The Smaller of Mars’s Two Moons

The folks from the Mars Reconnaissance Orbiter HiRISE team at the University of Arizona just released a very cool pic of Deimos. The scale of this view is 20 meters per pixel, so that means that anything about 60 meters or larger can be seen clearly.

You can see very subtle variations in the surface color — red in the smoothest areas and less red near areas where the impact craters are fresh. These color variations are probably caused when surface materials are exposed to the environment of space (UV radiation, etc.). That typically leads to darkening and reddening. Brighter and less-red surface materials haven’t been exposed to space nearly as long, since they were likely recently uncovered by impacts or downslope movements of surface “dirt” called regolith. I think this is a pretty marvelous view, considering that both the camera and Deimos were moving with respect to each other.