A rotating wheel space station, bublik city or von Braun wheel, is a hypothetical wheel-shaped space station originally proposed by Konstantin Tsiolkovsky in 1903 and expanded by Herman Potočnik in 1929.

In 1959, a NASA committee opined that such a space station was the next logical step after the Mercury program. The Stanford torus, proposed by NASA in 1975, is an enormous version of the same concept, that could harbor an entire city.

NASA has never attempted to build a rotating wheel space station, for several reasons. First, such a station would be very difficult to construct, given the limited lifting capability available to the United States and other spacefaring nations. Assembling such a station and pressurizing it would present formidable obstacles, which, although not beyond NASA's technical capability, would be beyond available budgets. Second, NASA considers the present space station, the International Space Station, to be valuable as a zero gravity laboratory, and its current microgravity environment was a conscious choice.

In the 2010s, NASA explored plans for a Nautilus X centrifuge demonstration project. If flown, this would add a centrifuge sleep quarters module to the ISS. This makes it possible to experiment with artificial gravity without destroying the usefulness of the ISS for zero g experiments. It could lead to deep space missions under full g in centrifuge sleeping quarters following the same approach.