Object Analysis

Deimos is the smaller and outermost of the two natural satellites of the planet Mars. It has a mean radius of about 6.2 km (3.9 mi). It takes 30.3 hours to orbit Mars. Like Phobos, it looks like a lumpy asteroid, leading to theories that it was captured from the asteroid belt by Jupiter's gravity and then passed to Mars.

Unlike Phobos, Deimos has a very smooth appearance. Its craters are filled with a thick layer of regolith (dust and rock) roughly 100 meters deep. This gives the moon a softened, weathered look compared to the jagged Phobos.

From the surface of Mars, Deimos would appear as a bright star rather than a full moon. It is gradually drifting away from Mars due to tidal forces, meaning that billions of years from now, Mars will lose this companion to the depths of space.