Thermal Control Design and Verification of Extravehicular Load Equipment

In order to solve the problem of frequency stability and transmission accuracy decrease caused by temperature fluctuation during on-orbit operation of an extravehicular load equipment, a highly efficient thermal control scheme is proposed which bases on passive thermal control as the main approach and active thermal control as the auxiliary method . The scheme employs a single-phase liquid cold plate as the main heat dissipation surface, and 10-unit multi-layer insulation components for comprehensive encapsulation. High thermal conductivity materials are utilized to achieve efficient heat conduction. Simultaneously, heating sheets and TEC semiconductor ceramic sheets are used for precise temperature control. Through finite element simulation analysis of temperature distribution under both high and low temperature conditions and optimization design, the temperature variation of key components is controlled within ±0.5 K. The ground constant-temperature thermal balance experiment and the in-orbit data results indicate that this scheme effectively suppresses the interference of temperature fluctuations on the load equipment, significantly improves the overall temperature uniformity of the equipment. It enables photodiodes and other sensitive devices to operate within the optimal temperature range (25-50°C). The temperature change rate of temperature-sensitive devices on the extravehicular load equipment is better than 0.1 K·min^–1, meeting the on-orbit stability requirements of high-precision time-frequency transmission systems. It can provide an important reference for the thermal control design of similar space load equipment.