Deimos (moon)

Deimos (or Mars II) is the smaller moon of Mars. Its name comes from the Greek word for terror. Its orbital period is 30.3 hours, which is 1.263 days.

Deimos is only 15 kilometers in diameter. It is covered with craters, as Earth's moon and other bodies without an atmosphere are.

Discovery and naming

Deimos was discovered by Asaph Hall at the United States Naval Observatory in Washington, D.C. on 12 August 1877.^[1]

It is named after the god Deimos in Greek mythology, who was one of Mars' sons, and means Panic.

Physical characteristics

Deimos is not spherical with triaxial dimensions of 15 × 12.2 × 11 km.^[2] Deimos is made up of rock rich in carbonaceous material. It is has lots of craters.^[3] Escape velocity from Deimos is 5.6 m/s.^[4] The apparent magnitude of Deimos is 12.45.^[5]

Exploration

The Soviet Phobos program sent two probes to Phobos. In case Phobos 1 succeeded, Phobos 2 could have been sent to Deimos. Both probes launched successfully in July 1988.

In 1997 and 1998, the proposed Aladdin mission was selected. The plan was to visit both Phobos and Deimos, and launch projectiles at the satellites. The probe would collect the dust kicked into space as it made a slow flyby. These samples would be returned to Earth for study three years later.^[6]

Also, the sample-return mission called Gulliver to Deimos, in bringing 1 kilogram (2.2 pounds) of material from Deimos to Earth.^[7]

Another concept of sample-return mission from Phobos and Deimos is OSIRIS-REx 2, which would use heritage from the first OSIRIS-REx.^[8]

In March 2014, a mission was proposed to place an orbiter on Mars orbit by 2021 and study Phobos and Deimos. It is called Phobos And Deimos & Mars Environment (PADME).^[9][10]