As far as I know it was Hans Oberth who first suggested¹ that an orbital habitat might consist of a hollow cylinder containing air and spinning on its axis to produce artificial gravity on the inside surface by the centrifugal effect. But these days, and in English, such structures are much better known as “O’Neill cylinders” after a proposal by Gerard K. O’Neill². O’Neill’s “Island Three” actually consists of two parallel and counter-rotating Oberth cylinders each with a a co-rotating set of mirrors, a linking framework, and a separate agriculture ring, but usage marches on. The structures that I am going to describe in the rest of this post are single cylinders without any windows, not instances of O’Neill’s actual proposal. Nevertheless I suppose that in Flat Black they are called “oneills”, not “oberths”.
There were orbital habitats in the Solar System, with permanent residents, in the century before the Destruction of Earth. But most of them were built in Earth orbit, and those were depopulated or destroyed in the destruction of Earth. The space habitats far enough from Earth to survive the radiation were mostly evacuated of the following decade and a half, the residents stripping the surviving space assets for everything salvageable and retreating by flinger to such colonies as seemed most likely to support space industries. That cannibalisation, and the ensuing centuries without maintenance, has left those habitats in poor condition: some have even been effectively destroyed. I’ll have to look at costings to see whether any of them are likely to have been built as oneills³.
A few of the most developed and prosperous colonies built orbital habitats during the Age of Isolation and the Age of Piracy, but these were very vulnerable to attack and to blockade during the Formation Wars, and most became un-viable and were evacuated and not maintained during the Formation Wars. Again, I’ll have to do some modelling before I decide whether any were oneills.
During the Formation Wars the personnel of the Eichberger Foundation⁴ lived in spaceships and in surviving orbital & asteroid habitats in Mayflower’s system. Theirs was very much a life in space, but they did not have resources to spare for building on a grandiose scale. Then for forty years after the Treaty of Luna came into effect the Empire concentrated its investible savings on building up its commercial space fleet and orbital operations. Only about 540 ADT did the Eichberger Foundation switch from intense re-investment and reveal that the Empire was immensely rich.
The [old] Capitol
The first oneill that the Empire built was the first Capitol, which was constructed in orbit around the ruins of Old Earth. The [old] Capitol housed a senate building, a paramount court building, a palace, administrative offices, accommodations etc. on a scale and in a setting that would awe visitors. As is supposed of the L’Enfant Plan for Washington D.C., the (old) Capitol was designed to create an overwhelming impression of grandeur and power, and to give the secretary-general and the president of the Imperial Council the biggest home-court advantage in the known universe.
The [old] Capitol was ready for occupation in 549 ADT.
Sectors and sector HQs
In 547 the Empire set up a system of sectors in the periphery. Twenty systems between about 105 and 120 light-years from the Capitol were established as reinforcement depots, to cut down the time it took for the Imperial missions in remote systems to send for and receive back-up. High commissioners were posted to these sector headquarters to supervise⁵ the resident commissioners in the several colonies of the sector and receive representations from the colonies’ governments, each SHQ became the seat of a fleet HQ of the Imperial Navy, a Divisional HQ of the Imperial marines, a sector court of appeals, divisions of the various assistance services receiving reports and allocating resources and personnel between colonies. An Imperial university was founded in each SHQ, besides a naval academy, an Imperial marines training base, and a bunch of reinforcement depots for this and that.
The Empire built an oneill to accommodate each SHQ; twenty of therm, named after great harbor and port cities on Old Earth. Like the [old] Capitol, they were built to overawe, but they were built later by a richer and more confident Empire that had the experience of building the [old] Capitol to work from.
The New Capitol
After 557 the Empire’s revenues from real estate development on new worlds started to augment its profits from the interstellar transport monopoly. Its operations became more expansive, intensive, and complex. A new generation of Imperials (including many recruits from the colonies) were less acculturated to living in confined habitats. The [old] Capitol became crowded. Furthermore, the prospect emerged that, starting in fifty years, the Senate was going to start steadily increasing in numbers as new worlds became independent colonies. And further still the scale of the [old] Capitol was no longer overwhelming visitors and senators, whose worlds were now more highly developed and who were now jaded by their experience of SHQs.
So a new capital was built, on a vast scale. The New Capitol is huge, stupefying in its scale, planned to accommodate expected expansion for centuries. It contains forests The capital was transferred to the New Capitol in 582, during the paralysis of the Establishment Crisis.
The Old Capitol was refitted and refurbished as a residential habitat for the Imperial family and headquarters of the Imperial Office, with an Imperial Marines Academy, Staff College, botanical garden, zoological park, historical, anthropological, technological, war, and art museums, and astonishing memorial to Old Earth.
Facilities and features in the Old Capitol are named, e.g. “The Palatine Elementary School”, “The Palatine Museum of Anthropology”, “The Palatine Zoological Park”, but the Palace is a structure in the New Capitol…. It’s official name is now perhaps “The Palatine Orbital Habitat”, but the facility is actually called “the Old Capital”.
The Empire has large orbital operations in several systems that are not part of the administrative framework described above.The are the economic and technological powerhouses that make up the Suite. Besides that such worlds as New Fujian, though passed over for SHQ locations because they are not far enough out into the periphery, have the industrial capacity to support a naval dockyard where their sector capitals (e.g. Metheglin) cannot.
These naturally require Imperial orbital habitats for significant populations. I have not estimated whether an oneill is more economic at the relevant scale than a collection of large stanfords.
¹ Neue Projekte für Raketen- und Raumfahrt, 1954
² The High Frontier: Human Colonies in Space, 1976
³ Rather than as “stanfords” (which seem likely to be cheaper except at very large scale), as habitat wheels attached to free-fall factories, refineries, orbital docks etc., or even as free-fall habitats.
⁴ And other survivors of the destruction of Mayflower, plus sympathisers who joined the cause.
⁵ But not co-ordinate, really. The isolation of colonies is such that there are few projects that require co-ordination of effort