Description: Gas sensing in a space environment is difficult. Commercial off the shelf (COTS) devices are not qualified to measure multiple gas constituents in various space platforms. This project proposes to execute an SBIR Phase III in partnership with Vista Photonics, Inc. to evaluate and mature a high-performance infrared laser sensor technology for three distinct, but related prototype gas-sensing architectures. The technical approach combines the proven high-performance of wavelength modulation spectroscopy (WMS) with the long wavelength interband cascade laser (ICL) optical sources, distributed feedback (DFB) and established vertical cavity surface-emitting laser (VCSEL) technology. The approximately three-year project will take lessons learned from several SBIR Phase I, Phase II, and program-funded Phase IIe and III activities including the Multi-Gas Monitor (MGM) major constituents technology demonstrator, the advanced space suit portable life support system (PLSS) CO2 sensor, and the several projects targeting combustion product monitoring. The ultimate goal will be to advance each platform to a stage whereby it can be poised for incorporation into a flight demonstrator for each NASA program, namely the AES advanced PLSS (APLSS) gas sensor, the In-Flight Contingency Monitor (IFCM) for Orion, and the Post-Landing Contingency Monitor (PLCM) for Orion. All devices will simultaneously be developed based on similar optical detection techniques and utilizing a core electronics architecture that will be radiation tolerant.