The Moon

The Moon was the largest satellite of the planet Earth.

Origins and early history
Earth's moon was originally the moon of the homeworld of the Cthalctose, a sentient species which existed 60 million years BCE. It housed, then, the Genesis of Cthalctose, designed to terraform alien worlds (such as, in the future, Earth) to an environment capable of supporting their species (NA: Eternity Weeps). Because of its origins outside of the Sol system, then, the Moon wasn't seen to form at the same time as the Earth itself (DW: The Runaway Bride). The Silurians reported that it did not appear in Earth's sky until later in their history. (DW: Doctor Who and the Silurians)

20th century
Prior to 2001 there was a base on the Moon at Tycho crater. Movements suggesting active lifeforms further north in the Eratosthenes crater were spotted as early as 1924. (visittorchwood.co.uk)

By the late 20th century, the Cyberman had established a base on the dark side of the Moon which served as the staging area for a fleet poised to invade Earth. It also could fire missiles at approaching craft such as the Doctor's TARDIS which had materailized in space nearby. (DW: The Invasion)

21st century
The Moon was, up until (and possibly beyond) the 21st century considered neutral ground under Galactic Law, meaning that if law-enforcement agents such as the Judoon, who would have broken Galactic Law to conduct their affairs on Earth, had free reign to do so on its satellite. Accordingly, the Royal Hope Hospital was transported from London to the Moon by Judoon searching for a Plasmavore murderer. (DW: Smith and Jones)

Human bases
During an unpsecified time before the end of the 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).

Later history
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. A penal colony still existed at this time. (DW: The Long Game, Bad Wolf)


 * 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.

Miscellaneous information

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