Spinning the ISS to achieve artificial gravity would be possible if the ISS had been designed for that from the beginning, but as far as I know it wasn't, so th

Spinning the ISS to achieve artificial gravity would be possible if the ISS had been designed for that from the beginning, but as far as I know it wasn't, so they'd have to either replace the whole thing or construct an addition that spins. I'd like to see ISS greatly expanded now that access to space is getting cheaper, but given the constraints, designing vacuum sleeping bags is reasonable. (Also, expanding our range of techniques to limit the adverse effects of zero-G is useful in the long run. Ideally we won't have many people who need to be in zero-G for extended periods of time even if travelling to space becomes routine, but still the knowledge is good to have just in case.)