月球卫星最优小推力变轨研究

对利用小推力发动机将月球探器从双曲线轨道转移到圆轨的燃料最省转移问题,进行了研究,首先,将问题分解为双曲线到椭圆的转移和从椭圆到目标圆轨道的转移两步,然后,分别利用遗传算法解决了冲量假设下的最估转移、小推力加速民政部下从双曲线到椭圆的转移轨道优化,以及转移时间有约束情况下的从椭圆到圆轨道的转移轨道优化问题。     

月球探测及月球重力场的确定

针对近年月球探测渐成热点和我国即将发射“嫦娥卫星”的状况,本文首先归纳了月球各项几何与物理特性以及月球探测的经济、科学和战略意义.然后,讨论了月球重力场在探月中的作用,并对国外月球重力场研究的发展历程、主要方法及面临的困难进行了综述.最后,结合我国“嫦娥工程”,对我国月球重力场探测的可行性,从航天运载能力、轨道跟踪手段、重力场恢复技术以及方法创新等方面进行了分析,以期为我国自主确定月球重力场模型提供参考依据.     

对月球重力场特征的理解

依据克莱门汀号和月球勘探者号月球探测器所获得的数据所建立最新的地球重力模型和地形模型,为人类深入了解月球内部性质及其演化特征,提供新的平台.M.T. Zuber (1994) 和 M. A. Wieczorek (1998) 所建立的月壳全球模型,为利用最新月球着力资料研究月球内部构造和演化,揭示月球上独特的“物质瘤”之成因等科学问题,开凿了先河.本文通过对现有的月球重力和地形数进行分析和计算,提出作者对月球内部物质分布特征的理解和一些认识.从宏观角度看,月球布格重力异常与月球地形起伏是相关的,统计结果表明它们呈弱负相关,从均衡角度来说,在月球停止大规模内部物质运动之前,月球壳幔可能已基本达到均衡;从Mascon深度估算结果来看,一些大型的Mascon基本属于玄武岩浆“充填”型的,少数Mascon可能与月幔柱有关,如东方海Mascon.     

Limited By Cost: The Case Against Humans In The Scientific Exploration Of Space

Human space flight represents a heady mix of bravery and drama which can be inspirational to nations and to humankind but at huge economic cost. Due to the current high launch costs only a handful of people have ventured beyond low Earth orbit and walked on the Moon, propelled by aspirations related more to the Cold War than to science. Problems with reusable launch vehicle development mean that severe launch cost limitations will exist for some time. Meanwhile, cheaper robotic probes have visited all the planets except Pluto, flown by comets, landed on Mars, Venus and an asteroid, have probed Jupiter's atmosphere and studied the Universe beyond our own solar system with telescopes. Using these data we are determining mankind's place in the Universe. Public interest in the historic Eros landing eclipsed a simultaneous space walk at the fledgling International Space Station and the Mars Pathfinder landing generated hundreds of millions of website hits in a few days. Given the fact that hundreds of Mars missions could be flown for the still-escalating cost of the International Space Station, the unsuitability of human bodies for deep space exploration, and the advances in 3-d and virtual reality techniques, we discuss whether human exploration needs a place in a realistic, useful and inspirational space programme. This revised version was published online in July 2006 with corrections to the Cover Date.     

The Case For Renewed Human Exploration Of The Moon

The European Space Agency, ESA, is currently studying 3 high-energy astronomy missions that use the International Space Station (ISS). These are Lobster-ISS, an all-sky imaging X-ray monitor, the Extreme Universe Space Observatory (EUSO) which will study the highest energy cosmic rays by using the Earth's atmosphere as a giant detector and XEUS — the X-ray Evolving Universe Spectroscopy Mission, a potential successor to ESA's XMM-Newton X-ray observatory. These first 2 missions will he attached to the external platforms on the Columbus module, while XEUS will visit the ISS to attach additional X-ray mirrors to enlarge the original 4.5 m diameter mirrors to the 10 m diameter required to observed redshifted iron lines from massive black holes in the early Universe. This revised version was published online in July 2006 with corrections to the Cover Date.     

Celestial n-Body Coupling in the Lunar Orbit Theory

Making use of the fact that, in the solar system, the angular momentum is carried predominantly by the planets while the mass is beared almost entirely by the Sun, an iterative scheme is devised to solve approximately the n-body contributions of the lunar orbit problem. The scheme envisages the Moon-Earth-Sun three-body subsystem as being nested in the grand Earth-Jupiter-Sun system. In the planetocentric representation, the orbital motion of the Sun about the solar system center of mass is transmitted to the third body via the second primary body in both the grand and nested three-body systems. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cosmic Ray Effects on the ISOCAM Long Wave Detector

The ISOCAM detector is subjected to transient effects induced bycosmic rays, the so-called glitches. This paper is focused onthe ISOCAM long wave detector. The predicted glitch rates havebeen re-evaluated by taking into account secondary particlesproduction in the materials surrounding the LW detector. We showin this preliminary study that the difference between thepreviously predicted glitch rate and the observed rate may beexplained by secondary particles.     

Glitch effects in ISOCAM Long Wave detector

One of the main limitations to the sensitivity of observations carried out withthe ISOCAM infrared camera comes from the responsivity variations and glitchescaused by impacts of charged particles. After more than 28 months of successfuloperations, the predicted glitch rate has been re-evaluated and compared toin-flight measurements. Glitch properties have been studied in orderto improve the removal algorithms, and thus the ultimate sensitivity of ISOCAM.All informations about the glitch phenomenon are very useful in order toprepare next space experiments.     

从地面发射月球探测器的窗口选择

典型的月球探测器飞行轨道包括地球停泊轨道段、地月转移轨道段、月球卫星轨道段和着月轨道段。首先介绍了设计从地面发射月球探测器轨道典型的约束条件;然后,借助于二体假设,建立解析表达式,分析各种约束对窗口选择的影响,给出了各轨道段概略的飞行时间和粗窗口;最后,利用精确的探测器轨道动力学模型,计算精窗口,并给出了一则算例,所得结论可为月球探测器轨道发射、轨道设计提供依据。     

月球重力场研究及其应用进展

月球重力场研究及相关应用是月球科学探测中的重要内容之一。本文回顾了月球重力测量及月球重力场模型、月球地形模型等主要研究进展,总结了月球重力场（包括地形）在月球内部结构研究,特别是在月壳结构以及月球质量瘤等方面取得的研究成果。此外,月球重力场还应用于月幔／月核研究、月球均衡状态、月球物质成分及月球演化历史的研究中。随着我国嫦娥探月计划的实施,利用其探测数据建立自主重力场模型及地形模型成为我国探月研究的基础工作之一。在此基础上可开展月壳结构、月球均衡状态、月球质量瘤及月壳成分等研究,同时借鉴地球科学中相关学术思想和方法技术,从而促进对月球及类地行星等结构的研究。