Large enough that it could almost have formed the nucleus of a protostar in its own right, Jupiter’s massive size makes the Jovian System one of the most challenging places in the system to colonize. Jupiter’s powerful magnetic  eld means that its inner moons— and the outer ones, when their orbits pass through its immense magnetotail—are bombarded with enough ionizing radiation to kill transhumans not protected by the heaviest of shielding within a matter of hours. There are sixty-three moons and moonlets in the Jovian system, but only the well-explored, populous, regular moons are described here.

Resources and Economics

Jupiter’s powerful gravity well is a major hindrance to gas mining in the planet’s atmosphere, as even craft that do not succumb to the violent, centuries-long atmospheric storms can achieve escape velocity with only the most powerful propulsion systems. Given the need for heavy shielding on such craft, gas mining on Jupiter is not nearly as efficient as on Saturn. Jupiter has a tenuous ring system, much less dense than Saturn’s, which extends out for 20,000 kilometers around the planet, encompassing the orbits of its two closest moonlets.

However, Jupiter’s gravity is also a valuable resource. Craft bound for Saturn and beyond can slingshot themselves outward by circling the planet to pick up velocity, cutting months or years off their trips.

Habitats and Moonlets

Most of Jupiter’s moons are really captured asteroids, lacking the size and geological complexity of planetary bodies. All are occupied. Some were converted to habitats; others host only Junta military and mining outposts. The Jovian moonlets consist mostly of carbonaceous rock, poor in metal, with some of the larger moonlets having layers or even cores of ice. Beehive habitats and Reagan cylinders predominate in the Jovian system. Reagan cylinders (called “sarcophagus habs” by every other faction) are an inef cient variation on the O’Neill cylinder in which excavators hollow out an immense, cylindrical cavern in a rocky asteroid and then alter the asteroid’s rotation with external thrusters to simulate gravity.

Other habitat types are rare in Jovian orbit, especially within 2 million kilometers of the planet, where the radiation is strongest. For a bioconservative faction unwilling to adopt radiation-resistant morphs, the Junta is in a poor location. Shielding their populace beneath tons of rock is a necessity. Despite its military hegemony, the Junta can’t control all of Jovian space, and there are things it can’t do on its own—like exploring Europa. A number of unaligned habitats and surface settlements exist in the ring system and the orbits of the Galilean moons.


The largest of the moonlets, hollow Amalthea is probably the most livable sarcophagus habitat due to the large lake created from its icy core. Living on Amalthea carries some prestige among citizens. Rumor has it that most of the residents are well-placed RAND think tank personnel, most of whom work on defense projects. A fusion-powered axial light tube illuminates the 30-kilometer diameter central cavern, whose landscape is patterned after the subdivisions and office parks of an early 21st-century suburb. All buildings have envirosealing so that the occasional bouts of environmental sepsis resulting from the poorly regulated interior ecosystem can be purged with toxin bombs. Less fortunate support personnel dwell in the beehive warrens crisscrossing the moonlet’s crust between cavern and surface. Like most of Jupiter’s moonlets, Amalthea’s space crawls with patrol craft and killsats, making approach for unauthorized craft problematic at best. 1.5 million transhumans live on Amalthea.


Beneath Io’s tenuous, patchy atmosphere of volcanic gases and neutral atomic dust lies a barren, grayish yellow, rocky surface coated with a thin frost of sulfur dioxide. Tidal heating caused by gravitational interaction with Jupiter makes Io the most volcanically active body in the system—so active that the meteor cratering found on every other planet and moon is completely absent on Io. Massive volcanic calderas, lakes of molten rock, and geysers of sulfur dot the surface, with eruptions and accompanying seismic activity lasting months or years. Volcanic zones on Io reach surface temperatures of up to 1,500 degrees Kelvin, hotter than any body in the system.

For all that, transhumanity’s worst peril on Io is radiation. Ejecta from geysers and volcanoes flow with Jupiter’s magnetic  eld to form a titanic, toroidal flux tube that rotates with Io around the gas giant. Travelers to Io must either use the heaviest radiation shielding available or resleeve into synthetic morphs.

Transhuman activity on Io centers around scientific research and harvesting the volatiles ejected by Io’s geysers, particularly sulfur. Bases tend to be modular and mobile due to the everchanging seismic activity. The Governments’ most notorious prison, Maui Patera Rehabilitation Center, is dug into a (mostly) extinct caldera wall north of the equator.


Europa has no atmosphere and lies within the fearsome magnetosphere of Jupiter, and as such its surface is bombarded with enough radiation for an unshielded transhuman to receive an irrevocably fatal dosage within a few days—much faster when Europa’s orbit passes through Jupiter’s immense magnetotail. As a result, transhumans on Europa dwell beneath the icy crust, largely in the ocean below, adopting a variety of aquatic and amphibious morphs for survival. The only surface facilities are the heavily-shielded ice elevator heads at Conamara Chaos and several other points through which reactor mass and other crucial supplies can be delivered to the Europans below.

Transhumanity is still exploring and imaging the Europan ocean  oor, a task complicated by the hideous pressures at work in these waters, which are ten times as deep as the Earth’s oceans. A further surprise awaiting transhumanity was the terrain. The geology of Europa suggested that beneath the ice would be fathomless depths of black water ending at a depth of nearly 500 kilometers in a relatively flat, featureless sea bed. Were Europa a lifeless ball of ice and rock, this would be the case, but over the estimated billion years since the rise of life on Europa, tiny lithoderms (analogs to Earth’s coral) have built silicate reefs that rise to within a few hundred meters of the ice crust. It is on these biologically formed mountain tops, home to complex ecosystems, that the Europans have built their habitats.

While based on water-carbon chemistry like life of Terran origin, life on Europa is completely autocthonic, having originated beneath an impenetrable ice sheet that cut off Europa’s subsurface ocean completely from outside. This is in marked contrast to Terran life, which many biologists have theorized might be the result of galactic panspermia, the slow diffusion of microbes through the vacuum of space aboard comets or asteroids. As such, the fauna of Europa are of great interest to transhuman bioscience.

Ganymede and Callisto

Nearly as large in size as Luna, but darkly colored and not as heavily cratered, Ganymede and Callisto are very similar worlds. Neither is as dense (nor has as much gravity), as their mantles consist of more ice than iron rock. Both possess abundant volatiles and water (albeit frozen), making them ideal candidates for habitation. Ganymede, with its differentiated surface of rocky and icy terrain, has an iron core and thus a faint magnetic  eld. Callisto, the smaller of the two, is composed mostly of icy silicate clays. As on Luna, most cities on Ganymede and Callisto are built below ground to shield them from meteor impacts (and, on Ganymede, from Jupiter’s radioactive bombardment).

While within the “protection” of the Jovian government, both moons are a patchwork of city-states. Some are full members of the Jovian polity, while others are only tolerated. Ganymede tends to swing more heavily toward the government, as its citizens still see the Junta-maintained infrastructure—accurately or not—as necessary in such a hostile environment. Callisto, outside the worst radioactive effects of the Jovian magnetosphere, is an easier place for technoprogressivism to gain a foothold.


The nucleus of this city-state was a research station founded by a coalition of Paci c Rim nations in Callisto’s Valhalla region, a massive primordial impact zone where the icy subsurface lies exposed, simplifying extraction of clean water. When the Fall came, Hyoden, which had long faced labor shortages, opened itself to those refugees who could make it to Jupiter. Now Hyoden has two million inhabitants, making it the largest city-state on Callisto and the largest non-Junta state in the Jovian system. Hyoden is itself heavily militarized, as the tendency of the local authorities to turn a blind eye toward operatives using their territory for forays against the Junta makes for uneasy relations with their powerful neighbor.


Situated along the southern edge of the vast, rocky plain called Galileo Regio, almost on Ganymede’s equator, Liberty (population 7 million) is the Junta’s largest planetary city-state. It is closely tied to Liberty Station, a major shipyard and defense installation in geosynchronous orbit. Major industries include shipbuilding, space construction, fabrication, and security products and services. The Castle, the central security network point from which all surveillance data collected in the Junta is monitored and processes, is rumored to be in or near Liberty. Liberty is mostly underground, but it boasts a number of parks in armored surface domes. If one were to spend enough time topside, one would see the deceleration torches of incoming metal asteroids from the belt bound for the shipyards lighting up the sky several times a day.


The Trojans and Greeks are two 600 million-kilometer-long arcs of scattered, icy rock asteroids sharing the orbit of Jupiter. They orbit in the stable L4 and L5 points sixty degrees ahead of and behind the giant planet. Mars and Neptune also have Trojan asteroids, but when someone speaks of, “the Trojans,” they’re normally talking about the Jovian groups. In the early days, L4 asteroids (ahead of Jupiter) are named after Greek heroes of Homer’s Iliad; L5 asteroids (trailing Jupiter) are named after heroes of Troy. Asteroids discovered more recently break the old convention, as there are far more objects in the Trojans than there were characters in the Iliad.

Politically, the Trojans and Greeks may be thought of as a collection of sometimes overlapping neighborhoods whose inhabitants tend to group around particular cultures, factions, and sometimes languages. A neighborhood in the Trojans might span anywhere from 250,000 to 2 million kilometers at its widest point. Within neighborhoods, almost everyone knows one other. Because of the wide dispersion of resources, Trojan habitats tend to be small—from one to two thousand people—and built largely along scum barge or cluster lines (although it is never advisable to refer to someone’s habitat as a scum barge unless they refer to it that way first).

Resources and Economics

Although the sheer size of the two regions means a lot of cultural diversity, anarcho-collectivism is a powerful meme here and the reputation economy is prevalent. On one hand, neighborhoods, habitats, and even individuals are expected to be self-sufficient. Unlike the denser Main Belt, the Trojans lack the safety net provided by pervasive transhuman presence. The ideal Trojan or Greek is a Neo-Renaissance being, incredibly competent in a wide variety of fields. A person who can’t maneuver in zero g; maintain their gear, ship, and hab; and navigate between rocks and habitats can have a tough time surviving. At the same time, a spirit of cooperation prevails. Bartering services or even gifting them to gain reputation is common. Everyone appreciates a specialist, as long as they’re not specialized at the expense of baseline self-sufficiency.

Prospecting and salvage are major activities in the Trojans, where metals and rare elements are scarce and settlers don’t usually have the economic muscle to import raw materials from elsewhere. However, the Trojans are rich in silicates, volatiles, and carbonaceous materials. Necessity has led to many innovations in materials science. Beyond the simple problem of raw materials, the widely scattered habitats of the Trojans have to be wildly inventive on many levels to retain their independence. New robot, morph, and vehicle designs appear all the time, enabling an unusual array of business and leisure activities, like whaling (organizing a flash flotilla to rapidly mine asteroids and comets with erratic orbits as they pass near the Trojans), mekking (simulated—or sometimes real—combat between robotic suits or synthetic morphs on uninhabited asteroids with interesting terrain), and shrining (stealthing up on another habitat and resurfacing it with nanosculpters to create an art object—mostly a scum barge pastime).

Lot 49


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