Enceladus was a moon of Saturn.
Astronomical data
Enceladus was small and had no atmosphere. From space it looked white and barren. The northern hemisphere was ravaged by craters, while the southern hemisphere was smoothed out by cryovolcanoes. Underneath the surface was liquid water, which would occasionally spew out from fissures and freeze. Some of this ice would also be added to the rings of Saturn. (PROSE: The Wheel of Ice)
History
In the 21st century, humans started to colonise the moons of Saturn. There were no permanent colonies on Enceladus, partially because of more convenient resources and partly due to the fear of native life. Instead, some of the children who worked on the Mnemosyne Cincture on Mnemosyne would vacation on Enceladus. When the Second Doctor was visiting the Mnemosyne Cincture, Phee Laws and Sam Laws took Jamie McCrimmon skiing on Enceladus. (PROSE: The Wheel of Ice)