CO2 Monitoring in Space Simulations for Future Bioregenerative Life Support Systems

Regulation of carbon dioxide (CO₂) concentration is a key factor in maintaining safety and habitability in isolated environments. Elevated CO₂ levels are known to impair cognitive functions, disrupt physiological homeostasis, and increase long-term health risks for crew members during extended missions in isolation. Although numerous chemical and mechanical methods exist for removing excess CO₂ from enclosed spaces, they can be unreliable due to wear, system degradation, or limited resources. These limitations highlight the need for sustainable life support strategies. Although the main principles are known in general, there is a missing gap regarding the crew composition. In this work, we focused particularly on this parameter to determine how biodiversity in humans, especially circadian rhythms in confined space, affects levels of CO₂ in isolated environments [1].

Data from twelve analog space mission simulations conducted in the AATC habitat, with a total usable area of 57 m², were analyzed to evaluate different operational and crew scenarios. Correlations between environmental and physiological data were taken into account.

The results show that variations in crew size, metabolic activity, and life support system efficiency significantly influence atmospheric stability. The findings provide quantitative guidelines for defining safe operational thresholds, optimizing CO₂ scrubber placement, and developing redundancy strategies within Environmental Control and Life Support Systems (ECLSS). This study contributes to the development of resilient life support architectures for future long-duration crewed missions in isolated environments.