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131.
基于混杂系统的空间飞行器悬停控制 总被引:2,自引:1,他引:2
基于空间飞行器的轨道动力学原理,利用混杂系统模型研究了悬停轨道问题,建立了悬停轨道的混杂系统模型;借此模型,针对目标星轨道为椭圆的情况,提出了等距离悬停轨道控制和椭圆悬停轨道控制两种方案,分别推导出在这两种方案下对悬停星所施加的控制力。数值仿真结果表明,分别对悬停星施加相应的控制力,能够实现对目标星的悬停。 相似文献
132.
Helene L. Winters Deborah L. Domingue Teck H. Choo Raymond Espiritu Christopher Hash Erick Malaret Alan A. Mick Joseph P. Skura Joshua Steele 《Space Science Reviews》2007,131(1-4):601-623
The MESSENGER Science Operations Center (SOC) is an integrated set of subsystems and personnel whose purpose is to obtain,
provide, and preserve the scientific measurements and analysis that fulfill the objectives of the MErcury Surface, Space ENvironment,
GEochemistry, and Ranging (MESSENGER) mission. The SOC has two main functional areas. The first is to facilitate science instrument
planning and operational activities, including related spacecraft guidance and control operations, and to work closely with
the Mission Operations Center to implement those plans. The second functional area, data management and analysis, involves
the receipt of science-related telemetry, reformatting and cataloging this telemetry and related ancillary information, retaining
the science data for use by the MESSENGER Science Team, and preparing data archives for delivery to the Planetary Data System;
and the provision of operational assistance to the instrument and science teams in executing their algorithms and generating
higher-level data products. 相似文献
133.
Our scientific forefathers discuss the interrelationships between water, climate, the atmosphere, and life on Earth and other
terrestrial planets at a workshop in Nichtchatel, Switzerland. 相似文献
134.
Metallic and Oxidized Aluminum Debris Impacting the Trailing Edge of the Long Duration Exposure Facility (LDEF) 总被引:1,自引:0,他引:1
A total of 87 microcraters >30 m in diameter that were found in gold substrates exposed on the trailing edge of the non-spinning Long Duration Exposure Facility (LDEF) yielded analyzable projectile residues in their interiors. Using qualitative SEM-EDS analysis methods, some 60 of these craters were formed by natural cosmic-dust particles, while 27 residues (31%) were assigned to orbital debris (Hörz et al., 1993). The far majority of the orbital-debris impacts, 24 (89%) of the 27 events, contained only aluminum in their X-ray spectra. The present study evaluates these aluminum-rich residues in detail and employs a windowless X-ray detector, which permits for the analysis of low-Z elements and specifically of oxygen. This makes it possible to discriminate between oxidized (Al2O3) and metallic (Al) projectiles from dramatically different sources, the former produced during solid-fuel rocket firings, the latter resulting from explosively or collisionally disrupted spacecraft.Of the 24 craters analyzed with the windowless detector, 13 (54%) contained Al2O3 and 11 (46%) yielded structurally disintegrated Al metal. The oxidized residues preferentially occur in the smaller craters, all <60 m in diameter. Corresponding particles on LDEF's trailing edge are <35 m in diameter. Some 70% of this particle population is composed of Al2O3. Although solid-fuel rocket exhaust products are typically <5 m in size, they tend to coagulate into crusts at the rocket nozzle to be shed occasionally as relatively large, aggregate particles. Structurally disintegrated, metallic fragments compose one-third of all particles <35 m, but they dominate all particles >35 m, and thus all craters >60 m. These findings clearly establish that solid-rocket exhaust particles, as well as explosively or collisionally produced debris, exist in low-inclination, high-eccentricity orbits in sufficient quantities that they must be accounted for in models describing the present and future orbital-debris population at typical Shuttle and Space Station altitudes. 相似文献
135.
针对圆轨道径向或迹向欠驱动航天器编队重构控制问题,提出了欠驱动脉冲控制方法。首先,基于圆轨道欠驱动航天器相对运动动力学模型,分析了两类欠驱动条件下的系统可控性和重构可行性。然后,解析推导了两类欠驱动条件下实现重构所需的最少脉冲次数以及对应的速度增量消耗。最后,设计数值仿真算例,验证了本文提出的欠驱动脉冲控制方法的正确性。仿真结果表明:径向和迹向欠驱动条件下均可实现圆轨道编队重构。与全驱动控制方法相比,欠驱动控制方法可有效避免由推力器故障引起的重构任务失效,故而提高了控制系统的灵活性与可靠性。 相似文献
136.
137.
利用1980年Nimbus-7卫星网络点资料(温度场)对中层大气行星波的空间结构进行诊断和分析后发现,行星波扰动主要集中于冬半球,夏半球及赤道地区上空的扰动则相对较弱,但也不可忽视.冬半球行星波扰动中的瞬变波部分可以跨过赤道向夏半球传播,且传播主要集中于20kin和70km两个高度层附近.波数1冬季以准定常行里波为主,夏季瞬变行星波与准定常行星波波幅相当.行星波扰动的波幅从冬到夏的衰减主要表现在波数1和波数2上,波数3变化不大. 相似文献
138.
空间太阳电池板银互连片原子氧效应模拟试验 总被引:2,自引:0,他引:2
空间太阳电池板可作为空间飞行器的动力源,但由于原子氧在空间太阳电池板银互连片上的腐蚀作用,可能影响空间太阳电池板的有效寿命.因此,在北航流体所设计的原子氧效应地面模拟试验设备中,对空间太阳电池板的银互连片进行了抗原子氧效应地面模拟试验研究.获得了银箔和不同防护镀层材料在原子氧环境中的不同剥蚀结果,这为进行银互连片表面的原子氧防护提供了必要的应用和设计依据. 相似文献
139.
140.
Chang-Yin Zhao Ming-Jiang Zhang Hong-Bo Wang Wei Zhang Jian-Ning Xiong 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Based on the orbital resonance model, we study the two-dimensional phase plane structure of the motion of space debris orbiting the geosynchronous ring under the combined effects of the tesseral harmonics J22, J31 and J33 of the Earth’s gravitational field. We present the main characteristic parameters of the two-dimensional phase plane structure. We also analyze the stability of the two-dimensional phase plane structure with numerical method. Our main findings indicate that the combined effects of the tesseral harmonics J22, J31 and J33 fully determine the two-dimensional phase plane structure of the space debris, and it remains robust under the effect of the Earth’s actual gravitational field, the luni-solar perturbations and the solar radiation pressure with the normal area-to-mass ratios. 相似文献