“2001: a Space Odyssey” Special Effect


I must have first watched 2001 over 30 years ago and it struck me as a masterpiece of story, special effects and musical score. It is not everybody’s cup of tea but an Internet site still puts it in the top 100 films of all time. By today’s standards the computer images supplied by IBM are not so great, but in their day they were striking. The film is arguably Stanley Kubrick at his best.

There are several sections of the film where the actors are seen to defy gravity. I chose to re-create the section where Bowman and Poole walk toward a revolving airlock and enter it while apparently starting to revolve themselves. The PAL DVD time index for this is 1:08 and for Blu-ray or NTSC DVD it is 1:11. Old versions of the film may be different due to edits of the opening score. Interestingly over 40 years later Inception used a similar special effect.


First of all was to work out how it was done. The actors cannot be defying gravity so initially they must be in a stationary tube with the far tube rotating. When they enter the far tube it must become stationary so the closer tube must start rotating in the opposite direction to keep continuity of movement. But we never see this tube moving so the camera must be mounted to the tube. I found an article on the Internet that verified this.

To keep the relative motion I used just one motor and a differential to each of the rotating cylinders. Differentials distribute an input drive to two outputs allowing varying speeds for each but the sum of the speeds is always the same.


This presented no serious problems but care was needed.

  1. No stray light can enter the mechanism because when the tubes change speed, the light patterns coming in will also change. Therefore all holes must be bolted up. This required almost 800 washers for finish protection using almost my entire supply.
  2. The main figure (for ease of operation I chose only one), needs to be pulled along the tunnel and the only place this can be done is from the centre of the far tube. The man has a threaded boss on him which is loosely attached to an 11 ½” screwed rod. The screwed rod passes through a socket coupling forming the centre of the far tube. The socket coupling is held in place by two rods with four collars on the rods. When the figure gets to the exit hatch the screwed rod is twisted to detach him.
  3. Tube turning is quite simple. The far tube has a stop which stops it from turning when the exit hatch is at the bottom. The other tube is kept motionless by my hand until the far tube is nearing its stop.
  4. The area is a bit dull so a light is mounted near the camera with power through a commutator.


  1. The screwed rod is pushed through the socket coupling and connected to the man who is placed in near the camera.
  2. The near tube is positioned with camera in normal shooting position. The far tube is positioned about a ¼ of a turn after the stop.
  3. With hand on the near tube the motor is started. The man is slowly pulled to the far tube. Once the stop is approached, the hand is taken off the nearer tube and the man is pulled into the far tube. Slowly pull him above the closed exit hatch.
  4. Open the hatch from the outside and twist the screwed rod to release the man while holding his legs. Slowly pull the man out. The man’s legs are slightly extendible so it is not possible to see my fingers gripping the legs.

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