熱控次系統 (Thermal Control Subsystem, TCS) 是人造衛星必要的次系統之一，所有機構、電子與光學元件皆有其允許的溫度範圍，過高或過低溫都可能降低元件性能、減損使用壽命甚至造成失效，因此熱控之主要目的為確保衛星在所有任務模式下皆能操作於安全溫度範圍內。本文以福衛五號為例，介紹國家太空中心 TCS 自主研發的能量，針對熱控設計、分析、硬體組裝、環境測試與飛行驗證進行論述。

Thermal Control Subsystem is one of the absolutely essential subsystems for satellite. All the mechanical, electrical and optical equipment could, if encountering a temperature level which is too high or too low, be damaged or its performance and life could be severely affected. Thus the main purpose of TCS is to ensure the satellite can be maintained within their temperature limits for all mission phases. This paper describes the NSPO’s research achievement on FORMOSAT-5 TCS design, analysis, hardware integration, environmental test and fl ight validation.