In the 22nd century, the outer reaches of Sol System were generally considered to be second rate territories when compared to Luna, Mars and the Belt. Whilst the great powers were gaining prestige from their interstellar colonisation projects, the gas giants and their moons remained largely unexplored and undeveloped. Even with fusion-drive spacecraft the outer planets seemed too remote to be of much value. The few outposts beyond the Belt were established by second and third rank polities.
In the aftermath of the War of Martian Independence, the Han colony on Callisto, and the Greater Azanian and Australian outposts on Ganymede declared themselves independent from their parent nations. The research station on Europa soon followed. Nobody much cared at the time when the newly-formed Jovian League claimed ownership of Jupiter and its moons, and seized control of the small transnat mines on Io and Himalia.
In the 2210s and 2220s the Jovian League began mining the atmosphere of Jupiter for helium-3, an important fuel for fusion reactors and drives. At first the high cost of extracting the gas from a gas giant atmosphere made Lunar 3He much more attractive. In 2228, however, the Praesidium imposed huge tariffs on helium-3 exports. The Belt responded by turning to the now considerably cheaper supplies from Jupiter. The influx of helium revenue and its increased importance to the Solar economy rapidly changed the backwater status of the League. Although by no means a great power, the Galilean colonies are no longer a joke.
Out at Saturn the story was fairly similar. The first outpost on Titan was a Cyrax research station. Over many decades, this station accreted various industrial centres, disitilling nitrogen from the air. These facilities had mostly been built by coporations based in the Belt or on the moon itself. In the absence of any obvious enternal control, the colony developed into a free city, with regulations, (loose) laws and coordination provided by the Titan Supervisory Authority. The TSA owed allegience neither to the major corporations of the Ceres Combine, nor to Earth, and so the cataclysmic collapse of Terran imperialism barely affected life in Titan City.
What helium-3 did for the Jovian League, nitrogen has done for Titan: the gas is vital for the expansion of the Belt habitats. The atmosphere of Titan is the obvious source as the moon is far from the power of Earth, and has a thick, nitrogen-rich atmosphere combined with low gravity. Gaining control of Titan would thus be a considerable coup for one of the factions. For the best part of a century, the moon has been the front line of the cold war between the factions, and between the Belt and Earth. Titan City has become famous for spy scandals and assassinations, while warships of a dozen factions maintain an uneasy standoff in orbit. During this time the TSA has played the factions against each other, skillfully maintaining a precarious balance.
The future of Ad Astra