Development of a Test Protocol for Spacecraft Post-Fire Atmospheric Cleanup and Monitoring

Fire detection, post fire atmospheric monitoring, fire extinguishing, and post fire atmospheric cleaning are vital components of a spacecraft fire response system, Preliminary efforts focused on the technology evaluation of fire detection, post fire atmospheric monitoring and post fire cleanup systems under realistic conditions are described in this paper. While the primary objective of testing is to determine the performance of a smoke mitigation filter, supplemental evaluations measuring the smoke-filled chamber handheld Commercial Off The Shelf (COTS) atmospheric monitoring devices (combustion product monitors) are conducted. The test chamber consists of a 1.4 cubic meter (50 cu. ft.) volume containing a smoke generator. The fuel used to generate the smoke is a mixture of polymers in representative quantities of materials involved in a circuit board fire — this was labeled as a typical spacecraft fire as suggested by Sribnik, et al.¹ Two fire conditions were examined, termed a no flame and flame. No Flame events are produced by pyroiyzing the fuel mixture in a quartz tube furnace with forced ventilation to produce a white, lingering type of smoke, Flame events are produced by igniting the smoke at the outlet of the tube furnace producing combustion characterized by a less opaque smoke with black soot. Findings are that carbon monoxide is a major indicator of each fire as determined by electrochemical sensor measurements. Acid gas measurements were recorded but cross interferents are currently uncharacterized. Electrochemical sensor measurements and sample acquisition techniques from photoacoustic sensors are being improved. Overall, this research shows that fire characterization using traditional analytical chemistry techniques is required to verify measurements recorded using COTS atmospheric monitoring devices.