Description: The Compound Specific Analyzer - Combustion Products is used on the International Space Station as a warning monitor of smoldering or combustion events and, after any fire event, to indicate that toxic gas levels have subsided for safe re-entry of the crew to the affected area. This monitor is being phased out of service. Southwest Sciences Inc. proposes to develop a replacement laser-based sensor using wavelength modulation spectroscopic absorption. This device would be capable of real-time measurements of the four most important gases of interest at concentration levels relevant to pre-combustion events and with a one second response time. This battery-operated device would be hand-held, use very little electrical power, and have a multi-year lifetime without the need for consumables, re-calibration, or maintenance, in contrast to the currently-used sensor. The Phase I research would perform a trade study and then test the most promising opto-mechanical designs for making simultaneous measurements of the four gases in a single optical cell with a minimal number of lasers. It would also demonstrate the ability to make multiple gas measurements over a wide range of concentrations using a single spectral scan. This work will allow us to design, test and build a prototype sensor in Phase II.

Benefits: Successful development of an integrated, robust fire detection sensor will allow NASA to adopt a high-reliability system for detection of smoldering and/or fires in the International Space Station and other manned spacecraft. Such systems will become more important as we begin extended-duration flights to the Moon and Mars. The same gas sensing platform also could be used for meeting the needs for a multi-gas sensor for monitoring cabin air, gas regeneration, and life support systems. Longer term NASA applications could include adaptation of the instrument for measurements of the componenets of planetary atmospheres, using space-qualified electronics and further ruggedization of the mechanical and thermal design. Applications could include measurements of atmospheric gases on Mars (e.g. water vapor, methane), Venus (SO2), Titan (methane, ethane), or other future planetary missions.

This same gas sensor could also be used on a wide variety of platforms (e.g. aircraft, balloons, ground-based network, etc.). Since it is designed for long-term operation with minimal attention and maintenance, it is expected to find use in validation of remote data sensing satellites and for in situ measurements in atmospheric research. Other Governmental and commercial needs include the development of fire sensors for other agencies and applications, such as in submarines or aircraft, as well as compact, general purpose fire and industrial gas sensors.