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排序方式: 共有283条查询结果,搜索用时 218 毫秒
121.
Adolfo L. Méndez Berhondo Ramón E. Rodríguez Taboada Paolo Zlobec Ana K. Díaz Rodríguez 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Source length scales are estimated for the September 14, 2005 solar noise storm from the spectral and temporal observed characteristics of the background continuum fluctuations and clusters of Type I bursts. The characteristic height of the magnetic structure where the noise storm source is located and the size of the source where Type I bursts clustering takes place were calculated. A lower limit for the height of the magnetic structure supporting the noise storm at 237 MHz was estimated too. 相似文献
122.
Émilie Hardy Agnès Levy Gilles Métris Manuel Rodrigues Pierre Touboul 《Space Science Reviews》2013,180(1-4):177-191
The MICROSCOPE space mission aims at testing the Equivalence Principle (EP) with an accuracy of 10?15. The test is based on the precise measurement delivered by a differential electrostatic accelerometer on-board a drag-free microsatellite which includes two cylindrical test masses submitted to the same gravitational field and made of different materials. The experiment consists in testing the equality of the electrostatic acceleration applied to the masses to maintain them relatively motionless at a well-known frequency. This high precision experiment is compatible with only very little perturbations. However, aliasing arises from the finite time span of the measurement, and is amplified by measurement losses. These effects perturb the measurement analysis. Numerical simulations have been run to estimate the contribution of a perturbation at any frequency on the EP violation frequency and to test its compatibility with the mission specifications. Moreover, different data analysis procedures have been considered to select the one minimizing these effects taking into account the uncertainty about the frequencies of the implicated signals. 相似文献
123.
This paper lists all geostationary and near-geostationary objects contained in ESA's DISCOS database. 相似文献
124.
E Chassefière J-L Bertaux J-J Berthelier M Cabane V Ciarletti G Durry F Forget M Hamelin F Leblanc M Menvielle M Gerasimov O Korablev S Linkin G Managadze A Jambon G Manhès Ph Lognonné P Agrinier P Cartigny D Giardini T Pike W Kofman A Herique P Coll A Person F Costard Ph Sarda Ph Paillou M Chaussidon B Marty F Robert S Maurice M Blanc C d'Uston J-Ch Sabroux J-F Pineau P Rochette 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,34(8):1702-1709
In view to prepare Mars human exploration, it is necessary to promote and lead, at the international level, a highly interdisciplinary program, involving specialists of geochemistry, geophysics, atmospheric science, space weather, and biology. The goal of this program will be to elaborate concepts of individual instruments, then of integrated instrumental packages, able to collect exhaustive data sets of environmental parameters from future landers and rovers of Mars, and to favour the conditions of their implementation. Such a program is one of the most urgent need for preparing human exploration, in order to develop mitigation strategies aimed at ensuring the safety of human explorers, and minimizing risk for surface operations. A few main areas of investigation may be listed: particle and radiation environment, chemical composition of atmosphere, meteorology, chemical composition of dust, surface and subsurface material, water in the subsurface, physical properties of the soil, search for an hypothesized microbial activity, characterization of radio-electric properties of the Martian ionosphere. Scientists at the origin of the present paper, already involved at a high degree of responsibility in several Mars missions, and actively preparing in situ instrumentation for future landed platforms (Netlander--now cancelled, MSL-09), express their readiness to participate in both ESA/AURORA and NASA programs of Mars human exploration. They think that the formation of a Mars Environment working group at ESA, in the course of the AURORA definition phase, could act positively in favour of the program, by increasing its scientific cross-section and making it still more focused on human exploration. 相似文献
125.
Aaron L. Gardony Tad T. Brunyé Caroline R. Mahoney Holly A. Taylor 《Spatial Cognition & Computation》2013,13(4):319-350
Abstract Research has demonstrated navigational aids impair spatial memory, but has not considered important spatial cognitive concepts. For example, impairment may stem from spatial perspective switches between route-based aids and survey-based memory assessments. Further, the verbal format of aid instructions may selectively interfere with verbal working memory (VWM). To address these potential explanations, participants navigated desktop virtual environments in a goal-directed manner. In each within-participants condition, participants either navigated with a verbal or tonal aid that presented mixed spatial perspective instructions or without aid. Both aids yielded slight navigational advantages and steep spatial memory costs despite their mixed perspective instructions. The equivalent impairment between information formats suggests navigational aids impair spatial memory by dividing attention rather than selective interference of VWM. 相似文献
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V. Dehant H. Lammer Y. N. Kulikov J.-M. Grießmeier D. Breuer O. Verhoeven Ö. Karatekin T. Van Hoolst O. Korablev P. Lognonné 《Space Science Reviews》2007,129(1-3):279-300
In light of assessing the habitability of Mars, we examine the impact of the magnetic field on the atmosphere. When there
is a magnetic field, the atmosphere is protected from erosion by solar wind. The magnetic field ensures the maintenance of
a dense atmosphere, necessary for liquid water to exist on the surface of Mars. We also examine the impact of the rotation
of Mars on the magnetic field. When the magnetic field of Mars ceased to exist (about 4 Gyr ago), atmospheric escape induced
by solar wind began. We consider scenarios which could ultimately lead to a decrease of atmospheric pressure to the presently
observed value of 7 mbar: a much weaker early martian magnetic field, a late onset of the dynamo, and high erosion rates of
a denser early atmosphere. 相似文献
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