NASA Mars Picture of the Day: Springtime for Dunes

Mars Global Surveyor Mars Orbiter Camera

MGS MOC Release No. MOC2-810, 6 August 2004

NASA/JPL/Malin Space Science Systems

The springtime retreat of the north polar seasonal
frost cap is progressing on schedule. This
Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC)
image shows the state of defrosting north polar sand
dunes just three days ago on 3 August 2004. Dark areas
on the dunes are patches of bare sand; bright areas are
remnants of frost deposited during the previous winter.
Summer will arrive on 20 September 2004. These dunes are located
near 76.3°N, 263.5°W. Their steepest slopes, known
as the slip face of each dune, point toward the
northeast (upper right), indicating wind transport of sand
from the southwest (lower left).
The image covers an area about 3 km (1.9 mi) across and
is illuminated by sunlight from the lower left.

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.