Pluto
The Pluto Special Economy Zone, or simply Pluto, is a member state of the Sol Central Government, situated on the planet of same name. It is mostly known for rampant crime and poverty, along with a large amount of derelict habitats and a (relatively) booming salvage industry.
History
Pluto was never a lucrative colonization target: it had no atmosphere, its only resources were various kinds of ice, and it is in an remote location. These factors, however, helped to make it the hub of activity it once was. When Humanity got comfortable in their own star system, they looked to the stars, and saw new places to expand to. The problem, at the time, was a lack of faster-than-light travel. To reach any place in matter of decades rather than millennia, vessels would need a immense amount of fuel to achieve extremely high speeds necessary for escape.
Thus, the Transplutonian Sling was envisioned - an ambitious joint project by several governmental agencies and corporations. The fuel infrastructure was established on Pluto. Mining outposts on the surface began extracting the frozen gasses, with domes to house the maintenance technicians. Refineries and orbital refueling docks for spaceships appeared. Orbital habitats to house the workers and crew while awaited orbital transfer time window began to crop up. Slower-than-light ships would top off their tanks here, and perform gravitational slingshot maneuvers using other Kupier belt objects for free acceleration.
The Sling going operational marked the beginning of a Golden Age for Pluto. Nearly every ship going on extrasolar mission passed through it at this point. The crew members of those ships were well-paid – often in advance – were willing to cut loose before the deep and dangerous cryotrip into unknown. Sensing an untapped market, establishments providing all sorts of entertainment started popping up. Bars opened in unused bays and gambling dens in abandoned maintenance nooks; with the construction of more orbital stations, several casinos were built solely to cater to crews preparing to leave. The crime naturally followed, with authorities willing to let them do their thing as long as they did not interrupt the operation of the Sling. It became something akin to Terran Age of Sail Nassau, a free port under nominal governmental oversight. It is believed that around this time the peculiar lingo called "Gutter" started spreading from here, a confusing mixture of various languages and local slang, used by the criminals to avoid leaving incriminating things on record.
This boom lasted until the creation of the first gateways. Fewer and fewer ships had to take STL routes to their destinations, leaving just a few odd Expeditionary Corps vessels, who also found better starting points than Pluto. Corporations started shutting down their facilities as profits dried up, and scrapping them for any salvageable material to make up for the losses. Few gas mining facilities still remained, subsidized heavily by the government. Without the money and clientele, most "entertainers" moved back towards core worlds. The decay set in.
Current State
Now Pluto is the least developed of SCG states in the Sol system, and its prospects are grim. Most of planet's population is employed salvaging abandoned infrastructure for scrap metal, recycling it on-planet. Some half-joke they are packing up Pluto before leaving for good.
SCG is trying to bring the place up to the level of other Sol worlds with development projects, humanitarian aids and grants to local businesses. Citizen enjoy the same rights and benefits as other SCG citizens, but few teachers, doctors, and police officers want to move to work in Pluto, so they are often overwhelmed.
Sizable portions of the population have turned to crime to make ends meet, with larger gangs controlling parts of bigger habitats, or sometimes even whole small stations. Nominally government is still in charge there, but any attempt to prevent gang operations is met with brutal retaliation, so most officers posted there don't feel it's worth it. Several years ago a gang-incited riot on one of habitats deteriorated to the point that the First Fleet had to be called in to help in restoring order.
The special SFP taskforce was dispatched to Pluto to investigate and crack down on most disruptive gangs and their leadership. The already dangerous job is often complicated by unwillingness of local law enforcement to cooperate, either because they fear the retribution, or because they're dirty themselves.
Abundance of salvage and experienced tech-savvy (and desperate) workers makes it a popular destination for those who want to do some maintenance or modifications on your ship without taking valuable time of customs and law enforcement. "Plutonian cargo bays" (often refitted from corporate vaults) are famous for their stealth among smugglers.
One of few corporations to maintain a presence here is WaffleCo. They have a factory arcology near The Donut, one of most prominent geographical features of Pluto. Rumor goes that they only stay on Pluto to maintain contacts with underworld for their less savoury dealings. WaffleCo continues to deny these outrageous allegations.
Geography
Pluto itself remains a dusty icy ball on the outer edge of Sol. Its surface consists of flat, rolling plains, with some sparse, spiked peaks, and deep crevices. Craters cover some parts of the world, but it is mostly a desolate plain. Pluto's most prominent plain is The Heart; the heart-shaped plain remains a tourist attraction for people and aliens visiting the Sol system. There is an underground ocean roughly 100 km deep under surface.
Pluto has several moons, with biggest being Charon. They're all settled in same manner as Pluto, though smaller moons were abandoned earlier as their resources were depleted.
Since the infrastructure was built for spaceships stopping in orbit, the vast majority of Plutonian infrastructure is orbital. The largest station is Port Lagrange; it consists of several habitation rings, with government offices (including the Governor's Office) and central docks located in the inner rings, and cheap domiciles in the outer rings.
As Pluto and its orbital space was envisioned to function more as a facility than a settlement, most habitats still have names like Orbital-24C, though some areas have legally petitioned to have their names changed, to anything from New Earth to Deadend.
Ground installations are, generally, domes, housing technicians who maintain the mining rigs and refineries. Most of these are abandoned as the demand for gas dried up. There are still some active domes most notably the WaffleCo arcology and Snowplow, one of few active mining facilities. There is also a small Expeditionary Corps outpost tasked with exploration of the underground ocean. It's often considered a training assignment to let Corpsman get used to real fieldwork.
Culture
Faced with their economically apocalyptic situation, most Plutonians develop a dark sense of humor to cope.
The people there are remarkably diverse, as generations of sailors intermingled with the locals; many Plutonians can trace their heritage to all corners of Sol.
Enlisting in Fleet or EC is often the only ticket off-planet young people have, and a lot are willing to go for it.
Pretty much everyone on Pluto know Gutter, but it's not something to brag about. People who speak it outside of criminal dealings are mostly wannabe gangsters, or just not very bright.