Mars Global Surveyor
Mars Orbiter Camera

MOC--The First Year--Top 10

Wind: Recent Sand Movement


Mars Global Surveyor Mars Orbiter Camera Release:          MOC2-82
Mars Global Surveyor Mars Orbiter Camera Image ID:         588303947.50805

255 KByte GIF image


Observations by the Mars Global Suveyor (MGS) Mars Orbiter Camera (MOC) obtained in July, August, and September 1998, suggest that some of the windblown dunes on Mars are active today, despite the planet's relatively thin atmosphere. Martian air at the surface of the planet is about 100 times thinner than Earth's air at Sea Level.

Mars geologists have known since 1972 that Mars has big, low-albedo (dark-toned) sand dune fields. One area of dunes, in particular, is quite extensive and circles the north polar ice cap of the red planet. The north polar dunes were not visible to MOC until late July 1998, because the region had been in winter-time darkness between mid-February and mid-July of 1998. When the Sun finally rose over the north polar regions, MGS MOC saw that the dunes were coated with thin, bright frost. In some places, however, the frost had been removed to reveal the dark sand beneath. Some of these dark spots show streaks of sand that was blown out over the surface of the frost-covered dunes. Because the frost can only be as old as the most recent winter (which ended mid-July), the streaks indicate that sand has been moving very recently on the martian surface. Observation of sand movement can be helpful in determining the rate of windblown sediment transport on Mars--a key factor in assessing risk posed by sand and dust to future landers, rovers, and human explorers.

The picture shown here--MOC image 50805--was taken on August 22, 1998. The image has a resolution of about 2.5 meters (8 feet) per pixel. The scene is 1.8 km (1.1 miles) by 1.1 km (0.7 mi) in size. North is toward the upper right, illumination is from the lower left, and the center is located at 76.96°N, 217.24°W. (CLICK HERE for a context image). The image was also the subject of an earlier MGS MOC release on October 31, 1998.

Note: This MOC image is made available in order to share with the public the excitement of new discoveries being made via the Mars Global Surveyor spacecraft. The image may be reproduced only if the image is credited to "Malin Space Science Systems/NASA". Release of this image does not constitute a release of scientific data. The image and its caption should not be referenced in the scientific literature. Full data releases to the scientific community are scheduled by the Mars Global Surveyor Project and NASA Planetary Data System. Typically, data will be released after a 6 month calibration and validation period.

Click Here for more information on MGS data release and archiving plans.

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.

To MSSS Home Page