台湾海峡7.3级地震余震活动的月相效应

利用福建地震月报目录,对1994年 9月16日台湾海峡南部M_S 7.3地震的余震活动月一定震级以上的频次进行统计的结果表明,台湾海峡余震活动在一个朔相效应进行了研究。对望月内的变化是有起伏的,起伏明显地受月相的调制,起伏的变化在朔、望、上下弦附近出现相对极值,并且频次起伏的幅度可达地震活动平均频次的80%以上,从而证明了余震活动的月相效应是明显存在的,其影响是不可忽略的。另外,通过对月相效应的谐波分析还表明,余震月相效应的基本特征是具有1/4月波和半月波的周期性。研究余震活动的月相效应对强余震的预报 及其区域应力场的变化有一定的科学意义和实用价值。     

月球引力场和磁场探测新进展

简要地回顾了前苏联、美国探测月球引力场和磁场的历史,介绍了各国的探月计划;较详细地介绍和分析了美国克莱门汀(Clementine,Cl）和月球探测者(Lunar Prospector,LP)两艘飞船探测月球引力场和磁场的最新成果：Konopliv A S等根据月球探测者数据绘制的最新月球重力图(LP100j,月球正面n=90,背面n=60),Halekas J S等根据月球探测者电子反射测量数据绘制的第一张全月球磁场图,Zuber M T等根据克莱门汀数据制作的月球(自由空间和布格)重力异常图和月壳厚度图;提出了开展有关研究工作的几点建议。     

月球花岗岩--比较行星学意义

与大陆地壳广泛出露的花岗岩不同,在月球表面仅发现了少量细小的花岗岩碎屑,此外有长英质组分以熔体包裹体形式出现于月球玄武岩的矿物中。月球花岗岩碎屑的主要矿物为石英、钾长石和钙质斜长石,具花斑状结构;含少量铁橄榄石、单斜辉石、钛铁矿、锆石、磷灰石、白磷钙矿等矿物,缺少含水矿物。月球花岗岩富K2O,富Ba,相容元素(Cr、Sc、Co、V)含量比其它月岩低,具有平坦或Ⅴ型的REE型式,负Eu异常明显。它们的化学特征可以用硅酸盐液态不混熔来解释。月球花岗岩的结晶年龄在4．4～3．9Ga间,具有至少8个年龄峰,可能代表了与花岗岩形成相关的8次独立的岩浆事件。由于月球花岗岩成因和分布对于认识月球演化和岩浆作用历史至关重要,在新一轮的深空探测中,应更加重视对月球花岗岩的研究。     

月震与月球内部结构

阿波罗（Apollo）登月计划在月球表面上布设的月震仪为探索月球内部结构提供了极佳资料来源,本文综述了近年来对月震资料的分析及利用月震资料研究月球内部结构的相关研究结果。月震仪记录到的振动信号主要分为天体撞击、月震和局域震动三类。天体撞击又分为流星体撞击和人造天体撞击,其震源位于月球表面。月震按震源深度分布分为浅源月震与深源月震,前者的震源深度大约为50～220km,释放的能量较大但发生次数较少,记录信号以高频成分为主;后者的震源深度大约为700～1150km,并具丛集性,与潮汐应力有关。局域震动在月球日出与日落时出现,被认为是由近月表的热破裂和变形过程所产生。月球内部结构的多数研究集中于月震仪下方月壳厚度计算及上月幔一维速度模型的建立。结果表明月壳平均厚度大约为40km,而不是早期研究得到的60km左右;通过现有的月震资料还不能得到月球下月幔、月核、月球深部间断面的相关信息。文章最后对月球内部的进一步研究做了总结和展望。     

月球测绘在月球探测中的应用

根据探月历史概述了月球测绘与月球探测的关系、月球探测的焦点和我国探月计划；分析研究了月球测绘的关键技术；论述了月球测绘在月球探测中的应用。     

云南地区强震活跃期与平静期的某些特征

重点研究了20世纪以来云南4次强震活跃期的酝酿及启动过程，发现地壳内构造能量的多年加速积累是形成云南强震活跃期的必要条件，而月球的运行位置及地表涝旱振荡的加剧又进一步调控着活跃期的时间。在此基础上，建立了一套预测云南强震活跃期的定量判据，并应用于对云南地区下一强震活跃期的实际监视中。     

Advances in the study of lunar opposition effect

1Introduction Thelightscatteredfromthesurfacesofsolarsys temobjectsbearsinformationonthenatureoftheirsur faces,whichcanimproveourknowledgeontheorigin andevolutionofthewholesolarsystem.Theopposition effectreferstothenarrowpeakintheintensityoflight scatteredfromaparticulatemediumdirectlybackin thedirectiontowardthesource,whichalsomeansthe brightnessincreaseswithdecreasingsolarphaseangle (Hapkeetal.,1998).Itisoneofthemajorchallen gesinopticsofplanetarysurfaces.Seeliger(1887) discoveredfirstly…     

Imaging and power generation strategies for chandrayaan-1

The Chandrayaan-1 mission proposes to put a 550 kg lunarcraft into Geostationary Transfer Orbit (GTO) using the Polar Satellite Launch Vehicle (PSLV) which will subsequently be transferred into a 100 km circular lunar polar orbit for imaging purposes. In this paper, we describe certain aspects of mission strategies which will allow optimum power generation and imaging of the lunar surface. The lunar orbit considered is circular and polar and therefore nearly perpendicular to the ecliptic plane. Unlike an Earth orbiting remote sensing satellite, the orbit plane of lunar orbiter is inertially fixed as a consequence of the very small oblateness of the Moon. The Earth rotates around the Sun once a year, resulting in an apparent motion of Sun around this orbit in a year. Two extreme situations can be identified concerning the solar illumination of the lunar orbit, noon/midnight orbit, where the Sun vector is parallel to the spacecraft orbit plane and dawn/dusk orbit, where the Sun vector is perpendicular to the spacecraft orbit plane. This scenario directly affects the solar panel configuration. In case the solar panels are not canted, during the noon/midnight orbit, 100% power is generated, whereas during the dawn/dusk orbit, zero power is generated. Hence for optimum power generation, canting of the panels is essential. Detailed analysis was carried out to fix optimum canting and also determine a strategy to maintain optimum power generation throughout the year. The analysis led to the strategy of 180‡ yaw rotation at noon/midnight orbits and flipping the solar panel by 180‡ at dawn/dusk orbits. This also resulted in the negative pitch face of the lunarcraft to be an anti-sun panel, which is very useful for thermal design, and further to meet cooling requirements of the spectrometers. In principle the Moon’s surface can be imaged in 28 days, because the orbit chosen and the payload swath provide adequate overlap. However, in reality it is not possible to complete the imaging in 28 days due to various mission constraints like maximum duration of imaging allowed keeping in view the SSR sizing and payloads data input rate, time required for downlinking the payload data, data compression requirements and visibility of the lunarcraft for the Bangalore DSN. In each cycle, all the latitudes are swept. Due to the constraints mentioned, only 60‡ latitude arc coverage is possible in each orbit. As Bangalore DSN is the only station, half of the orbits in a day are not available. The longitudinal gaps because of non-visibility are covered in the next cycle by Bangalore DSN. Hence, in the firstprime imaging season, only 25% of the prime imaging zones are covered, and an additional threeprime imaging seasons are required for a full coverage of the Moon in two years. Strategy is also planned to cover X-ray payload coverage considering swath and orbit shift.     

Telerobotic exploration and development of the Moon

There has been a debate for the last thirty years about the relative merits of human versus robotic systems and we argue here that both are essential components for successful lunar exploration and development. We examine the role of robots in the next phases of exploration and human development of the Moon. The historical use of robots and humans in exploration is discussed, including Apollo-era exploration, International Space Station, and deep-water petroleum exploration. The technological challenges of lunar operations are addressed in the context of how robotic systems can be designed for robust and flexible operations. System design recommendations are given based on the lessons learned from terrestrial and space robotics.     

Determination of lunar surface ages from crater frequency—size distribution

Crater size-frequency distribution is one of the powerful techniques to estimate the ages of planetary surfaces, especially from remote sensing studies. This has been applied to images of the Moon obtained from Clementine mission in 1994. Simple techniques of measurement of the diameter of the craters (in pixels) are used and converted into linear dimensions. Among the several maria studied, the results of Mare Humorum and the central region of Mare Imbrium are reported. The results are compared with age estimates from other sources.