NASA scientists are intensifying their investigation into a vision disorder that affects 70% of astronauts on long-duration space missions, as new research reveals the condition poses mounting risks for future Mars exploration 1 2. Space- Associated Neuro-Ocular Syndrome (SANS) causes crew members to experience blurred reading vision, swollen optic discs, and flattened eyeballs that can persist for years after returning to Earth
The matierals science is actually the bigger hurdle than profitability - we’d need carbon nanotubes or similar to handle the tensile stress of a rotating structure that big, since conventional materials would literally tear themselves apart at the rotation speeds needed for 1g.