An important problem seen in manned spaceflight is the nausea that appears regularly during the three first days of the flight, and that disappears after five days. Methods of detecting ruptures in electrophysiological signals are studied in order to lower susceptibility to space motion sickness through biofeedback training, and for the early detection of nausea when using extra-vehicular activity equipment. A simulator will allow the subject to control functions of his body and to use biofeedback to control space motion sickness and stress.