 Deimos, like Mars' other moon, Phobos, has spectra, albedos, and densities similar to those of a C- or D-type asteroid.Like most bodies of its size, Deimos is highly non-spherical with triaxial dimensions of 15 × 12.2 × 11 km, making it 56% of the size of Phobos.Deimos is composed of rock rich in carbonaceous material, much like C-type asteroids and carbonaceous chondrite meteorites.