Thermal Control of Spacecraft Mountings and Interfaces: A Review

Heat dissipated in conduction cooled spacecraft components must be transported across the component base plate/spacecraft mounting plate interface preparatory to final radiation to the space sink. Proper engineering requires that this be accomplished in readily predictable ways, with small temperature differentials, using reliable and practical hardware. This paper conducts a review of the subject and provides design guidance. Areas covered are background and general principles; conductance of bare interfaces (or joints) under uniform pressure; conductance of bare bolted joints; thermal/structural analysis; conductance of bolted joints with thermal enhancement fillers. In addition, the review deals with a variety of special mountings, such as honeycomb panels and thermal doublers, and with a number of bolt patterns. The approach taken is that of division of the mounting region into a region near the bolt where contact occurs between the plates, with the remainder a region, lacking contact, governed by lateral conductance. Both for the contact region and the overall region --for bare joints and those filled with a thermal gasket or RTV compound --empirical correlations, test data and/or investigator recommendations are provided for predicting heat transfer coefficients and conductances. Design guidance is provided for both thin rectangular doublers where it is assumed that the additional contact conductance due to the doubler can be ignored, and thick axisymmetric doublers where the additional contact conductance is considered.