Space Station EVA Systems Trade-Off Model

A procedure has been developed to predict program costs for conducting extravehicular activity from Space Station. Space Transportation System EMU historical data has been used as a basis for performing the development and production phases. Complexity and risk factors are used to compare costs for various configuration options. Operations costs utilze ground, launch, and on-orbit penalty factors derived from operations analysis and EVA hardware configuration and performance data. Scar costs are based upon weight and flight or ground personnel overhead factors. The model compares nine separate configurations and extends from FY 1987 through the first ten years of Space Station operations. A spreadsheet format together with a grouping of the program constraints promotes rapid recalculations when new input data is desired.