Compact Optical Carbon Dioxide Monitor for EVA

Breath respiratory species measurement during extravehicular activity (EVA) or intravehicular activity (IVA) is a demanding application for optical sensing techniques. Yet optical techniques offer many advantages including high-precision, fast response, and strong species selectivity. Accommodation within spacesuits demands that optical sensors meet stringent size, weight and power requirements. The next generation of emerging NASA Constellation spacesuits requires a new generation of CO2 sensing technology with performance beyond that presently in use on the Shuttle/ISS extravehicular mobility unit (EMU). Vista Photonics proposes to develop rugged, compact, low-power optical sensor prototypes capable of selectively determining carbon dioxide at EVA-relevant concentrations suitable for Constellation Configuration Two Spacesuits. Design variations include dual CO2 sensors for feeding into astronaut metabolic rate determination and simultaneous humidity measurement for automated suit thermal control. The enabling technology for meeting stringent NASA mission requirements is a new low power infrared optical source that provides the high-sensitivity of established optical absorption detection techniques.