排序方式: 共有43条查询结果,搜索用时 15 毫秒
31.
G. Cremonese A. Sprague J. Warell N. Thomas L. Ksamfomality 《Space Science Reviews》2007,132(2-4):291-306
The Mariner 10 spacecraft made three flyby passes of Mercury in 1974 and 1975. It imaged a little less than half of the surface
and discovered Mercury had an intrinsic magnetic field. This paper briefly describes the surface of Mercury as seen by Mariner
10 as a backdrop to the discoveries made since then by ground-based observations and the optimistic anticipation of new discoveries
by MESSENGER and BepiColombo spacecraft that are scheduled for encounter in the next decade. 相似文献
32.
Oleg Korablev Mikhail Gerasimov J. Brad Dalton Kevin Hand Jean-Pierre Lebreton Chris Webster 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
An international effort dedicated to the science exploration of Jupiter system planned by ESA and NASA in the beginning of the next decade includes in-depth science investigation of Europa. In parallel to EJSM (Europa-Jupiter System Mission) Russia plans a Laplace-Europa Lander mission, which will include another orbiter and the surface element: Europa Lander. In-situ methods on the lander provide the only direct way to assess environmental conditions, and to perform the search for signatures of life. A critical advantage of such in situ analysis is the possibility to enhance concentration and detection limits and to provide ground truth for orbital measurements. The science mission of the lander is biological, geophysical, chemical, and environmental characterizations of the Europa surface. This review is dedicated to methods and strategies of geophysical and environmental measurements to be performed at the surface of Europa, and their significance for the biological assessment, basing on the concept of a relatively large softly landed module, allowing to probe a shallow subsurface. Many of the discussed methods were presented on the workshop “Europa Lander: Science Goals and Experiments” held in Moscow in February 2009. Methods and instruments are grouped into geophysical package, means of access to the subsurface, methods of chemical and structural characterization, and methods to assess physical conditions on the surface. 相似文献
33.
针对航天软件自动化测试和测试通用性要求的不断提高,提出基于DAQ(数据采集)和FPGA(现场可编程门阵列)的星务软件测试平台构建方案,在PXI(PCI eXtensions for Instrumentation,外设部件互联标准在仪器领域的扩展)系统环境下应用NI(美国国家仪器公司)的DAQ板卡和FPGA板卡实现星务软件外围数据的仿真模拟,应用Lab-VIEW编程实现信号的解析和良好的人机交互界面。在实际测试中,它能够很好地完成一系列星务软件的自动化动态测试、故障模拟测试等,大大缩短了测试周期,提高了测试效率。此平台完全满足航天软件现代化测试的要求,具有开发周期短、使用效率高、通用性强等优点。 相似文献
34.
An Event Horizon Imager(EHI) Mission Concept Utilizing Medium Earth Orbit Sub-mm Interferometry 下载免费PDF全文
KUDRIASHOV V MARTIN-NEIRA M ROELOFS F FALCKE H BRINKERINK C BARYSHEV A HOGERHEIJDE M YOUNG A POURSHAGHAGHI H KLEIN-WOLT M MOSCIBRODZKA M DAVELAAR J BARAT I DUESMANN B VALENTA V PERDIGUES ARMENGOL J M DE WILDE D MARTIN IGLESIAS P ALAGHA N VAN DER VORST M 《空间科学学报》2021,41(2):211-233
Submillimeter interferometry has the potential to image supermassive black holes on event horizon scales, providing tests of the theory of general relativity and increasing our understanding of black hole accretion processes. The Event Horizon Telescope (EHT) performs these observations from the ground, and its main imaging targets are Sagittarius A* in the Galactic Center and the black hole at the center of the M87 galaxy. However, the EHT is fundamentally limited in its performance by atmospheric effects and sparse terrestrial (u,v)-coverage (Fourier sampling of the image). The scientific interest in quantitative studies of the horizon size and shape of these black holes has motivated studies into using space interferometry which is free of these limitations. Angular resolution considerations and interstellar scattering effects push the desired observing frequency to bands above 500 GHz.
This paper presents the requirements for meeting these science goals, describes the concept of interferometry from Polar or Equatorial Medium Earth Orbits (PECMEO) which we dub the Event Horizon Imager (EHI), and utilizes suitable space technology heritage. In this concept, two or three satellites orbit at slightly different orbital radii, resulting in a dense and uniform spiral-shaped (u,v)-coverage over time. The local oscillator signals are shared via an inter-satellite link, and the data streams are correlated on-board before final processing on the ground. Inter-satellite metrology and satellite positioning are extensively employed to facilitate the knowledge of the instrument position vector, and its time derivative. The European space heritage usable for both the front ends and the antenna technology of such an instrument is investigated. Current and future sensors for the required inter-satellite metrology are listed. Intended performance estimates and simulation results are given. 相似文献
This paper presents the requirements for meeting these science goals, describes the concept of interferometry from Polar or Equatorial Medium Earth Orbits (PECMEO) which we dub the Event Horizon Imager (EHI), and utilizes suitable space technology heritage. In this concept, two or three satellites orbit at slightly different orbital radii, resulting in a dense and uniform spiral-shaped (u,v)-coverage over time. The local oscillator signals are shared via an inter-satellite link, and the data streams are correlated on-board before final processing on the ground. Inter-satellite metrology and satellite positioning are extensively employed to facilitate the knowledge of the instrument position vector, and its time derivative. The European space heritage usable for both the front ends and the antenna technology of such an instrument is investigated. Current and future sensors for the required inter-satellite metrology are listed. Intended performance estimates and simulation results are given. 相似文献
35.
推进剂液位检测技术研究及仪器设计 总被引:1,自引:0,他引:1
通过对多种液位检测技术对比分析 ,提出一种利用超声波技术由储罐底部直接测量的方法 ,介绍了基于该方法的测量原理和仪器实现。此方法能够较好解决分界面明显的液位检测问题 ,但是对于一些气 -液界面模糊的介质的液位检测存在一定的问题 。 相似文献
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38.
E. Bozzo P. Romano C. Ferrigno P. Esposito V. Mangano 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Supergiant fast X-ray transients are a subclass of high mass X-ray binaries displaying a peculiar and still poorly understood extreme variability in the X-ray domain. These sources undergo short sporadic outbursts (LX∼ 1036–1037 erg s−1), lasting few ks at the most, and spend a large fraction of their time in an intermediate luminosity state at about LX∼ 1033–1034 erg s−1. The sporadic and hardly predictable outbursts of supergiant fast X-ray transients were so far best discovered by large field of view (FOV) coded-mask instruments; their lower luminosity states require, instead, higher sensitivity focusing instruments to be studied in sufficient details. In this contribution, we provide a summary of the current knowledge on supergiant fast X-ray transients and explore the contribution that the new space mission concept LOFT, the Large Observatory for X-ray Timing, will be able to provide in the field of research of these objects. 相似文献
39.
Yuichiro Ezoe Tomoki Kimura Satoshi Kasahara Atsushi Yamazaki Kazuhisa Mitsuda Masaki Fujimoto Yoshizumi Miyoshi Graziella Branduardi-Raymont Kumi Ishikawa Ikuyuki Mitsuishi Tomohiro Ogawa Takuya Kakiuchi Takaya Ohashi 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
For the future Japanese exploration mission of the Jupiter’s magnetosphere (JMO: Jupiter Magnetospheric Orbiter), a unique instrument named JUXTA (Jupiter X-ray Telescope Array) is being developed. It aims at the first in-situ measurement of X-ray emission associated with Jupiter and its neighborhood. Recent observations with Earth-orbiting satellites have revealed various X-ray emission from the Jupiter system. X-ray sources include Jupiter’s aurorae, disk emission, inner radiation belts, the Galilean satellites and the Io plasma torus. X-ray imaging spectroscopy can be a new probe to reveal rotationally driven activities, particle acceleration and Jupiter–satellite binary system. JUXTA is composed of an ultra-light weight X-ray telescope based on micromachining technology and a radiation-hard semiconductor pixel detector. It covers 0.3–2 keV with the energy resolution of <100 eV at 0.6 keV. Because of proximity to Jupiter (∼30 Jovian radii at periapsis), the image resolution of <5 arcmin and the on-axis effective area of >3 cm2 at 0.6 keV allow extremely high photon statistics and high resolution observations. 相似文献
40.
外弹道数据处理中航向角精确计算方法 总被引:1,自引:0,他引:1
针对国内靶场在外测事后数据处理中航向角计算存在的问题,深入分析了传统计算方法存在的缺陷,提出了两种新的航向角计算方法——坐标法和速度法,并提供了两种方法的算法和模型。在理论分析的基础上,采用实测数据对新旧三种方法比较分析,最后验证速度法是目标瞬时航向角最佳计算方法。 相似文献