月球表面次级中子辐射环境仿真研究

由于缺少磁场和大气,宇宙线高能粒子轰击月壤可以形成月球特有的强中子辐射环境,并对航天员和电子设备造成潜在威胁。文章采用蒙特卡罗方法仿真研究宇宙线高能粒子辐射与月壤成分核反应产生的次级中子能谱特征,给出不同太阳活动、不同月壤深度下月球中子能谱特征和空间分布特征。仿真结果表明,宇宙线高能粒子导致的次级中子随着月壤深度的增加先增大后减小,大约在1 m深度达到最大值,深度越深银河宇宙线诱发的中子贡献越大。相关结果可为我国后续载人月球探测任务的辐射防护设计提供参考。     

月球表面次生伽马与中子辐射环境模拟研究

月球表面以银河宇宙射线（GCR）为主引发的次生伽马谱和次生中子谱表征月壤的元素组成以及水冰含量,对于下一阶段的月球探测与资源原位利用是值得研究的重要内容。文章通过蒙特卡罗方法简单模拟与分析银河宇宙射线环境下月球表面簇射的伽马与中子辐射环境,结果表明：月球次生伽马谱具有明显的氢（2.23 MeV）、铝（0.83 MeV）、钙（3.53 MeV）、氧（6.13 MeV）、硅（1.77 MeV）谱线特征,水含量对其影响不大,但在高水含量时氢的谱线更为明显;月球表面次生中子谱形与月壤中水冰含量密切相关,随水冰含量增加热中子通量下降,0.01 eV中子的通量在20%含水量时比不含水时下降了72%。建议在后期月球探测计划中使用小型、低功耗的中子/伽马复合探测器,实现我国首次原位月球伽马/中子辐射环境探测,为未来进一步勘探月球原位水资源、矿产资源积累反演的基线数据。     

月球重力场环境对月球卫星轨道影响分析

文章分析了月球复杂的重力场环境对月球卫星轨道运行的影响。通过月球卫星冻结轨道与地球卫星冻结轨道的对比分析,结果表明月球重力场存在较大异常,并由此引起月球卫星轨道发生较大漂移。另外,月球冻结轨道在带谐项影响下还存在中等周期的漂移,仅简单考虑带谐项系数无法求得完美的月球冻结系数。由于月球重力场异常对绕月卫星的影响与地球轨道卫星情况相比存在很大差异,因此月球轨道卫星的长期运行与控制策略的设计必须充分考虑此影响。     

月球表面热环境测量方案的研究

月面热环境探测是我国探月工程中的一项必要工作,具有重要的工程意义和科学意义。文章主要探讨月球表面热环境的测量技术方案,为研制一种技术性能先进并可在我国探月工程中搭载的月面热环境测量仪器作好必要的技术准备。这是一种兼顾工程需要与科学性的用于热测量的有效载荷,可实地获取月表热环境特性参数,既可为后续的月面活动提供可靠的热控设计依据,又可为月球的相关科学研究提供必要的基础数据。     

未来月球及深空探测中的动力学环境问题

近年来,越来越多的空间机构将月球和深空探测作为未来空间探测的重点。未来随着深空探测任务复杂度的增加,其面临的动力学环境也更加复杂。文章分析了月球和深空探测过程中所面临的动力学问题,介绍了现有月球和深空探测中主要动力学环境试验的情况,最后提出了未来月球和深空探测所面临的动力学环境模拟挑战和建议。     

On a lunar space elevator

We consider a space elevator system for lunar surface access that consists of a space station in circumlunar orbit, a cable reaching down to some meters above the surface and a magnetically levitated vehicle driven by a linear motor. It accelerates the load to be lifted to the speed of the cable end. Loads to be delivered are either put on the vehicle and slowed down by it or they are slowed down by a sand braking technique in a mare terrain. It is technically possible to operate this transport system nearly without fuel supply from Earth. We calculate various steel cable dimensions for a static stress maximum of $\text{1}\text{5}\text{th}$ of the tensile strength. The process of takeover is considered in detail. Five ways of eliminating the adverse large cable elongation due to the load are described. The touchdown process and behaviour of the cable after disconnection are analysed. The positive difference between the speed of the load at takeover and cable end can excite a large inplane swing motion. We propose to damp it by a dissipative pulley that hangs in a loop of wire leading to the ends of two beams mounted on the space station tangentially to the orbit, the pulley's core being connected with the load. Roll librations are damped by energy losses in the elastic beams; damping can be reinforced by viscous beam elements and/or controlled out-of-plane motions of the beams. We argue in favour of the possibility of fast deployment. The problems of vehicle vibrations and agglutination at sand braking blades are underlined and their combined experimental investigation is suggested.     

Assessment of the radiation environment on the Moon

In connection with projects on a manned base on the Moon, the assessment of radiation risk to staff of the base owing to galactic (GCR) and solar (SEP) cosmic radiation becomes very relevant. The paper describes the methodology for assessing the radiation environment on the lunar surface and in the depths of lunar soil taking into account the primary and secondary radiation caused by protons and nuclei of GCR and SEP. Calculated fluencies of particles are used to estimate the average annual absorbed and equivalent local doses in tissue. Contribution to the dose of secondary neutrons at depths of lunar soil exceeds the contribution of protons. Contribution to the dose of secondary particles generated by GCR nuclei should be taken into account.     

月球表面热环境测量技术调研分析

月面热环境探测是我国探月工程中的一项必要工作,具有重要的工程和科学意义。文章从工程角度确定了月面热环境测量的主要物理参数,分析了现阶段我国探月工程中实现月面热环境测量的技术条件和要求;对国内外有关材料热物性测量技术进行了综合调研,了解了国内外关于开展行星表面热环境探测的技术及应用现状;在结合我国航天测量技术的基础上对月面热环境测量所涉及的关键技术进行了分析,并初步勾勒出我国探月工程中月面热环境测量装置的指标、任务和实现方案。     

中国探月工程发展及对空间环境与材料研究的需求

文章首先介绍了中国探月工程的发展规划,包括已取得和预期取得的科技成果;随后对我国未来深空探测提出发展设想并进行展望;最后指出探月工程的发展很大程度上受制于对空间环境的认识以及高性能新材料的开发与应用技术,因此必须加强这两方面的研究。     

模拟载人探月中航天员空间辐射风险评估

空间辐射是长期载人航天飞行任务中影响航天员健康的重要风险因素。为了探求载人探月过程中对空间辐射的合理防护方式,文章借助空间辐射场模型对"嫦娥三号"飞行任务在不同质量厚度材料屏蔽下的舱内空间辐射环境进行了仿真计算,并确定了航天员各器官接受的空间辐射剂量、剂量当量以及有效剂量等辐射防护量以进行辐射风险评估。结果表明,随着屏蔽厚度的增加,航天员的各组织或器官的吸收剂量和剂量当量以及有效剂量均明显降低;采用质量屏蔽的方法对低于100 Me V的质子具有很好的防护效果,但对高能质子或重离子的防护效果不明显。计算和分析显示,载人探月过程中,只要采取适当的防护措施,航天员的空间辐射风险是可控的。     

Performance of a small and low-cost chamber to simulate lunar surface environment

The performance of a small and low-cost metal chamber built to simulate the pressure and temperature conditions of lunar surface was assessed and the results are presented. This chamber is intended for studying the physical properties of lunar surface and subsurface (using soil simulants) and also to validate the technology readiness of certain newly developed payloads planned for future lunar surface missions (Lander/Rover). It is possible to reach down to ∼10⁻⁷ Pa under specific conditions and maintain the temperature of the sample under investigation to lunar day and night temperatures. The designed system has been subjected to various tests to evaluate its performance and suitability for carrying out experiments in a simulated lunar environment.     

A socio-economic evaluation of the lunar environment and resources: II. Energy for the selenosphere

This first of several study papers, based on a fundamental paper presented in 1972, provides an independent conceptual analysis and evaluation of the lunar environment as industrial base and habitat. A selenosphere system strategy is outlined. The underlying concept is that of one or several lunar industrial zones for resource extraction and on-surface processing, integrated with a circumlunar zero-g processing capability, serving markets in geolunar space. A classification of lunar elements by utilization category is presented. Lunar oxygen is a prime candidate for being an initial economic “drawing card”, because of its value for fast transportation in geolunar space, requiring significantly fewer ships for equal transfer capability per unit time than electric transports which, however, have value, especially between geosynchronous and lunar orbit. The reduced development difficulties of controlled fusion outside the atmosphere and its advantages for extracting oxygen and other elements in quantity are summarized. Examples of lunar cycle management as fundamental exoindustrial requirement for economic resource enhancement are presented. The principal initial socio-economic value of lunar industry lies in the use of lunar resources for exoindustrial products and operations designed to accelerate, intensify and diversify Earth-related benefits. In the longer run, lunar settlements are a highly suitable proving ground for studying and testing the complex matrix of technological, biological, cultural, social and psychological aspects that must be understood and manageable before large settlements beyond Earth can have a realistic basis for viability. The lunar environment is more suitable for experimentation and comparatively more “forgiving” in case of failures than is orbital space.     

绕月与月面探测热环境及影响因素研究

为全面分析绕月和月面探测器可能经历的热环境作为热控设计依据,文章给出了典型高度和β角的环月圆轨道中,绕月探测航天器接收的太阳和月球红外热流密度及其变化规律。针对复杂月表地形,提出并采用月面三维月壤热模型,计算给出了不同太阳高度角下月面探测器在常规平坦月表的外热流密度情况,定量研究了月面山丘高度及其与探测器距离对探测器表面接收红外热流的影响程度,定性分析了复杂月表地形和月尘对探测器表面红外热流的影响。     

火星表面辐射环境分析

火星表面没有全球性磁场保护,存在较强的辐射环境。文章基于Mars-GRAM模型和MCD模型的火星大气数据、“海盗号”（Viking Lander 1/2）及“探路者号”（Pathfinder）等测量得到的火星土壤数据、银河宇宙射线环境（CREME 96模型）以及太阳宇宙射线环境（1989年10月太阳事件）,采用基于GEANT4的粒子输运方法,分析得到了火星表面辐射环境;并与“好奇号”火星车辐射评价探测器（Radiation Assessment Detector,RAD）实测值进行了比较。结果显示：次级伽马光子和中子通量分析值与实测值偏差不超过50%,辐射剂量分析值与实测值偏差不超过5%。火星表面辐射环境可用于分析航天员在不同位置处遭遇的人体剂量,作为载人火星任务着陆点数据参考。     

Variations of radiation environment onboard the ISS in the year 2008

Using the data of high-sensitivity dosimetric units DB-8, variations of the radiation environment onboard the International Space Station (ISS) during the year 2008 are analyzed. Very low level of solar activity was observed throughout this time, and no proton events occurred. It is shown that the variations of the mean daily dose rate during this period were caused by variations in the height of the ISS flight.     

关于空间辐射环境标准的探讨

在分析国外现行的空间辐射环境标准的基础上,提出制定和实施空间辐射环境数据标准、环境分析与效应标准、设计标准以及试验标准是保证航天型号能够承受空间辐射环境的有效手段.     

空间辐射环境单粒子效应研究

文章介绍了空间辐射环境对航天器电子元器件产生的单粒子效应的国内外研究情况,从环境模拟方法、模拟试验设备、单粒子效应及防护以及飞行试验等方面进行了分析比较。文章对国内研究发展提出了一些建设性的建议。     

深空辐射环境对航天活动的危害及对策

深空辐射环境是影响深空探测任务的一个主要因素,它主要包括太阳粒子事件、银河宇宙射线、俘获辐射带和黑体表面辐射。文章分析了它对航天活动的危害,并探讨了相应的对策。     

航天器内环境模拟技术

在载人航天中,航天员的辐射危险性是必须受到重视的问题。航天器的内环境是一个复杂的复合场,受外部辐射场和屏蔽材料等多种因素的影响,单一的探测技术很难探测得到内部辐射场的性质特点,而且无法对辐射危害进行评估。文章从射线与物质相互作用的角度出发,对NASA所用航天器内环境的模拟技术进行了介绍,并介绍了根据我国国情已往开展的相关研究工作,包括在Geant4软件包的基础上,将射线与物质相互作用的处理方法进行扩展,开发新的软件,编制SRP(Space Radiation Protection)程序等。     

深空辐射环境及其效应的分析与比较

深空辐射环境对深空探测活动将带来严重的威胁。文章首先对深空辐射环境及效应进行了分析,接着对月球、火星、木星和土星等不同星体的辐射环境及效应进行了详细的探讨及比较。文章得到的结论可为深空探测器的设计和航天员的防护设计提供重要的指导与帮助。