Nano Sensors for Gas Detection in Space and Ground Support Applications

Personnel living in a space environment as well as technicians and engineers preparing spacecraft for launch can potentially be exposed to small amounts of hazardous gases. It is therefore important to be able to detect, identify, and quantify the presence of a gas, especially when its presence could lead to a fatal situation. The use of small and sensitive sensors can allow for the placement of these devices over a large area, thus allowing for a more precise and timely determination of a gas leak. ASRC Aerospace and its research partners are developing nano sensors for the detection of various gases, including but not limited to: H₂, NH₃, N₂O₄, hydrazine, and others. Initial laboratory testing has demonstrated the capability to detect the gases in concentrations lower than parts per million. Testing and development is continuing to improve the response and recovery times, and to increase the sensitivity of the devices. Different coatings and electrodes are currently being evaluated to determine the optimum configuration for the detection of a variety of gases. The small footprint of the nano sensors allows for several devices, each responsive in a different way to different gases, to be placed into a single substrate. Multiple devices embedded into a single substrate results in increased reliability and in a decrease in the need for periodic calibrations. The use of different coatings will result in a small electronic nose capable of distinguishing between different gases. A multi-channel signal conditioner amplifier built on a small multi chip module is used to process the output of the sensors and to deliver a signal that can be remotely monitored. All the data is digitized and transmitted over the same cable pair used to power the amplifier. Multiple outputs can be connected to a single cable pair in order to minimize the added weight and expense associated with cabling in a spacecraft. The sensors will be run through a qualification process to evaluate their suitability for space applications. We are expecting to have fully functional sensors available for initial field deployment and testing by the end of the year 2006. ASRC Aerospace is the prime contractor at the Kennedy Space Center for the University Affiliated Technology Development Contract (USTDC).