Titan is the largest moon of the ringed planet Saturn. A dull orange in colour, it is larger than Earth's moon but smaller than Earth, and is composed mainly of frozen water and rock. It is also where the judges of Mega-City One, the residence of Judge Dredd in his strip in 2000 AD, are sent if they break the law. To enable them to survive two decades of hard labour on the moon's surface – the dreaded 'Titan twenty' – prisoners are given radical surgery without anaesthetic, including the replacement of their mouth and nose with metal filters to help them breathe (bent judges don't deserve space suits). Notable residents have included Aimee Nixon and Judge Dredd's twin brother Rico. Unsurprisingly, it was the setting for the Dredd story 'Titan' by Rob Williams and Henry Flint (see picture). Just imagining endless days breaking rocks in the subzero temperatures with the planet Saturn filling the sky overhead like the face of some stern god of Justice sends shivers down one's spine.
On the bright side, prisoners are allowed to have pencils and notebooks.