The cities of Enceladus

Region: Communal Space.
Settlement age: 125 years.
Population: 5 million.
Allegiance: Independent - Saturn Collective.
Distance to Earth: 1.6 billion kilometers

Out of the four gas giants in the Solar System, Saturn is by far the most hospitable, with its resourceful moons, gentle magnetosphere and proximity to Mars and the asteroid belt. Though both Jupiter and Neptune harbour a few permanent settlements, Saturn is home to a true planetary society, spread across its major moons -- Titan, Mimas, Enceladus, Tethys, Dione, Rhea and Iapetus. Founded by Japanese, French and Nigerian migrants of the second space era, at the tail end of the Low Age, the moons of Saturn, contrary to many a Solar System settlement, have prospered into the interstellar century. The spiritual and political home to the Starmoth Initiative, the moons of Saturn are the main population hub of the outer Solar System and a glimpse into what humankind would have achieved, had it settled the surroundings of Sol instead of expanding into the great void. All the moons are linked by the Saturnian kinetic exchange system, a network of mass drivers that allows the moons to swap cargo and energy inside the Saturn system, and towards the inner planets.

Titan

The largest of all moons, Titan was the first and obvious targets of Saturn settlement efforts, more than a century ago. Covered in a petrochemical fog, riddled with methane rivers and lakes, engulfed in ice, Titan is as hostile as it was when the first migrants stepped foot on its surface. Its million inhabitants live in nest cities, not unlike the walled bunker locales of the mid-Low Age. The metropolises of Titan are located near the poles, where methane rains are rarer, or alongside the largest lakes, where liquid hydrocarbons are used to cool the ice and prevent it from giving way. The energy economy of Titan relies on wind turbines, kinetic transfers from Saturn, and the thermal decomposition of tholins in dedicated plants. Over a century of sustained presence, Titan developed a very peculiar architectural style, relying heavily on stilts and bridges, to the point its nest cities have no "ground" to speak of, instead towering under the red clouds as vast fields of bridged platforms. Titan is a world of minarets, aqueducts, arches and belltowers; golden lights seep from stained glass windows, and in the whispers of half-lit alleys, its diligent populace dreams of the cold ocean below.

Mimas

The smallest natural sphere in the Solar System is entirely unremarkable. Protected from solar radiation by Saturn's magnetosphere, it has been carved out by a sect of Selenite gardeners, and houses the galaxy's largest low-gravity forest.

Enceladus

Saturn's crown jewel, this icy moon is home to two million inhabitants, most of which are housed in Babylon Harbour, the O'Neill cylinder in high Enceladian orbit. Covered in ice, Enceladus is tidally heated by Dione and maintains an intense cryovolcanic activity. After Europa proved to be a disappointment, harbouring only bacteria, Enceladus was the seat of humankind's first encounter with complex extraterrestrial life. Its intricate ecosystem revolves around underwater oases located around the hydrothermal vents at the bottom of the global ocean and has been meticulously preserved by the first settlers. Human cities are located alongside deep canyons in the outer crust, with spherical habitats hanging beneath the ice layer, where they enjoy the warmth of the sea, and very liveable pressures, around 5 bars. Sixty-five kilometers below the underwater cities, the seabed allows for direct access to Enceladus' minerals-rich core. For more than eighty years, core mining ensured Enceladus' supremacy in the settlement effort; in recent years, however, mining activity has died down in favour of interplanetary imports through Saturn's kinetic exchange system. The mining techniques developed on Enceladus, which favour laser drilling of extremely narrow holes to limit both geological and environmental impact, have been used with great success on many similar worlds across human space. As the golden age of Saturn waned with the advent of the geometry drive, it turned its gaze towards the outer stars. With its glass libraries hanging above the abyss, its delicate lifeforms, its gold-sewn surface spaceports and its cold gardens carved in billions of years of ice, Enceladus is a haven for scientists and explorers alike.

Tethys

Bombarded by solar radiation, with an execrable delta-v budget and two mundane sub-moons, Tethys is actively hostile to settlement attempts. Even in the interstellar age, it is rarely surveyed, let alone traded with, though recent satellite sweeps indicate that it harbours a small community of Outer Church nuns.

Dione

Enceladus' sister moon is too unstable and its ice layer too thick to allow for settlement. The Starmoth Initiative maintains several laboratories on its surface, however, allowing access to wells that reach into the underground ocean, seventy kilometers below the crust. The planet only harbours basic archaea colonies, whose only oddity is that they bear a striking resemblance to now-extinct Enceladus lifeforms, hinting at panspermia between the two moons. The Starmoth Initiative's hostile environment training program includes deep dives in Dione's waters.

Rhea

Large but light, Rhea is mostly made of ice and dust, and has no core, only a central sphere made of pressurised ice. The surface is riddled with craters, and no underground ocean has been found. Minerals and metals are mixed with the ice and thus easily accessible; for the better part of the previous century, mining on Rhea was extremely cost-competitive compared to asteroid belt imports, and on a par with Enceladus core mining. The planet remains a major mining and manufacturing centre, with its shipyards gleaming above the dusty wastes, and large excavations supplementing the old craters. The moon is home to several ship manufacturers, including the Alsephina Shipyards, and houses rover races alongside its equator.

Iapetus

The furthest of all major moons, Iapetus is the main gate of the kinetic exchange network, with very favourable Hohmann transfer windows towards the inner solar system. Administered by a joint Titan-Enceladus authority, it is a fairly secretive place, where the fierce spirit of the first migrants lives on. It is rumoured to house the Eye of Saturn, a space-to-space particle beam using Iapetus as a heat sink and capable of striking would-be invaders from a light-second away.

llustration by Mark Molnar for Eclipse Phase, distributed by Posthuman Studios under a Creative Commons Attribution Non-Commercial Share-alike 3.0 Unported License.