Callisto

The third of Jupiter's icy Galilean moons to be settled, Callisto was partially terraformed in the late 2150s; however, during the final phase of the project, one of the satellites responsible for maintaining a magnetic field around Callisto malfunctioned. The planet began to once again freeze over, although the process was stopped before it became uninhabitable. After that spectacular failure, the terraformation of Callisto was abandoned, as it would have had to have been started again from the beginning. Instead, the habitable part of the world around its equator was colonized and large metropolises sprang up around the planet's midline like a girdle. Long, lonely stretches of road were constructed between them, but the southern and northern hemispheres were left unsettled, as the air was too thin and too cold to live with an iota of comfort. In the century and a half since, Callisto's population has grown only slightly, and it is considered a fairly minor world by Federation standards. It is that fact itself that makes Callisto a hotbed of crime and corruption. Callisto's economy has a lesser disparity between the rich and poor than Ganymede, but its living conditions are much harsher than its sister moons.

During the solar civil war, Callisto saw some of the bloodiest and most intense fighting in the Solar System. The criminal syndicates on Callisto harbored and protected much of the population during the war, and garnered a great degree of power and authority as a result. With over 15% of the population either indebted to or working for various criminal organizations, the moon is often viewed as a miniature mob state.