Phobos (moon) break up when it reaches approximately 2.1 Mars radii. When Phobos is eventually torn apart by tidal forces, a fraction of the debris will likely form a planetary ring around Mars, which may last from one million to one hundred million years. The origin of the Martian moons is still controversial. Phobos and Deimos both have much in common with carbonaceous C-type asteroids, with spectra, albedo, and density very similar to those of C- or D-type asteroids. Based on their similarity, one hypothesis is that both moons may be captured main-belt asteroids. Both moons have very circular orbits which lie
Solar System Exploration Research Virtual Institute on one or more aspects of lunar science investigations of the Moon (including lunar samples), from the Moon, and on the Moon. In 2013 the NLSI became the Solar System Exploration Research Virtual Institute and expanded its scope to include Near-Earth asteroids and Phobos and Deimos. The Solar System Exploration Research Virtual Institute (SSERVI) is composed of thirteen U.S. teams, and ten international partners. The teams are listed below: US TEAMS: Focus: Formation of terrestrial planets and asteroid belt, modeling of the Moon's origin and Phobos/Deimos, history of NEAs and lunar bombardment, NEA origins, identification and characterization boulder.swri.edu Focus: Studies