@HighFrontierDoc @nss Actually that is an illustration from Dandridge Cole and Donald Cox’s 1964 book “Islands in Space” that precedes the High Frontier by a decade or so.

@HighFrontierDoc Baby steps first. This is a cross-section of a MetroCircus in an asteroid. The solar/galactic radiation shielding mass does not spin. Only the city spins. It is much easier to build than the colony depicted above.