar Layered Deposits
Target Name: Mars
Is a satellite of: Sol (our sun)
Mission: Mars Express (MEX)
Mars Global Surveyor (MGS)
Spacecraft: Mars Express Orbiter
Mars Global Surveyor Orbiter
Instrument: MARSIS
Mars Orbiter Laser Altimeter
Product Size: 1784 x 460 pixels (width x height)
Produced By: JPL
Full-Res TIFF: PIA09222.tif (2.466 MB)
Full-Res JPEG: PIA09222.jpg (124.4 kB)

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Click here for annotated version of PIA09222 Bright Lower Echo in Radargram of South Polar Layered Deposits
Annotated Version

The upper image is a radargram from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS), showing data from the subsurface of Mars in the ice-rich layered deposits that surround the south pole. The lower image shows the position of the ground track (white line) on a topographic map of the area based on Mars Orbiter Laser Altimeter data. The images are 1,250 kilometers (775 miles) wide.

The MARSIS echo trace splits into two traces on the left side of the image, at the point where the ground track crosses from the surrounding plains onto the elevated layered deposits. The upper trace is the echo from the surface of the deposits, while the lower trace is interpreted to be the boundary between the lower surface of the deposits and the underlying material. The strength of the lower echo suggests that the intervening material is nearly pure water ice. Near the image center, the bright lower echo abruptly disappears for unknown reasons. The time delay between the two echoes reaches a maximum of 42 microseconds left of center, corresponding to a thickness of 3.5 kilometers (2.2 miles) of ice. The total elevation difference shown in the topographic map is about 4 kilometers (2.5 miles) between the lowest surface (purple) and the highest (red).

MARSIS is an instrument on the European Space Agency's Mars Express orbiter. NASA and the Italian Space Agency jointly funded the instrument. The Mars Orbiter Laser Altimeter flew on NASA's Mars Global Surveyor orbiter.

Image Credit:
NASA/JPL/ASI/ESA/Univ. of Rome/MOLA Science Team

Image Addition Date:
2007-03-15