This Mars Global Surveyor wide angle view of the Martian south polar region was acquired on September 12, 2001, four years to the day after the spacecraft first began to orbit the Red Planet.

Photo: NASA/JPL/Malin Space Science Systems

The bright area at the center of the image is the permanent south polar cap -- the part of the cap that will remain through the coming summer. The bright areas that surround the center make up the seasonal frost cap that was deposited during southern winter, which ended June 17, 2001. The dark area in the lower right corner results from two phenomena -- the seasonal frost is subliming away much faster in this region, and the area is darker because it is closer to the night side of the planet. The fuzzy or hazy zone that covers most of the left side of the image consists of afternoon clouds and fog.

The polar frosts contain both water and carbon dioxide ices. Clouds of condensing water ice crystals are common over parts of the polar cap at this time of year.

For scale, the permanent cap at the center of the image is about 420 km (260 mi) across. Sunlight illuminates the scene from the upper left. Summer in the southern hemisphere will begin in mid-November 2001.

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.