Mars Express HRSC (High Resolution Stereo Camera) image of Phobos taken on 9 January 2011 at a distance of 100 km with a resolution of 8.1 m/pixel. Phobos is approximately 27 × 22 × 18 km and orbits Mars at a distance of 6000 km above the planet’s surface, or 9400 km from the center of the planet.

Photo credit: ESA/DLR/FU Berlin (G. Neukum)