Research On Thermal Control Technology Of Lightweight Wide Space Camera

In recent years,with the rapid development of space optical remote sensing technology,low-cost and lightweight optical remote sensing satellites are increasingly favored by domestic and foreign aerospace institutions,universities and satellite technology companies.The constraints of R&D cost and development cycle make remote sensing satellite technology tend to develop in the direction of miniaturization,high performance and mass production to meet the needs of rapid networking of inorbit satellites.At the same time,the optical load carried on the micro-satellite has also been designed and adjusted adaptively.As the requirements of space optical remote sensor for imaging quality become higher and higher,the thermal control system has gradually changed from a marginal supporting role to a leading role that cannot be ignored;moreover,the interior space of the lightweight space camera is narrow and the heat source distribution is relatively concentrated,which is different from the traditional thermal control technology.Therefore,it is urgent to carry out the research on the key technology of thermal control of micro lightweight space camera.This paper will carry out research on the key technology of thermal control for a lightweight wide-range space camera,a payload carried on a micro-satellite.First of all,the paper summarizes the typical thermal control technology of space optical remote sensor at home and abroad,introduces different thermal control design schemes,summarizes the characteristics of different schemes,and provides reference for the thermal control design of this paper.In addition,the common thermal control methods in spacecraft thermal design are also summarized,including passive thermal control and active thermal control.In the next thermal design,these methods will be applied and explored respectively.Then the structure,mission characteristics and space environment of the camera are analyzed,and the variation range of the angle between the sun vector and the orbit plane is calculated based on the orbit parameters;the external heat flow of the camera is calculated by combining the orbital parameters and the camera’s flight attitude,and the external heat flow curve of the heat dissipation surface is drawn,which provides an important basis for the thermal control design of the camera.Then the overall thermal design of the camera is carried out in detail.According to the thermal control index of each part of the camera,the thermal design of the camera’s mounting surface,main frame,and imaging electric box is carried out by combining active and passive thermal control methods.The camera body is covered with multi-layer thermal insulation components and installed with the platform thermal insulation to minimize the impact of the external environment on the camera temperature;according to the structural characteristics and external heat flow,± Y of the camera is selected as the heat dissipation surface;an active heating zone is set in the lens barrel to control the temperature of the imaging lens group by means of radiation and conduction;the detector,FPGA and other internal heat sources divert heat to the heat dissipation surface for heat dissipation by setting a reasonable heat conduction path.At the same time,the finite element simulation software is used to establish the finite element model of the lightweight wide-range space camera,and the thermal balance equation is established for the nodes according to the energy conservation equation,and the boundary conditions are analyzed and calculated.Then,according to the thermal control design scheme,the thermal simulation analysis of the camera is carried out,and the temperature distribution under three working conditions of extreme high temperature,extreme low temperature and storage is calculated respectively.After processing the simulation results,the simulation results show that all thermal control indicators meet the requirements.Finally,based on a lightweight wide-range space camera,research was conducted on the simulation analysis and improvement measures of infrared heating cages.A system simulation model of infrared heating cage black plate heat flux meter was established using finite element method,and the influence of traditional infrared heating cage control methods on the uniformity of simulated surface total energy and heat flux density was analyzed.By appropriately expanding the size of the heating cage and adjusting the sticking position of the heat flux meter,while ensuring that the total arrival energy meets the conservative design principle,the difference between the simulated average heat flux density and the target heat flux density is reduced,and the uniformity of the heat flux density on the simulated surface is improved.And a black chip heat flux meter was developed for measuring external heat flux in thermal balance experiments.Through comparative calibration experiments,the error sources of the heat flux meter were analyzed,and a faster responsive black chip heat flux meter was successfully produced.