Two celestial satellites, commonly called moons, orbit Mars. Their names are Phobos and Deimos. Both satellites are small and irregularly shaped and are most likely fragments of larger objects that were broken apart in collisions.
According to the Smithsonian National Air and Space Museum, Phobos has a radius of 13 miles and is about 3,700 miles away from Mars. Taking a little more than seven hours to orbit Mars, it completely circles the planet more than three times in a Martian day.
Deimos has a radius of only 8 miles and is located 14,580 miles from Mars. This satellite takes about 30 hours to circle the planet.