2019年十大太空故事

2019年见证了太空领域所取得的多项突破。在太阳系内,一个探测器对小行星表面之下的物质进行了采样;天文学家对海王星存档图像的仔细筛查发现了它迄今最小的卫星。此前对冥王星进行了近距离探访的探测器又飞过了另一个更为遥远的天体,为了解行星演化的历史打开了新的窗口。一个新的探测器着陆到了火星上,意在首次了解火星表面之下正在发生些什么。     

Classification of Grove Mountains meteorites and its significance

Meteorites are the extraterrestrial rocks, which provide insights into the origin and evolution of the solar system. During the past half century, a great number of meteorites has been discovered on the Antarctic Ice Sheet, confirming that the Antarctica is the most important meteorite concentration area on the earth. Since the first four Antarctic meteorites were found in Grove Mountains in 1998, a total of 9834 meteorites have been collected by four subsequent expeditions. It opens a new field of meteorite study in China, and also accumulates a great deal of scientific samples for China. Recently, classification of Grove Mountains meteorites has been carried out for 6 years, and made following progresses: (1) 2433 meteorites, which include many special meteorites, e.g. Martian meteorites, ureilites and carbonaceous chondrites, have been classified. (2) the Antarctic meteorite curation and the sample sharing system are set up preliminarily. (3) the classification procedure, the management of meteorite samples, and the application procedure for the Antarctic meteorites are completed after the systematic classification during these years. (4) young generation researchers on meteorite are trained through the cooperation of many universities and institutes on meteorite classification.     

Geochemistry of the Martian Meteorite GRV 99027

GRV 90027 is a Martian lherzolitic shergottites (L-S) containing poikilitic, non-poikilitic, and melted pocket components. GRV 99027 is mainly composed of olive (55 vol%) and pyroxene (37.5 vol%), with minor maskelynite (6 vol%) and chromite (1.5 vol%), and trace whitelockite and troilite, ect. In this paper, the mineralogy and petrology of GRV 99027 are reported; in addition, the geochemical characteristics of the REEs and H isotopes in the GRV 99027 are also further investigated. The ΣREE in GRV 99027 is relatively low; HREEs are enriched in olivine and pyroxene grains; LREEs are enriched in plagioclase with a high positive Eu anomaly. High ΣREE value is found in rare mineral whitlockite (less than 0.2 vol%), LREE≈HREE, and whitlockite has a negative Eu anomaly. The REE distribution patterns of the whole -rock of GRV 99027 is similar to but different from that of other L-S Martian meteorites, indicating that they came from different location of Mars. GRV 99027 has a high δD value. Different water-bearing minerals give different contribution for δD value. The δD of phosphates generally does not correlate with water content, and δD has a weak negative correlation with water content. GRV 99027 can be classified as an L-S Martian meteorite based on mineralogical assemblage patterns, REE distribution patterns, and hydrogen isotope. The isotope data of Sr, Nd, Pb, Os and REE from other L-S Martian meteorites were collected to discuss the formation history of the GRV 99027. Similar to other L-S Martian meteorites, GRV 99027 originated from part of Mar's mantle; during one strong impact event about 4M years ago, the meteorites were ejected from deep mantle into space, and traveled for a different duration in space (indicated by different cosmic exposure time), and captured by the Earth later in different time, ultimately falling on the Antarctica as L-S Martian meteorites.     

“凤凰”铲起火星冰

美国国家航空航天管理局星期二宣布：该局的“凤凰”号火星着陆器（Phoenix Mars Lander）刮起了一些冰土,以供其携带的仪器进行分析。     

欧空局"火星登陆器"和"火星电离层和测地实验"计划

该文全面介绍了欧洲空间局的“火星登陆器(NetLander)”及其“火星电离层和测地实验(NEIGE)”项目。具体叙述了项目的科学目标与内容、实现途径、组织机构、工程技术方面的框架,以及目前最新的进展状况。希望借此能为我国开展相关工作提供参考与借鉴．     

火星南极有个大冰盖

火星探测近来捷报频传，众多证据不断证明液态水曾在这个星球上流淌。科学家日前又发现，在火星的南极，存在一大片广袤的冰盖，如果融化，整个火星表面将被11米深的水层所覆盖。     

火星可能藏大量地下水

科学家普遍认为，如今干燥的火星历史上相当湿润。火星上的水究竟去了哪里？曾有一些科学家提出，远古火星大气中的水可能是被太阳风“吹干”的。但瑞典和法国科学家的一项新研究成果对此提出了质疑。     

火星的地下水

HACA(美国国家航空航天局)获得了来自由俄罗斯科学院宇宙研究所专家研制、并安装在“火星奥德赛”轨道仪器上的高能中子探测器的资料,资料证实,在大部分火星地表下,隐藏着大量氢化合物,很可能是水。在沿着火星东经180°暂时无名的区域也发现了同样的水层。在两种情况下,它们也许被薄层含很少量水汽、完全干燥的土壤覆盖。除此之外,仪器测到了以冰和硬质颗粒混合物形态存在的大量地面以下的水汽,后者可能在最近的数十亿年间,以冻结的形态位于该处。看来,部分融化的冰以液态流出火星地表,形成对某种形态生命有利的区域。业已确定,在火星…     

火星探测器精密定轨定位与火卫一低阶重力场研究EI北大核心CSCD

论文详细地研究了火星探测器精密定轨定位理论与方法。从火星轨道器精密定轨问题入手,重点对欧空局火星快车号探测器进行了相关研究。通过梳理定轨策略,全面处理了火星快车多普勒跟踪数据,获得了高精度的火星快车重建轨道。同时在国际上首次融合处理多次火星快车飞掠火卫一期间的观测数据,提高了火卫一低阶重力场模型的精度。     

火星探测器行星际定轨两种数据处理方案比较

计算了由于形状、姿态和表面性质不准确导致火星探测器行星际定轨存在较大光压模型误差时,两种不同定轨方案(方案1只估计光压系数,方案2同时估计光压系数和随机加速度)对光压模型误差的补偿效果。在方案2中建立了高斯马尔科夫模型表征光压模型导致的加速度误差,并选取了合适的随机模型参数。仿真分析表明方案2可以有效补偿光压模型误差,避免滤波发散,提高定轨精度。