![Click here for larger version of figure 1 of PIA12112](https://webarchive.library.unt.edu/eot2008/20090901060156im_/http://photojournal.jpl.nasa.gov/figures/PIA12112_fig1_thumb.jpg) |
![Click here for larger version of figure 2 of PIA12112](https://webarchive.library.unt.edu/eot2008/20090901060156im_/http://photojournal.jpl.nasa.gov/figures/PIA12112_fig2_thumb.jpg) |
Figure 1 | Figure 2 |
The north polar region of Mars is surrounded by a large sea of dark sand
dunes that become covered by seasonal carbon dioxide frost. As the
northern hemisphere begins to warm in the spring, the frozen carbon
dioxide changes from a solid to a gas. The wind blows from an
east-northeasterly direction and leaves dark streaks behind (exposed
basalt) from the evaporating carbon dioxide. This image displays
defrosting sand dunes in an unnamed crater.
The High Resolution Imaging Science Experiment, which took this image, is
the most powerful telescopic camera ever sent to another planet.
NASA's Jet Propulsion Laboratory, a division of the California Institute
of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for
NASA's Science Mission Directorate, Washington. Lockheed Martin Space
Systems, Denver, is the prime contractor for the project and built the
spacecraft. The High Resolution Imaging Science Experiment is operated by
the University of Arizona, Tucson, and the instrument was built by Ball
Aerospace & Technologies Corp., Boulder, Colo.