Science fiction gave us the spinning wheel space station, but the real International Space Station is a jumble of tubes where astronauts float. This episode explains why the wheel was proposed, what weightlessness does to the body, from fluid shifts and puffy face syndrome to losing up to 2 percent of bone mass a month, and how centrifugal acceleration works using the equation a equals negative omega squared r and a salad spinner analogy. The hosts describe why a larger radius and a slower spin of one to two revolutions per minute are needed to avoid Coriolis-driven motion sickness.

The history runs from the 1869 story The Brick Moon to Herman Potocnik's 1929 solar-powered geostationary wheel, Tsiolkovsky's rotating greenhouse, and Wernher von Braun's 1952 Collier's design for an 80-person, 250-foot station assembled in orbit. NASA's 1960s  ...