HIGH-TC THERMAL BRIDGES FOR SPACE-BORNE CRYOGENIC INFRARED DETECTORS

Several space-borne infrared detectors require cryogenic temperatures for successful operation. As a result, mission durations are substanti ally limited due to cryogen evaporation. The electrical leads connecti ng the detectors to the amplification electronics comprise a significa nt portion of the heat load on the dewar (i.e., 20% for some systems). Currently, manganin wires are used for these connections, due to the alloy's low thermal conductivity at cryogenic temperatures. However, r eplacement of these leads with high Tc materials would result in a sub stantial reduction in thermal loss, translating into approximately 10- 15 % enhancement in mission lifetime. The potential for using the hig h-Tc materials as thermal bridges to replace the manganin connections is currently under investigation at NASA-LaRC.