Investigation on Performance Difference of 35 K Cryogenic Heat Transfer System in Ground and Space Environment

In order to solve the problem of cryogenic heat dissipation of space infrared detection system and ensure its cryogenic operating environment, an integrated system of cryogenic acquisition and heat transfer in 35 K temperature range was designed and developed based on pulse tube cooler and cryogenic loop heat pipe. The system consists of a neon cryogenic loop heat pipe, two sets of pulse tube cooler in 35 K temperature range, one pulse tube cooler in 150 K temperature range, thermal insulation screen, temperature measurement / heating components, control system. It has completed ground single-level and satellite-level thermal vacuum tests, and completed space flight tests in 2020. Heat transfer tests under horizontal attitude and anti-gravity conditions were carried out in the ground stand-alone test to ensure that the system could work stably in space microgravity. The whole-satellite test verified the working characteristics of the system under the heat dissipation condition of the satellite platform, and the space flight test obtained the working performance of the system under space microgravity. This paper introduces the thermal performance of the system in different stages, including supercritical start-up characteristics, steady-state operation performance, etc. The results have verified the correctness of relevant design, and this paper focuses on comparing the performance differences in different stages, and analyzes the possible reasons.