Callisto Base was established in 2109, 11 years after the First
Message from Jupiter had given mankind the principles of
MEST-Curvature Application, which made it possible for them to
travel freely throughout the Solar System.
Callisto Base' function was to monitor Jupiter for further
Messages, or signs of life. At first it was a humble Solar
Ranger observation outpost with a crew of 30, but conditions on
Callisto allowed for expansion: there was water ice available
upon the surface. Mining operations went into operation in the
30's and the Base became a town of about 1500 inhabitants, mostly
located inside the large ringformed Asgard basin.
Second largest of Jupiter's 17 moons, Callisto was foremost
chosen because it lies just beyond range of the far-spanning
magnetoshpere which emanates from Jupiter, periodically
bombarding the 3 nearer large moons with ferociously deadly
radiation that can produce temperatures of 300 to 400 million
degrees celcius. Callisto is also a very stable environment
among Jovian moons, without the volcanic activity of Io, or
Europa's brittle surface of floating ice.
Callisto is 4800 km in diameter and orbits Jupiter at a radius of
1,880,000 km every 16.6 earth days.