Optical Characteristics' Degradation Of ZnO Thermal Control Coatings Under Irradiation

Satellites'thermal control system is one of the most important systems in keeping the satellites'electronic components working under an appropriate temperature. Thermal control coating, which usually consists of binding agent, white paint, aluminum foil, acetylene black, etc. is one of the most common materials using in satellites'thermal control system, playing a key role of passive thermal control. However, the coating on the surface will be affected by many factors in space, when the satellite runs in the orbit. The charged particles radiations, such as electron and proton, and ultraviolet irradiation would increase the white paint's absorption and generate the degradation of its optical characteristics. The optical characteristics'degradation of the thermal control coating are so important problems to consider and evaluate, hence it is necessary to estimate the performance's degradation of the white paints used in long-term satellites within its mission period. One of the important methods is the simulation experiments in the earth. Building the model based on analyzing the mechanisms of radiation effect is the most need to do, which can be used to evaluate the long-term degradation status.The purpose of the paper is to study the test and evaluate methods for space radiation effect of ZnO white paint which is a typical thermal control coating used in Satellites.To kown its trend of optical characteristics'degradation by tests.To research its mechanisms of radiation effect. And to establish a modle for its optical characteristics' degradation under space radiation on these basis.Continue to study the prediction methods for ZnO white paint's optical characteristics' degradation under space radiation.The study of the paper consists of four parts, such as:(1) Studing of simulation test methods for space radiation effect of ZnO white paint which is a typical thermal control coating.(2) Testing and researching for the optical characteristics' degradation of ZnO white paint under simulated space radiation.(3) Studing for the modle of the optical characteristics'degradation of ZnO white paint under radiation.(4) Studing of the fitting and prediction methods for the optical characteristics'degradation of thermal control coating under space radiation.By carring out the testing and researching of this paper, progress was gained as below:(1) Put forward the calculation methods for the parameters of equivalent simulation irradiation test. And made an applicable project conducted the simulated test of irradiation and characteristics measurement for thermal control coatings.(2) Have got a mount of datum about optical characteristics' degradation of ZnO white paint thermal control coating under sorts of space irradiation.Researched and understood its rule of optical characteristics'degradation.(3) Have established two deferent theorical modles for change of spectrum absorption of ZnO white paint under electron irradiation, and achieved creative progress.Some key parameters in these modles can be maken certain by calculation and analysis upon tests.The accuracy of these modles has been validated through test, so they can be used to predict the optical characteristics'degradation of ZnO white paint thermal control coating under space irradiation, and will be applicated in engineering.(4) The modles studyed in the paper can be extended to theorical prediction for the optical characteristics'degradation of other thermal control coatings under space irradiation. The methods of the paper for researching and building the modles are advanced, and offer an effective way for mechanism research and modle build on optical characteristics' degradation of different materials under different sorts of irradiation.(5) This paper has maken a project to develop the software which will analyse and predict the optical characteristics'degradation of thermal control materials under space irradiation.It has established a nice foundation for calculation of materials'optical characteristics' degradation under space environment, and for evaluation and long time prediction on optical characteristics'degradation of typical thermal control coatings under electron, proton, and ultraviolet irradiation.