Asaph Hall announces the discovery of Mars’ two moons. These moons are named Phobos (fear) and Deimos (flight). In Roman mythology, these names are attributed to the sons of the god of Mars, Aphrodite. The moon Phobos measures 26.6 km across its widest point. It orbits mars every 7.65 hours at an average distance of 9,378 km in a circular orbit 1 degree Mars' equator. Deimos measures approximately 15 by 12 by 11 km and orbits the planet every 30.3 hours at an average distance of 23,459 km away.