Volatile content of lunar volcanic glasses and the presence of water in the Moon's interior

The Moon is generally thought to have formed and evolved through a single or a series of catastrophic heating events, during which most of the highly volatile elements were lost. Hydrogen, being the lightest element, is believed to have been completely lost during this period. Here we make use of considerable advances in secondary ion mass spectrometry to obtain improved limits on the indigenous volatile (CO(2), H(2)O, F, S and Cl) contents of the most primitive basalts in the Moon-the lunar volcanic glasses. Although the pre-eruptive water content of the lunar volcanic glasses cannot be precisely constrained, numerical modelling of diffusive degassing of the very-low-Ti glasses provides a best estimate of 745 p.p.m. water, with a minimum of 260 p.p.m. at the 95 per cent confidence level. Our results indicate that, contrary to prevailing ideas, the bulk Moon might not be entirely depleted in highly volatile elements, including water. Thus, the presence of water must be considered in models constraining the Moon's formation and its thermal and chemical evolution.     

月球探测的进展与我国月球探测的科学目标

在简述月球探测的历程与趋势的基础上,强调当代月球探测的总体目标为：(1)研究月球与地月系的起源和演化,特别是月球大气层与磁场的消失,矿物与岩石的分布和形成环境、月壤和内部层圈结构的形成以及月球演化的历程;(2)探测月球的资源、能源和特殊环境的开发利用及对人类社会长期可持续发展的支撑。我国不载人月球探测划分为绕、落及回三个阶段。为了全球性、整体性重新认识月球,绕月卫星探测的科学目标为获取全月面三维影像,探测14种有用元素的全球分布与丰度,探测月壤厚度并估算^3He资源量以及太阳活动对空间环境的影响。“落”为月球探测器软着陆就位探测和月球车巡视探测,建立月基光学、低频射电和极紫外天文观测平台。“回”为月球探测器软着陆就位探测和取样返回地面。     

月壤工程地质特性综述

根据国内外的最新研究成果,综述了近年来月壤工程地质力学特性研究的新进展.首先简述了月壤的矿物特征与化学成分,分析了月壤的级配、颗粒形态与孔隙率等物理性质;然后总结了月壤的变形特性与强度特征,阐述了目前模拟月壤的主要类别,及其内摩擦角、弹性参数等力学参数的研究成果;最后指出月壤研究中存在的问题,即模拟月壤试验必须注意环境变量(如弱重力)及化学成分对于工程地质性质的影响,同时应加强对月壤动力性质方面的研究.     

月神及月崇拜探微

古人膜拜天体自然,并演绎了不少神话传说,对月亮的崇拜也是如此。古代月神话与月崇拜大致包括三个方面的内容：古人月神观念产生的原因,认为月神观念的产生和发展,与早期农牧业生产和农牧业社会是分不开的;中国古代神话中的几种月神形象：月母常羲,月神西王母,嫦娥奔月等;月神话的寓意。     

基于虚拟现实环境的六轮月球车运动性能分析

为了仿真试验月球车在月面环境的运动性能,利用虚拟现实技术建立了月球车仿真试验环境.以一种六轮月球车为原型建立了物理模型,并给出了计算机求解方法,实现了六轮月球车在月面环境下进行运动性能分析的仿真试验.通过对比该月球车设计原型的真实试验结果和仿真试验结果,验证了虚拟仿真的正确性.为月球车设计带来了一个有效的辅助工具.     

俄罗斯未来月球探索与开发计划解析

 月球是当前深空探索与开发的焦点。近年来，俄罗斯出台了围绕月球探索与开发的多项政策并制定了本国月球计划，以月球无人探测器为先遣，继而开展载人登月，最终实现月球基地永久驻留的发展路线日渐清晰。从战略规划、实施阶段、配套技术能力等方面，探讨了俄罗斯月球探索与开发计划，综合判断发现，俄罗斯是目前唯一一个针对月球基地做出明确建设规划的国家，并在有意愿参与国际合作月球轨道平台项目的同时，制定了本国月球轨道站计划且稳步推进相关技术开发工作，为俄罗斯未来在月球探索与开发领域可能率先取得重大突破奠定了基础。     

月球多色测光的最新研究进展

近几十年来，月球多色测光研究成为天文学一个重要领域．尤其是近年Clementine飞船作了几乎整个月球表面的多色测光，得到高分辨月球多色图像．联系Apollo等飞船取回月球样品的实验结果，结合理论研究和新的分析方法，揭示于全月球表面和区域的特性．本文综述一些重要进展和最新成果，包括一些主要概念(反照率，位相函数、全月面累积测光和区域测光)、测光模型、分光反照率测定结果，尤其是Clemmentine飞船资料的分析研究结果——光度参数、月面温度分布、FeO和TiO2分布、月壤成熟度、盆地抛出物、火山沉积物和区域地质．     

The modeling analysis of microwave emission from stratified media of non-uniform lunar cratered terrain surface for Chinese Chang-E 1 observation

In China’s first lunar exploration project,Chang-E 1,the multi-channel (3.0,7.8,19.35,37 GHz) microwave radiometers were aboard the satellite,with the purpose of measuring microwave brightness temperature from lunar surface and surveying the global distribution of lunar regolith layer thickness,and global evaluation of 3He content.To analyze the modeling of microwave radiative transfer from three-layered media of lunar surface,some factors,such as the cratered lunar surface roughness,scattering of regolith particulate medium with temperature profile,are discussed.Based on the statistics of the lunar cratered terrain and using Monte Carlo (MC) method,the cratered lunar surfaces are numerically generated.The triangulated network is utilized to divide the undulated lunar surface into discrete triangle meshes with the size 10 m as a digital surface topography.The reflectivities of each plane mesh are calculated,and the average reflectivity for all MC-realized lunar surfaces is obtained.It is found that under the spatial resolution of 30 km×30 km of Chang-E 1 radiometer observation,the lunar surface can be well modeled as a flat surface.It makes the predominance of the parameters,such as the regolith layer thickness and stratified structures,to be studied.Using the radiative transfer equation of stratified media with dense scatterers,the scattering coefficient of the regolith particulate medium is found negligible,and the emission is mainly governed by the absorptive property of the medium.Brightness temperature of multi-layered media,i.e.lunar soil,regolith layer with temperature profile and underlying rock media,are derived and calculated,and relevant main factors to affect the modeling and emission simulation are analyzed.     

变驱动半径两轮并列式月球车的稳定性分析

为了适应月球探测的特点和要求,提出了一种两轮并列式月球车结构,并分析了其驱动原理和性能.为了更好地适应两轮车系统的视觉导航及多车对接所具备的稳定性需要,设计了一种变驱动半径的两轮并列式月球车系统模型.针对两轮车系统的稳定性进行数学建模,采用变驱动半径结构和状态反馈控制进行仿真,结果表明,变驱动半径结构可以有效地实现两轮车系统的稳定性控制.     

New moon from an old hand

The outcome of the Apollo lunar exploration program 1969-1974 was a model of lunar petrogenesis which ignored the probability of selective volatilisation of gases and alkalis from fire-fountaining lunar basalts. It overlooked the fact that the average compositions of the erupted basalts were those of plagioclase-saturated and low-pressure cotectic liquids on eruption, clearly indicating that they were not primary magmas. The basalts may have undergone evolution by gabbro fractionation within the lunar crust, perhaps in large lava lakes now solidified as the lunar maria. The existing model involving a global magma ocean and plagioclase flotation to form the lunar crust arises solely from the incorrect assumption that the basalts are primary magmas. The plagioclase flotation hypothesis requires the presence of a significant positive europium anomaly in the lunar highland crust, and was founded upon its alleged presence. However, that positive anomaly is neither established by the original data set nor by the much broader current data set. Critical observations, and experiments which will advance the debate are suggested, and alternative interpretations outlined.     

太阳风离子在月面的反射过程及对月面电场的影响

为探究月表磁异常区对太阳风离子产生反射的原理, 基于嫦娥二号卫星携带太阳风离子探测器的探测数据, 用单粒子模拟法反演太阳风离子运动, 并分析离子入射角和反射角的分布. 实验结果表明： 太阳风离子先被月壤向各方向大范围散射, 再被月面电场向天顶方向加速; 太阳风中, 月面有45~75 V电势, 该正电势对月面反射的太阳风离子有显著影响.     

月球探测车的动力学建模与仿真分析

针对月球的复杂地形环境,利用多体系统动力学的理论,将月球探测车作为一个多刚体系统,对其进行动力学分析,建立了软地面环境下的月球探测车动力学模型.并利用ADAMS软件对所建立的动力学模型进行求解和仿真分析,为月球探测车控制系统的设计与数值计算提供了理论依据.     

对“嫦娥”一号激光高度计数据的外部标定

在利用“嫦娥”一号绕月卫星激光高度计LAM载荷数据获取月面高程时,测量数据在月球质心固连坐标系中的径向误差是主要的观测误差来源之一．数据分析表明,“嫦娥”一号探测器和LAM载荷的使用了两级晶体振荡器,它们的独立工作导致的星．地时间同步和飘移将给激光测高数据带来误差．本文对激光高度计LAM数据中存在的时标漂移、卫星轨道径向误差以及LAM晶体振荡器地面定标的系统整体偏差等进行了分析和修正,实现了对激光高度计数据的外部标定,三类误差来源的大小范围分别是0．7—1．2m,～10m,一145m．在此基础上得到了新的360阶次的地形模型CLTM—s03．利用新得到的地形模型发现菲兹杰拉德一杰克逊盆地和南极区域的阿门德森一甘斯温特盆地是月面II型质量瘤区域．     

F2层临界频率的太阴半日周期扰动分析

大气太阴潮汐对ES层和F2层有影响,在ES层和F2层的参数中均发现以太阴半日周期的振荡.通过分析中低纬地区10个台站F2层临界频率(foF2)的太阴半日分量变化,得到以下结论:foF2太阴半日潮有日变化和季节变化.不同的纬度,太阴半日潮的日变化、季节变化不同.武汉foF2太阴半日潮出现最强的月份、武汉中层低热层大气太阴半日潮汐风最强的月份、武汉ES层参数的太阴半日潮最大值出现的月份均相同,这表明,中层和低热层大气太阴半日潮汐和ES层、F2层的太阴半日潮汐有非常强的相关性.     

日月食限的计算

日月食的观测对太阳物理学、天文学及其它相关学科的研究有重要意义．然而准确的日月食预报却离不开日月食限的计算．本文研究了日月食计算方法，力求简单易懂，以便于课堂教学和进行科普教育．     

月球重力场模型研究进展及展望

第一,整理了自人类开始探月以来所有和月球重力相关的探测卫星,以及自学者开始研究月球重力场以来所有重要的月球重力场模型。第二,根据探月跟踪模式的发展过程,详细介绍了各阶段跟踪模式的原理,并以示意图的形式展现,同时列举了各阶段跟踪模式下的重力场模型。第三,对月球重力场反演方法进行了介绍,主要包括短弧积分法和天体力学法。第四,对各个探月阶段具有代表性的重力场模型进行介绍,主要包括：8×4重力场模型、Lun60D、LP165P、SGM100i和GL0420,并进行了精度对比,发现最新一代模型精度比之前提高了4个数量级。第五,介绍了本团队在月球重力探索方向研究进展。第六,介绍了月球重力场模型在探究月球内部构造和卫星定轨方面的应用,并结合现代技术以及目前重力场反演的不足,提出以后可以改进的方案：应用重力梯度仪和获取月球表面真实重力数据。     

一种刚柔耦合模块化月球科考站的构型设计与分析

月球探测是我国的战略性项目,其最后一步也是最关键的一步就是月球科考站的建设。为了能给具体的科考站建设问题提供一些经验,本文针对月球科考站的建设问题,提出了一种刚柔耦合的充气式展开的月球科考站构型设计,并介绍了各层的设计用途及其功能。通过运用商用软件ABAQUS进行仿真分析的方法研究了所设计出的科考站在月面上无月震影响的静载工况,以及有月震影响下的动载工况的工作情况。结果表明：本文提出的科考站各层的结构在这两种情况下都能维持较为良好的力学性能。可见本次设计的科考站具有良好的可实施性,可以为工程实践提供一些帮助。     

Automated detection of lunar craters based on object-oriented approach

The object-oriented approach is a powerful method in making classification. With the segmentation of images to objects, many features can be calculated based on the objects so that the targets can be distinguished. However, this method has not been applied to lunar study. In this paper we attempt to apply this method to detecting lunar craters with promising results. Craters are the most obvious fea- tures on the moon and they are important for lunar geologic study. One of the important questions in lunar research is to estimate lunar surface ages by examination of crater density per unit area. Hence, proper detection of lunar craters is necessary. Manual crater identification is inefficient, and a more efficient and effective method is needed. This paper describes an object-oriented method to detect lunar craters using lunar reflectance images. In the method, many objects were first segmented from the image based on size, shape, color, and the weights to every layer. Then the feature of ＂contrast to neighbor objects＂ was selected to identify craters from the lunar image. In the next step, by merging the adjacent objects belonging to the same class, almost every crater can be taken as an independent object except several very big craters in the study area. To remove the crater rays diagnosed as craters, the feature of ＂length/width＂ was further used with suitable parameters to finish recognizing craters. Finally, the result was exported to ArcGIS for manual modification to those big craters and the number of craters was acquired.     

An early lunar core dynamo driven by thermochemical mantle convection

Although the Moon currently has no internally generated magnetic field, palaeomagnetic data, combined with radiometric ages of Apollo samples, provide evidence for such a magnetic field from approximately 3.9 to 3.6 billion years (Gyr) ago, possibly owing to an ancient lunar dynamo. But the presence of a lunar dynamo during this time period is difficult to explain, because thermal evolution models for the Moon yield insufficient core heat flux to power a dynamo after approximately 4.2 Gyr ago. Here we show that a transient increase in core heat flux after an overturn of an initially stratified lunar mantle might explain the existence and timing of an early lunar dynamo. Using a three-dimensional spherical convection model, we show that a dense layer, enriched in radioactive elements (a 'thermal blanket'), at the base of the lunar mantle can initially prevent core cooling, thereby inhibiting core convection and magnetic field generation. Subsequent radioactive heating progressively increases the buoyancy of the thermal blanket, ultimately causing it to rise back into the mantle. The removal of the thermal blanket, proposed to explain the eruption of thorium- and titanium-rich lunar mare basalts, plausibly results in a core heat flux sufficient to power a short-lived lunar dynamo.     

月球卫星三线阵CCD影像模拟

讨论了由月球DEM和正射影像模拟月球卫星三线阵CCD立体影像的原理和方法,其中重点讨论了月球卫星三线阵传感器投影中心外方位元素模拟、模拟影像像元到月球DEM的投影点求解、考虑月球表面BRDF效应的影像灰度纠正三部分.本文在通常的基于共线方程的投影模拟方法的基础上考虑了月球表面的BRDF效应,对模拟影像进行了灰度纠正.模拟影像像元到DEM的投影点求解采用正算迭代方法,投影过程在月固坐标系下进行,进行长航带影像模拟时可减小月球曲率带来的投影误差.