New sensor technology is required to face the challenging tasks associated with future space exploration involving missions to the Moon and Mars. The safety and well-being of the crew critically depends on early detection of threats as well as maintaining stable and acceptable conditions in the crew habitat. Prototype sensor technology being developed on this project addresses both aspects. Carbon monoxide formation is a reliable indicator of evolving fire threats and this gaseous combustion product allows rapid early detection. A highly sensitive carbon monoxide sensor is proposed for early, fast and unfailing fire detection. Current fire detectors are prone to fatigue and have insufficient sensitivity, selectivity and time-response. Smoke detectors cannot detect early stages of combustion and become unreliable if exposed to dust particulates. A second project part addresses habitat air composition monitoring. A multi-species device will be developed to simultaneously monitor oxygen, carbon dioxide and moisture. The optical sensors developed on this project have unique features like fast response, high precision and strong species selectivity. Design criteria such as small footprint, low weight, low power consumption as well as internal calibration and continuous sensor health monitoring will be implemented to provide spaceflight optimized sensors. An absorption approach using modulation techniques implemented on size optimized platforms will be applied.