Pluto (Earth-5875)

Pluto, formally designated 134340 Pluto, is a dwarf planet in the Kuiper belt, in the Sol system, and the second largest dwarf planet in the system, after Eris.

History
While humans colonized the planet during the species' intrasolar expansion, it was never formally inhabited, and instead was used for the mining of resources and establishment of research stations, such as the remote scanning outpost Democritus. In early 2552, the Democritus detected Cortana's slipspace signal and messaged Dr. Catherine Halsey's log to Fleet Admiral Sir Ernst Hood. All Pluto stations were destroyed when the Covenant arrived in the Sol system in October 2552. By 2561, the UNSC Auriga was orbiting Pluto when it docked with the smuggler freighter Betty.

Trivia

 * In Roman mythology, Pluto was the God of the Underworld.