首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   26篇
  免费   0篇
  国内免费   1篇
航空   12篇
航天技术   2篇
航天   13篇
  2022年   2篇
  2021年   2篇
  2019年   1篇
  2018年   4篇
  2017年   1篇
  2013年   1篇
  2012年   3篇
  2010年   2篇
  2009年   1篇
  2008年   2篇
  2007年   5篇
  2004年   1篇
  1996年   1篇
  1994年   1篇
排序方式: 共有27条查询结果,搜索用时 191 毫秒
21.
Cosmic Research - As recent studies onboard various spacecraft have shown, one unresolved technical problem of manned interplanetary flights at the moment is the high radiation background of...  相似文献   
22.
Boynton  W.V.  Feldman  W.C.  Mitrofanov  I.G.  Evans  L.G.  Reedy  R.C.  Squyres  S.W.  Starr  R.  Trombka  J.I.  d'Uston  C.  Arnold  J.R.  Englert  P.A.J.  Metzger  A.E.  Wänke  H.  Brückner  J.  Drake  D.M.  Shinohara  C.  Fellows  C.  Hamara  D.K.  Harshman  K.  Kerry  K.  Turner  C.  Ward  M.  Barthe  H.  Fuller  K.R.  Storms  S.A.  Thornton  G.W.  Longmire  J.L.  Litvak  M.L.  Ton'chev  A.K. 《Space Science Reviews》2004,110(1-2):37-83
The Mars Odyssey Gamma-Ray Spectrometer is a suite of three different instruments, a gamma subsystem (GS), a neutron spectrometer, and a high-energy neutron detector, working together to collect data that will permit the mapping of elemental concentrations on the surface of Mars. The instruments are complimentary in that the neutron instruments have greater sensitivity to low amounts of hydrogen, but their signals saturate as the hydrogen content gets high. The hydrogen signal in the GS, on the other hand, does not saturate at high hydrogen contents and is sensitive to small differences in hydrogen content even when hydrogen is very abundant. The hydrogen signal in the neutron instruments and the GS have a different dependence on depth, and thus by combining both data sets we can infer not only the amount of hydrogen, but constrain its distribution with depth. In addition to hydrogen, the GS determines the abundances of several other elements. The instruments, the basis of the technique, and the data processing requirements are described as are some expected applications of the data to scientific problems.  相似文献   
23.
24.
ExoMars is a two-launch mission undertaken by Roscosmos and European Space Agency. Trace Gas Orbiter, a satellite part of the 2016 launch carries the Fine Resolution Neutron Detector instrument as part of its payload. The instrument aims at mapping hydrogen content in the upper meter of Martian soil with spatial resolution between 60 and 200 km diameter spot. This resolution is achieved by a collimation module that limits the field of view of the instruments detectors. A dosimetry module that surveys the radiation environment in cruise to Mars and on orbit around it is another part of the instrument.This paper describes the mission and the instrument, its measurement principles and technical characteristics. We perform an initial assessment of our sensitivity and time required to achieve the mission goal. The Martian atmosphere is a parameter that needs to be considered in data analysis of a collimated neutron instrument. This factor is described in a section of this paper. Finally, the first data accumulated during cruise to Mars is presented.  相似文献   
25.
Mitrofanov  I. G.  Kozyrev  A. S.  Lisov  D. I.  Litvak  M. L.  Malakhov  A. A.  Mokrousov  M. I.  Benkhoff  J.  Owens  A.  Schulz  R.  Quarati  F. 《Space Science Reviews》2021,217(5):1-47
Space Science Reviews - Volatiles and refractories represent the two end-members in the volatility range of species in any surface-bounded exosphere. Volatiles include elements that do not interact...  相似文献   
26.
Low mass M- and K-type stars are much more numerous in the solar neighborhood than solar-like G-type stars. Therefore, some of them may appear as interesting candidates for the target star lists of terrestrial exoplanet (i.e., planets with mass, radius, and internal parameters identical to Earth) search programs like Darwin (ESA) or the Terrestrial Planet Finder Coronagraph/Inferometer (NASA). The higher level of stellar activity of low mass M stars, as compared to solar-like G stars, as well as the closer orbital distances of their habitable zones (HZs), means that terrestrial-type exoplanets within HZs of these stars are more influenced by stellar activity than one would expect for a planet in an HZ of a solar-like star. Here we examine the influences of stellar coronal mass ejection (CME) activity on planetary environments and the role CMEs may play in the definition of habitability criterion for the terrestrial type exoplanets near M stars. We pay attention to the fact that exoplanets within HZs that are in close proximity to low mass M stars may become tidally locked, which, in turn, can result in relatively weak intrinsic planetary magnetic moments. Taking into account existing observational data and models that involve the Sun and related hypothetical parameters of extrasolar CMEs (density, velocity, size, and occurrence rate), we show that Earth-like exoplanets within close-in HZs should experience a continuous CME exposure over long periods of time. This fact, together with small magnetic moments of tidally locked exoplanets, may result in little or no magnetospheric protection of planetary atmospheres from a dense flow of CME plasma. Magnetospheric standoff distances of weakly magnetized Earth-like exoplanets at orbital distances 相似文献   
27.
This paper surveys the status of Russian space activities in terms of budget, operational satellite systems, workforce and industrial capabilities. There is inequality between companies and particularly between various tiers of cooperation in production. In the current situation international cooperation, both in the form of joint non-commercial ventures and integration into the global space market, is considered vital for sustaining national space capabilities.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号