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
Mars One is divided among the seven payloads as follows: In 2022, a robotic rover was proposed to be launched to Mars in order to scout a landing site for the 2027 lander and a site for the Mars One colony. At the same time, a communication satellite would be launched, enabling continuous communication with the future landed assets. In 2024, six cargo missions were proposed to be in close succession, consisting of two living units, two life-support units, and two supply units. A spacecraft transporting four astronauts was proposed to meet a transit vehicle bound for Mars. In 2025, the landing