Nanoengineered Hybrid Gas Sensors for Spacesuit Monitoring

Extravehicular Mobility Units (EVU) are the necessary to perform elaborate, dynamic tasks in the biologically harsh conditions of space from International Space Station (ISS) external repairs to human exploration of planetary bodies. The EVUs have stringent requirements on physical and chemical nature of the equipment/components/processes, to ensure safety and health of the individual require proper functioning of its life-support systems. Monitoring the Portable Life Support System (PLSS) of the EVU in real time is to ensure the safety of the astronaut and success of the mission.N5 Sensors will demonstrate an ultra-small form factor, highly reliable, rugged, low-power sensor architecture that is ideally suited for monitoring trace chemicals in spacecraft environment. This will be accomplished by our patent-pending innovation in photo-enabled sensing utilizing a hybrid chemiresistor architecture, which combines the selective adsorption properties of multicomponent (metal-oxide and metal) photocatalytic nanoclusters together with the sensitive transduction capability of sub-micron semiconductor gallium nitride (GaN) photoconductors. For the phase I project we will demonstrate oxygen, carbon dioxide, and ammonia sensor elements on a single chip. Innovative GaN photoconductor design will enable high-sensitivity, low power consumption, and self-calibration for the sensor current drift. The multicomponent nanocluster layer design enables room-temperature sensing with high selectivity, resulting in significant power saving and enhanced reliability. The fabrication of the sensors will be done using traditional photolithography and plasma etching. The nanocluster functionalization layer will be deposited using sputtering methods. The sensor testing will be carried out to determine sensing range, sensitivity, selective, and response/recovery times.