NASA Mars Picture of the Day: Frosty North Polar Dunes

Mars Global Surveyor Mars Orbiter Camera

MGS MOC Release No. MOC2-601, 10 January 2004

NASA/JPL/Malin Space Science Systems

While it is summer in Gusev Crater, where the Mars
Exploration Rover, Spirit, is operating, it is
winter in the martian northern hemisphere. Just this
week, the north polar dune fields began to emerge into
sunlight after months of frigid darkness.
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC)
view of frost-covered north polar dunes
was acquired on 8 January 2004.
The steepest slopes on the dunes–their slipaces–point toward
the upper right (northeast), indicating that the dominant
winds responsible for their formation came from the opposite
direction (lower left, southwest). Sunlight illuminates
these dunes from the lower left, which may seem surprising
because the brightest slopes on the dunes face the lower right.
The brighter slopes are a frost phenomenon; most likely, these
are areas with thicker frost deposits. In summer, the dunes would
not have frost and would appear much darker than their surroundings.
This early view of north polar dunes in winter is located
near 75.8°N, 266.3°W. This view
covers an area 3 km (1.9 mi) wide.

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, California.
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,
California and Denver, Colorado.