Crezv Factors 



The work, rest, and recreation 

 schedule is a crucial factor in 

 minimizing performance 

 degradation. While perform- 

 ance progressively deteriorates 

 as a function of flight length 

 and rest never completely 

 restores performance during a 

 long-duration mission, a proper 

 work/rest schedule can mini- 

 mize and retard this process 

 (18,19). 



Time management and the 

 sequencing and arranging of 

 interactions and activities are 

 fundamental to crew compat- 

 ibility and motivation. An 

 important aspect of this is crew 

 workload. Workload problems 

 have been evident throughout 

 the manned space program 

 (12). Overload leads to dis- 

 satisfaction and to decreased 

 performance, which in turn 

 can compromise and endanger 

 a mission. Underload, or too 

 little work, also causes diffi- 

 culties, for it can affect crew 

 morale negatively and waste 



valuable opportunities. Important questions include: What workloads are required 

 for extravehicular activity (EVA) operations? Are the requirements too demanding? 

 What kinds of tasks and activities can be designed to keep crew members active 

 and highly motivated during long-duration missions? 



Payload Specialist Ulf Merbold works out with the Spacelab 1 exercise facility. 



As noted earlier, the crew will spend more time monitoring increasingly 

 automated and complex systems, which can result in boredom and frustration 

 and in a significant performance problem. Measures should be developed to 

 provide relief from highly monotonous and routine tasks. Task design and 

 assignment should be studied carefully to avoid problems of workloads that are 

 too demanding or overly monotonous. In addition, research is needed to develop 

 interactive work programs between the crew and the scientific and technical 

 apparatus of the mission. The activities must approximate real tasks and be 

 skillfully programmed so that the interactions between operator and machines are 

 a key factor in sustaining performance. Research is also required in crew fatigue, 

 particularly the relationship between fatigue and decreased performance and the 

 types and scheduling of tasks to circumvent problems associated with fatigue. 



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