SiC-Microhotplate Sensor Array for Spacecraft Environmental Monitoring

A critical need exists for sensing and monitoring of spacecraft environments since the accumulation of toxic gases poses a serious threat to human health and systems integrity. Contaminants of particular concern include formaldehyde, hydrogen cyanide and ammonia which have a maximum allowable concentrations of 40 ppb, 1 ppm and 10 ppm respectively. Present technologies for monitoring these gases at these levels are inadequate for spacecraft applications, as they all suffer from some combination of (a) large mass, (b) high power requirements (c) low sensitivity, (d) poor selectivity, (e) poor long-term stability and (f) high maintenance. Boston MicroSystems, Inc. proposes to develop a Spacecraft Environmental Monitor which overcomes these limitations, by integrating semiconducting metal oxide (SMO) conductometric thin films onto its miniaturized low mass and ultra-low power SiC microhotplate gas sensor platform. The proposed Spacecraft Environmental Monitor will provide a highly sensitive, selective, and stable instrument for precise measurement of a wide variety of volatile organic compounds, as well as CO, H2, hydrazine and NOx. Boston MicroSystems? unique and mechanically robust SiC microhotplate design eliminates the mechanical and chemical degradation responsible for long-term drift in sensor response as is characteristic of traditional microhotplate conductometric gas sensors.