O'Neill's designs assumed 1 - 2 rpm to make 1 g at the rim, implying humungous sized structures. But all the actual studies on Coriolis effects on humans imply higher angular speeds can be adapted to successfully - 6 tohink 10 rpm gets quoted in the sources.

Personally I think we won't see O'Neill's for a LONG time - not until either better radiation shielding is developed and/or mass-in-space gets way cheaper. An inert mass shield against cosmic rays weighs multi-million tons for all the big O'Neill designs and even the Stanford Torus is ultra-heavy. It's damned hard to supply that sort of mass cheaply - sure it's in-space, but there's a cash and time-cost to actually retrieving it, and currently there's no decent price on it to make it worth-while.

Easier to leave the mass in-place and live in tunnels on asteroids, at least at first. And if humans adapt to that style of life will we even bother to replicate Earth-like conditions?

Adam

Not pessimism, just scepticism.