The low levels of gravity (microgravity) in space cause significant changes in astronauts' eyes and vision after six to 12 months aboard the International Space Station (ISS), according to a study published in the IEEE Open Journal of Engineering in Medicine and Biology.
That’s been known for a long time. What we don’t know is what reduced gravity will do. We really need a space station that can simulate martian and lunar gravity.
I can’t wait until we have our first rotating space station. Both Space Development Corporation and Vast Space have announced plans, but it will probably be another five to ten years until they start bending metal for the hardware.