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9月中旬,我国第二颗月球探测卫星嫦娥二号成功从172万千米外深空,传回第一批科学探测数据。这些数据是嫦娥二号从月球飞往日地拉格朗日L2点过程中,太阳风离子探测器、太阳高能粒子探测器、Y射线谱仪等三种有效载荷开机,所获取的空间环境探测数据。根据工程总体安排,将于近日择机再次开启部分有效载荷,执行科学探测任务。 相似文献
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在绕月探测工程的五大系统中,最引人注目的就是嫦娥1号绕月探测卫星。因为它是中国第一个月球探测器,它将走近月球直接获取大量有价值信息,其能 相似文献
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嫦娥二号7米分辨率全月球影像图发布 总被引:1,自引:0,他引:1
2012年2月6日,探月工程嫦娥二号月球探测器获得的7米分辨率全月球影像图在北京发布,表明我国探月工程又取得了一项重大科研成果。嫦娥二号是我国发射的第二颗月球探测器, 相似文献
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"嫦娥一号"月球探测卫星真空热试验的初步思路 总被引:1,自引:1,他引:0
文章介绍了月球环境条件、设计月球探测器需要考虑的环境因素、以及绕月飞行的"阿波罗"服务舱(service module)真空热试验的外热流模拟情况,对中国"嫦娥一号"月球探测卫星的真空热试验提出了初步设想. 相似文献
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The results of studying the interaction of two types of the solar wind (magnetic clouds and solar wind of extremely low density) with the Earth's magnetosphere are discussed. This study is based of the INTERBALL space project measurements and on the other ground-based and space observations. For moderate variations of the solar wind and interplanetary magnetic field (IMF) parameters, the response of the magnetosphere is similar to its response to similar changes in the absence of magnetic clouds and depends on a previous history of IMF variations. Extremely large density variations on the interplanetary shocks, and on leading and trailing edges of the clouds result in a strong deformation of the magnetosphere, in large-scale motion of the geomagnetic tail, and in the development of magnetic substorms and storms. The important consequences of these processes are: (1) the observation of regions of the magnetosphere and its boundaries at great distances from the average location; (2) density and temperature variations in the outer regions of the magnetosphere; (3) multiple crossings of geomagnetic tail boundaries by a satellite; and (4) bursty fluxes of electrons and ions in the magnetotail, auroral region, and the polar cap. Several polar activations and substorms can develop during a single magnetic cloud arrival; a greater number of these events are accompanied, as a rule, by the development of a stronger magnetic storm. A gradual, but very strong, decrease of the solar wind density on May 10–12, 1999, did not cause noticeable change of geomagnetic indices, though it resulted in considerable expansion of the magnetosphere. 相似文献
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嫦娥一号卫星的初步科学成果与嫦娥二号卫星的使命 总被引:3,自引:0,他引:3
嫦娥一号卫星于2007年10月24日在西昌卫星发射中心成功发射,2009年3月1日受控落月,在轨运行495d,一共取得了1.37Tbyte的原始科学探测数据,在此基础上生产出4Tbyte科学应用数据产品。通过对这些科学探测数据的初步分析和应用研究,已经获得了包括"我国首次月球探测工程全月球影像图"等在内的一系列科学成果,圆满实现了预期的各项科学目标,为推动我国月球与行星科学的研究和后续月球探测工程的开展奠定了重要基础。嫦娥二号卫星在嫦娥一号卫星取得圆满成功之后,进行了一系列技术改进,作为探月二期工程的先导星,将于今年年底前发射升空。嫦娥二号卫星从发射到第一次近月制动所经历的时间由13d缩短为5d,环月轨道高度由200km降低为100km,CCD相机的像元分辨率由120m提高到10m,激光高度计测量月面高程由1次/s提高到5次/s。嫦娥二号卫星将重点开展对月面着陆区地形地貌的精细探测,试验验证相关关键技术,为探月二期月面软着陆奠定科学和技术基础。 相似文献
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The solar system galactic frontier—the region where the expanding solar wind meets the surrounding galactic medium—remains poorly explored. The sheer size of the essentially asymmetric heliosphere calls for remote techniques to probe the properties of its global time-varying three-dimensional boundary. The Interstellar Boundary Explorer (IBEX) mission (launch in 2008) will image the region between the termination shock and the heliopause, the heliospheric sheath, in fluxes of energetic neutral atoms. Global imaging in extreme ultraviolet (EUV) will likely be the next logical step in remote exploration of the galactic frontier from 1 AU. Imaging in EUV will establish directional and spectral properties of (1) the glow of singly charged helium (He+) ions in the interstellar and solar wind plasmas; (2) emissions of hot plasma in the Local Bubble; and (3) characteristic emissions of the solar wind. Global imaging with ultrahigh sensitivity and ultrahigh spectral resolution will map the heliopause and reveal the three-dimensional flow pattern of the solar wind, including the flow over the Sun's poles. This article presents the emerging concept of the experiment and space mission for heliosphere global imaging in EUV. 相似文献
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Barkhatov N. A. Korolev A. V. Zastenker G. N. Ryazantseva M. O. Dalin P. A. 《Cosmic Research》2003,41(6):529-538
One-dimensional MHD simulations of solitary sharp and strong disturbances (impulses) of the interplanetary magnetic field and plasma of the homogeneous solar wind were performed. The characteristics of a disturbance of this type, recorded onboard the WIND spacecraft (SC) rather far from the Earth, were taken as initial conditions. The results of numerical experiments simulating the evolution of this disturbance in the moving interplanetary plasma, whose parameters correspond to observations of the WIND and INTERBALL-1 SC, show the efficiency of the computer code developed with the special purpose of investigating low-frequency wave events in the space environment. The calculated characteristics of the impulse resulting from the evolution are in good agreement with parameters of the disturbance recorded by the INTERBALL-1 SC closer to the Earth. In particular, the impulse expands due to imbalance of thermal and magnetic pressures, but keeps its abrupt boundaries. It was demonstrated that stable plasma objects, corresponding to stationary MHD solutions, could really exist in the solar wind plasma for a long time. 相似文献
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Role of the ionosphere for the atmospheric evolution of planets 总被引:1,自引:0,他引:1
We have synthesized current understanding, mainly observations, with regard to ion escape mechanisms to space from the ionosphere and exosphere of Titan and Earth-type planets, with the intent to provide an improved input for models of atmospheric evolution on early Earth and Earth-type planets and exoplanets. We focus on the role of the ionosphere and its non-linear response to solar parameters, all of which have been underestimated in current models of ancient atmospheric escape (4 billion years ago). Factors that have been overlooked include the following: (1) Much larger variation of O(+) outflow than H(+) outflow from the terrestrial ionosphere, depending on solar and geomagnetic activities (an important consideration when attempting to determine the oxidized state of the atmosphere of early Earth); (2) magnetization of the ionopause, which keeps ionospheric ions from escaping and controls many other escape processes; (3) extra ionization by, for example, the critical ionization velocity mechanism, which expands the ionosphere to greater altitudes than current models predict; and (4) the large escape of cold ions from the dense, expanded ionosphere of Titan. Here we offer, as a guideline for quantitative simulations, a qualitative diagnosis of increases or decreases of non-thermal escape related to the ionosphere for magnetized and unmagnetized planets in response to changes in solar parameters (i.e., solar EUV/FUV flux, solar wind dynamic pressure, and interplanetary magnetic field). 相似文献
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Recent observations have detected trace amounts of CH(4) heterogeneously distributed in the martian atmosphere, which indicated a subsurface CH(4) flux of ~2 x 10(5) to 2 x 10(9) cm(2) s(1). Four different origins for this CH(4) were considered: (1) volcanogenic; (2) sublimation of hydrate- rich ice; (3) diffusive transport through hydrate-saturated cryosphere; and (4) microbial CH(4) generation above the cryosphere. A diffusive flux model of the martian crust for He, H(2), and CH(4) was developed based upon measurements of deep fracture water samples from South Africa. This model distinguishes between abiogenic and microbial CH(4) sources based upon their isotopic composition, and couples microbial CH(4) production to H(2) generation by H(2)O radiolysis. For a He flux of approximately 10(5) cm(2) s(1) this model yields an abiogenic CH(4) flux and a microbial CH(4) flux of approximately 10(6) and approximately 10(9) cm(2) s(1), respectively. This flux will only reach the martian surface if CH(4) hydrate is saturated in the cryosphere; otherwise it will be captured within the cryosphere. The sublimation of a hydrate-rich cryosphere could generate the observed CH(4) flux, whereas microbial CH(4) production in a hypersaline environment above the hydrate stability zone only seems capable of supplying approximately 10(5) cm(2) s(1) of CH(4). The model predicts that He/H(2)/CH(4)/C(2)H(6) abundances and the C and H isotopic values of CH(4) and the C isotopic composition of C(2)H(6) could reveal the different sources. Cavity ring-down spectrometers represent the instrument type that would be most capable of performing the C and H measurements of CH(4) on near future rover missions and pinpointing the cause and source of the CH(4) emissions. 相似文献
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采用风洞实验和数值模拟方法研究平板表面圆柱形粗糙单元引起的M=3超声速边界层转捩问题。实验采用纳米粒子示踪平面激光散射技术(NPLS)对流动结构进行测量。共考察了1mm、2mm和4mm三个不同的粗糙度条件。采用五阶精度加权紧致非线性格式(WCNS-E-5)对风洞实验进行数值模拟和对比。实验及计算表明:粗糙元对边界层干扰后诱导了尾迹流向涡的形成,流向涡通过抬升机制产生剪切层和流向速度条带等不稳定结构;实验流动图像显示,剪切层不稳定在边界层转捩过程中起重要作用;随着粗糙元高度增加,流动分离范围和转捩区域明显扩大,转捩位置有提前的趋势。 相似文献