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351.
C. Pardini L. Anselmo 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
On 11 January 2007, the People’s Republic of China conducted a successful anti-satellite test against one of their defunct polar-orbiting weather satellites. The target satellite, called Fengyun-1C, had a mass of 880 kg and was orbiting at an altitude of about 863 km when the collision occurred. Struck by a direct-ascent interceptor at a speed of 9.36 km/s, the satellite disintegrated, spreading the cataloged fragments between 200 and 4000 km, with the highest concentration near the breakup height. By the end of April 2008, 2377 pieces of debris, including the original payload remnant, had officially been cataloged by the US Space Surveillance Network. Of these, nearly 1% had reentered the Earth’s atmosphere. This deliberate act is the largest debris-generating event on record, and its consequences will adversely affect circumterrestrial space for many years. 相似文献
352.
航天器微流星体及空间碎片环境与风险分析 总被引:1,自引:0,他引:1
微流星体及空间碎片的高速撞击威胁着长寿命、大尺寸航天器的安全运行 ,导致其严重的损伤和灾难性的失效。文章对低地球轨道微流星体及空间碎片环境进行了分析 ,给出了微流星体及空间碎片对航天器威胁方向的确定方法 ,得到了空间碎片撞击航天器相对撞击角的概率分布以及地球对微流星体遮挡的影响。编制了风险分析软件 ,以采用单防护屏防护结构的柱状低地球轨道航天器为例进行风险分析。 相似文献
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飞机操纵系统中因舵机输出较快,助力器响应较慢而存在相互运动碰撞,影响操纵品质和飞行安全。对发生碰撞的机理进行了深入分析,建立了舵机与助力器运动特性匹配关系和用于碰撞研究的数学模型,通过实例,找到了对碰撞最有影响的参量。 相似文献
355.
《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2023,71(1):539-555
The number of Earth orbiting objects is constantly growing, and some orbital regions are becoming risky environments for space assets of interest, which are increasingly threatened by accidental collisions with other objects, especially in Low-Earth Orbit (LEO). Collision risk assessment is performed by various methods, both covariance and non-covariance based. The Cube algorithm is a non-covariance-based method used to estimate the collision rates between space objects, whose concept consists in dividing the space in cubes of fixed dimension and, at each time instant, checking if two or more objects share the same cube. Up to now its application has been limited to the long-term scenarios of orbital debris evolutionary models, where considering the uncertainties is not necessary and impractical. Within operative contexts, instead, medium-term collision risk analysis may be an important task, in which the propagation-related uncertainties play a prominent role, but the timescale poses challenges for the application of standard covariance-based conjunction analysis techniques. In this framework, this paper presents an approach for the evaluation of the medium-term collision frequency for objects in LEO, called Uncertainty-aware Cube method. It is a modified version of the Cube, able to take the possible errors in the space objects’ position into account for the detection of the conjunctions. As an object’s orbit is propagated, the along-track position error grows more and more, and each object could potentially be in a different position with respect to the one determined by numerical propagation and, thus, in a different cube. Considering the uncertainties, at each time instant the algorithm associates more than one cube to each object and checks if they share at least one cube. If so, a conjunction is detected and a degree of confidence is evaluated. The performance of the method is assessed in different LEO scenarios and compared to the original Cube method. 相似文献
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探测器安全着陆是行星探测的关键环节,而目前着陆成功率偏低,进行安全着陆风险研究有着非常现实的工程需求.为此,首先分析探测器结构与着陆方式,梳理行星表面影响安全着陆的主要因素,明确着陆安全判据,然后基于蒙特卡罗思想,模拟行星表面地貌和探测器着陆方式,给出了探测器在盲降下安全着陆概率估计的仿真方法.在此基础上,考虑探测器尺寸和着陆区域面积,对探测器安全着陆概率进行敏感性分析,结果表明探测器的尺寸对安全着陆概率有显著影响. 相似文献
360.
在系统初步设计阶段,针对初步危险分析过程中缺乏具体、明确的实施方法,提出了基于危险要素的危险分析技术.确定对象中的危险元素,对部件进行分类,结合不同类型部件各种可能的状态,考虑其对危险元素的影响,分析可能的触发机制并得出相关的威胁/对象,识别设计中的危险和薄弱环节.以飞机燃油系统为例,验证了该分析技术的实用性和有效性.在系统的初步方案设计阶段,该方法能够与设计方案相结合,全面分析可能存在的危险,为后续设计和危险分析提供工作侧重点,并适用于后续研制阶段的安全性分析工作. 相似文献