Space habitats are a wide catagory of structures that include any space-based artificial construct made for the purpose of housing living creatures. A habitat may be independent or part of a larger cluster. It may be focused on sustaining its population or it may be a scientific or industrial installation supporting another population.
Common types of habitat:
Freespheres
Habitats which are (usually) spherical with no or negligible artificial gravity. The habitat contains a bubble of atmosphere and the inhabitants are usually adapted to microgravity conditions and movement. Cheap to produce but unfit for long-term habitation without access to extensive biotechnology.
Cylinders
Enclosed rotating habitats that have a length greater than their radius. These are the most common habitats as they are cheap to produce and can easily be made to provide tolerable gravity without the need for expensive artificial gravity technology. Properly shaped asteroids may be hollowed out, made to spin, and turned into a cylinder habitat.
Platforms
Medium-sized, flat objects that make extensive use of expensive artificial gravity technology. Usually prestige projects due to high upkeep costs.
Tori
Rotating habitats with a radius far greater than their length, some may be so large that they can maintain a dense atmosphere while the inner edge of the ring remains open to space. More difficult to engineer than cylinders but external sunlight can be used for a semi-natural day-night cycle, as well as making biosphere engineering considerably easier.
Rings
Also known as Dyson rings, these are continuous rings completely encircling a parent star. None have been constructed to date, as the engineering difficulties of keeping the orbit stable and the ring itself structurally sound are enormous. However the large energy collection possibilities and population capacity along with the prestige gained in overcoming these complexities have inspired many attempts at constructing these installations, typically around dwarf stars.
Shells
Also known as Dyson shells, these are contiguous spheres completely surrounding a parent star. The sheer material requirements are almost always larger than the supply available within the system, and shells present even more stability issues than rings. No serious attempts at constructing a shell has been made.
Common types of cluster:
Swarms
Minimally organised clusters not centered on any particular parent gravity well.
Constellations
Clusters orbiting a (usually populated) parent world, often in close formation and sometimes in geostationary orbit.
Lagger swarms
Swarms orbiting another body's lagrange point. Common in systems with large amounts of trojan asteroids.
Dyson bands
Clusters consisting of large amounts of habitats roughly equally distributed along the same orbit directly around a parent star.
Dyson spheres
Clusters consisting of large amounts of habitats orbiting directly around a parent star in a coordinated manner so as to collect as much solar power as possible.
