The Kuiper Belt contains a mixture of millions of icy bodies ranging from dwarf planets such as Pluto, Makemake and Haumea down to bodies less than 20km across. The first mission to this region was the New Horizons probe, passing Pluto and Charon in 46 AT and 2014 MU69 in 50AT. Several more flyby and orbiting missions were followed by the first autonomous lander in 119 AT; this included a rover powered by a radioisotope thermoelectric generator, which operated for nearly ten years. The first manned landing (on Pluto) in 290 AT was followed by sporadic colonisation of several other objects, but most of the Kuiper Belt and the Oort Cloud were still largely untouched by colonisation even at the end of the Interplanetary Age.
At this time Mars, the Belt, and the Gas Giants were the high frontier, there was talk of sending a mission to Tau Ceti, and not many individuals wished to spend years in the resource-poor Kuiper and Oort regions, where the sun is nothing but a bright star in the cold sky.
But by the start of the Solsys Golden Age early megacorps such as Oort Mining, High Frontier Developments, and Interplanetary Ice were selling franchises to anyone who wished to mine and develop the outer halo bodies of the Sol System. Encouraged by generous loans, tens of thousands took up the offer. Many small family and clan owned asteroid companies also invested in this new development. Some of those involved went bankrupt, some went mad, some were ill-equipped or incompetent with the machinery. But for many it was a way out of the hopelessness and despair of the overcrowded arcologies and slums of Old Earth.
Over the next century or so, waves of prospectors, idealists, eccentrics, loners, and small venture miners settled the Kuiper Belt and the Oort Cloud, in exactly the same way they had settled the asteroid belt, the moon, and Mars in the recent past. And a similar pattern of diverse interwoven cultures and subcultures, clades and sub-clades, developed in that time. If anything the diversity of the Haloists or Haloers, as they came to be known, was even greater than of the Belters, for by now humankind had evolved into more species and races - superiors, space adapts, cyborgs, provolves (mostly Sapientchimps and Enhanced Dolphins), baselines and nearbaselines - and every combination in between, developed the new "wild west" of the cold distant frontier, relishing in the freedom, while the big transport, development, and mining corporations raked in the profits.
The coming of the Backyarders
This period saw the widespread dissemination of pirate nanotech and the so-called nanotech window, when it became possible for so-called Backyarders to 'grow' spaceships very cheaply using nanite assemblers, virtually in one's back yard. Very few of the backyard jobs were really spaceworthy; fewer again were able to cross the vast interstellar distances to found colonies or - more often - invade those outsystems that already had colonies. Most simply taxed the resources of the Belters, the Genetekkers, the Outersystemers, and the Haloists, who, if they were kind-minded took in the newcomers, and if they were not chased them away, even peppering their vessels with dust or sand accelerated from magnetic catapults if the backyarders were too insistent.
The Haloers had a very poor regard for the backyarders, who they correctly surmised were not interested in the austere beauty of the icy comet cores and unblinking stars, but simply wanted a resting place where they could patch their ships, refuel, and move on to their real destination, other solar systems. But as both fuel, building materials, and construction material were in short supply in the Halo (the only thing that was even slighty common was ice), the Backyarders were stuck there, and came to resent their isolation as much as the Haloers resented having them there. When they were forced to work for their share things became even worse, and most were incompetent or ill-equipped to manage the mining equipment, unable to cope with the microgravity (only a few Haloist outposts were rotated to give Earth, Mars, or even Luna-normal gravity), and unwilling to abide by the resource-hoarding lifestyle, which was often even harsher than what they had in the slums back on Earth, Mars and Luna. But in one sense the Backyarders were fortunate - they escaped the Technocalypse.
It is an ironic historical fact that the technoplagues that decimated the inner and much of the outer solar system hardly touched the Haloists. They were so far out and so far apart from each other that it was hard for the nanites to find them. Many of the nanites were thermal-powered, and there was precious little heat out there. Add to that the distribution of instructions for freeware blue goo that was being frantically broadcast by the authorities and it is not surprising that the Haloists escaped so lightly. In fact Haloist culture does not even speak of a "dark age" at all - the dark age was something that affected the inners, and in their eyes yet another illustration of Inners inferiority and vulnerability.
The dark ages of the solar system was actually the high point of Haloist civilization. During the four hundred years in which humanity sheltered behind blue goo shields and aioid defences, and only gradually ventured out to slowly and painstakingly reclaim the solar system, the Haloists developed the infrastructure of their habitats, exchanged knowledge, ideas, art, and culture (which was anything from austerely minimalist to blatantly ostentatious, depending on the habitat and the preferred aesthetic) and slowly diffused outwards into interstellar space. Some even ventured inwards in blue-goo protected ships, and claimed a number of abandoned asteroids that had either been already disenfected of grey goo or that they were able to disinfect.
The rise of the Federation in the 29th and 30th centuries meant the end of the Haloist ascendancy. The Solar System, rich in resources, energy, and processing power, was on the rise again.
Some Haloers came to a mutually constructive agreement with the Federation, finding the new government a lot more reasonable than the old mining megacorps had ever been. Others retreated once again, regarding anything heliocentripedal as "the enemy", and joining the Backgrounders and other hider clades with which they had good relations (in fact some Backgrounders were themselves originally Haloers). Still others maintained a sort of easy neutrality, just wanting to be left alone.
For the most part the Haloers got their wish. From the very start the Federation was interested in expanding outwards to the stars; in fact many of the Founders, seeing how humanity had escaped decimation by a hair's breath during the dark ages, realized the only way to ensure continuity of the race and of civilisation was to have as many colonies in as many different solar systems as possible, each one - even the most isolated - with a full record of all human knowledge, culture, and achievement.
As the Federation expanded outwards, some Haloist clades did likewise. They fitted fusion and, later, amat drive units onto their comet cores, making them into nomadic ships able to travel at anything up to a tenth the speed of light (most Haloists refused to go faster, realising how quickly dust hitting their habitat at high velocity could erode it). Others - especially during the later Federation, Emergence, and Expansion periods - migrated to new solar systems on transports, and started anew there, founding new clades and dynasties. Wherever the Inners went, the Haloers went as well.
Today there are an unknown number of Haloists of all kinds - ranging from lo tech to ultra tech, from nearbaseline to extremely derived (and in some cases even unrecognisable as human). In addition to conventional biont tweaks, there are also cyborg and vec haloers. Most are very traditional, and some are incredibly inbred (100th generation clones are not uncommon). They are most numerous in the Inner Sphere, where they have been the longest, but haloist outposts are not unknown in the Outer Volumes, and even as far as the Frontier.
The Typical Lo Tech Haloist Culture
Lo Tech Haloist Culture, such as the Marians, tends to inhabit a single kuiper or oort type body for centuries, even millenia, only moving on when the entire mass has been completely used up. Setting up a new colony is never easy, as equipment is usually of First Federation vintage or even nanocloned Late Interplanetary age (which is often preferred for reasons of clade pride and cultural identity). Although ice is usually common, other building materials are rare. Most habitats consist of a diamondoid shell (assembled from local soot) within the ice core, and volatiles extracted from the ice. Baseline and nearbaseline clades actually rotate their habitats, but most haloers are microgravity adapted. Although oxygen, water and hydrogen are plentiful, there is little carbon, silicates, etc, and total biomass is generally low. Scarce resources are acquired through trade with other haloer clades or colonies, or more rarely, inners. For isolated haloers life is precarious, as a single accident - e.g. a hydrogen explosion or a depressurisation of the habitat - may result in everyone's death before help can arrive. Even in fairly densely populated (in Haloist terms) regions it can take hours or days to reach the nearest colony. But the lo tech haloists are a hardy and resourceful folk, and have learned to manage well on very little. And their skilful construction techniques mean that fatalities and serious accidents are rare.
Lo Tech Haloism tends to be a regimented, closed society where everybody and everything had its place. Generations grow up not knowing any other world. The politics of scarcity, control and self-sufficiency is almost a clade ideology.