How did they walk upside down in “2001: A Space Odyssey”?

Dear Cecil:

I just realized the other day that I have never understood how they walked upside down in the spaceship in the movie 2001: A Space Odyssey. It looked like they walked around the inside of a cylinder. How'd they do it, Cecil?

Cecil replies:

This may disappoint you fans of high-tech special effects, but several sequences in 2001 made use of a technique that had once been used in a Fred Astaire movie, of all things. One number in Stanley Donen’s 1951 musical Royal Wedding required Astaire to dance over the walls and ceiling of his London apartment, an effect accomplished by mounting the entire apartment set inside a cylinder. The set was turned on rollers as Astaire danced, hopping from floor to ceiling as the apartment revolved underfoot. The camera, bolted to the “floor” of the apartment, turned with the set–and so, on the screen, the set appeared to be perfectly stationary: Astaire was dancing on the ceiling when the ceiling was actually the floor, if you follow me.

Stanley Kubrick used the same gimmick several times in 2001. There’s an early scene in which a stewardess carrying a food tray steps into a sort of cylindrical vestibule and proceeds to walk up the wall, with the result that she pivots through 180 degrees and ends up completely upside-down. Later, aboard the Jupiter mission, we see one of the astronauts jogging a couple times around the cylindrical interior of the spaceship. In both cases the set rotated while the actor remained more or less stationary. The Jupiter mission set was 38 feet in diameter and was mounted on a steel framework much like a ferris wheel. “The camera was on a gimbaled mount [attached to the moving set], and the [camera] operator was in a gimbaled seat,” Kubrick has been quoted as saying. “As the [set] rotated at three miles per hour, the camera was constantly adjusted by the operator to keep the actor in the picture. The effect on the screen is that the camera is standing still and the actor is walking up and around the top and down the other side.” Combined with the already shifted perspective of the dope-crazed members of the audience, the effect is irresistible. For pictures of the sets, see Jerome Agel’s The Making of Kubrick’s 2001 (1970).

Send questions to Cecil via cecil@straightdope.com.

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