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An event in which electronic insulation consisting of polytetrafluoroethylene undergoes thermodegradation on the Space Station Freedom is considered experimentally and theoretically from the initial chemistry and convective transport through pulmonary deposition in humans. The low-gravity environment impacts various stages of event simulation. Vapor-phase and particulate thermodegradation products were considered as potential spacecraft contaminants. A potential pathway for the production of ultrafine particles was identified. Different approaches to the simulation and prediction of contaminant transport were studied and used to predict the distribution of generic vapor-phase products in a Space Station model.

It is well known that selection of the pressure/oxygen ratio for a human space habitat is a critical decision for the well-being and mission performance of astronauts. It has also been noted how this ratio affects the requirement for pre- and post-breathing and the type and flexibility of EVA/EHA astronaut suits. However, little attention has been paid to how these issues interact with various mission design strategies. Using the first manned mission to Mars as a baseline mission, we have separated the mission into its component parts as it relates to habitat type (i.e., the Earth-Mars interplanetary vehicle, the ascent/descent vehicle, the base, human rover vehicles, etc.) and have determined the oxygen resupply requirements for each part as they reflect a mission design strategy. These component parts form a matrix where duration of stay, loss of oxygen due to leakage and usage, and oxygen resupply needs are calculated.

The safety of astronauts in habitats beyond Earth has always represented a challenge to the disciplines of environmental health and occupational medicine. The forthcoming long duration missions present new challenges in space environmental health. The space habitat is similar to a small tight building. Both chemical and microbial contaminants have the potential to accumulate in an atmosphere of limited volume and turnover. Microgravity and the absence of convection currents will produce unusual behavior of suspended particles and of fluid and mass transport in the habitat and life systems. The response of astronauts to both toxic chemicals and infective biota may differ from the Earth-based situation. Their physiological status is altered in not totally understood ways in microgravity, and there is the potential of additional stress from solar and cosmic radiation. They will be exposed to a diverse range, concentration and type of potential contaminants.