South Polar Cap

After the Odyssey spacecraft had completed a full Mars year of observations of the red planet Image of the Day looked back over this first mars year. Focus was on fourthemes: 1) the poles - with the seasonal changes seen in the retreatand expansion of the caps; 2) craters - with a variety of morphologies relating to impact materials and later alteration, both infilling and exhumation; 3) channels - the clues to liquid surface flow; and 4) volcanic flow features. While some images have helped answer questions about the history of Mars, many have raised new questions that are still being investigated as Odyssey continues collecting data as it orbits Mars.
This image was collected March 5, 2002 during the southern summer season. Layering in the South polar cap interior is readily visible and may indicate yearly ice/dust deposition. Note also the strong east-northeast linearity, which suggests winds in this region have been unchanged in prevailing direction for some time.