The Moon

The Moon was one of Earth's five moons, it being the original one, four more being placed into Earth orbit by the Fourth Great and Bountiful Human Empire (DW: The Long Game). Its origin is unknown, but it apparently did not form with the Earth, and the Silurians reported that it did not appear in Earth's sky until their time. (DW: The Runaway Bride, Doctor Who and the Silurians)

Moon bases
By at least 2001 the Judoon built a base on the Moon at Tycho crater. Movements suggesting active lifeforms were spotted in 1924. (visittorchwood.co.uk, DW: Smith and Jones)

Humans first built a base on the Moon in the mid to late 21st century, originally for the T-Mat system (DW: The Seeds of Death), but later for controlling the Earth's weather. (DW: The Moonbase).