Dust Hip Deep on Phobos . ... Credit Copyright: Mars Global Surveyor Project , MSSS , JPL , NASA Explanation: Landing on the Martian Moon Phobos might be harder than previously thought. The reason: Moon dust . Recent photographs of Phobos have indicated that a layer of fine powder estimated to be a meter deep covers the whole surface. ... The above high-resolution picture of Phobos was taken last month by the Mars Global Surveyor spacecraft now orbiting Mars . ... NASA Official: Jay Norris. ...