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Short-arm centrifuge

(January 12, 2003) The short-arm centrifuge subjects an astronaut to conflicting sensory input and is used to study the astronaut's perception of motion. It was part of the Spatial Reorientation Following Space Flight investigation conducted on crewmembers. During space flight, the vestibular organs no longer respond in a familiar way. In particular, when astronauts undergo a linear acceleration (eg, bending their heads forward) while in space, their otoliths are not properly stimulated. This creates a sensory conflict, which must be resolved by the brain to maintain orientation. When they first return to Earth, astronauts are again disoriented because of sensory conflict. They undergo a period of spatial reorientation as their brains reconcile what their eyes see and what their vestibular system senses. Recovery can take anywhere from hours to days depending on the length of the mission. (Source: NASA/Marshall Space Flight Center [Redstone Arsenal, Alabama]. NASA ID: 0300115. Public domain.)