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
Colonization of Mars of life forms, including humans, to survive unaided on Mars's surface. Some ideas of possible technologies that may be able to contribute to the actual terraforming of Mars have been conjectured, but none would be able to bring the entire planet into the Earth-like science fiction habitat pictured. Mars lacks enough gravity to hold on to any kind of substantial atmosphere, which in turn means that the planet will remain cold and cloudless, and the extremely scarce surface water frozen. Mars has no global magnetosphere as Earth does. Combined with a thin atmosphere, this permits a significant amount of ionizing