No-maintenance orbital colonies

Thermionic generators need no moving parts, a rotating
cylinder, rotating about the long axis, like a dumb
bell, would be stable indefinetly, heat dumping via
thermionic transfer would also last. As far as counter
rotating cylinders or docking hubs are concerned,
magnetic bearings would have no wear, but the magnets
might lose integrity over time. Micro meteor wear and
tear could be a problem, unless there was a massive
rocky shield surrounding the rotating system.
Yeah, lots of possibilities for stories there.
Eco system degradation might impell the inhabitants to
assume a great deal of responsiblity for manageing the
eco interaction. Some good story possibilities there
as well,,,