Design and implementation of circumlunar return and reentry spacecraft thermal control system

Abstract

There are three aspects of difficulties in the thermal control system design of circumlunar free return and reentry spacecraft. In the on orbit-working mode, large thermal load is required to be rejected; in the storage mode, the heat load is small and additional heating is needed, while heat insulation is required in the reentry. Moreover, the technique of equipments' heat collection, transmission, rejection and insulation in the narrow space is very difficult. To arrange the complex thermal requirements, a new thermal control hierarchy system for small reentry spacecrafts based on the flexible and self-adaptable heat switch is constructed for the first time, and an integrative flexible and efficient thermal control system based on heterogeneous loop heat pipe (LHP) is successfully developed. The on-orbit flight data show that the actual heat-transfer capability of the pivotal thermal product LHP is more than 65 W in the temperature-controlled working mode, while the heat leak is less than 2 W in the blocking mode, and the ratio of thermal conductivity is more than 30, which means a good realization of the heat switch function, and ensures that the temperature levels of all the circumlunar free return and reentry flight test vehicle equipments are better than index requirements.