Dimorphos is satellite asteroid of the larger asteroid Didymos within the solar system. The two asteroids comprise a binary asteroid system within the solar system, with Dimorphos accounting for roughly 1% of the mass of the system. Dimorphos is roughly 160 meters (520 feet) in diameter. It orbits Didymos every 11.9 hours, with an orbital radius of approximately 1.2 kilometers (0.7 miles). As such, it has an orbital speed of about 17 centimeters per second relative to Didymos.[1][2][3]
The binary system of Didymos' and its satellite have an orbital location that varies between Earth orbit and just outside Mars' orbit.