Mars Global Surveyor
Mars Orbiter Camera
South Polar Cap, Summer 2000
MGS MOC Release No. MOC2-225, 27 April 2000
This is the south polar cap of Mars as it appeared to the Mars Global
Surveyor (MGS) Mars Orbiter Camera (MOC) on April 17, 2000. In winter
and early spring, this entire scene would be covered by frost. In
summer, the cap shrinks to its minimum size, as shown here. Even
though it is summer, observations made by the Viking orbiters in the
1970s showed that the south polar cap remains cold enough that the
polar frost (seen here as white) consists of carbon dioxide. Carbon
dioxide freezes at temperatures around -125° C (-193° F).
Mid-summer afternoon sunlight illuminates this scene from the upper
left from about 11.2° above the horizon. Soon the cap will
experience sunsets; by June 2000, this pole will be in autumn, and the
area covered by frost will begin to grow. Winter will return to the
south polar region in December 2000. The polar cap from left to right
is about 420 km (260 mi) across.
CLICK HERE for Full Resolution View
(940 KBytes).
Image Credit: NASA/JPL/Malin Space Science Systems
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,
CA. 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, CA
and Denver, CO.
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