对欧空局轨道碎片模型的评价

文章评价了颗粒大于1cm的碎片模型,它包含大于10cm的一组粒子和介于1～10cm之间的粒子,它们是由空间暴露模拟得到的。接着讨论了尺寸范围介于0.1～10mm之间的小粒子束流。假定这些粒子主要是由小粒子与卫星碰撞产生的。这种碰撞主要发生在450～500kin的高度范围内(空间站高度),碰撞与否还取决于轨道高度和离心率。     

智能产品数据服务环境

提出了一种支持复杂工程系统多学科协同设计优化的产品数据管理方法及基于系统优化任务的智能产品模型数据组织模式。通过工程控制结构模型，定义了产品优化任务，并为设计任务自顶向下进行产品模型控制提供了途径。利用产品主模型技术实现数据的完整性，通过设计任务的语境模型产生数据高保真的分析视图以及关联数据环境实现产品主模型和分析模型的一致性。整个产品数据通过协作数据对象的封装，以WEB服务的形式，使优化设计人员通过网络透明地获取产品数据。为了支持基于INTERNET的协同产品开发，采用了基于OPENHSF的流格式作为产品数据的显示方式。     

Proposed strategies for optical observations in a future European Space Surveillance network

Two ESA-funded feasibility studies that aimed to develop observation strategies, to propose suitable sensor architectures, and to assess the expected performance of an independent European Space Surveillance System were carried out during the last years. The French company ONERA led two study teams comprising a number of European companies.     

Investigations of the evolution of optical characteristics and dynamics of proper rotation of uncontrolled geostationary artificial satellites

On the base of the photometrical data an analysis of the periods and light curves of the uncontrolled artificial satellites was performed.     

Debris flux comparisons from the Goldstone Radar,Haystack Radar,and Hax Radar prior,during, and after the last solar maximum

The continual monitoring of the low Earth orbit (LEO) debris environment using highly sensitive radars is essential for an accurate characterization of these dynamic populations. Debris populations are continually evolving since there are new debris sources, previously unrecognized debris sources, and debris loss mechanisms that are dependent on the dynamic space environment. Such radar data are used to supplement, update, and validate existing orbital debris models. NASA has been utilizing radar observations of the debris environment for over a decade from three complementary radars: the NASA JPL Goldstone radar, the MIT Lincoln Laboratory (MIT/LL) Long Range Imaging Radar (known as the Haystack radar), and the MIT/LL Haystack Auxiliary radar (HAX). All of these systems are highly sensitive radars that operate in a fixed staring mode to statistically sample orbital debris in the LEO environment. Each of these radars is ideally suited to measure debris within a specific size region. The Goldstone radar generally observes objects with sizes from 2 mm to 1 cm. The Haystack radar generally measures from 5 mm to several meters. The HAX radar generally measures from 2 cm to several meters. These overlapping size regions allow a continuous measurement of cumulative debris flux versus diameter from 2 mm to several meters for a given altitude window. This is demonstrated for all three radars by comparing the debris flux versus diameter over 200 km altitude windows for 3 nonconsecutive years from 1998 to 2003. These years correspond to periods before, during, and after the peak of the last solar cycle. Comparing the year to year flux from Haystack for each of these altitude regions indicate statistically significant changes in subsets of the debris populations. Potential causes of these changes are discussed. These analysis results include error bars that represent statistical sampling errors.     

A fast numerical approach for Whipple shield ballistic limit analysis

Whipple shield is widely used on manned spacecraft, numerical simulation is an important way for obtaining the ballistic limit. The large population of particles and the large space span of Whipple shield simulation model restrict the computational efficiency. A fast numerical approach is presented for Whipple shield ballistic limit analysis. First, the critical penetration analysis of the rear walls is converted into specific impulse analysis delivered by the secondary debris cloud, because the maximum of specific impulse is the main determinant of the penetration. The dual plate simulation model is then converted into single plate model and the population of particles is reduced. Second, based on the isotropic expansion theory of secondary debris cloud, the specific impulse analysis is further converted into particle position and velocity analysis when the stable secondary debris formed. The space span of the simulation model is reduced. An example of Whipple shield ballistic limit analysis is provided for the verification of the fast numerical approach, it shows that this approach can significantly increase the computation efficiency with acceptable accuracy.     

Analytical and semi-analytical investigations of geosynchronous space debris with high area-to-mass ratios

This paper provides a Hamiltonian formulation of the averaged equations of motion with respect to short periods (1 day) of a space debris subjected to direct solar radiation pressure and orbiting near the geostationary ring. This theory is based on a semi-analytical theory of order 1 regarding the averaging process, formulated using canonical and non-singular elements for eccentricity and inclination. The analysis is based on an expansion in powers of the eccentricity and of the inclination, truncated at an arbitrary high order.     

A ballistic limit equation for hypervelocity impacts on composite honeycomb sandwich panel satellite structures

During a recent experimental test campaign performed in the framework of ESA Contract 16721, the ballistic performance of multiple satellite-representative Carbon Fibre Reinforced Plastic (CFRP)/Aluminium honeycomb sandwich panel structural configurations (GOCE, Radarsat-2, Herschel/Planck, BeppoSax) was investigated using the two-stage light-gas guns at EMI. The experimental results were used to develop and validate a new empirical Ballistic Limit Equation (BLE), which was derived from an existing Whipple-shield BLE. This new BLE provided a good level of accuracy in predicting the ballistic performance of stand-alone sandwich panel structures. Additionally, the equation is capable of predicting the ballistic limit of a thin Al plate located at a standoff behind the sandwich panel structure. This thin plate is the representative of internal satellite systems, e.g. an Al electronic box cover, a wall of a metallic vessel, etc. Good agreement was achieved with both the experimental test campaign results and additional test data from the literature for the vast majority of set-ups investigated. For some experiments, the ballistic limit was conservatively predicted, a result attributed to shortcomings in correctly accounting for the presence of high surface density multi-layer insulation on the outer facesheet. Four existing BLEs commonly applied for application with stand-alone sandwich panels were reviewed using the new impact test data. It was found that a number of these common approaches provided non-conservative predictions for sandwich panels with CFRP facesheets.     

单层板撞击成坑声发射辨识及参数估计研究

空间碎片撞击航天器的威胁对发展在轨感知系统提出需求,为研制基于声发射技术的感知系统,有必要研究利用声发射波形分析对防护结构进行损伤模式辨识的方法。文章利用超声传感器进行了铝弹丸超高速撞击单层板的声发射信号采集实验及其数值仿真,并对波形在时域和频域内进行分析,结果表明:声发射波形的主波谷值随撞击速度增加而线性增加,直到防护结构被击穿;声发射波形中的高频分量与低频分量幅值之比存在一个区别成坑模式与击穿模式的阈值。基于上述结果提出了一种在撞击弹丸尺寸已知条件下辨识成坑模式并对其撞击速度及其弹坑尺寸进行估计的方案。     

空间碎片的空间密度算法研究

由于空间碎片的影响, 空间环境日益恶劣,有必要建立空间碎片环境工程模型对空间碎片撞击航天器进行风险评估.本文研究了空间碎片环境模型中的重要环节, 即碎片的空间密度问题,在统计理论与椭圆轨道理论基础上,分析及推导了空间碎片在空间中的分布状况及空间密度,并得出了碎片空间密度的空间坐标函数解析表达式.同时对引入假设条件的合理性进行了讨论,并利用双行元数据对结论进行了验证, 利用本文方法得出的结果与双行元数据吻合.