Introduction

This chapter deals with the thermal design, analysis, and performance of a wide variety of spacecraft mechanical interfaces, as well as thermal predictive methods for use with those interfaces. Heat removal from electronic units is a foremost spacecraft concern, and thus the problem of developing an optimal conductive interface between unit baseplate and spacecraft mounting is critical. The elements of this very difficult problem must be addressed sequentially at increasingly higher levels of complexity: the engineer needs to consider the effects of uniform pressure between plates in vacuum, the use of bolts or screws to join plates, the effects of fluid in the gap between plates, and the use of interface fillers. The interface problem is compounded by structural and thermal hardware, including honeycomb mounting panels, heat pipes, and thermal doublers. For problems such as this, combined thermal and structural analysis is an important design and evaluation tool. Some thermal interfaces must be compliant rather than rigid; others must reduce and minimize rather than enhance heat transfer. Still others involve composite or polymer materials. In addition, some interfaces must transfer heat across mobile bearings. All of these issues are addressed in this chapter, with the object of providing practical design and analysis aids, performance predictions, and guidance to the practicing spacecraft thermal engineer. Chapter 16 contains a more detailed discussion of the theoretical models of thermal contact resistance...