Leading fire signatures of spacecraft materials: Light gases, condensables, and particulates

The primary goal of this research is to provide recommendations for the eventual development of more effective and efficient fire sensors to be installed in space vehicles and habitats. An entirely new ground-based testing facility that generated fire signatures was developed to perform the combustion and pyrolysis experiments of eight different practical spacecraft materials. The flaming and smoldering of polymers approved by the National Aeronautics and Space Administration (NASA) generate three types of residues: condensables, light gases, and particulates. The residues were characterized by gas chromatography (GC), Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). The analysis was interpreted as a function of oxygen concentration, temperature, and flow direction. Key findings are that the combustion of some materials such as Kevlar and cotton can only be identified by light gases, while the combustion of other materials, such as silicone and melamine, is best detected using a particulate-specific sensor. The implications during a fire event, its suppression, astronaut health in post-event cleanup as well as material recommendations are briefly discussed.