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星座设计中避免卫星碰撞问题的研究 总被引:1,自引:0,他引:1
随着小卫星技术的发展 ,越来越多的航天任务采用小卫星星座来完成 ,在星座的设计过程中需要考虑的因素众多。本文从星座运行的安全性角度 ,分析了星座中卫星发生碰撞的机会和碰撞概率 ,对星座中存在的卫星之间可能发生的碰撞问题进行了研究 ,并提出了解决方法 相似文献
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《Acta Astronautica》2014,93(1):311-320
The mission planning of GEO debris removal with multiple servicing spacecrafts (SScs) is studied in this paper. Specifically, the SScs are considered to be initially on the GEO belt, and they should rendezvous with debris of different orbital slots and different inclinations, remove them to the graveyard orbit and finally return to their initial locations. Three key problems should be resolved here: task assignment, mission sequence planning and transfer trajectory optimization for each SSc. The minimum-cost, two-impulse phasing maneuver is used for each rendezvous. The objective is to find a set of optimal planning schemes with minimum fuel cost and travel duration. Considering this mission as a hybrid optimal control problem, a mathematical model is proposed. A modified multi-objective particle swarm optimization is employed to address the model. Numerous examples are carried out to demonstrate the effectiveness of the model and solution method. In this paper, single-SSc and multiple-SSc scenarios with the same amount of fuel are compared. Numerous experiments indicate that for a definite GEO debris removal mission, that which alternative (single-SSc or multiple-SSc) is better (cost less fuel and consume less travel time) is determined by many factors. Although in some cases, multiple-SSc scenarios may perform worse than single-SSc scenarios, the extra costs are considered worth the gain in mission safety and robustness. 相似文献
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为了实现对航天器在轨解体事件及其碎片分布特性的快速分析,中国空气动力研究与发展中心(CARDC)开发了SFA(Spacecraft Fragmentation Analysis)软件。该软件主要基于CSBM航天器解体模型开发形成,同时集成了NASA的标准解体模型。SFA软件具有解体程度分析、解体碎片生成、碎片分布统计等功能,并可以实时显示计算结果、绘制统计曲线。文章着重介绍了SFA软件2.0版的功能模块、主要算法、界面及使用方法等,并针对Iridium 33-Cosmos 2251碰撞、Solwind P78航天器解体等在轨事件进行了分析。 相似文献
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编队卫星碰撞规避方法研究 总被引:1,自引:0,他引:1
对编队卫星碰撞规避方法进行了研究。通过递推编队卫星的初始状态协方差阵,将碰撞概率密度函数在危险区域积分获得编队卫星的碰撞概率。当碰撞概率大于安全阈值时,向卫星施加最小脉冲速度修正量Δv,在垂直于终止时刻相对速度的平面机动一定距离以降低碰撞概率。仿真结果表明:用计算的碰撞概率能较好地预测编队卫星的潜在碰撞危险,所选机动策略有效。 相似文献
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Life support components are evaluated for application to an idealized closed life support system which includes an algal reactor for food production. Weight-based trade studies are reported as "break-even" time for replacing food stores with a regenerative bioreactor. It is concluded that closure of the life support gases (oxygen recovery) depends on the carbon dioxide reduction chemistry and that an algae-based food production can provide an attractive alternative to re-supply for longer duration missions. 相似文献
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提出了双层板防护结构的超高速碰撞数值模拟的工程算法模型,采取理论分析、经验公式和数值模拟相结合的研究方法来模拟碎片云的产生,以及碎片云对结构的破毁过程。本模型中,碎片云的产生采用理论分析和经验公式得到,结构响应采用有限元动力学软件Dyna3D进行计算。数值模拟结果与文献中给出的破坏效果基本一致,说明提出的工程算法是可行的,模拟得到的结果能定性的描述相应的超高速碰撞的现象,得到基本正确的结果。 相似文献
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卫星超高速撞击解体碎片特性的试验研究 总被引:1,自引:0,他引:1
为了研究超高速撞击下卫星解体碎片的分布特性,在弹道靶上开展了三次模拟卫星的超高速撞击试验。发射铝合金钝锥弹丸以3.2km/s~4.2km/s的速度撞击模拟卫星,对解体碎片进行回收、测量和统计分析,结果表明:碎片累积数量与碎片特征尺寸/特征质量在对数坐标系中基本呈直线关系,且碎片尺寸分布和质量分布在形式上和规律上具有高度相似性。通过数据拟合得到了碎片尺寸和质量分布的具体函数形式,分析了碎片质量分布与尺寸分布之间的内在关系。将试验结果与NASA标准解体模型进行了比较,讨论了两者的差别及其原因。
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To date, NASA's “Near Earth Object Program” has discovered over 5500 comets and asteroids on trajectories that bring them within “the neighborhood” of Earth's orbit. Nearly 1000 of these objects are classified as “potentially hazardous,” passing within 0.05 astronomical units of Earth's orbit. Discovery rates of such threatening bodies increase each year. Given this multitude of threats, in addition to evidence that the planet has absorbed many impacts over its history, it is reasonable to assume that another object will strike the Earth at some point in the future. Consequently, researchers have studied and proposed several mitigation techniques for such an occurrence. This study seeks to determine how effectively the attachment of a tether and ballast mass would divert the trajectory of such threatening objects. Specifically, the study analyzes the effects over time of such a system on objects of varying orbital semimajor axis and eccentricity, using various tether lengths and ballast masses. It was determined that the technique is most effective for NEOs with high eccentricity and small semimajor axis, and that system performance increases as tether length and ballast mass increase. 相似文献
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用于验证数值仿真的Whipple屏超高速撞击试验结果 总被引:8,自引:3,他引:8
为提供验证超高速撞击数值仿真所需的试验结果,给出了在中国空气动力研究与发展中心超高速所进行的铝质Whipple屏超高速撞击试验部分结果。试验中,球形弹丸均为LY12铝合金材料,直径为0.4~0.5cm;靶材为间距10cm、厚0.192cm的LY12板材。撞击速度为4.47~6.15km/s,撞击角为0°和45°。给出的试验结果包括弹丸和靶材参数、撞击速度、撞击角、弹孔尺寸、后墙损伤情况和碎片云激光阴影照片等。实验结果表明,撞击速度越高,Whipple屏的防护效果越好,而斜撞击比正向撞击造成的破坏更严重。 相似文献
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将微机电系统(MEMS)技术应用于微推进系统可以降低成本,减少风险,并可满足微型航天器对性能、体积和质量等的特殊要求。本文针对微电热推力器(FMMR)和微型双组元液体火箭发动机的技术方案进行研究,采用直接蒙特卡罗(DSMC)方法,对影响FMMR工作特性的因素进行了研究,并对其进行了性能评估;应用商用FLUANT软件,计算并分析了二维喷管流场的附面层情况;对无毒液体推进剂进行点火试验选择。研究结果表明,对于FMMR当采用H2O作为推进剂工质,比冲为68.247s,推力为0.225mN,效率为52.6%。通过采取其它措施可以进一步提高比冲、推力和效率。对于微型双组元液体火箭发动机,采用醇类作燃料时,起动平稳、响应时间短。通过系统集成和一体化设计,微推进系统在未来微型航天器上具有广阔的应用前景。 相似文献