The role of manned extravehicular activity in reducing the cost of space payloads

Substantial cost savings and performance improvement will result by the use of Extravehicular Activity (EVA) to supplement or replace automation. Taking an all-pallet version of Langley Research Center's Advanced Technology Laboratory payload as an example, $54.5 million should be saved by EVA over automation, considering deployment and stowing only. Additional savings should accrue when reduced-reliability equipment (where permitted) is substituted for high reliability equipment and EVA is used for repairs. More comprehensively, launch and operation costs could also be reduced by elimination of the need to return to the ground for repairs; and production spending might be reduced when an entire vehicle was saved by manned EVA repair not feasible via automation. Potential disadvantages include increased cost due to development and manufacture of EVA equipment, payload provisions to enable EVA interfaces, training, orbiter modification, and prevention of EVA-caused contamination. Possible applications to the Space Shuttle missions are discussed.