New pictures of Mars' south polar cap and a global view of a dust storm occurring there were released Friday by the imaging team for NASA's Mars Global Surveyor spacecraft.
Marking the four-year anniversary of its arrival at Mars, Global Surveyor's camera took a wide-angle view of the Martian south polar region on Sept. 12, 2001.
Several dramatic dust storms that began a few months ago also are seen in a color image (at right). One is located near the Martian equator, and the other is shown northwest of the Ascraeus Mons volcano.
The bright area at the center of the color 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.
Dust storm view
Southern spring on Mars began in late June 2001 with a series of large dust storms that in some regions were still occurring each day well into September.
By early July, the Martian atmosphere was so hazy that opportunities for high resolution imaging of the planet were very limited.
A wide-angle black-and-white camera view (at right) obtained by the Mars Global Surveyor's camera shows a large dust-raising event that occurred on July 8, 2001, as cold, raging winds blew off the frozen south polar cap (bottom) and rushed toward the network of troughs known as Labyrinthus Noctis near the martian equator (center).
A second, smaller dust storm can be seen near the top just left of center, northwest of the Ascraeus Mons volcano (uppermost dark elliptical feature). To give a sense of scale, Ascraeus Mons is large enough to nearly cover the state of Washington, home of the well-known (and much smaller) Mount St. Helens volcano. Sunlight illuminates the scene from the left, and north is toward the upper right.
Mars Global Surveyor is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C. The camera system is operated by Malin Space Science Systems.
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