despite a big push for dispersed habitats in many nations since the advent of cheap intercosmic shipping and robust logistics, the majority of humans still live in large space stations: the polis. with deep enough skies to harbor their own weather, a polis contains a vast population ranging from the tens of millions to potentially hundreds of billions, usually occupying a hollowed-out asteroid pumped with air and laced with a tether-bound web of thousands of floating neighborhoods or districts; various spindistricts operate at a mixture of different gravity levels.

their scale is sufficient to wield their own independent industrial base and the largest can outclass planets in workforce and materiel - mighty nations unto themselves, where everyone lives only a couple hours' train ride away from one another. massive radiators tower over their surfaces, giving the city wings, or rings.