These vestibular problems in the absence of gravity..].

Timsit C

For a few years, more and more astronauts complain to endure space motion sickness during the two or three first days of their mission. This is due to the repetition of shifting and sudden head movements, which becomes possible by the increasing of volume of the new space stations. To avoid that payload specialists onboard be obliged to renounce to conduct planned experiments, it has been necessary to find effective solutions to detect by ground based tests the candidates sensitive to space motion sickness and perfect therapeutic means able to avoid unexpected arrival of these symptoms, and even to treat them. The best results are undeniably obtained by the "Biofeedback" and the "tolerance" training, but we base wide hopes on ginger roots and on tolerance with sensorial deprivation lockers. However, we must not disregard the trigger action of emotional factors and anxiety in space motion sickness. The European mission SPACELAB-1 has been marked by the display of a caloric nystagmus during the vestibular experiments in weightlessness. If no explanation is given to this phenomenon, it will be necessary to call in question the role of the thermal convection described by Barany in the appearance of the caloric nystagmus