Cabin Air Quality Dynamics On Board the International Space Station

Spacecraft cabin air quality is influenced by a variety of factors. Beyond normal equipment offgassing and crew metabolic loads, the vehicle’s operational configuration contributes significantly to overall air quality. Leaks from system equipment and payload facilities, operational status of the atmospheric scrubbing systems, and the introduction of new equipment and modules to the vehi- cle all influence air quality. The dynamics associated with changes in the International Space Station’s (ISS) configuration since the launch of the U.S. Segment’s laboratory module, Destiny, is summarized. Key classes of trace chemical contaminants that are important to crew health and equipment performance are empha- sized. The temporary effects associated with attaching each multi-purpose logistics module (MPLM) to the ISS and influence of in-flight air quality on the post-flight ground processing of the MPLM are explored. INTRODUCTION DESIGN CONSIDERATIONS A crewed spacecraft cabin is considered the ”ultimate in tight building design”.[l] As with a tight building, low leakage rates, a small specific volume, and the use of a host of advanced materials of construction contribute to conditions that may lead to unhealthy air quality if appro- priate care is not exercised during the design, construc- tion, and operation of a spacecraft. For this reason, designing for cabin air quality must balance