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首页> 外文期刊>Acta astronautica >The MESSENGER mission: Results from the first two Mercury flybys
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The MESSENGER mission: Results from the first two Mercury flybys

机译：信使任务：前两次水星飞越的结果

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摘要

NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft is well into its voyage to initiate a new era in our understanding of the innermost planet. During 2008 MESSENGER flew by Mercury twice and completed the initial spacecraft reconnaissance of the planet begun 34 years earlier by Mariner 10. MESSENGER observations have illuminated how the 1500-km-diameter Caloris basin was a focus for magmatic and deformational activity. High-resolution images show evidence for volcanic vents, pyroclastic deposits, and volcanic flooding of its interior. Lobate scarps, discovered by Mariner 10, are the dominant tectonic landform across the planet and collectively record greater contraction of the surface than inferred from Mariner 10 images. On portions of the surface not seen by Mariner 10 are young craters with prominent ray systems that span most of a hemisphere. Variations in visible and infrared spectral reflectance correlate with geological units. The lack of an infrared absorption band near 1 μm indicates a low ferrous oxide content in surface silicates, but absorption of thermal neutrons by surface material suggests the presence of surface iron in concentrations similar to low- to intermediate-Fe lunar soils. The most unanticipated result to date is the dynamic and complex nature of Mercury's exosphere-magnetosphere system. Magnetometer measurements point to a dynamo origin for Mercury's main magnetic field, but that field is substantially modified by the planet's small, dynamic magnetosphere. Emission-line measurements have revealed the distribution of neutral sodium, calcium, and magnesium in the exosphere and tail; plasma spectrometer observations indicate that these and other species become ionized to populate the planet's magnetosphere. MESSENGER'S third Mercury flyby on 29 September 2009, the last prior to orbit insertion in 2011, largely duplicated the geometry of the second but added new observations of the planet's surface and a new perspective on the in situ environment as solar activity continues to change. A Participating Scientist Program has brought the Science Team to its current strength of 48 scientists and their associates. The spacecraft continues to perform as designed in its challenging thermal environment. Use of solar radiation pressure for maintaining momentum balance and supplementing maneuver capability is helping to maintainrnpropellant reserves that could enable an extended mission. The MESSENGER team is continuing its informal interaction with members of the BepiColombo project to maximize the overall scientific return from both the missions.
机译：NASA的水银表面，太空环境，地球化学和测距（MESSENGER）航天器正进入其航行之路，从而开启了我们对最内层行星的理解的新纪元。在2008年，信使号两次乘水星飞行，并完成了水手10年34年前开始的对行星的首次太空船侦察。信使号观测结果阐明了直径1500公里的卡洛里斯盆地是岩浆活动和变形活动的重点。高分辨率图像显示出火山喷口，火山碎屑沉积物以及内部火山喷发的证据。水手10发现的叶状陡崖是整个地球上的主要构造地貌，与从水手10图像推断的相比，总体记录的地表收缩更大。在水手10看不见的部分表面上有年轻的陨石坑，其射线系统横跨整个半球。可见光谱和红外光谱反射率的变化与地质单位相关。在1μm附近没有红外吸收带表明表面硅酸盐中的氧化亚铁含量较低，但是表面材料对热中子的吸收表明表面铁的存在浓度类似于中低铁月球土壤。迄今为止最令人意外的结果是水星大气圈-磁层系统的动态和复杂性。磁力计的测量指向水星主磁场的发电机起源，但是该磁场被行星的小型动态磁层实质上改变了。发射线测量表明，中性钠，钙和镁在气圈和尾巴中的分布。等离子体光谱仪的观察表明，这些和其他物种被电离，从而构成了地球磁层。信使号于2009年9月29日进行了第三次水星飞越，这是2011年轨道插入前的最后一次，很大程度上重复了第二次的几何形状，但是随着太阳活动的不断变化，增加了对行星表面的新观测以及对原位环境的新观察。参与科学家计划使科学团队目前拥有48名科学家及其同事。航天器在充满挑战的热环境中继续按设计运行。利用太阳辐射压力来维持动量平衡和补充机动能力，有助于维持推进剂储备，从而可以延长飞行任务。 MESSENGER团队将继续与BepiColombo项目成员进行非正式互动，以最大程度地提高这两次任务的总体科学回报。

著录项

  • 来源
    《Acta astronautica》 |2010年第8期|P.681-687|共7页
  • 作者

    Ralph L. McNutt Jr.; rnSean C. Solomon; rnPeter D. Bedini; rnEric J. Finnegan; rnDavid G. Grant;

  • 作者单位

    The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, M/S MP3-E128, Laurel, MD 20723, USA;

    rnDepartment of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, N.W., Washington, DC 20015, USA;

    rnThe Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, M/S 4-283, Laurel, MD 20723, USA;

    rnThe Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, M/S 23-282, Laurel, MD 20723, USA;

    rnThe Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, M/S 4-283, Laurel, MD 20723, USA;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    mercury; planetary science; MESSENGER;

    机译：汞;行星科学信使;

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