Global Surveyor sees changes of Martian ice cap Spaceflight Now

Extended mission operations for the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) has provided thousands of opportunities to image sites previously seen by the camera. Often, these are chances to see if anything on the planet has changed. The most surprising changes were documented starting in August 2001, when the south polar cap emerged from winter darkness. In 1999 MOC found that the south polar cap exhibits an array of bizarre layers, arcuate scarps, and “swiss cheese” holes and pits. How these formed was unknown. Once MOC began to re-image theseareas in 2001, however, the team discovered that the polar scarps had changed. They had retreated approximately 3 meters (about 3 yards) in less than one Mars year (a Mars year is 687 Earth days long). In some places, small buttes completely disappeared.