Composed mostly of silicate rock and water ice, Ganymede is one of only a handful of orbital bodies in the Sol System with an intrinsic magnetosphere, likely owing to convection within the moon's liquid iron core. The surface of Ganymede is a barren landscape, cracked and spalled by eons of impact craters and tidal heating from nearby Jupiter. With a subsurface water ocean buried beneath an icy crust, low gravity, and no atmosphere, Ganymede is inhospitable to human life and habitation is only possible with sealed and regulated environments.
The first known visit to Ganymede was made by the Shadows following the end of the First Shadow War, 1000 year before the Third Age. It was one of two known locations in the Sol System where they chose to hide one of their Vessels in preparation for their eventual return.
Ganymede was first discovered by humans on January 7th 1610 by Italian astronomer Galileo Galilei. His observations also reveal what would be later refereed to as Jupiter's Galilean moons; the others being Io, Europa and Callisto. Though closer observations were made by robotic probes launched in the late 20th and 21st Century, it wasn't until the 22nd Century that the satellite would be visited by humanity. As with nearby Io and Europa, a mining operation was set up to exploit Ganymede's mineral resources, while deep within the glacial crust, an ultra-secret facility know as the "Icehouse" is established.
In 2195, Psi Corps Director Kevin Vacit visited Ganymede to place a time-locked and heavily encrypted file in Icehouse's data archives before departing human space with his one-man ship aboard a Centauri transport, bound for the nearest jumpgate to Vorlon space.
In 2237 a dispute over working conditions lead the local miners to engage in a series of strikes. The government orders in troops to break-up the strike, resulting in the death of Neeoma Connoly's father who is shot and killed.
In 2256 a meeting at the Icehouse facility between Dr. Morden and Psi Corps Director Johnston is interrupted by the unexpected arrival of MetaPol Psi Cop Alfred Bester and his Black Omega Squadron. Bester successfully manages to stage an assassination of the Director, causing his section of the facility to flood with the freezing waters of Ganymede's sub-surface ocean.
In 2260 a Shadow vessel was discovered buried under the surface. Having already lost a similar vessel discovered in Syria Planum on Mars some years back, Interplanetary Expeditions and Earthforce New Technologies attempted to keep this ship to themselves by merging one of their own people to act as the ship's CPU. The process was not handled correctly and the ship went berserk, breaking though the dome and firing on the colony.
The Whitestar, which had arrive to late to prevent the merging engaged the ship and lured it into Jupiters atmosphere where it was caught in the gravity well and crushed by the gas giant's dense atmosphere, before jumping away from the EAS Agamemnon. Earth Alliance President Morgan Clark used the incident as an excuse to invoke martial law across the entire Alliance, citing direct threats to planetary security. A chain of events that would soon lead to the outbreak of the Earth Alliance Civil War.
In 2265, in the midst of the Telepath War, the Resistance captures the Icehouse facility from Psi Corps control and discovers Director Vacit's time-locked file. Resistance leader Lyta Alexander calls in her financial backer and CEO of Edgars Industries; Michael Garibaldi. She soon persuades him to fund an expedition to Vorlon space in an effort to prevent the Corps from finding the place where telepaths were first created and with it, the secret to creating more powerful teeps.