To realize the continuous high space-time resolution observation of solar activity,such as sun’s magnetic field,solar flares and coronal mass ejections.Therefore,our country puts forward the science mission to study of space solar observation,carrying the Space Ultraviolet Solar Telescope(UVST)to the sun-synchronous orbit with real-time observation of solar activity.Both ultraviolet wavebands and visible wavebands are needed to detect simultaneously of UVST,and the thermal control is the key to the normal and efficient operation of the primary mirror and detector of the telescope.In order to make the primary mirror and detector meet the required temperature target and ensure the imaging quality of the optical system,the thermal control technique of the primary mirror and detector of the UVST was deeply studied in this paper.Firstly,the significance of solar activity observation and research status of space solar telescope are summarized,and the technique development and research of thermal control technique for primary mirrors and detectors of space solar telescopes at home and abroad are epitomized.On this basis,the structure and thermal design tasks of the primary mirror and detector of UVST are analyzed,and the significant and difficult problems of thermal control are faced by the primary mirror of UVST with high absorption rate,large heat absorption and demand for high temperature heat dissipation,and the detector module with requirement for cryogenic refrigeration are expounded.Secondly,the relative position relationship among the sun,the satellite and the earth and the characteristics of the space environment are analyzed.Thermal analysis software is used to calculate the instantaneous external heat flow on each surface of UVST under the conditions of high and low temperature in orbit.The results show that2.5W of solar direct ray energy is absorbed by the surface of the primary mirror.Under high and low temperature conditions,the heat flow of the shady surface of UVST reaches the outside of the mirror is the smallest,and the external heat flow is relatively stable,which is suitable for the heat dissipation surface of the high-power detector module.At the same time,the thermal design of the primary mirror and detector components of UVST is carried out in detail,and the composition of the thermal control system is analyzed.Firstly,the structural characteristics of the primary mirror and detector assembly are analyzed.Then,according to the thermal design requirements of the primary mirror and detector,such as the working temperature,the size of the internal heat source,and the temperature difference between the surrounding components,the key thermal design parameters affecting the temperature of the primary mirror and detector assembly are analyzed,and the main heat dissipation scheme is determined.The primary mirror adopts a new type of flexible and high thermal conductivity graphene material to dissipate heat through passive thermal control,while the detector adopts a cold finger connected with radiator and active thermal control to carry out detailed thermal design.Finally,the reliability of the thermal control system of active temperature control loop is analyzed,and the results show that the thermal control system of the primary mirror and the detector meet the on-orbit reliability requirements.Thirdly,the thermal simulation analysis of the primary mirror and detector components is carried out.The in-orbit condition of the system is determined by combining the characteristics of external heat flow,mission requirements and flight attitude.Finite element simulation software is used to build the finite element model of the primary mirror and the detector,and the temperature level of the primary mirror and the detector assembly under extreme high and low temperature conditions is calculated.The results show that both the primary mirror and the detector assembly meet the requirements of temperature index.Lastly,carried out the primary mirror and detector of thermal equilibrium test,the temperature of the primary mirror in high temperature conditions can effectively reduce to below 40 ~oC,satisfies the requirement of temperature indicator.The experimental results are consistent with the simulation results,which verifies the correctness of the thermal design of the primary mirror.At the same time,the temperature distribution data of the detector assembly test was obtained,and the important thermal design parameters of the simulation analysis model of the detector were modified.After the modification,the temperature difference between the simulation analysis and the test results of each component of the detector was less than 1.2 ~oC,and the temperature of the detector all met the requirements of the thermal control target. |