The majority of the habitats are cylinder cities, though there are a number of larger rings, small stations and mining outposts on the larger asteroids.
The inner surface of a Cylinder is covered with farms and parks; most of the inhabitants live in the cylinder walls. The cylinders average 60km in length and 20km in diameter, giving several thousand square kilometres of internal surface. Attached to the ends of the cylinder are axial docks, airlocks, communication systems and non-rotating freefall factories.
Older cities that have expanded to overflow their original habitat are made up of several cylinders, joined by frameworks linking their axes. The structures linking the habitats are usually built as equilateral triangles, with the habitats forming the edges of a prism. In such a multi-cylinder city each of the cylinder habitats is a deme, a sub-division of the polis. Large free-fall complexes attached to the city framework are sometimes also granted deme status.
The future of Ad Astra