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An analytical model for calculation of the thrust and pressure modulation of a solid propellant rocket by means of a fluidic vortex valve with secondary combustion has been developed. Thrust control by the vortex valve method was found superior to the axial injection of control flow. Addition of oxygen in the injected flow improves the energetic performance of the system as well as the thrust modulation capability. Experiments have been conducted using a mixture of nitrogen and oxygen as the injection gas. The two main parameters investigated in a series of experiments were the oxygen percentage in the injection gas and the ratio between the mass flow rates of the control gas and the solid propellant combustion products. The results show an increase of thrust by a factor of 2 for a 25% addition in mass flow rate by secondary injection at optimal conditions. 相似文献
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H. Taylor P. Cloutier M. Dryer S. Suess A. Barnes R. Wolff A. Stern 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(7):343-346
During the summer of 1979, solar coronal structure was such that a sequence of recurrent regions produced a corresponding sequence of corotating solar wind streams, with pronounced downstream signatures. One of these stream events passed Earth on July 3, and was observed later at Venus late on July 11th, with similar characteristics. Corresponding in-situ measurements at Earth from the Atmospheric Explorer-E satellite and at Venus from the Pioneer Venus Orbiter are examined for evidence of comparable perturbations of the planetary ionospheres. The passage of the stream shock front is found to be associated with pronounced fluctuations in n(0+) which appear as pronounced local depletion of ion concentrations in both ionospheres. The ionosphere disturbances appear to be closely associated with large variations in the solar wind momentum flux. The implied local ionospheric depletions observed at each planet are interpreted to be the consequence of plasma redistribution, rather than actual depletions of plasma. 相似文献
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Maurizio Martignano Mikael Wolff Uwe Brauer Paul Kiernan 《Acta Astronautica》2007,61(11-12):1053-1060
The European Space Agency (ESA) initiated a joint project with the National Aeronautics and Space Administration (NASA) and industry partners for improved authoring and execution of Operations Data File (ODF) procedures. The system consists of an authoring tool and a viewer. The authoring tool is currently used by NASA and ESA to write/convert ODF procedures. The viewer will be used onboard the International Space Station (ISS) starting from Flight Increment 11. The new system, thanks to its interaction capability, will help astronauts and operators in the execution of checklist and logic flow procedures that ensure precise performance of experiments and smooth operation of the various systems. 相似文献
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NASA的马歇尔航空中心(位于阿拉巴马州的Hunstville)无疑要肩负更具挑战性的重要使命,因为他们需要负责研发一系列大型地月火箭发射至月球上的指定地点.时至今日,马歇尔航空中心已成为高级"地球至轨道"推进系统和技术方面的佼佼者.
1975年7月15日,马歇尔航空中心研发的Salum 1-B装载着美国和苏联首次合作的成果飞向了太空,此即Apollo-Soyuz计划.完成阿波罗项目后,马歇尔团队随即投入更有挑战性的工作中,设计一种代表革命性飞越的运载系统:航天飞机. 相似文献
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瑞士威力铭-马科黛尔公司 《航空制造技术》2008,(13)
瑞士加工中心制造商威力铭-马科黛尔公司着重于质量和生产效率,主要活跃于航空/航天、精密机械、钟表和医疗行业,并以其为用户提供的高性能交钥匙解决方案而著称. 相似文献
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S.A. Wolff L.H. Coelho M. Zabrodina E. Brinckmann A.-I. Kittang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Successful growth and development of higher plants in space rely on adequate availability and uptake of water and nutrients, and efficient energy distribution through photosynthesis and gas exchange. In the present review, literature has been reviewed to assemble the relevant knowledge within space plant research for future planetary missions. Focus has been on fractional gravity, space radiation, magnetic fields and ultimately a combined effect of these factors on gas exchange, photosynthesis and transport of water and solutes. 相似文献