Toxicological evaluation of the Columbia spacecraft

The toxicology procedures developed for the Space Shuttle program to evaluate and eliminate contaminants in the cabin atmosphere characterized, and results from STS missions 1-5 are reviewed. Shuttle maximum-allowable-concentration standards (SMAC) equal to 10-50 percent of those established for normal 40-h work weeks on the ground have been established for a broad range of substances, and outgassing data are employed in choosing spacecraft construction materials. Gases are removed by the atmospheric revitalization system (CO2-removal bed, catalytic oxidizer, and dehumidifier). Whole-gas and adsorbed-gas samples are employed in ground-based and inflight measurements of contaminants: results are presented in tables. A total of 152 substances, of which 64 were well defined, were detected in STS-1-5. Only the toluene contamination on STS-2 (17 ppm compared to the SMAC of 20 ppm) was considered serious.