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Jurewicz A.J.G. Burnett D.S. Wiens R.C. Friedmann T.A. Hays C.C. Hohlfelder R.J. Nishiizumi K. Stone J.A. Woolum D.S. Becker R. Butterworth A.L. Campbell A.J. Ebihara M. Franchi I.A. Heber V. Hohenberg C.M. Humayun M. McKeegan K.D. McNamara K. Meshik A. Pepin R.O. Schlutter D. Wieler R. 《Space Science Reviews》2003,105(3-4):535-560
Genesis (NASA Discovery Mission #5) is a sample return mission. Collectors comprised of ultra-high purity materials will be
exposed to the solar wind and then returned to Earth for laboratory analysis. There is a suite of fifteen types of ultra-pure
materials distributed among several locations. Most of the materials are mounted on deployable panels (‘collector arrays’),
with some as targets in the focal spot of an electrostatic mirror (the ‘concentrator’). Other materials are strategically
placed on the spacecraft as additional targets of opportunity to maximize the area for solar-wind collection.
Most of the collection area consists of hexagonal collectors in the arrays; approximately half are silicon, the rest are for
solar-wind components not retained and/or not easily measured in silicon. There are a variety of materials both in collector
arrays and elsewhere targeted for the analyses of specific solar-wind components.
Engineering and science factors drove the selection process. Engineering required testing of physical properties such as the
ability to withstand shaking on launch and thermal cycling during deployment. Science constraints included bulk purity, surface
and interface cleanliness, retentiveness with respect to individual solar-wind components, and availability.
A detailed report of material parameters planned as a resource for choosing materials for study will be published on a Genesis
website, and will be updated as additional information is obtained. Some material is already linked to the Genesis plasma
data website (genesis.lanl.gov). Genesis should provide a reservoir of materials for allocation to the scientific community
throughout the 21st Century.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Paul S. Butterworth 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(9):177-184
In April 1972 OAO-2 obtained broadband filter measurements of the Galilean satellites from 2100 to 4300 Å. All four bodies were shown to have low albedos declining towards shorter wavelengths, thus constraining the proportions of their surfaces that could be covered by reflective frosts. Although the vast data return from Voyager spacecraft has for the first time permitted a detailed comparison of Galilean satellites with terrestrial planets, it has not removed the need for continuing long time-base observations of the former. Since January 1978, IUE has repeatedly obtained Galilean spectra within the range 1150 to 3200 Å. Observations of Io have placed an upper limit on the global abundance of SO2 in its atmosphere. Spectral variations with phase have allowed spatial mapping of surface reflectance in the case of Io, and may enable volcanic activity to be monitored. 相似文献
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M. Combes Th. Encrenaz R. Courtin J. Caldwell T. Owen V. Moore R. Courtin K.H. Fricke V. Moore P.S. Butterworth 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(9):169-175
The first unambiguous identification of ammonia in the upper atmosphere of Jupiter has been obtained from the observation of individual NH3 bands in an IUE high resolution spectrum in the 2100–2400 Å spectral range. The variation with wavelength of the strengths of these NH3 bands implies that the NH3 abundance has to be strongly reduced by photolysis in the upper jovian atmosphere. Preliminary analysis by means of scattering models shows that the ammonia mixing ratio cannot be constant with altitude. The mixing ratio NH3/H2 ranges from 5 10?8 to 5 10?7 at the 250 mb pressure level, and decreases as P or P2 toward higher altitudes. 相似文献
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