Psychological effects of space flight.

P S Y C H O L O G I C A L EFFECTS of space flight may arise from central nervous system changes produced by physiological stress or from emotional reactions to various aspects of the flight. Since either of these may disrupt crew performance or impair the health of crew members, potential sources of adverse psychological change must be identified and steps to control it must be taken. Man's behavior in space may be affected by any stressor which alters the functions of his central nervous system. The effects of acceleration t heat, noise, and vibration, problems with food and oxygen supply or waste disposal, radiation, and toxic fuels should all be studied psychologically as well as physiologically. It is apparent, however, that changes induced by these conditions are minimized by planning the vehicle and mission to keep stress levels as low as possible, by careful selection of crew members, and by training and conditioning to improve tolerance. Responsibility for this lies with physiologists and others who are primarly concerned with these areas. At the same time, it must be remembered that psychological variables may be sensitive measures of the intensity of physiological stress. It is consequently helpful for psychologists and psychiatrists to be involved in planning, monitoring, and follow-up studies of space missions and related on-the-ground experiments. The other effects of space flight are produced by its symbolic implications the aspects of a mission which alter behavior because of their meaning to the traveler. These cannot be studied as directly and precisely as the effects of objectively describable environmental changes.