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 Exploration Program on Earth, could be used by microscopic life forms living under the Mars' surface. Life on Mars can also be searched for by finding signatures of past and present life or biosignatures. Relative carbon abundance and the location and forms that it can be found in can inform where and how life may have developed. Also, the presence of carbonate minerals, along with the fact that Mars' atmosphere is made up largely of carbon dioxide, would tell scientists that water may have been on the planet long enough to foster the development of life. Another goal of the MEP is