Habitats

A habitat, in its most common usage, refers to any artificially constructed dwelling in which large numbers of Humans or other sapient beings permanently reside, outside of a habitable world. The two most common types of large habitats in Human Space are Spin Habitats and Dome Habitats, built in space and on planetary bodies, respectively. Prior to Humanity's reverse-engineering and large-scale adoption of wormhole gateways, it is estimated that as much as half of the Human race lived on Habitats in the Solar System and nearby star systems. Since then, however, many habitable worlds have been discovered and opened to colonisation, which resulted in much of Humanity abandoning Habitats in the 24th Century, causing many old Habitats in Earth Space to be converted into nature preserves or agricultural facilities. Today, it is estimated that around a quarter of Humanity permanently reside in Habitats, including mobile Habitats used by Stellar Nomads.
Spin Habitats take the shape of large cylinders or pill-shaped structures orbiting planets, moons, or stars, which are perpetually spinning to artificially simulate gravity in their interiors. They range greatly in size, from a few hundred metres in diameter and a few kilometers long, to dozens of kilometers in diameter and over a hundred kilometers long. Most, however, are approximately 10km in diameter and 40-50km in length. While in some cases, parts of the Habitat are constructed of transparent material to allow in sunlight, more commonly sunlight is either reflected into the Habitat through a series of mirrors, or simulated with artificial lights.
Dome Habitats are large, transparent domes built on a planet or planetoid's surface, containing a breathable atmosphere, allowing a small settlement, or part of a larger one, to reside within. They allow for otherwise uninhabitable worlds to be settled by humans. While they are much cheaper than Spin Habitats, they cannot control the level of gravity they experience, which is usually suboptimal for Human life, and are built on a planet's surface, meaning it is more difficult for spacecraft to reach them.