Shellworld

Shellworlds are a type of artifical habitat that look like a regular planet from the outside. However, instead of being a solid sphere, Shellworlds are a series of concentric matryoshka doll-like layers supported by massive pillars. Each level of the shell can have its own mix of atmosphere an climate, although most are devoted to high capacity habitation, and because the inner levels are sealed and artifically heated, they can be in locations where the local star doesn't offer much heat or light. The Federation of Xah and the Northup Alliance make extensive use of the techology, with some of the most populated bodies in Known Space being Shellworlds.

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Example Shellworld

Suloch is one of the Federation of Xah's most populated single bodies that isn't a Ringworld or Topopolis, and is an important local manufacturing and research station. It's manufacturing output is sufficient to keep this system and several neighbouring systems supplied, and its food output is also substantial. Almost 20 trillion individuals call it home, over 90% of the system's entire population. It's status also makes it an important military base for the Warrior caste, who have large portions of the surface devoted to ship yards and training.

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Utility

Massive transport conduits, over a hundred kilometers wide connect all the levels, allowing traffic to pass between them, spread out at regular intervals around the Shellworld, although there is smaller-scale connections between levels themselves. Specialised vessels are typically the only ones allowed to travel in the transit conduits, but some traffic controllers allow access to regular space craft as well.
There are a number of different shell types found in most Shellworlds:
Outer level: the outer level mainly consists of ship docks, vents for volatiles released from more inner levels, heat sinks to help alleviate heat build-up, and shielding for asteroid impact and radiation.
Agriculture: Shell levels can be tightly controlled for atmospheric content and light levels, which allows vast internal farms, providing food for the world's inhabitants, and also for export to other worlds.
Residential: Entirely given over to housing, population density on a shell can vary from the high density of hive levels, to the spacious residential levels found on the high class shells in rich Northup Alliance worlds.
Industrial: Levels where the vast populations of the hives work to manufacture goods and all other things required by a modern society. Whilst in the NorthUp Alliance, a lot of the tasks are automated, the Federation of Xah utilises its vast Worker caste population in this regard.
Water: The regular water levels found in most Shellworlds have several purposes. They provide volatiles for fusion reactors, drinking water for the inhabitants, protect inner levels from external radiation, and for the higher level members of the castes, provide recreational space.
Facilities: The most inner level on any Shellworld is given over to the facilities that allows the world to function.

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Manufacturing

Shellworlds are constructed in their shells, building outwards until the structure is the required size. Most are around the same diameter as a typical Terran style world, around 12 to 20 thousand kilometers in diameter, but larger and smaller versions can be found. Smaller Shellworlds tend to be found in the orbit of gas giants, whereas the larger one are found far from a star's habitation zone, usually to make it easier and quicker for FourDrive enabled vessels.
Whilst a minority of Shellworlds are made from excavated rocky worlds, most are constructed from exotic materials such as carbon nanofibers, materials able to withstand the unusual stresses that shellworlds exert on themselves.

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World Classification: Shellworld
Star Classification: Any
Max. Population None

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