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ASDA was developed to evaluate the heat and mass transfer characteristics of advanced pressurized suit design concepts for use in low pressure or vacuum planetary environments. The model incorporates a generalized 3-layer suit, constructed with the Systems Integrated Numerical Differencing Analyzer '85 (SINDA '85), with a 41- node FORTRAN routine that simulates the transient heat transfer and respiratory processes of a human body in a suited environment. User options for the suit include a liquid cooled garment, a removable jacket, a CO2/H2O permeable layer and a phase change layer. The model also has an option to isolate flowing oxygen in the helmet from stagnant or flowing gas in the torso and limbs. Options for the environment include free and forced convection with a user input atmosphere, incident solar/infrared fluxes, radiation to a background sink and radiation and conduction to a surface. Results from a study of Mars suit concepts will also be presented.

An Extravehicular Mobility Unit (EMU) Portable Life Support Subsystem (PLSS) has among its primary functions requirements to remove metabolically generated heat and respiratory byproducts to maintain an atmosphere which is both physiologically safe and comfortable for the Extravehicular Activity (EVA) crew person. The EMU thermal control system interacts with the crew member through the Liquid Cooling and Ventilation Garment (LCVG), which circulates the ventilation gas to remove carbon dioxide, humidity, and trace contaminants, and the cooling water to remove metabolically produced heat. To maintain thermal comfort, the crew member may vary the LCVG inlet water temperature. The thermal interaction between the EMU and the crew member is very complex and highly dependent upon the individual crew member's cooling preferences and the exterior environment.