固液相变材料（PCM）是一种受欢迎的航天器被动热控制方法，适用于轨道热通量入射或机载设备波动较大的情况。 PCM热控制系统由一个容器组成，容器内装有能够发生相变的物质。当航天器表面温度升高时，PCM通过熔化吸收多余的热量。如果温度降低，则PCM可以通过固化提供热量。 许多类型的PCM系统在航天器中用于不同类型的热传递控制。 本部分介绍了相位控制材料的特性和性能。 还描述了现有的PCM系统。购买本文件时可获得的所有当前修订均包含在购买本文件中。

Solid-liquid phase-change materials (PCM) are a favoured approach to spacecraft passive thermal control for incident orbital heat fluxes or when there are wide fluctuations in onboard equipment. The PCM thermal control system consists of a container which is filled with a substance capable of undergoing a phase-change. When there is an the increase in surface temperature of spacecraft the PCM absorbs the excess heat by melting. If there is a temperature decrease, then the PCM can provide heat by solidifying. Many types of PCM systems are used in spacecrafts for different types of thermal transfer control. Characteristics and performance of phase control materials are described in this Part. Existing PCM systems are also described.All current amendments available at time of purchase are included with the purchase of this document.