Pressure-Optimized Optical Breath Gas Analyzer for Portable Life Support Systems

Optical detection of gaseous carbon dioxide, water vapor (humidity), and oxygen is desired in Portable Life Support Systems (PLSS) incorporating state-of-the-art CO2 scrubbing architectures. Earlier broadband detectors are nearing their end of life, and recent advances in laser diode technology make replacement of earlier technology compelling. The function of the infrared gas transducer used during extravehicular activity (EVA) in the current spacesuit is to measure and report the concentration of CO2 in the ventilation loop. The next-generation PLSS requires next-generation CO2 sensing technology with performance beyond that presently in use on the Shuttle/International Space Station extravehicular mobility unit (EMU). Accommodation within spacesuits demands that optical sensors meet stringent size, weight, and power requirements. A sensor is required that is compact, low power, low mass, has rapid sampling capability, can operate over a wide pressure range, and can recover from condensing conditions.