Introduction

The purpose of a thermal-control system is to maintain all of a spacecraft's components within the allowable temperature limits for all operating modes of the vehicle, in all of the thermal environments it may be exposed to (i.e., those discussed in Chapter 2). To illustrate how thermal control is achieved, this chapter describes some typical thermal designs. While these designs are currently in wide use, they are not the only possible thermal designs for the spacecraft and components examined here, and creative alternative solutions to thermal design problems are always desirable. The designs described in the following discussions should therefore be considered examples only.

Establishing a thermal design for a spacecraft is usually a two-part process. The first step is to select a thermal design for the body, or basic enclosures, of the spacecraft that will serve as a thermal sink for all internal components. The second step is to select thermal designs for various components located both within and outside the spacecraft body. The following sections give a qualitative description of typical designs. For a more detailed discussion of the...