NASA Mars Picture of the Day: Exhuming South Polar Crater

Mars Global Surveyor Mars Orbiter Camera

MGS MOC Release No. MOC2-629, 7 February 2004

NASA/JPL/Malin Space Science Systems

The large, circular feature in this image is an old meteor
impact crater. The crater is larger than the 3 kilometers-wide
(1.9 miles-wide) Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC)
image, thus only part of the crater is seen. The bright mesas
full of pits and holes–in some areas resembling swiss cheese–are
composed of
frozen carbon dioxide. In this summertime view, the mesa slopes
and pit walls are darkened as sunlight causes some of the
ice to sublime away. At one time in the past, the crater shown here
may have been completely covered with carbon dioxide ice, but, over
time, it has been exhumed as the ice sublimes a little bit more
each summer. The crater is located
near 86.8°S, 111.6°W.
Sunlight illuminates this scene from the upper left.

Malin Space Science Systems and the California Institute of Technology
built the MOC using spare hardware from the Mars Observer mission.
MSSS operates the camera from its facilities in San Diego, California.
The Jet Propulsion Laboratory’s Mars Surveyor Operations Project
operates the Mars Global Surveyor spacecraft with its industrial
partner, Lockheed Martin Astronautics, from facilities in Pasadena,
California and Denver, Colorado.