Summary 



groups living in microgravity for lengthy periods. The most pressing issues for 

 extended human missions, which will offer only limited possibilities for 

 emergency rescue and return to Earth, involve crew/environment interactions, 

 interpersonal interactions, human/machine interface, crew selection, command and 

 control structure, and crew motivation. 



Environmental factors and life support requirements directly relate to both the 

 physiological and psychological well-being of the space crew. The primary 

 concerns in this area include identifying requirements for a regenerative food, air, 

 and water system, developing an environmental monitoring system capable of 

 detecting all possible sources and types of contamination, determining the most 

 workable systems to support EVA operations, and analyzing habitability 

 requirements for extended missions. 



The development of a bioregenerating life support system is especially challenging. 

 NASA's Controlled Ecological Life Support Systems (CELSS) Program focuses on 

 combining biological and physicochemical processes to provide food, air, and 

 water by recycling materials inside the spacecraft. Ground-based research indicates 

 that such a system is feasible. The behavior of plants in space, however, is not 

 well understood. 



Operational Medicine considers the health care of astronauts, particularly during 

 long-duration missions. The most important operational issues include the 

 development of requirements for the Health Maintenance Facility (HMF), 

 definition of medical requirements for a Crew Emergency Return Vehicle (CERV), 

 development of a data base for astronaut health records, and establishment of 

 training programs for inflight medical specialists. 



Recommendations: In addressing the ground- and space-based research needed 

 to resolve the outstanding issues pertinent to human space missions of extended 

 duration, NASA should: 



• Immediately expand its program of ground-based research to resolve the 

 outstanding questions about physiological deconditioning, radiation exposure, 

 potential psychological difficulties, and life support requirements that may limit 

 stay times for personnel on the Space Station and more extended missions. 



• Plan an orderly, phased introduction of advanced life support and EVA 

 technology into future manned space systems. 



• Design and build a suite of variable-gravity facilities for life sciences research. 



• In allocating payload and support resources for the Space Station, give first 

 priority to life sciences research that will make human missions of extended 

 duration possible. 



• Take a number of steps, including the following, to ensure crew health and 

 safety on the Space Station and missions of longer duration: include a physician 

 among the crew, develop a Crew Emergency Return Vehicle to allow transport of 

 crew members to Earth in urgent situations, and develop the capabilities of the 

 Health Maintenance Facility for use on a possible human mission to Mars. 



