Phobos (moon)

Phobos is the larger and innermost of the two moons of the planet Mars, the second being Deimos. It is the scene of the first Doom episode, Knee-Deep in the Dead. "Phobos" is Greek for "fear".

Behind the scenes
In Doom, Phobos is depicted with Earth-like gravity, a thick atmosphere, and tall, seemingly vegetation-covered mountains; the sky texture for the episode was derived from a photograph taken of Yangshuo Cavern in China. In reality, Phobos is a rock 20 kilometers in diameter with gravity less than a thousandth of that on Earth, and no atmosphere (even if an atmosphere could be generated artificially, the moon's gravity would be insufficient to hold it in place without its own artificial gravity (see Gressen gravity generators)). To be more plausible, Doom 3 moved the plot to Mars.