Moons of Mars: Phobos right and Deimos left seen by spacecraft Viking Orbiter 1 and 2 (NASA: phobdeim.gif).

Phobos has a mean radius of about 11 km and Deimos 6 km. Both satellites are believed to be captured asteroids composed of carbon-rich rock and both are heavily cratered from impacts of meteoritic debris. (Source: NASA.)

Back to PICTURES