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81.
82.
Ray P. Linville 《Space Policy》1986,2(3)
Most of the recent discussions concerning Soviet space activities focus on the new systems and emerging technologies, particularly those with military application. How the military capabilities of these systems and technologies will be used is equally important. Their employment will be guided by current Soviet thinking and policy concerning military actions in space. This policy has its origins in Soviet military doctrine which emphasizes offensive systems. Although the Soviet space programme denies having any military objectives, it is guided by a historical link with the Soviet military and directed by decisions made within the framework of Soviet doctrine. Additional insights into Soviet thinking concerning the militarization of space can be gained from recent treaties which the Soviets have signed concerning military space activities. 相似文献
83.
For Space Transportation System (i.e. Space Shuttle) launched satellites destined for a Geosynchronous Earth Orbit (GEO), there is a need for cost-effective, versatile propulsion systems to provide the perigee burn, i.e. to boost the satellite from Low Earth Orbit (LEO) to Geosynchronous Transfer Orbit (GTO). Surveys of commercial spacecraft activities and future GEO satellite requirements indicate that a spacecraft propulsion system that will provide the perigee burn for a broad range of future commercial satellites would have an excellent market potential.Parametric studies to investigate and define attractive perigee-burn upper propulsion systems (i.e. an Upper Propulsion Stage, or a UPS) are presented. The feasibility and payload capacilities that could be provided by a UPS assembled from essentially off-the-shelf components and subsystems, and the benefits that could be achieved by using major subsystems specifically tailored for the application are presented. The results indicate that attractive UPS configurations can be defined using either off-the-shelf or optimized major subsystems. 相似文献
84.
智能天线结构模糊自适应变形控制实验研究 总被引:2,自引:1,他引:2
基于dSPACE半物理仿真系统和所研制的压电作动器,设计并构建了智能天线结构实验平台,进行了结构变形控制实验研究。实验中采用常规PID作为基本控制方法,并在此基础上设计了一种模糊自适应PID控制器,将两种方法对应的不同控制效果进行了对比。结果表明:在所给的实验条件下,基于压电材料可实现对智能天线结构变形的控制,作动器控制变形量最大可达166μm;两种控制方法均可对结构变形进行控制,模糊自适应方法的绝对位置控制精度达到±0.5μm;应用模糊自适应PID控制方法对结构进行变形控制,较之常规PID控制方法能够降低系统响应的超调量,缩短稳定时间,提高控制精度,得到更好的控制过程。 相似文献
85.
The transport characteristics of macroparticles, charged by the solar radiation under microgravity conditions, were investigated by analyzing the videorecords of experiments carried out onboard the Mirorbital station. The temperature, distributions of velocities, charge, friction coefficient, and diffusion coefficient were obtained for bronze particles. 相似文献
86.
通过分析返回舱在着陆时所具有的水平速度也可能对着陆安全构成威胁的事实,论述了为返回舱增加横向缓冲装置的必要性,由此提出亟需解决的问题——在返回舱着陆下降过程中测量其水平运动速度。提出了全新概念的以视觉图像为唯一信息来源的返回舱水平速度测量方法,仅以双目摄像机系统作为传感器,避免了对返回舱原有传感器系统的改造。通过对着陆区域地面图像的采集和在线处理,利用双目交会测量原理得到返回舱当前的大地坐标和姿态。仿真实验证明,方法简单易行,测量结果可靠。 相似文献
87.
L. M. Zelenyi M. S. Dolgonosov A. A. Bykov V. Yu. Popov Kh. V. Malova 《Cosmic Research》2002,40(4):357-366
Using both analytical and numerical models of the collisionless anisotropic current sheet generated by the impinging flows of transient ions, we have studied the self-consistent solutions taking the plasma trapped in the sheet into account. It is demonstrated that there exists a limited window in the space of system parameters where self-consistent solutions can exist. When the density of the quasi-trapped plasma is sufficiently large, a redistribution of the total current can be a cause of the sheet decay, when the local current of the trapped particles compensate (totally or in part) the main current in the center and at the edges of the sheet, while the total current generated by ions on the trapped trajectories vanishes. 相似文献
88.
89.
Within the European space platform program the EURECA is being established as a ground-based platform for short microgravity missions. The development towards a serviceable platform for longer, scientific missions is described. The plan of an advanced space-based platform for increasing payload demands is outlined. The platform design and the adaptation to scientific missions and servicing operations are investigated. The cost-effective utilization of the different platform types using new operational concepts is analyzed in parametric life cycle cost calculations for different payloads and mission scenarios. 相似文献
90.
The European Space Agency (ESA) contribution to the International Space Station (ISS) goes much beyond the delivery of hardware like the Columbus Laboratory, its payloads and the Automated Transfer Vehicles. ESA Astronauts will be members of the ISS crew. ESA, according to its commitments as ISS international partner, will be responsible to provide training on its elements and payloads to all ISS crewmembers and medical support for ESA astronauts. The European Astronaut Centre (EAC) in Cologne has developed over more than a decade into the centre of expertise for manned space activities within ESA by contributing to a number of important co-operative spaceflight missions. This role will be significantly extended for ISS manned operations. Apart from its support to ESA astronauts and their onboard operations, EAC will have a key role in training all ISS astronauts on ESA elements and payloads. The medical support of ISS crew, in particular of ESA astronauts has already started. This paper provides an overview on status and further plans in building up this homebase function for ESA astronauts and on the preparation towards Training Readiness for ISS crew training at EAC, Cologne. Copyright 2001 by the European Space Agency. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Released to IAF/IAA/AIAA to publish in all forms. 相似文献