从月球逃逸探测小行星的发射机会搜索

从月球逃逸探测小行星的发射机会搜索因需考虑日、地、月引力的影响而使问题变得复杂。针对该多体系统的发射机会搜索问题,提出了一种分层渐近的搜索方法。该方法首先通过分析地月系质心与小行星的几何关系,搜索从地月系质心到小行星的发射机会,进而以地月运动为研究对象,推导出了从月球轨道切向逃逸机会的判别条件,并基于此判别条件及等高线图法对逃逸机会进行了搜索。同时,为提高所得发射机会在多体模型下的轨道修正收敛性,给出了基于月心逃逸轨道参数为终端约束的日-地与日-地-月动力学模型的轨道渐近修正方法。最后,以近地小行星(3908)Nyx和(190491)2000 FJ20为例,搜索其从月球逃逸的发射机会,仿真计算表明了该方法的有效性。     

基于圆型限制性三体模型的借力飞行机理研究

针对星际探测中的借力飞行技术,基于圆型限制性三体模型,深入研究了全相位角情况下借力飞行自由参数与借力飞行轨道变化之间的关系。在圆型限制性三体问题的假设下,通过正向与逆向积分相结合的方法,给出了圆型限制性三体系统中,通过借力飞行实现逃逸与俘获以及顺行轨道与逆行轨道转变的条件,并以地月系统为例,给出了通过月球借力飞行实现地月系统俘获与逃逸的借力飞行参数选择区域。同时,也给出了通过月球借力飞行实现轨道类型转变的参数变化范围。最后,讨论分析了借力飞行高度、速度和借力相位角对借力飞行轨道能量变化量的影响,进一步揭示借力飞行自由参数与借力飞行轨道变化之间的关系。     

美国“月球大气与尘埃环境探测器”

2013年9月613,NASA发射了“月球大气与尘埃环境探测器”（LADEE）,用以验证新一代月地激光通信技术和探测月球大气、尘埃环境等。     

美将发射探测器研究月尘

美国航空航天局（NASA）正计划用一个小型轨道器来研究月尘的秘密。称为“月球大气与尘埃环境探测器”（LADEE）的该探测器将耗资8000万美元,拟搭乘发射另一个探测器的火箭飞向月球,发射时间是2011年。此次探测任务将持续100天,研究对象是月球非常稀薄的大气和无处不在的月尘。NASA正在推进重返月球计划,拟在2020年前让宇航员乘“牵牛星”着陆器重返月面。为此,对月球大气及其附着性很强的尘埃有清楚的认识至关重要。     

直接再入大气的月球返回轨道设计研究

直接再入大气的月球返回轨道是月球采样返回任务普遍采用的飞行方案。文章将月-地转移轨道设计与再入大气仿真相结合,通过两级修正策略和落点匹配使月球返回轨道既满足再入界面约束又满足再入点地理位置约束。两条分别采用弹道式和弹道-升力式再入的月球返回轨道的计算结果表明,此方法是有效的。     

载人登月前奏

在月球上着陆是登月式飞船的关键技术,因为在月球上着陆与在火星和金星上着陆不同,月球上没有大气层,所有靠大气阻力的着陆手段都无法应用,只能依靠反向推力制动。     

月球无人采样返回任务概念设想

分析了无人月球采样任务,包括采样及封装方式分析,飞行过程选择与轨道初步方案,月面软着陆方式选择,月球轨道交会对接的需求,月面起飞上升的要点,地球大气高速再入返回器的外形选择等。在此基础上提出了三种不同的无人月球采样返回任务概念设想,并对其进行了简要比较和分析。     

美探测器以撞月结束使命

因燃料耗尽,NASA“月球大气与尘埃环境探测器”（LADEE）4月18日按预定计划高速撞击了月球背面。撞击发生在美东部夏令时18日0时30分至1时22分之间,估计撞击时速为5800公里。NASA将利用其“月球侦察轨道器”来找出撞击地点,并了解更多撞击情况。     

行星自动探测器热工况制定的方法及其热真空试验

论述了 Lavochkin 科学制造公司完成的火星、月球、维加探测器热工况制定的基本方法,该公司是金星4-16号、火星2-7号、月球15-24号、登月车1-2号、维加1-2号及其它一些航天器的主要设计者。在模拟进入火星大气、金星大气云层和到达金星表面的环境时,为制定自动探测器热工况,需要考虑许多复杂的方式。     

知识资料窗

月球着陆月球着陆不同于火星着陆和金星着陆。因为月球没有大气层，所有靠大气阻力的着陆手段（制动襟翼、降落伞和机翼）都不起作用，只能依靠反向推力制动。所以，无论是载人登月舱还是自动探测器都采用制动火箭减速加上着陆缓冲的办法在月球上实现软着陆。航天器在绕月...     

CHANG'E-2 lunar escape maneuvers to the Sun–Earth L2 libration point mission

This paper addresses lunar escape maneuvers of the first Chinese Sun–Earth L2 libration point mission by the CHANG'E-2 satellite, which is also the world's first satellite to reach the L2 point from a lunar orbit. The lunar escape maneuvers are heavily constrained by the remaining propellant and the condition of telemetry, track and command, among others. First, these constraints are analyzed and summarized to design a target L2 Lissajous orbit and an initial transfer trajectory. Second, the maneuver mathematical models are studied. The multilevel maneuver schemes which consist of phasing maneuvers and a final lunar escape maneuver are designed for actual operations. Based on the scheme analysis and comparison, the 2-maneuver scheme with a 5.3-h-period phasing orbit is ultimately selected. Finally, the mission status based on the scheme is presented and the control operation results are discussed in detail. The methodology in this paper is especially beneficial and applicable to a future multi-mission instance in the deep space exploration.     

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。     

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.     

The ethics of treading on Neil Armstrong''s footprints

The Moon landings of the Apollo programme irrevocably changed the way we see ourselves. Most significantly, this was the first time that humans had set foot on a celestial body other than Earth. The program has left a number of sites on the Moon as well as on Earth. While the management of the sites and artefacts on Earth is fairly straightforward as they are subject to national heritage legislation, it is not so simple with the sites and artefacts on the lunar surface. Moreover, the sites on the Moon differ in one unique aspect from all other heritage sites on Earth: the absence of a lunar atmosphere of any note means that all foot- and track prints of the astronauts are preserved providing a total record of the pioneering phases of human exploration of the Moon. The nascent developments of space tourism, including proposals for lunar heritage tourism, however, threaten the preservation of these traces on the Moon. This paper discusses the terrestrial and in particular the extraterrestrial heritage of the Apollo programme. Set out are the management ethics that need to apply on the lunar surface if this unique heritage is to have a future.     

Determination of the width of a corridor of re-entry into the atmosphere for the problem of launching a spacecraft into a circumplanetary orbit after braking in the atmosphere

A method of calculating the optimal trajectories of a spacecraft re-entry into the atmosphere is considered under the condition of minimization of a re-orbit burn at the apocenter of the segment of escape from the atmosphere and taking into account a constraint on the maximum overload.     

月球采样机械臂系统设计及试验验证

在对月球采样返回任务需求及探测器系统任务剖面进行分析的基础上，设计并研制了一种轻量化、大负载、高精度、宽采样范围月球采样机械臂系统。该系统主要由4自由度机械臂及两种不同采样形式的末端采样器组成，可对不同指定区域浅层月壤进行铲、挖、浅钻等多形式采集。在综合考虑机械臂系统器上布局的基础上，基于运动学模型对采样机械臂的可达采样区域进行仿真分析，提出采样机械臂月面采样策略。基于等尺寸着陆器模拟平台，开展了针对3种不同密实度模拟月壤的采样试验，采样试验结果表明在可达采样空间内，采样机械臂对不同密实度月壤均具有较好的适应性，最大采样深度可达30 mm，最大单次采样量可达270 g，单次采样时间小于2 min。     

航天器环境工程研究与展望

文章对航天器环境工程的发展进行了科学的探讨。文章指出：开展高可靠、长寿命航天器环境试验评价及防护技术研究,是航天器环境工程的长期重点发展方向;开展月球探测器特殊环境效应与模拟试验技术的研究,是探月工程的需求;航天器环境效应综合预示系统及航天器虚拟总装工艺技术,是未来发展的趋势;而建立空间环境天地一体化应用系统和建立空间环境试验与总装生产体系,是未来发展的模式。     

Simulation of rocket plume and lunar dust using DSMC method

When lunar modules land on the Moon, dust impingement on the lunar module components and deposition on the thermal and optical surfaces would cause many serious problems. The emphasis of this research is on simulating the interaction of rocket plume and lunar dust using the direct simulation Monte Carlo (DSMC) method. The method is extended to model the movement and collision stages of rarefied plume gas and dust particles, including three collisional mechanisms: molecule–molecule, molecule–particle and particle–particle collisions. The reflection of gas molecules on the particle surface is computed by an indirect approach based on the coordinate transformation. Neighboring-cell contact detection scheme is applied to check for contacts between all possible particle pairs. The simulation results show that the acceleration of dust particle is mostly determined by the parameters of plume field. In the computational regions with larger gas density and velocity the particles can be accelerated to larger velocity and convected to higher temperature.