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Aldrin A Amara A Aris L Baierl N Beatty P Beaulieu C Behnke T Castegini R Chauhan A Cojanis P Dayawansa P Diop M Eito K Engle S Feretti S Gassama H Genova B Goulding C Janjua J Jansaeng T Jousset F Kopik A Laurin C Leggatt J Li H Mezzadri M Miura A Nolet S Ogami S Patry J Patten L Payerne C Peer G Prampolini M Rheaume C Saary J Spehar D Sufi A Sun B Thompson JB Thomson W Trautner R Tursunmuratov M Venet V Wilems E Wilson H Wittwer K Wokke F Wu Y Zhou S Zilioli I 《Acta Astronautica》2002,51(1-9):637-646
Issues about commercialization of space have been a growing concern in the past decade for the space community. This paper focuses on the work from a team of 51 students attending the Summer Session Program of the International Space University in Bremen, Germany. CASH 2021 (Commercial Access and Space Habitation) documents a plan that identifies commercial opportunities for space utilization that will extend human presence in space, and will chart the way forward for the next 20 years. The group selected four commercial sectors that show the most promise for the future: tourism, entertainment, space system service, assembly and debris removal, and research and development/production. The content of this document presents the results of their research. Historical activities in each of the commercial sectors are reviewed along with the current market situation. To provide a coherent background for future commercialization possibilities a scenario has been developed. This scenario includes a postulated upon ideal future and includes social, political and economic factors that may affect the space industry over the timeline of the study. The study also presents a roadmap, within the limited optimistic scenario developed, for the successful commercialization of space leading to future human presence in space. A broad range of commercially viable opportunities, not only within the current limits of the International Space Station, but also among the many new developments that are expected by 2021 are discussed. 相似文献
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The distortion of a pseudorandom scanned TV signal caused by flutter and skew introduced by the tape recording apparatus is analyzed theoretically. Specifically, the signal-to-noise ratio is computed for a typical system, under the assumption that the distortion can be considered to be additive random noise with a Gaussian amplitude distribution. 相似文献
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G. Randall Gladstone Steven C. Persyn John S. Eterno Brandon C. Walther David C. Slater Michael W. Davis Maarten H. Versteeg Kristian B. Persson Michael K. Young Gregory J. Dirks Anthony O. Sawka Jessica Tumlinson Henry Sykes John Beshears Cherie L. Rhoad James P. Cravens Gregory S. Winters Robert A. Klar Walter Lockhart Benjamin M. Piepgrass Thomas K. Greathouse Bradley J. Trantham Philip M. Wilcox Matthew W. Jackson Oswald H. W. Siegmund John V. Vallerga Rick Raffanti Adrian Martin J.-C. Gérard Denis C. Grodent Bertrand Bonfond Benoit Marquet François Denis 《Space Science Reviews》2017,213(1-4):447-473
The ultraviolet spectrograph instrument on the Juno mission (Juno-UVS) is a long-slit imaging spectrograph designed to observe and characterize Jupiter’s far-ultraviolet (FUV) auroral emissions. These observations will be coordinated and correlated with those from Juno’s other remote sensing instruments and used to place in situ measurements made by Juno’s particles and fields instruments into a global context, relating the local data with events occurring in more distant regions of Jupiter’s magnetosphere. Juno-UVS is based on a series of imaging FUV spectrographs currently in flight—the two Alice instruments on the Rosetta and New Horizons missions, and the Lyman Alpha Mapping Project on the Lunar Reconnaissance Orbiter mission. However, Juno-UVS has several important modifications, including (1) a scan mirror (for targeting specific auroral features), (2) extensive shielding (for mitigation of electronics and data quality degradation by energetic particles), and (3) a cross delay line microchannel plate detector (for both faster photon counting and improved spatial resolution). This paper describes the science objectives, design, and initial performance of the Juno-UVS. 相似文献
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Schulze-Makuch D Méndez A Fairén AG von Paris P Turse C Boyer G Davila AF António MR Catling D Irwin LN 《Astrobiology》2011,11(10):1041-1052
In the next few years, the number of catalogued exoplanets will be counted in the thousands. This will vastly expand the number of potentially habitable worlds and lead to a systematic assessment of their astrobiological potential. Here, we suggest a two-tiered classification scheme of exoplanet habitability. The first tier consists of an Earth Similarity Index (ESI), which allows worlds to be screened with regard to their similarity to Earth, the only known inhabited planet at this time. The ESI is based on data available or potentially available for most exoplanets such as mass, radius, and temperature. For the second tier of the classification scheme we propose a Planetary Habitability Index (PHI) based on the presence of a stable substrate, available energy, appropriate chemistry, and the potential for holding a liquid solvent. The PHI has been designed to minimize the biased search for life as we know it and to take into account life that might exist under more exotic conditions. As such, the PHI requires more detailed knowledge than is available for any exoplanet at this time. However, future missions such as the Terrestrial Planet Finder will collect this information and advance the PHI. Both indices are formulated in a way that enables their values to be updated as technology and our knowledge about habitable planets, moons, and life advances. Applying the proposed metrics to bodies within our Solar System for comparison reveals two planets in the Gliese 581 system, GJ 581 c and d, with an ESI comparable to that of Mars and a PHI between that of Europa and Enceladus. 相似文献
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Philip R. Harris 《Space Policy》2005,21(1):75-76
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Philip P. Chandler II 《Space Policy》1985,1(1):7-9
This article contrasts the political motivations behind the US space station initiative with those underlying the European Space Agency's Long Term Plan. Philip Chandler concludes that European cooperation in NASA's space station programme (SSP) will serve three needs: to buy time; to allow European users to undertake longer, manned experiments; and, to keep the Spacelab teams intact. However, in itself the SSP holds little value for Europe. 相似文献