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 in 2024, and one in 2026 which would not be returning to Earth. Although the announcement garnered much international publicity, the concept has been criticized by scientists, engineers, and those in the aerospace industry. Mars One is noted as being very short on funding, lacking critical concepts about hardware, life support, electrical power supply, and has been criticized as glossing over logistics, medical concerns, and protection against space radiation. The concept has been called a suicide mission both in academia, spaceflight, and international news. By February 2015, two conceptual studies were done by contractors. Despite the criticism and lack of