Systems Engineering 



EVA Systems 



The work needed to develop EVA systems that can be maintained in orbit is 

 challenging and must be expedited. Suits will have to be maintained on the Space 

 Station, a requirement that cannot be met using present EVA systems. The 

 particular type of system to be developed will be determined according to such 

 parameters as the kinds and amounts of work needed. The more there is to do, 

 the higher the premium on efficient operations. Currently, 6 hours of EVA satellite 

 maintenance have been factored into the guidelines (3). However, EVA operations 

 may be much more rigorous than these guidelines allow. The endurance of 

 astronauts during servicing activities sets the upper limit on how much EVA can 

 be accomplished. One factor limiting astronaut endurance has been suit design. In 

 soft suit technology, higher pressures result in decreased flexibility, particularly in 

 the hands. In hard suit technology joint mobility solutions appear promising, but 

 dexterity problems remain unresolved. 



These photographs illustrate two prototypes of next-generation spacesuits. Vic Vykukal tries out a suit designed at ARC that employs 

 hard-suit technology. At right, Astronaut Jerry Ross wears a hybrid soft/hard suit designed at JSC. The relatively high pressures 

 within these suits alloic astronauts to conduct extravehicular activity without lengthy decompressurization from the atmosphere of a 

 spacecraft. 



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