Mars has two moons, Phobos [FOH-bohs] (above left) and Deimos [DEE-mos] (above right) These are extremely small moons (Phobos being the larger of the two) that have extremely fast orbital periods. Phobos (fear) and Deimos (panic) were named after attendants of the Roman god of War, Mars. Their surface compositions are similar to the C-type (blackish carbonaceous chondrite) asteroids that exist in the asteroid belt that lies beyond Mars . While some scientists speculate that Phobos and Deimos are captured asteroids, other scientists point to evidence that contradicts this theory. Both Deimos and Phobos are covered with craters. Deimos has a smoother appearance caused by partial filling of some of its craters. Phobos shows striated patterns which are probably cracks caused by the impact event which created the largest crater on the moon. On the left is an image of Deimos taken by the Mars Pathfinder Lander.