Designing Artificial Gravity

Prolonged weightlessness wrecks astronaut health - bone loss, muscle atrophy, vision damage - so long missions need gravity. And if weightlessness is just the absence of a floor pushing you, the fix is simple in theory: spin the spacecraft.

Stand on the inside of a rotating ring, and the wall pushes you inward, providing the centripetal acceleration that keeps you moving in a circle. You feel pressed outward against that wall, so it becomes your "floor." A ring 200 meters across, spinning at about 3 turns per minute, would mimic Earth's gravity. So why don't we build them?

• A massive rotating structure is hard to engineer in orbit
• The Coriolis effect makes you dizzy at small diameters
• Every kilogram in orbit costs thousands of dollars