The Satellite Deimos 

Deimos [DEE-mos] (meaning panic) is a moon of Mars and was named after an attendant of the Roman war god, Mars. Discovered by Asaph Hall in 1877, Deimos is a dark, crater filled satellite.

The graphic on the left depicts 6 views of Deimos from different angles (Copyright Calvin J. Hamilton).
The graphic on the right shows the topography map of Deimos (Copyright Calvin J. Hamilton).

It is composed primarily of C-type surface materials originating, or at least similar to the C-type (a brackish carbonaceous chondrite) material found in the asteroid belt. Deimos was probably caught by the gravitational field on Mars that slung it into orbit.