Crucible

The Crucible is a space station that was captured by the Daleks and is roughly the size of a planet. The Master mentioned the Crucible saying "I was there when the Daleks took control of the Crucible" (DW: The Sound of Drums). The Crucible has a metallic outer shell but a rocky, sandy interior suggesting that the Daleks modified an alreday existing planet. Human prisoners were taken for an unknown variety of testing during the Dalek invasion of Earth in 2009. (DW: Journey's End)

Behind the Scenes
The Crucible may be the station made for the Shadow Proclamation.