posted by jessica on .
In designing rotating space stations to provide for artificial-gravity environments, one of the constraints that must be considered is motion sickness. Studies have shown that the negative effects of motion sickness begin to appear when the rotational motion is faster than approximately 2 revolutions per minute. On the other hand, the magnitude of the centripetal acceleration at the astronauts' feet should equal the magnitude of the acceleration due to gravity on earth. Thus, to eliminate the difficulties with motion sickness, designers must choose the distance between the astronaut's feet and the axis about which the space station rotates to be greater than a certain minimum value. What is this minimum value?
The maximum angular velocity w is
2 rpm*2 pi(rad/rev)/60 (sec/min) = 0.209 rad/s
R w^2 = g, with the requirement that w < 0.209 rad/s
w^2 = g/R < (0.209 rad/s)^2 = 4.39*10^-2
R > 9.8/4.39*10^-2 = 220 m
I don't think there are currently any plans for a space station that large.
The Russia/USA space station ISS, which is currently up there, does not rotate. The one depicted in the movie 2001 was supposed to produce only 1/6 the acceleration of gravity. For more about rotating space stations real and fictional, see