【作者】 卢春莲；

【导师】 周彦平；

【作者基本信息】 哈尔滨工业大学 ， 光学工程， 2010， 博士

【摘要】 航天器目标辐射特性的研究在航天技术、空间对抗、遥感探测及通讯导航等各领域都有着非常重要的意义。而对于空间对抗技术,尤其需要掌握对航天器目标辐射特性进行抑制的方法,这将有利于保持空间优势。本文在航天器目标红外及可见光辐射特性研究的基础上,通过实验探讨了空间环境对目标辐射特性的影响效应,并提出了对航天器目标辐射特性进行抑制的方法。具体完成了如下的工作:(1)航天器目标红外辐射特性及其环境效应研究在分析航天器目标内外热源的基础上对航天器目标的红外辐射特性进行研究。建立了基于航天器目标热平衡的温度场计算模型,同时考虑表面反射及自身辐射等因素,建立了航天器目标红外辐射通量计算模型。由航天器目标红外辐射的可探测特性分析可知目标表面的平均温度值,决定了目标的可探测特性。通过空间光学系统表面沾染实验,研究空间沾染引起的航天器目标红外辐射特性环境效应。由实验结果可得:表面沾染对航天器常规表面材料的目标表面辐射特性的影响效应是使其表面发射率增大,温度升高,红外辐射特性增强。(2)航天器目标可见光辐射特性及其环境效应研究建立了基于航天器目标表面漫反射性质的目标可见光辐射特性分析计算模型,以某地球同步轨道卫星为例,采用基于蒙特卡罗的非序列光线追迹方法,对航天器目标可见光辐射特性进行计算和分析,用探测器上接收的辐照度值来描述卫星目标的可见光辐射特性。同时,由航天器目标可见光辐射的可探测特性研究可知目标表面的平均反射率值,决定了目标的可探测特性。由于卫星实体的对称性,不同观测角度上探测的卫星光学辐照度也具有对称性,且辐照度值与观测距离平方成反比关系。通过航天器目标各组件材料的空间辐射环境效应模拟实验,研究空间辐射对目标可见光辐射特性的影响效应,由实验结果知:空间辐射的影响效应是个长期累积效果,短期辐射对航天器常规表面材料的目标可见光辐射特性几乎没有影响,长期的空间辐射使得航天器目标可见光辐射特性明显随着辐射时间增长而增大。(3)航天器目标红外辐射特性抑制方法研究本文提出采用在目标表面包覆真空多层绝热薄膜结构的方法来抑制航天器目标表面的红外辐射特性,该方法能够在不改变目标内部结构的情况下将目标表面温度降至最低,使得其表面红外辐射特性大大降低直至接近于空间环境背景辐射,辐射的峰值波长偏移出各种红外探测器窗口,使得探测器无法从背景环境中发现目标,大大减小了其被红外探测器发现的概率及探测距离。(4)航天器目标可见光辐射特性抑制方法研究提出了在航天器目标的表面设计中采用镜面表面设计,且目标本体设计成多面体结构的方法对航天器目标可见光辐射特性进行抑制,并且对典型的轨道和目标外形进行计算分析,由分析的结果可知该方法使得地基可见光探测器对目标的探测范围明显减小,并且由探测到的目标光学特征无法准确判断目标本身的真实外形特征,从而探测器对目标的探测概率大大降低,实现了有效抑制目标可见光辐射特性的目的,且该方法在实际应用中是确实可行的。(5)红外辐射特性抑制用多层绝热薄膜结构传热分析及实验研究在传热机理分析的基础上,对用于航天器目标红外辐射特性抑制的多层绝热薄膜结构进行传热分析,建立了空间环境辐射传热模型,模型对膜系结构的设计和应用具有很好的指导意义。为了验证膜系结构的红外辐射特性抑制性能,选择10层的Al/Kapton/Ge膜系结构进行空间环境模拟实验,实验结果为该膜系结构将航天器目标表面光谱辐射出射度降低了两个数量级,且辐射峰值波长偏移到了20μm以外,对航天器目标的红外光谱辐射特性具有很好的抑制效果。实验结果不如模型计算结果理想,存在一定误差,是由于实验过程中存在不可避免的接触导热及其它热源的辐射传热,通过对实验误差来源的分析和计算,可知实验中测温系统的热传导是实验误差的最主要来源,后续实验应采用非接触测温系统,最大限度地减小该项误差来源,将使实验结果更好地验证模型计算结果。更多还原

【Abstract】 Research on radiation characteristics of spacecraft target has very important application values in fields of aerospace technology, space countermeasure, remote sensing detection, and communication-navigation. For space countermeasure the mastery of radiation characteristics restrain technology of spacecraft target is particularly important, which leads to the maitain of a favorable space sueriority. Based on the study on radiation characteristics of spacecraft target, contamination and radiation effects on the radiation characteristics of spacecraft target and the radiation characteristics restrain technology of spacecraft target are investigated in this paper. Details are as follows:1. Infrared radiation characteristics and its environmental effects of spacecraft targetBased on the study on space environment, radiation characteristics of spacecraft target is investigated. According to the internal and external heat flux of spacecraft target, a temperature field model of target is built. The model can be used to calculate the surface temperature distribution of target. If considering the surface characteristics of the target, infrared radiation flux model can be built, which be used to calculate the target infrared radiation flux distribution. Analysis of surface contamination and space radiation effects on spacecraft target is given. Space optical systems surface contamination testing and space radiation testing are designed to study the effects. Surface contamination on spacecraft target mainly makes the surface gray rise. So the infrared radiation characteristics of spacecraft target increase and infrared radiation characteristics of different surface becomes uniform.2. Visible radiation characteristics and its environmental effects of spacecraft targetA visible radiation characteristics model is built. Take a geosynchronous orbit communications satellite of our country for example, the non-sequential ray-tracing method based on Monte-Carlo technique is used to calculate the visible radiation characteristics of the target. The satellite visible radiation characteristics are expressed as irradiance accepted by the observation point detector. Bacause the symmetry of satellite body, the satellite irradiance value accepted by the detector in different observation angles has symmetry property. And the irradiance value is proportional to the square of the distance between observer and satellite. The space radiation effect is an impact of long-term cumulation. Testing and simulation analysis show that the visible radiation characteristics of spacecraft target almost keeps the same in the short-term space radiation. When the period of space radiation is longer than 5 years, the visible radiation characteristics of spacecraft target significantly increases with the time increasing. After the period of 15years space radiation, the visible radiation energy of spacecraft target becomes double.3. Infrared radiation characteristics restrain method of spacecraft targetCryogenic vacuum multilayer thermal insulation film structure is used to restrain the infrared radiation characteristics of spacecraft target in this paper, which is different from existing methods. This method does change the target shape and reduces the target temperature near to the environment temperature.According to the model analysis we find that target’s infrared flux was significantly reduced and its peak wavelength shift out of so all kinds of infrared detector window. So the detected probability is decreased.4. Visible radiation characteristics restrain method of spacecraft targetPolyhedral shape and mirror surface design is presented in the paper, which is used to restrain the visible spectral radiation characteristics of spacecraft target. This design decreases visible detected probability of spacecraft target. Examples are given to illustrate the comprehensive application of the method, which shows the excellent restrain effect.5. Heat transfer analysis and testing study of multilayer film structure used in infrared radiation characteristics restrain of spacecraft targetBased on the the heat transfer mechanism, heat transfer analysis of cryogenic vacuum multilayer thermal insulation film structure used in restrain infrared radiation characteristics restrain of spacecraft target is given in this paper. The classical radiation heat transfer models is built. The models are extremely instructive in the design and application of the film structure. For the perpose of verifying the infrared radiation characteristics restrain performance of the film structure, ten-layer Al/Kapton/Ge film structure was chosen to be tested in the space environment simulation testing. The results show that spectral radiation intensity becomes two orders of magnitude lower and its peak wavelength shift to longer than 20μm. Because of the inevitable contact heat transfer and radiation heat transfer from other heat sources, the testing results are not so good as analysis results of models. Contact heat transfer should be minimaized in application.更多还原