- Io (105,000 pop)
- Over 400 active volcanoes (most geologically active object in solar system)
- Tidal heating from friction generated with Jupiter and Galileans
- Volcanoes produce 500 km tall plumes of sulfur and sulfur dioxide
- Numerous peaks taller than Mount Everest
- Composed mostly of silicate rock around an iron and iron sulfide core
- Surface dominated by plains of sulfur and sulfur dioxide frost
- Average surface temperature -261 F
- Io Plasma Torus (ionization of oxygen and sulfur in atmosphere).
- Inside the heart of Jupiter’s magnetosphere (radiation hell - 3600 rem/day).
- Highest surface gravity of any moon in the solar system (not saying much though).
- Underground magma ocean 50 km thick.
- Major industry includes:
- Carbonates (very rare)
- Silicates (extremely common)
- Metals (uncommon)
- Energy production
- MHD (Magnetohydrodynamic) Generators consisting of loops of mag-sails hung around Io - transform radiative magnetospheric energy into electricity.
- Giant orbital electromagnets to disperse radiation risk from Io.
- Limited assembly and building capabilities exist with many modules needing to be purchased from other sources (usually Earth).
- The Ionian Combine is capable of some limited construction of drones and freighters.
- Capable of limited construction up to frigates and fighters.
- The Sovereign Republic of Ganymede - an ally of the Eastern Federation - and the Ionian Combine are in a state of open war characterized less by major military action and more by sponsored privateering - Ganymede is much more powerful, but has been forced to focus on her rival, the Commonwealth of Callisto.
- The Ionian Combine is not popular among the various polities, mostly because many polities suspect the Combine of using its own corporate divisions as an excuse for abrogating responsibility for various raids. The following polities are generally happy to sponsor raids and hostile action against the Combine:
- Collaborated Union of the Hildas Triangle
- Europan Consortium
- Republic of Titan
- Amalgamated Calpultin of Dione
- Democratic Republic of Triton
- The Ionian Combine has no allies, although individual corporate interests on Io certainly do.
Politics and Culture:
- Economically, Io is the single most important source for silicates, fissiles and energy in the Outer Worlds. It has more energy than it knows what to do with, a situation that is limited only by the ability to transport this energy.
- Io was settled by several corporate interests with a mixed history of both cooperation and fierce competition. This has ossified in the century or so since its settlement into a set of oligarchic families that are the remnants of the founding corporations.
- Io’s population is a tiny fraction of the population of the other three major moons of Jupiter.
- Much of the Ionian Combine's elite and oligarchic corporate headquarters exists in orbital habitats rather than on the surface; the surface is mostly used for expendable mining operations of various sorts.
- To an Ionian, “International Law” is another phrase for “Corporate Law”, while individual rights are the product of in some cases lifelong contractual agreements.
- A powerful underclass also exists surviving as a kind of grease between the corporate oligarchies. Identity assumption, assassination, smuggling, espionage and other services are all provided.
- The Ionian Combine is distrusted by basically everyone, since the lack of central control provides an irresistible smokescreen for oligarchic interests to get away with murder and other impieties.
- The oligarchies of the Ionian Combine have a code of conduct that does allow them to close ranks in the face of external threat, but as soon as said threat dissipates - and usually for some time before that point - the oligarchies are back at each others’ throats.
- To an Ionian, life is cheap and everything - and everyone - has a price.
- Where Europa is the biological high-tech capital of the Jupiter system, Io is the energy titan, and it leverages this usefulness to keep itself from being completely ganged up on; several times in its history the Ionian Combine has bribed other polities with energy export concessions to preserve itself.
- Io itself is exceedingly unstable, and as a result accidents, fatalities and destruction of habitats is quite common. Geological predictive science being a valued profession on Io, this contributes to the “life is fleeting” and “life is cheap” philosophies - habitats tend to be built quickly and cheaply with the understanding that you will almost certainly need to abandon them at some point.