In addition to these identified NASA applications, the proposed sensor system could be used in a wide range of commercial applications. The ability of the proposed system to uniquely identify large numbers of individual sensors, combined with a hand-held interrogation system, could make this type of approach useful for inventory purposes where knowing the temperature history of a set of products is significant. The temperature sensing capability could be applied to the monitoring of containers used for shipping products internationally. For such an application, a small, battery powered interrogation system could be included inside the packaging. This system could contain memory capable of logging the history of the container, so that upon delivery the recipient could download the data and see if the shipment was maintained at appropriate temperatures during transit. The ability to identify unique shipping containers has also been discussed recently in light of homeland security issues. If such a system could be made to tell the interrogator if the packaging had been tampered with, it would provide U.S. inspectors with a powerful tool to scan incoming shipments for potentially hazardous containers. The primary NASA application for the proposed sensor system would be the distributed wireless measurement of temperature, within cryogenic (and other) storage tanks, and as DFI for large area composite validation testing in facilities such as the thermal vacuum chamber (Plumbrook Facility). Numerous small, passive, lightweight sensors could be mounted in locations throughout the area to be monitored, and a central RF interrogation system could quickly scan through the sensors, providing rapid temperature distribution information. Due to wireless operation of the sensors, applications in tanks would require only one tank feed-through for the antenna, minimizing heat-loss pathways.
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