The dynamical environments analysis of surface particles for different shaped asteroids

Asteroids are coming to be a popular topic in the areas of astrophysical studies and deep space exploration recently. However, surface dynamics of asteroids is still a difficult problem. This paper aims at the motion analysis of surface particles for different asteroids. The dynamical analysis method of particles’ movement is given for three parts: global motion trend, local motion trend and static analysis. A dimensionless parameter ζ is defined to distinguish the predominant term to determine the distribution of effective potential. Three kinds of common asteroids: spheroidal asteroid, spindle-shaped asteroid and dumbbell-shaped asteroid are all discussed for those three parts with different parameter ζ. The motion trend of particles on the surface of each kind of asteroid is given. The static analysis of surface particles for different asteroids is also illustrated. Based on them, some common rules for different shaped asteroids are revealed. This paper could not only provide a reference for asteroid exploration missions but also be meaningful for the research of morphologic evolution of asteroids.     

高温合金大型薄壁精密铸件热控凝固过程热分析研究

航空发动机中的高温合金大型薄壁精密铸件在普通铸造时容易产生严重的疏松缺陷和晶粒尺寸不均匀的问题.本文采用热控凝固工艺(TCS)在K4169合金试板上对影响晶粒尺寸的因素进行了试验,并编制程序对采集到的温度数据进行热分析研究,得到了在试验用设备上实现均匀晶粒尺寸试板所对应的热参数G/R曲线及范围.     

大型空间环模设备总控系统工作站间的互连

本文给出了大型空间环模设备总控系统工作站间实现互连的原理和具体的实现步骤以及在实现的过程中各个部分的具体组成和实际物理含义及注意事项,并在具体实践中圆满地实现了各个工作站间的互连。     

萤火一号火星探测器综合电子分系统方案

对萤火一号(YH-1)火星探测器的小型化、集中式综合电子分系统方案设计进行了研究.介绍了双CPU单总线体系结构、系统重构设计、系统小型化设计和系统抗单粒子效应设计.给出了综合电子分系统软件功能及其采用的基于软件总线的开放式结构.设计的YH-1火星探测器综合电子分系统在有效实现小型化的同时能保持较高的可靠性,具自主故障诊断和系统重构的能力.     

细菌生物膜对航天器材料的危害及其防护简述

细菌生物膜是造成空间环境下航天器材料腐蚀的关键因素之一.文章简述了细菌生物膜的结构和形成机制、其对航天器材料的危害、主要评估方法以及防控策略,并提出目前防控策略在实际应用中存在的问题.当前的细菌生物膜防控策略主要分为3类:1)修改易感表面的特性以防止细菌生物膜形成;2)调节信号通路以抑制细菌生物膜的形成;3)施加外力以...     

卫星在轨抗辐照总剂量数据拟合及其应用

卫星在轨抗辐照总剂量数据是空间电子设备抗辐照校核以及加固设计的依据.用查表法进行抗辐照校核计算时,对于数据表中已有数据点可以精确计算,未知数据点无法精确分析.为进一步提高空间电子设备抗辐照校核计算的精度,同时为辐照特敏感器件选用提供依据,提高产品在轨可靠性.采用分段数据拟合的方法进行了多个型号在轨抗辐照总剂量数据的研究,以中位数为分界点将数据分成前后两部分,前半部分采用分段二次函数拟合,后半部分采用指数函数拟合,拟合精度高,相对误差小于4％,能够满足工程设计的需要.该方法已用于多个在轨型号的抗辐照校核计算,对于提高空间电子设备的可靠性具有积极意义.     

航天器柔性伸展附件非线性振动稳定性研究

研究由中心刚体和柔性伸展附件组成的非线性刚柔耦合系统，假设附件为有限变形梁，但本构方程是线性的。利用能量积分构造Ｌｙａｐｕｎｏｖ函数，根据部分变量稳定性定理，证明了当中心刚体无控制力矩，附件驱动力为零时，梁在等速伸展或收缩时的横向非线性振动是稳定的。     

挠性航天器伸展动力学分析

本文导出了带挠性伸展附件航天器姿态动力学方程，研究了附件伸展和振动对姿态动力学的影响。对于附件按指数规律伸展情况，以及附件长度的次方随时间线性变化情况，给出了姿态角速率的渐近公式。     

Dynamical analysis of a spinning solar sail

This paper discusses the orbit and attitude dynamics of a solar sail, and gives the sufficient conditions of a stable orbit and attitude coupled system. The stability of the coupled system is determined by the orbit stability and attitude stability. Based on the sufficient conditions, a spin-stabilized solar sail of cone configuration is proposed to evolve in the heliocentric displaced orbit. For this kind of configuration, the attitude is always stable by spinning itself. The orbit stability depends on the orbit parameters of the heliocentric displaced orbit, the ratio of the orbit radius to displaced distance and orbit angular velocity. If the center of mass and center of pressure overlap, it can be proved that the coupled system is stable when the orbit parameters are chosen in the stable region. When the center of mass and center of pressure offset exists, the stability of the coupled system can not be judged. A numerical example is given and the result shows that both the orbit and attitude are stable for the case.