Moons of Mars formed a large moon. Gravitational interactions between this moon and the outer ring formed Phobos and Deimos. Later, the large moon crashed into Mars, but the two small moons remained in orbit. This theory agrees with the fine-grained surface of the moons and their high porosity. The outer disk would create fine-grained material. While many Martian probes provided images and other data about Phobos and Deimos, only few were dedicated to these satellites and intended to perform a flyby or landing on the surface. Two probes under the Soviet Phobos program were successfully launched in 1988, but neither conducted the
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