Deimos is the smaller and outermost of the two natural satellites of Mars, the other being Phobos. Deimos has a mean radius of 6.2 km (3.9 mi) and takes 30.3 hours to orbit Mars. Deimos is 23,460 km (14,580 mi) from Mars, much farther than Mars' other moon, Phobos. It is named after Deimos, the Ancient Greek god and personification of dread and terror.
Deimos is known as the 'Battle Moon'. It was captured by the Republic after the Fall of Luna. It was recaptured by the Society Remnant at some point between the Siege of Phobos and the Kalyke Massacre.