Deimos

Deimos ("DEE mos") is the smaller and outermost of Mars' two moons. It is one of the smallest known moons in the solar system.

orbit:    23,459 km from Mars
diameter: 12.6 km (15 x 12.2 x 11)
mass:     1.8e15 kg

In Greek mythology, Deimos is one of the sons of Ares (Mars) and Aphrodite (Venus); "deimos" is Greek for "panic".

Discovered 1877 August 12 by Hall, photographed by Viking 1 in 1977.

Deimos and Phobos are composed of carbon-rich rock like C-type asteroids and ice. Both are heavily cratered.

Deimos and Phobos are probably asteroids perturbed by Jupiter into orbits that allowed them to be captured by Mars.