Deimos

Deimos is a natural satellite of the planet Mars with an average radius of 6.2 km (3.9 mi), and an escape velocity of 5.6 m (18 ft)/s (20 km (12 mi)/h).[4] It is the smaller and outer of Mars's two known moons, the other being Phobos. 23,460 km (14,580 mi) distant from Mars, Deimos takes 30.3 hours to orbit the planet at an orbital velocity of 1.35 km (0.84 mi)/s. Its systematic designation is Mars II. In English Deimos is pronounced /ˈdaɪməs/ DY-məs; also /ˈdiːməs/ DEE-məs; Greek: Δείμος; also DAY-moce or DEE-moce. In Greek mythology, Deimos was the twin brother of Phobos and personified Terror.