Fire Suppression Technology in Human-Crewed Spacecraft -A Trade Study

This paper discusses the current state of technology in reduced gravity fire suppression. The focus is on the unique issues associated with the CEV and future spacecraft including operation in reduced gravity and enriched oxygen ambients. Inert gas agents such as carbon dioxide, nitrogen and helium have different minimum extinguishing concentrations (MEC) in microgravity compared to normal gravity; in most instances the MEC in microgravity being higher than in normal gravity. This means that designs based on terrestrial standards will not offer the same factor of safety in microgravity. The results also show that the MEC is a strong function of ambient oxygen concentration in reduced gravity (as expected).