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951.
Brownlee DE Tsou P Atkins KL Yen CW Vellinga JM Price S Clark BC 《Acta Astronautica》1996,39(1-4):51-60
The STARDUST Discovery mission will collect samples of cometary coma and interstellar dust and return them to Earth. Five years after launch in February 1999, coma dust in the 1- to 100-micrometers size range will be captured by impact into ultra-low-density silica aerogel during a 6 kms-1 flyby of Comet Wild 2. The returned samples will be investigated at laboratories where the most critical information on these primitive materials is retained. The Jet Propulsion Laboratory will provide project management with Lockheed Martin Astronauts as the spacecraft industrial partner. STARDUST management will aggressively and innovatively achieve cost control through the use of Total Quality Management principles, the chief of which will be organization in a Project Engineering and Integration Team that "flattens" the traditional hierarchical structure by including all project elements from the beginning, in a concurrent engineering framework focusing on evolving Integrated Mission Capability. 相似文献
952.
The willingness of the European Union (EU) to acquire an important position by defining a well articulated space policy for Europe requires a redefinition of the roles of the various actors of this policy. This has been demonstrated at the last ESA Ministerial Conference despite the financial difficulties encountered by all spacefaring European countries. The European Space Science Committee (ESSC), an associated Committee of the European Science Foundation (ESF), actively participated in the elaboration of such a policy by presenting the point of view of the space scientific community and making recommendations to ensure that scientific space research is appropriately accounted for in overall European space policy. The ESSC is briefly described along with its activities and contributions to the definition of a European space policy. 相似文献
953.
Preflight training frequently has been proposed as a potential solution to the problem of space motion sickness. The paper considers successively the otolith reinterpretation, the concept for a preflight adaptation trainer and the research with the Miami University Seesaw, the Wright Patterson Air-Force Base Dynamic Environment Simulator and the Visually Coupled Airborne Systems Simulator prototype adaptation trainers. 相似文献
954.
The experiment was performed to ascertain whether man's ability to perform mechanical work would be altered as a result of exposure to the weightless environment. Skylab II crewmen were exercised on a bicycle ergometer at loads approximating 25%, 50%, and 75% of their maximum oxygen uptake while their physiological responses were monitored. The results of these tests indicate that the crewmen had no significant decrement in their response to exercise during their exposure to zero gravity. Immediately postflight, however, all crewmen demonstrated an inability to perform the programmed exercise with the same metabolic effectiveness as they did both preflight and inflight. The most significant changes were elevated heart rates for the same work load and oxygen consumption (decreased oxygen pulse), decreased stroke volume, and decreased cardiac output at the same oxygen consumption level. It is apparent that the changes occurred inflight, but did not manifest themselves until the crewmen attempted to readapt to the 1-G environment. 相似文献
955.
论述了用星载微波辐射计性能测试的地面定标系统。该系统由定标负载,定标接收机,转以,微波屏蔽暗室,微机及附件组成,利用微机对地面定标系统转台转速和SMR一些参数进行控制,并对测量定标数据进行实时采样,处理和显示。 相似文献
956.
957.
提出一种利用辅助序列进行PN序列捕捉的闭环系统,利用辅助序列估计本地PN序列与接收信号的相位差和方向,从而减小捕获时间。 相似文献
958.
959.
N Kanas V Salnitskiy E M Grund D S Weiss V Gushin O Kozerenko A Sled C R Marmar 《Acta Astronautica》2001,49(3-10):243-260
Background: Anecdotal reports from space and results from simulation studies on Earth have suggested that space crewmembers may experience decrements in their interpersonal environment over time and may displace tension and dysphoria to mission control personnel. Methods: To evaluate these issues, we studied 5 American astronauts, 8 Russian cosmonauts, and 42 American and 16 Russian mission control personnel who participated in the Shuttle/Mir space program. Subjects completed questions from subscales of the Profile of Mood States, the Group Environment Scale, and the Work Environment Scale on a weekly basis before, during, and after the missions. Results: Among the crewmembers, there was little evidence for significant time effects based on triphasic (U-shaped) or linear models for the 21 subscales tested, although the presence of an initial novelty effect that declined over time was found in three subscales for the astronauts. Compared with work groups on Earth, the crewmembers reported less dysphoria and perceived their crew environment as more constraining, cohesive, and guided by leadership. There was no change in ratings of mood and interpersonal environment before, during, and after the missions. Conclusions: There was little support for the presence of a moderate to strong time effect that influenced the space crews. Crewmembers perceived their work environment differently from people on Earth, and they demonstrated equanimity in mood and group perceptions, both in space and on the ground. Grant numbers: NAS9-19411. 相似文献
960.