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提出一种利用长短周期记忆(LSTM)神经网络模型动态预测无控再入过程中弹道系数(BC)值实现空间碎片高精度再入时刻预报。通过利用空间碎片两行根数(TLE)、简化通用摄动模型(SGP4)与公开的物体陨落时间作为实测数据样本,利用迭代修正BC值方法构建预测模型的训练集,由此构造用于预测BC值的LSTM模型预测BC,再采用高精度轨道外推动力学模型配合预测BC值预报再入时刻,结果表明基于LSTM模型预测BC的空间碎片再入时刻预报方法是可行的,在95%的置信度内,90天以上的再入时刻预报精度小于10%,30天预报精度小于8%。 相似文献
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航天器在空间遇到的不利环境可分为5类:真空、中性大气、等离子体、辐射和微型陨石及轨道碎片。它们都可能对在轨航天器产生不良影响。在特定情况下,这些影响还将十分严重,可导致航天器过早再入或损害其工程分系统,从而缩短航天器的使用寿命。因此,航天器的设计者在选择材料或确定机电分系统大小时必 相似文献
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空间碎片防护研究最新进展 总被引:2,自引:0,他引:2
空间碎片对在轨航天器的安全运行构成了严重威胁,对航天器的撞击事件频繁发生。随着空间碎片环境的日趋恶化,航天器的防护变得越来越重要。文章从空间碎片环境模型、撞击风险评估、航天器部件损伤、防护材料与结构的超高速撞击试验、撞击试验数据库建设、超高速发射设备、在轨撞击感知、机构间超高速发射设备交叉校验等方面对国内外空间碎片防护研究的进展进行了总结,并在此基础上给出我国未来空间碎片防护研究的发展建议。 相似文献
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CAST空间碎片超高速撞击试验研究进展 总被引:1,自引:1,他引:0
超高速撞击试验是开展载人航天器及大型应用卫星空间碎片超高速撞击风险评估和防护设计的基础,作为我国航天器环境效应和可靠性工程验证部门的北京卫星环境工程研究所在这个领域做了大量的工作。文章介绍了二级轻气炮超高速撞击地面模拟试验技术、典型防护结构防护性能的超高速撞击试验验证、载人航天器外露材料超高速撞击特性、毫米级弹丸7 km/s以上超高速稳定发射技术探索、高性能防护结构研究等方面的若干近期进展。展望了我国空间碎片防护需求和地面超高速撞击试验研究的发展方向。 相似文献
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文章利用一组二级轻气炮发射2017-T4 铝质球形弹丸撞击6061-T6单层铝板的地面试验数据,通过选择适当的函数模型,采用多元函数拟合的方法,得到了碎片云前端速度与靶板厚度、弹丸直径和弹丸速度关系的三元二阶多项式模型。再用另外一组数据对该模型进行检验,验证了其对碎片云前端速度具有较好的预测效果。将以上两组数据同样用于建立“无量纲化”模型进行碎片云前端速度预测,并与前述多项式模型的预测结果进行比较发现,该多项式模型预测的方均根误差及平均相对误差均明显优于“无量纲化”模型。该多项式模型可用于预测空间碎片撞击航天器产生的碎片云的前端速度,有助于航天器的空间碎片防护设计。 相似文献
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探测微小空间碎片的MOS电容传感器设计研究 总被引:1,自引:0,他引:1
获得在轨微小碎片环境数据,是建立、检验和完善微小碎片环境模型不可缺少的手段。国内空间碎片研究工作的深入开展,须要研制适合搭载到航天器上的微小碎片探测器,以完成轨道空间的微小碎片的质量、尺寸、速度及飞行方向等参数的测量。微小碎片撞击到金属-氧化物-半导体(MOS)电容传感器,会导致传感器放电和充电,通过检测充电过程的电脉冲信号,记录微小空间碎片撞击事件,从而获得微小空间碎片通量。文章就探测微小碎片的MOS电容传感器设计及其地面高速粒子撞击模拟试验进行了研究,并验证其探测微小空间碎片的可行性。 相似文献
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月地高速再入返回航天器时统设计及验证 总被引:1,自引:1,他引:0
《航天器工程》2016,(1):84-89
月地再入返回航天器在第二宇宙速度下实现服务舱和返回器分离,返回器以半弹道跳跃方式准确地再入并着陆在预定回收区,为了保证返回器的导航精度,对返回航天器的时间精度有一定的要求。为此,文章提出适用于二级信息拓扑结构的多舱段航天器的器上时间维护系统(简称"时统")和相应的地面验证系统设计。通过理论分析和地面验证试验,并结合月地高速再入返回航天器真实在轨飞行数据分析,证明此时统设计能够在较长时间内使月地再入返回航天器的器上时间精度保持在较高的水平。 相似文献
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In just 5 months, from September 2011 to January 2012, three campaigns of reentry predictions were carried out in support of the Italian civil protection authorities. The satellites involved were UARS, ROSAT and Fobos-Grunt, which received widespread attention for the marginal risk on the ground associated with their uncontrolled reentry. From the technical point of view, the three reentry campaigns offered the occasion to compare some semi-empirical thermospheric density models under varying solar and geomagnetic activity conditions, dealing with spacecraft characterized by quite different configurations, shapes, masses and attitude control. However, what made the experience substantially different from usual reentry test campaigns was the strict interaction with the civil protection community and the public. In fact, in order to provide understandable and unambiguous information useful for civil protection planning and applications, the nominal reentry time predictions were of no use, while a particular care was devoted to the definition of appropriate reentry uncertainty windows. The attention of the civil protection authorities was focused, of course, on the Italian territory, so the relevant question for any planning was the following: given a certain uncertainty window, where and when a fragment might have crossed the national airspace and hit the ground? In order to meet this demand, during the last 3–4 days of satellite residual lifetime, reentries where simulated over Italy to obtain quite accurate ground tracks, debris swaths and air space crossing time windows associated with the critical passes over the national territory still included in the current uncertainty window. This information was updated, if needed, but remained relatively stable and accurate until the reentry, not much affected by the actual trajectory evolution due to the varying air drag. In other words, it was easy to understand for people not familiar with orbital dynamics, unambiguous and remarkably stable, all qualities that made it very useful for civil protection applications. This paper presents the work done, the information issued to the Italian authorities, the results obtained and the lesson learned during the three above mentioned campaigns. They might be of some help and offer useful insights on reentry predictions for civil protection applications if really dangerous space objects were to decay from orbit without control in the future. 相似文献
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航天器跳跃式返回的再入动力学特性仿真 总被引:1,自引:0,他引:1
深空高速再入返回是航天返回技术面临的新问题。研究采用跳跃式返回方式解决高速再入产生的高过载、高热流峰值问题。建立了完整的航天器再入大气层飞行动力学模型;依据航天器跳跃式返回飞行剖面和返回飞行的运动特性,将再入大气过程划分为初始再入段、初次再入下降段、初次再入上升段、大气层外飞行段和二次再入段,详细研究了各飞行段航天器的动力学特性,简要分析了各阶段的制导任务。通过分析仿真结果,初步摸清了航天器深空飞行跳跃式再入动力学特性。 相似文献
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遗传算法在载人飞船返回轨道一体化设计中的应用 总被引:1,自引:0,他引:1
载人飞船返回再入轨道设计的主要任务是确定出标准返回轨道和再入制导规律。遗传算法具有全局寻优的特点,适合于工程设计的要求。文章探讨采用遗传算法实现飞船返回轨道的一体化设计,并给出飞船返回轨道设计步骤。 相似文献
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A model for the evolution of the low Earth orbit man-made debris population is presented and the results of several test cases discussed. Debris sources include normal operations in space, explosions occurring on spacecraft in orbit, and collisions between objects in orbit; the stochastic occurrence of these deposition events is modeled using Monte Carlo techniques. A technique for discriminating between objects populating long-life vs rapid-decay orbits is discussed and applied to the analysis of debris contributions from collisions of comparable sized objects. In varying degrees, each of the cases presented indicate there is cause for concern for spacecraft and space operations from the 1990s onward-man-made debris will play a role which may vary from presenting a considerable hazard to certain operations or certain spacecraft to effectively prohibiting the use of certain spaceccraft or space operations. 相似文献
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V. V. Mironov 《Cosmic Research》2003,41(2):204-208
A three-dimensional mathematical model and a program complex for modeling the external effect of small-sized space debris particles on a spacecraft are developed. On the basis of the rectangular contributions method a new technique is developed for restoring the density of small-sized space debris from a small number of recorded debris collisions with recording sensors. From the form of the density function the total number of points having reached the spacecraft surface is restored. The comparative results of modeling are presented. 相似文献