Ask the Astronaut: Why isn’t the space station shaped like a wheel?

The classic wheel-shaped space station concept of the 1950s.

Q: Why haven’t we embraced the pinwheel/circular design of a space station like the one in the movie, 2001: A Space Odyssey? Is it just plain old dollars and the logistics, or is the design flawed? Would it be a better habitat than the ISS? (Ryan O’Connell, Geraldton, Australia)

Wernher von Braun, the German rocket scientist who proposed such doughnut-shaped, rotating stations back in the early 1950s, certainly thought this was a promising design. But a rotating station must be structurally stronger than one orbiting in free-fall conditions; a beefier structure means the station is heavier, and thus more costly to build and launch. The U.S. Skylab station of the early 1970s was designed to be built cheaply using Apollo-Saturn V hardware; getting it up quickly and cheaply was more important than providing the astronauts with artificial gravity. And much of its scientific work was aimed at exploring the effects of free fall (or microgravity) on fundamental physical, chemical, materials science, or biomedical processes. A rotating station destroys that free-fall environment. The ISS was designed with free-fall science in mind, too, so artificial gravity was not considered. A rotating centrifuge for small lab animals was supposed to be a part of an ISS science module, but it was canceled for cost reasons. One recent proposal suggested adding a rotating section to ISS to prove the technology of artificial gravity for Mars travel. So far, cost has prevented any such design from ever getting past the drawing board.

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