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 named for the ancient Greek god of fear, and a son of Ares.

Doom Classic
According to the Doom Manual, Phobos is used to store nuclear waste, and is also the home of Teleportation experimentation with Deimos. Sometime before the game however, an experiment goes wrong, Deimos disappears from sight, the Phobos base is attacked by an unknown force, and the player's squad is sent up to investigate. The squad ends up being defeated sometime later, and the Lone Survivor ventures into the base, eventually defeating the Bruiser Brothers and supposedly dying (or knocked unconcious) after being teleported to Deimos.

In some conversions sections of the base appear to have grass or mossy loam within the perimenter of the buildings, rather than hard rock (as in the original).

Doom 64
Though not mentioned by name within the game, or the manual, what appears to be another of Phobos bases is visited during the game.

The product page at Nintendo.com stated;


 * Dawn of the Undead An unseen entity from beyond, cloaked by radiation, has rejuvenated the rotting carnage of Phobos. The demons are back. Your assignment is clear. Total annihilation.

Furthermore a section in a Nintendo Power article stated;

''We are receiving sporadic intermissions from Phobos, where it seems that a military base has been invaded. All of our current information is coming from a lone space marine who is fighting the incursion...''

The included artwork shows Mars from the surface of what appears to be Phobos.

One of the bases visited during his trip through the Phobos facility is a Terriformer which shows that humans were attempting to terriform the moon. In last level a pools of water and lava can be seen as well, showing further examples of geological changes to the moon.

In addition the manual refers to 'installations' plural in a another section which could be a reference to both Phobos and Deimos. However, it could be Mars Base as well as it is described to be 'planetary' base twice.

If it is set on Mars, it actually could be a reference to the Doom II's manual's story, which offered a different 'escape' for the Marine (Doom II), after he fought the forces of hell on Mars Base itself.

Whatever the case, the sky on the "Martian" levels of Doom 64 simply a starlit background, while others show shadowed mountains in the distance.

Doom RPG
In Doom RPG, the moon Phobos, and its orbit trajectory around Mars are seen when the Doom Marine is seen landing at the old Mars Outpost (Mars Research Facility).

Deimos's orbit trajectory is seen to pass near it (though the moon cannot be seen).

Doom 3
While the moons of Doom are not seen, the Marine visits two labs named after the moons of Mars. One of these is Phobos Labs. Phobos itself is mentioned in one of the facts given during a loading screen.

Phobos serves as an orbital communications relay station via the Phobos Routing Station Uplink.

Phobos orbit might be the ring seen on some of the maps.

Doom (2016)/Doom Eternal
The UAC established an outpost on Phobos, serving as a mining and communications relay. Until the destruction of the Argent facility on Mars, the Phobos outpost was repurposed into a defensive platform, housing the BFG-10000 to defend the UAC's monopoly on the Red Planet from space-bound demonic threats.

The Doom Slayer shows up on Phobos after the demon invasion has begun (over a decade later), and there are still living human scientists and guards in the base's command center. Other elements of the base include large defense cannons.

Doom: Annihilation
The second Doom movie is set on Phobos.

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. However the map of the base shows that there is no vegetation and its set in a crater. Strangely enough PSX Doom changes some of the ground textures giving parts of Phobos grey ash/sand like dune textures outside some of the windows (see outside window where the first green armor is found in the first level), and in some levels even marshy/moss-like loam or even grass near the base (see level 2). Doom 64 established that there was a Terriformer on Phobos. In later levels there is even a pool of water open to the 'air' (water was more common floor pattern seen in Doom 2), and lava near where the transporter to Hell is located (which seems to indicate the humans were changing the geology of the planet, in an attempt to terriform it).

In reality, Phobos is a small body, only about 14 miles (22km) in diameter, with gravity less than a thousandth of that on Earth, and no ability to retain an atmosphere: in addition, it is thought to be a rubble pile barely held together by a thin crust, hardly suited to major construction. Future releases (Doom 3 and the 2016 Doom) moved the plot to Mars (though Doom 3 establishes that a communications relay station is located on the moon, and 2016 still established that a base was located there, visited in Doom Eternal).

In the Doom 64 backstory it mentions that a 'planetary' base was sealed, and bombarded with "apocalyptic amounts of radiation" which allows the Mother Demon in a crippled state to resurrect the dead demons, a nearby satellite detects this and in a dying message relays this back to Earth, and the Doom Marine is sent back to this facility defeat the demons. Some interpret this facility to be Phobos although the reference to 'planetary' (twice) could also be a reference to the UAC Mars Base from Doom II backstory in which the Marine stopped an invasion. However, the webpage for the game, and and a backstory given in Nintendo Power confirm its set on Phobos.

The green radioactive Nukage can be found throughout Phobos in Doom 1, but only appears in one level of Doom 64 (the penultimate level of the Phobos base section of the game). Whereas pool of water and lava is found in the last level of the Phobos base tech levels.