The Neurolab shuttle mission (STS-90) was launched on April 17th 1997 and returned to Earth on May 3rd. The 16-day flight was dedicated to neuroscience research, in particular the effect of microgravity on the nervous system. Included in the Spacelab cylinder carried in the payload bay was a human short-arm centrifuge capable of generating a centripetal linear acceleration of 1-g along the subject's interaural or head vertical axes, in effect the first test of artificial gravity during manned flight.
Click here to see video of the centrifuge in action
The four payload crewmembers were exposed to centrifugation before, during and after flight, and binocular eye movements were measured using a video-based technique. The response of the otoliths, the portion of the vestibular (balance) system that measures linear acceleration, was determined from reflex eye movements (the linear vestibulo-ocular reflex). Results from previous missions had suggested that the sensitivity of the otoliths to low-frequency linear acceleration decreased following spaceflight, but our data showed that otolith-ocular reflexes were maintained both during and after the mission. One possibility is that intermittent exposure to artificial gravity, in the form of the 1-g centripetal acceleration generated during centrifugation in-flight, may have acted as a countermeasure to deconditioning of otolith-ocular reflexes.
Results from the Neurolab experiments are included in the Publications section. Supported by NASA grants NAS 9-19441 (B. Cohen PI, S. Moore Co-I) and NCC 9-128 (S. Moore PI).
