Quantum Cascade Laser System for Monitoring Ammonia and Formaldehyde

We propose a novel, infrared sensor for continuous monitoring of trace contaminants in spacecraft air. Our approach takes advantage of a new class of mid-infrared diode lasers and uses high sensitivity optical methods to achieve fully-automated sensors capable of long term, space-borne operation. Optical methods provide high sensitivity, rapid response, and freedom from false alarms. Extended space flights, including missions on board the International Space Station, have stringent requirements on environmental monitoring instruments: low power draw, low weight, and ruggedness plus fully automated, self-calibrating, and maintenance-free operation. Sensors must achieve high sensitivity because NASA's specifications for Spacecraft Maximum Allowable Concentrations (SMACs) are typically an order of magnitude lower than standards set by regulatory agencies for terrestrial environments. Our approach can meet all of the requirements identified above for space-borne sensors. The proposed work emphasizes in situ detection of ammonia and formaldehyde -- two compounds that are not easily quantified using traditional sampling and analysis methods -- and complements ongoing work at Southwest Sciences on hydrogen cyanide detection.