The Moon

The largest natural satellite of Earth, The Moon has a storied history.

Origin
The specific physical origin is unknown. It wasn't seen to form at the same time as the Earth (DW: The Runaway Bride), and the Silurians reported that it did not appear in Earth's sky until their time (DW: Doctor Who and the Silurians).

Human bases
By the late 21st century, Humans had at least one base on the Moon. One functioned as a T-Mat relay, co-ordinating T-Mat on Earth (DW: The Seeds of Death),

By 2070, a base housed the Gravitron, a machine for regulating Earth's weather. (DW: The Moonbase).

By 2540, it served as a penal colony for dissidents against the war between Earth's empire and the Draconians. (DW: Frontier in Space)

By the time of the Fourth Great and Bountiful Human Empire, the Earth had five moons. (DW: The Long Game)


 * We do not know if, by this time, the original natural moon still existed or the nature (artificial or natural) of the moons mentioned in passing.

Other bases

 * Sometime before the late 20th century, the Cybermen established a base on the dark side of the Moon capable which served as the staging area for a fleet poised to invade Earth. It also could fire missiles as the approaching craft such as the Doctor's TARDIS. (DW: The Invasion)


 * Prior to 2001 the Judoon built a base on the Moon at Tycho crater (visittorchwood.co.uk, DW: Smith and Jones). Movements suggesting active lifeforms further north in the Eratosthenes crater were spotted as early as 1924. (visittorchwood.co.uk)

Other information

 * Moonlight, concentrated in a laser-like beam, killed the Host at Torchwood House. (DW: Tooth and Claw)