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Torso Rotation

Canada's Torso Rotation Experiment (TRE) was sponsored by the Canadian Space Agency; Dr. Douglas Watt of McGill University in Montreal was the Principal Investigator for the TRE.

The voluntary act of fixing the head to the torso-as if wearing a neck brace-is called torso rotation. Many astronauts adopt this torso rotation position during spaceflight. Deliberate torso rotation on Earth usually leads to motion sickness; inadvertent torso rotation in space should have the same effect. At the root of the problem are tiny, poorly understood balance organs in the inner ear called otoliths. They usually keep us upright and balanced. But if suppressed too long, they can cause the dizziness and nausea symptomatic of motion sickness.

During the mission, astronauts wore a head and chin device, like a miner's lamp, to monitor movements of the eye, head and upper torso in crew members as they performed routine activities and to determine if the normal pattern of eye/head/body coordination is changed as a result of prolonged exposure to weightlessness. The head unit was connected to a backpack that contained a computer for acquiring and storing data. Four astronauts, including Bob Thirsk, took part in the study.

If inadvertent torso rotation is adopted by astronauts, they could be trained to avoid this practice. On Earth, similar suppression of the vestibular system by torso rotation may be a major contribution to many kinds of motion sickness experienced in cars, buses, planes and boats. If so, this information may provide a new perspective on the problem and may suggest methods of preventing the disorder.