Measurement of Apparent Thermal Conductivity of Multilayer Insulations at Low-Compressive Loads

Abstract

Four multilayer insulations, selected for potential applications on future multimission space vehicles, have been evaluated. The effective thermal conductivities of the insulations were determined at a minimum of four compressive loads between 104 and 10'1 psi. The equivalent thermal conductivity of one of the test specimens was determined at two compressive loads with interstitial helium gas pressure of ~3 and 1.0 torr. Particular attention was given to techniques for minimizing errors in obtaining thermal conductivity data. Double Goldized Kapton/Dacron B4A composite, displayed the lowest thermal conductivity and kp product of the four composites evaluated at compressive loads below 10 2 psi. Thermal conductivity of the multilayer insulations tested was insensitive to small changes in mechanical loading at 1.0 torr interstitial gas pressure, but became increasingly more sensitive to mechanical loading as the interstitial gas pressure was reduced.