William C. Schneider, D.Sci. 



Chairperson 



Gerald P. Carr, P.E., D.Sci. 

 Michael Collins 

 Peter B. Dews, M.D. 



Lauren Leveton, Ph.D. 



Staff Associate 



Crew Factors 



Within the next decade, NASA will plan enterprises that place small groups of 

 humans in space for extended periods of time. The success of extended missions 

 will require a thorough knowledge of how to establish conditions that enhance 

 human capabilities for living and working in space for prolonged periods of 

 isolation and confinement. This paper examines the major issues associated with 

 crew factors, particularly those issues associated with long-duration space flight: 

 crew/environment interactions, interpersonal interactions, human/machine 

 integration, crew selection, command and control structure, and crew motivation. 



Several assumptions are made about the characteristics of groups assigned to long- 

 duration missions in space. Crew size will most likely be small, with fewer than 

 10 crew members. Mission lengths will vary, but Space Station crew rotations of 

 60 to 180 days are being proposed, while a Mars mission will require isolation and 

 confinement for a 1- to 3-year period. In addition, many of the missions under 

 consideration — Mars, a lunar base, and even the Space Station — entail only a 

 limited possibility of emergency rescue and return to Earth. 



For the crew, long-duration space flight, such as on the Space Station and future 

 missions, will require separation from customary physical and social environments 

 and confinement within a highly limited and sharply demarcated environment (1). 

 This isolation and confinement, which is experienced in some similar ways by 

 submarine crews and Antarctic field research teams, produce stress, which can 

 increase as the mission lengthens. The stress, in turn, can result in boredom, 

 depression, irritability, increased anxiety, disturbed sleep, fatigue, hostility, and 

 lowered motivation (2,3,4). These symptoms reduce crew effectiveness and 

 productivity. 



Problems are now being recognized about the ways in which available space 

 capsules and systems affect human capabilities to perform effectively within a 

 small, confined, and isolated group in extended microgravity conditions. 

 Preliminary reports from long-duration Soviet missions are disquieting. It is 

 significant that concerns are being expressed by senior NASA administrators who 

 are not themselves life scientists. The expressed concern is no longer only about 

 physiological survivability, but also about the environment and systems needed for 



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