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30 September 1994 Long-term and thermal instability of carbon/carbon composite
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Very stringent dimensional stability requirements for metering rods of the NASA/Jet Propulsion Laboratory Cassini spacecraft NAC (Narrow Angle Camera) were the driving forces to select and conduct dimensional stability tests of several dimensionally stable materials. Carbon/carbon composite samples, among the other selected materials, were tested at the University of Arizona Dimensional Stability Laboratory. Fabry-Perot laser- interferometric techniques were used to measure dimensional changes to accuracies in the 0.01 ppm range. Coefficient of thermal expansion (CTE), thermal hysteresis and temporal stability test results at 27.5 degree(s)C and 38 degree(s)C are reported here. The test results indicate that this carbon/carbon composite material, made from 2D fabric and pitch base fiber, appears to be the best among all tested nonmagnetic materials. A CTE of -1.5 ppm/$DEGC over the temperature range of -48 degree(s)C to +52 degree(s)C is reported here along with a temporal stability <EQ 1 ppm/year. However, demonstration of a relatively high thermal hysteresis within the temperature range of -48 degree(s)C to +52 degree(s)C was unexpected and a cause for further evaluation. A possible procedure to resolve this issue and an alternate carbon/carbon material design are also suggested here.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Witold M. Sokolowski, Kyle A. Brown, Timothy P. O'Donnell, and Stephen F. Jacobs "Long-term and thermal instability of carbon/carbon composite", Proc. SPIE 2263, Current Developments in Optical Design and Optical Engineering IV, (30 September 1994);

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