Mars Global Surveyor
Mars Orbiter Camera

Frosted Dunes: Chasma Boreale in Early Spring

MGS MOC Release No. MOC2-147, 19 July 1999


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Chasma Boreale is a giant trough that nearly divides the north polar ice cap of Mars in two. The floor of this trough is mostly covered by dark sand dunes. This picture was taken in early spring, a time when the dark sand was still mostly covered by frost left over from the northern winter season. Small spots and streaks of dark sand can be seen emerging from under the frost in places, particularly along the edges of individual dunes. In summer, these dunes would look almost black compared to the rest of the scene. The shapes of the dunes indicate wind transport of sand from the top toward the bottom of the image. The frost is most likely to have been frozen water, rather than carbon dioxide, because the temeratures in spring were likely too high for solid carbon dioxide to be present. This picture was taken by the Mars Global Surveyor Mars Orbiter Camera in early September 1998. Illumination is from the right/upper right.


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.

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