Identifying Atmospheric Monitoring Needs for Space Station Freedom

The monitoring needs for Space Station Freedom were identified by examining: the experiences of past missions; ground based tests of proposed life support systems; a contaminant load model; metabolic production from an 8-person crew; and a fire scenario. Continuous monitoring is recommended for components critical for life support, and that intermittent analysis be provided for all agents that may exceed one-half the Spacecraft Maximum Allowable Concentration (SMAC). The minimum monitoring effort recommended includes continuous monitoring for: nitrogen (N₂), oxygen (O₂), carbon dioxide (CO₂), carbon monoxide (CO), water (H₂O), hydrogen (H₂), methane (CH₄), non-methane hydrocarbons, aromatic hydrocarbons, refrigerants, and halons. Information on over 70 compounds is presented on the rationale for monitoring, the frequency of analysis, and concentration ranges.