 It is well documented that a few days stay in space induces a change in the vestibular-ocular reflex reflecting a reinterpretation of sensory inputs following the disappearance of gravity. If the change of eye reflexes actually the result of a reinterpretation of sensory input, the investigators should also expect to see an alteration of the vestibular-cardiovascular reflexes. The modification of these reflexes may modulate the carotid baroreflex and thus participate in the post-flight cardiovascular deconditioning. 