Simulation of Space-Adaptation Syndrome on Earth.

The three Spacelab D-1 Scientist Astronauts were exposed to a 1.5 h centrifuge run in the supine position, resulting in a linear 3 g acceleration. They used their space experience to evaluate their readaptation to normal gravity and compared their observations with 'Space Adaptation Syndrome'. After the centrifuge runs, the vestibular visual system appeared to be modified in a very specific and reproducible manner. Readaptation to the normal 1 g environment took at least 6 h. During this period there was a striking similarity to the astronauts' experience during adaptation to weightlessness in space. Vestibular tests were subsequently performed, which confirmed these subjective findings.