Alpha Magnetic Spectrometer Main Radiators In-orbit Operation Temperature Data Analysis And Numerical Simulation

Space experiments and space exploration projects have always been at the forefront of international scientific research.Alpha Magnetic Spectrometer(AMS)is the first large particle physics detector installed on the International Space Station(ISS)to carry out long-term fundamental physics research in space,searching for the source of dark matter and antimatter,and exploring the origin of the universe.With ISS operating in near-Earth orbit,the complex and harsh space environment requires the thermal control system to keep the AMS equipment strictly within the operating temperature range to ensure its stability and service life during orbital operation.At the same time,the AMS,as a large station-mounted experimental device,is exposed to the space environment for a long time,and some thermal control components located in the outermost AMS main radiator are extremely vulnerable to the space environment.Therefore,the analysis of the thermal environment and temperature characteristics of the AMS in orbit operation and the monitoring of the performance of the thermal control system are crucial.In this paper,a combination of theoretical calculations,data analysis and numerical simulations is used to analyze the thermal environment and temperature characteristics of the AMS main radiator in orbit operation and the degradation of the surface coating on the radiating side of the main radiator,and the corresponding prediction studies are carried out.The heat balance analysis of the orbital environment of the AMS in orbit operation was carried out,and the relationship between the ISS operation parameters,the coating thermal radiation parameters and the variation of the external heat flow absorbed by the AMS was investigated.Theoretical calculations were performed for three external heat flows of AMS under normal operating conditions.The calculation results show that the external heat flow received by the main radiator in long-term orbital operation is mainly affected by the decay of the coating solar absorption ratio,the fluctuation of the total solar irradiance,and the angular and angular cyclic variations.Based on the thermal data of AMS in orbital operation,the temperature variation characteristics of the main radiator and the influencing factors are investigated.Through screening a large amount of thermal data,the influence law of thermal control coating degradation on the temperature of the AMS main radiator was focused on,and the analysis results showed that the temperature of the WAKE main radiator measurement points in the same month and under the same operating conditions between 2011 and 2017 increased year by year,and showed a linear relationship with the year of AMS operation in orbit.The system-level thermal network model of the AMS main radiator was established in the thermal analysis software Thermal Desktop,and the temperature of each node was calculated by SINDA/FLUINT? software,and the temperature of the node was substituted for the temperature of the corresponding measurement point of the main radiator during the simulation.The reliability of the model was verified by comparing the simulation results with the telemetry data of the corresponding operating conditions.The simulation results of several groups of different working conditions and different measurement points under the corresponding coating solar absorption ratios were also combined with a stepwise regression method to predict the degradation degree of the main radiator surface coating on the WAKE side,and the results showed that the average annual solar absorption ratio of the thermal control coating increased by 0.025 from 2011 to 2017,and the solar absorption ratio of the coating in 2017 was about 0.365.based on the research of a variety of thermal control coating parameters were simulated accordingly,and the effect of coating thermo-optical parameter changes on the temperature response characteristics of the main radiator was analyzed.In addition,the effects of the variation of total solar irradiation on the external heat flow of the main radiator and the accuracy of the numerical simulation were quantitatively analyzed by combining the telemetry data and numerical simulation results.