As I understand it, loss of calcium and bone density during prolonged weightlessness is a major problem when contemplating long-duration spaceflights (like a mission to Mars, for example).
One long-proposed solution is a habitat that spins to provide artificial gravity, but I understand that this concept has never actually been tested.
So suppose I want to build an experimental space habitat for 3 astronauts which is spun to provide artificial gravity. Assume it is a cylinder, sealed at both ends, and it spins around it’s long axis. How large a circumference would the habitat need?
Would the biggest Russian booster available be big and powerful enough to lift such a beast, or would assembly in orbit be necessary?
Finally, since the problem of loss of bone density was known from Soviet long duration flights on Salyut and Mir, why wasn’t ISS designed to spin? Too ambitious for the funds available?