Charon (moon)

Charon was a moon of Pluto, which was considered to be either the ninth planet of the Sol system or a dwarf planet.

As observed in ArcHivist Farazea's 14 Planet Theory, Charon was so relatively large that it could be described as Pluto's double planet. (AUDIO: Origins of the Cybermen)

History
In the mid 22nd century, the Earth government funded a research facility at the Charon colony to find useful applications for stunnel technology.

On 7 May 2157, the Daleks destroyed the surface of Charon. The scientists based there escaped to Mars with the aid of Chris Cwej.

By the 30th century, 800 years later, Charon was still highly radioactive. (PROSE: GodEngine)

Undated events
The Second Doctor, Ben Jackson and Polly visited Charon at some point in its history. (PROSE: Pluto)

Behind the scenes

 * Although Pluto was downgraded from full planet to "dwarf planet" in 2006, numerous stories produced prior to this date and set in Earth's future identify Pluto as a planet and Charon as its moon, suggesting that, in the Doctor Who universe at least, Pluto's planetary status was eventually restored.
 * and are two geological features on Charon named after elements from Doctor Who.