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MORE THAN HALF of all people who have traveled in space have experienced some form of motion sickness. This is no surprise to many researchers, given that the vestibular system, so finely tuned to respond to gravitational forces and visual cues on earth, is suddenly stripped of these familiar inputs in space.
What has fascinated many scientists, however, is that these unpleasant symptoms vanish after a few days in space. Without any conscious effort, astronauts make behavioral changes that reduce their sensations of disorientation and motion sickness.
For example, if astronauts want to view an object in their peripheral vision, rather than fixating on the object and then moving their head, as they would do on earth, they will unconsciously rotate their body with their head and then fixate on the object after it comes more centrally into view.
Coming Down to Earth
But not only does the astronaut's vestibular
Randall T. Space Motion Sickness, Hearing Loss, and Bifocals Meet Their Match In Vestibular System's Plasticity. JAMA. 1991;266(10):1335-1336. doi:10.1001/jama.1991.03470100027009