空间伸展臂的技术现状与难点

空间伸展臂是一类最基本的空间可展开结构,是大型复杂空间结构的基础,对迅速发展的空间活动有着十分重要的研究意义。文章总结并介绍了不同结构形式空间伸展臂的研究与应用情况,根据各方面性能进行了较为全面的对比分析,并从力学、材料、空间环境影响、振动控制几方面深入分析了空间伸展臂设计和应用的技术难点,初步探讨了空间伸展臂的发展方向,从而为空间伸展臂的设计、选型和分析提供必要的支持。     

基于非抽取小波包变换的信号滤波算法

对航天测控信号进行滤波处理,有利于改善信号品质,提高系统的测量性能。针对航天测控信号中的差分单程测距(DifferentialOne-wayRanging, DOR)信标信号等侧音信号,提出了基于非抽取小波包变换（Un-decimatedWaveletPacketTransform,UWPT）的滤波改进算法。该算法以功率平坦度为准则,判断某一节点是否需要继续分解。改进算法克服了以能量聚焦度为准则时算法误判停止分解或多重分解算法复杂、计算量大等的缺点,同时解决了阈值不易确定的问题。仿真结果表明改进算法在降低算法复杂度的同时,滤波性能相对有所提高。最后采用改进算法对仿真信号和在轨卫星数据进行处理,结果表明滤波后仿真信号差分相位估计精度提高约3倍、实测数据差分相位估计精度提高0.72倍。     

基于竞争环境下的舱位控制博弈模型分析

近年来,收益管理已然成为航空公司增加收益的重要手段,而收益管理模型也已广泛应用。在收益管理舱位控制的研究中,大部分是采用静态或动态建模的方法,针对某一个航空公司进行分析,而对竞争环境下的博弈模型的研究较少。本文在前人研究的基础之上,分析我国航空运输市场,给出一个舱位等级和多个舱位等级情况下的竞争博弈模型,通过对模型的分析可以得出影响舱位控制的因素。     

Debris dispersion effect in N-shape configuration

Spacecraft shields play an important role in shielding against the impact of space debris. Increasing the dispersion degree of the debris produced by the impact of the space debris on the bumper of configuration is able to lower the concentration of debris impacting on the rear plate and thus to reduce the risk of debris perforating the rear plate. In order to improve the dispersion degree, the N-shape configuration is proposed and studied by hypervelocity impact test with the velocity of 4.80 km/s and numerical simulation with the velocities ranging from 3.0 km/s to 7.0 km/s. As a comparison, the distribution of debris impacting on the rear plate is also investigated for the parallel triple-wall configuration with the same areal density. It is found that this degree is increased in the N-shape configuration due to the oblique plate, and therefore the risk of debris perforating the rear plate is reduced compared to the case of parallel triple-wall configuration.     

Optical orbital debris spotter

The number of man-made debris objects orbiting the Earth, or orbital debris, is alarmingly increasing, resulting in the increased probability of degradation, damage, or destruction of operating spacecraft. In part, small objects (<10 cm) in Low Earth Orbit (LEO) are of concern because they are abundant and difficult to track or even to detect on a routine basis. Due to the increasing debris population it is reasonable to assume that improved capabilities for on-orbit damage attribution, in addition to increased capabilities to detect and track small objects are needed. Here we present a sensor concept to detect small debris with sizes between approximately 1.0 and 0.01 cm in the vicinity of a host spacecraft for near real time damage attribution and characterization of dense debris fields and potentially to provide additional data to existing debris models.     

A Delphi-Based Framework for systems architecting of in-orbit exploration infrastructure for human exploration beyond Low Earth Orbit

The current debate in the U.S. Human Spaceflight Program focuses on the development of the next generation of man-rated heavy lift launch vehicles. While launch vehicle systems are of critical importance for future exploration, a comprehensive analysis of the entire exploration infrastructure is required to avoid costly pitfalls at early stages of the design process. This paper addresses this need by presenting a Delphi-Based Systems Architecting Framework for integrated architectural analysis of future in-orbit infrastructure for human space exploration beyond Low Earth Orbit. The paper is structured in two parts.     

Biobjective planning of GEO debris removal mission with multiple servicing spacecrafts

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.     

Criteria for developing and testing Transparency and Confidence-Building Measures (TCBMs) for outer space activities

Space systems play an important role in sustaining the development, prosperity and security of many nations. As more nations become critically reliant on space systems, questions of maintaining safety and strategic stability in outer space have come to the fore. Transparency and Confidence-Building Measures (TCBMs) for outer space activities have an important role to play in providing clarity about the intentions of States and in articulating norms of behaviour in outer space. TCBMs take several forms. They may be the elaboration of basic principles related to the exploration and use of outer space, political measures related to establishing norms of conduct, information-sharing activities to improve the transparency of outer space activities, operational practices which demonstrate a commitment to mutual cooperation in outer space, or consultative mechanisms. We present an analytical framework for evaluating potential TCBMs and illustrate the application of this framework to examples of potential operational, regulatory, treaty-based and declaratory TCBMs.     

适用于遥感器遮光罩的复合材料及工艺研究

针对空间遥感器系统的发展演变,分析了遮光罩所用材料体系的变化情况,重点总结了高性能纤维增强树脂基复合材料在空间遥感器遮光罩中的应用情况。从工程化应用水平来看,目前尚处于在替代传统材料满足型号产品需求的较低阶段,本文简要归纳了其中存在的主要问题。针对蜂窝夹层结构、光阑结构、薄壁壳体结构等不同类型的空间遥感器遮光罩,本文介绍了其所适用的复合材料及其成型工艺。同时,结合材料选择、设计工艺性、工艺设计等工程化应用中的关键环节,作了尝试性地探讨,并对高性能纤维增强树脂基复合材料的实际应用效果进行了评价。最后,就未来空间遥感器系统的发展对材料工艺的需求作了展望。