Phobos moon

Phobos (pronounced FOH-buhs) is one of two moons of the planet Mars. Phobos is the larger innermost moon, and is thought to be a rubble pile held together by a dark thin crust. In 30 to 50 million years, it will either collide with Mars or break apart and become a ring system. Both Phobos and Deimos may be asteroids captured by Mars in the distant past.

Phobos 4K pan-zoom image

Pan, zoom, or go full-screen with this megapixel image of Phobos.

Pan - Zoom - Fullscreen
  Source credit: NASA/JPL-Caltech/ASU/SSI

Phobos facts

Designation: Mars I
Magnitude: 11.8
Mass: 1.08 x 1015 kg
Radii: 13.5 x 10.8 x 9.4 km
Density: 1.89 gm/cm3
Distance from planet: 9,380 km
Rotational period: 0.319 days
Orbital period: 0.319 days
Orbital velocity: 2.14 km/sec
Eccentricity of orbit: 0.01
Inclination of orbit: 1.0 °
Albedo: 0.06
Atmosphere: none
Temperature: -40°C

Phobos surface features

There are a number of notable surface features on Phobos, including the infamous Phobos monolith.

Clustril crater
Drunlo crater
Flimnap crater
Gulliver crater
Limtoc crater
Opik crater
Reldresal crater
Skyresh crater
Stickney crater
Phobos monolith boulder