航天器环境试验和航天产品的质量与可靠性保证

介绍了航天器验证和试验标准近年来的发展现状 ,指出了这些标准在各国航天器验证中所起到的作用 ,同时讨论了在航天器研制中环境试验和可靠性试验的关系。由于航天器的特点 ,在整个验证工作中 ,环境试验和可靠性试验应该是统一的。通过全面的验证工作 ,特别是大量的环境试验 ,航天器的环境适应性和可靠性得到了保证。总的看法是 ,这些标准 ,只要应用得当 ,将能保证航天器的性能要求和在轨可靠性。     

国土星卫片图象的几何畸变与卫星姿态分析

主要讨论了国土星卫片的成象比例尺,卫星姿态误差对图象几何精度的影响及其姿态参数的控制精度等问题。在简化模型的前提下,按照严谨的数学关系,本文导出了卫片的比例尺和误差计算的数学解析式,并提出了在给定最大定位误差时,对卫星姿态控制精度的总体设计要求。     

车用锂离子电池直冷热管理系统用冷媒研究进展

电动汽车用直冷系统是未来电动汽车热管理系统的可行解决方案之一,在整车减重、改善温度一致性等方面具备较大潜力。冷媒是直冷热管理系统的重要组成,影响直冷系统制冷能力、效率、安全性等因素。选择高效、匹配的冷媒对直冷热管理系统设计格外重要。梳理了近年来电动汽车直冷热管理系统用冷媒的研究进展。首先,基于电动汽车工况阐述了锂离子电池的热特性需求与直冷热管理系统特性;其次,系统分析了常用冷媒特性的定义与表征;然后,详细介绍了单质冷媒与混合冷媒的研究进展;最后,总结了冷媒亟待解决的问题与未来展望,并为新一代直冷热管理系统用冷媒的发展提出了可行的研究方向。      

MELISSA: a potential experiment for a precursor mission to the Moon.

MELISSA (Micro-Ecological Life Support System Alternative) has been conceived as a micro-organism based ecosystem intended as a tool for developing the technology for a future artificial ecosystem for long term space missions, as for example a lunar base. The driving element of MELISSA is the recovering of edible biomass from waste, CO2, and minerals with the use of sun light as energy source. In this publication, we focus our attention on the potential applications of MELISSA for a precursor mission to the Moon. We begin by a short review of the requirements for bioregenerative Life Support. We recall the concept of MELISSA and the theoretical and technical approaches of the study. We present the main results obtained since the beginning of this activity and taking into account the requirements of a mission to the Moon we propose a preliminary experiment based on the C cycle of the MELISSA loop.     

A consensus approach to planetary protection requirements: recommendations for Mars lander missions.

Over the last several years, the nature of the surface conditions on the planet Mars, our knowledge of the growth capabilities of Earth organisms under extreme conditions, and future opportunities for Mars exploration have been under extensive review in the United States and elsewhere. As part of these examinations, in 1992 the US Space Studies Board made a series of recommendations to NASA on the requirements that should be implemented on future missions that will explore Mars. In particular, significant changes were recommended in the requirements for Mars landers, changes that significantly alleviated the burden of planetary protection implementation for these missions. In this paper we propose a resolution implementing this new set of recommendations, for adoption by COSPAR at its 30th meeting in Hamburg. We also discuss future directions and study areas for planetary protection, in light of changing plans for Mars exploration.     

基于对数势函数的深空探测器姿态规划与控制方法

针对深空探测器姿态约束机动问题,提出一种基于对数势函数的多约束姿态机动规划方法。首先,定义了两种姿态指向约束,即禁止约束和强制约束,并利用禁止约束和强制约束的性质构建了对数势函数作为Lyapunov函数;在此基础上采用改进退步法设计了探测器姿态机动控制器。数值仿真结果表明:该方法不仅在多约束情况下能够自主求出安全的机动路径,而且在分析和求解上计算效率较快,对于星上资源有限的深空探测器具有实际运用价值。     

多工艺路线可视化设计与评估方法

根据CAPP系统人机工程和工艺路线方案选择的需要,提出了一种基于图形控件和过程网的多工艺路线可视化设计与评估方法.该方法根据工艺路线的构成要素,设计建立了具有标示、工艺、图形和评估四个方面属性的工序控件、机床控件、特征控件和搬运控件等图形控件,采用图形控件的拖拽方式和网络图的表达方式构建工艺路线,实现了多工艺路线的可视化设计,并采用Dijkstra算法对过程网中的多条工艺路线进行评估,从而选择最优工艺路线.最后给出了某飞机结构件的应用实例.该方法能够更好地体现工艺师的设计思路,有效地进行工艺方案论证和决策.     

基于公理设计的产品可靠性要求实现方法

针对可靠性设计要求难以系统、全面落实到产品设计方案的问题,提出了一种基于公理设计的产品可靠性要求实现方法.首先,应用公理设计原理进行产品初步设计,从而确定其功能需求,并针对各项功能的保持要求进一步扩展功能保持需求（扩展的功能保持需求构成功能保持域,该域包含于功能域）,进而系统导出参数化的可靠性设计方案;其次,根据功能保持需求扩展或优化设计参数,构建考虑可靠性设计要求的域映射模型,并给出应用独立公理进行方案评价的方法.同时,以温度传感器设计为例贯穿全文,验证了所提出方法的可行性和有效性.      

基于COTS的某型大气数据计算机设计CSCD

大气数据计算机是无人机重要机载设备,为节省设计成本和时间,采用基于COTS的方法对大气数据计算机进行设计,给出了系统的硬件平台选型方案,以商用uc/os系统为底层操作系统,完成系统功能设计,并对设备的工作性能进行了验证,结果表明该方案合理可行,满足无人机设计使用要求。     

Determination of surface parameters and fluxes for climate studies from space observation. Methods,results and problems

Climate being the result of many interconnected processes, it can hardly be understood without models which describe these various processes as quantitatively as possible and define the parameters which are relevant for climate studies. Among those, surface processes and therefore surface parameters are now recognized to be of great importance. Some examples are discussed in the first part, showing the great interest to measure the relevant parameters on a multi-year basis, over large areas with sufficiently dense array and on a stable basis, in order to monitor climate changes or to study the impact on climate of the modifications of some relevant parameters which are analysed. Since space observations from satellites fulfil these requirements, it is clear that they will become very soon a fundamental tool for climate studies. Unfortunately, as it is discussed in the second part, satellites do measure only spectral radiances at the top of the atmosphere and the determination of the relevant surface parameters (or fluxes) from these radiances still raises many problems which have to be solved, although many progresses have already been made.The aim of this paper is therefore to review and discuss these problems and the various ways they have been tackled until now. The first part is devoted to an overview of what needs to be measured and why, while the existing methods for determining the most important surface parameters from space observations are presented in the second part where a particular attention is given to the theoretical and experimental validations of these methods, their limits and the problems still to be solved.     

一种高性能跳频信号源的设计与实现

设计了一种高性能跳频信号源。该信号源以FPGA为控制电路核心,在FPGA内部实现了信号源数字部分相关电路功能,利用高性能的AD9777实现数模转换,通过串行通信SPI接口控制AD9777的工作模式;该跳频信号源采用改进的L-G模型电路作为跳频序列发生器,采用正弦波直接频率发生器作为跳频信号源的基础。实验测试证明:该跳频信号源性能良好,能满足实际工程的需要。     

全球空间天气路线图及对中国的启示

随着科技的发展,空间天气对电力系统、通信导航系统和航天资产等遍布全球的技术基础设施的影响越来越深.需要加强对空间天气事件过程的理解,提升空间天气的预报能力,优化基础设施设计,从而减缓空间天气对社会造成的影响.基于这些需求,国际空间研究委员会(COSPAR)联合国际与日共存计划(ILWS)共同成立专家组,研究制定了全球2015-2025空间天气发展路线图.本文对该路线图进行介绍和解读,讨论该路线图对中国空间天气发展的启示.     

基于有限状态机的操作系统需求层形式化验证

操作系统是航天器必备的基本软件，操作系统的可靠性和安全性直接关系航天型号任务的成败.虽然目前已采用多种手段对操作系统进行可靠性和安全性保障，但仍存在不能完全排除缺陷的情况，因此对空间操作系统开展形式化验证研究势在必行.需求层验证是操作系统形式化验证的一部分，本文在分析操作系统需求的基础上，采用有限状态机在操作系统需求层进行形式化描述，并针对应用在某航天器上的SpaceOS2在需求层进行了建模，相应地在定理证明工具Coq中进行了描述建模；然后定义了六条操作系统应满足的全局性质并进行了形式化描述，给出了系统模型满足这些性质的机器可检查的证明.证明结果表明采用有限状态机方法对操作系统需求层进行形式化验证是可行的，为进一步全面形式化验证奠定了基础.     

基于QR分解求解带顶点三对角带状线性方程组

带顶点三对角带状线性方程组在实际问题的求解过程中经常遇到,一般情况下此类方程组没有实用有效的求解方法. 与现有一般基于LU分解的或其他一些迭代方法不同,基于实际很少采用的矩阵QR分解方法,利用其对各类矩阵普遍适用的优点,给合此类带状线性方程组的特点,提出并探讨了将QR分解应用于该类方程组的求解过程,既利用了QR分解保证足够的精度,又避免了一般QR分解过大的计算量. 分析和实际计算均表明,该方法在计算精度及计算量方面均满足实际应用的要求.     

轨道机动期间的姿态控制

论述了轨道机动期间的姿态控制的一般原则,以及对不同稳定方式的卫星姿态控制的要求,文章着重分析了三轴稳定卫星控制系统设计的关键技术问题。     

准平行光远距离动态重合度的自准直测量方法研究

针对野外、远距离、动态的重合度测量要求,提出了一种准平行光自准直测量方法,即发光和接收由一台仪器完成,发出光束为准平行光,反光器件为角锥棱镜,PSD或CCD将反回光转换成电信号,并最终以角度表达重合偏差。通过静态试验验证,证明此方法原理正确,方案可行,测量距离可达公里级,测量结果具有较高的准确度。该方法为实现角度的精确跟踪及专用跟踪仪的研制奠定了基础。     

Planetary protection, legal ambiguity and the decision making process for Mars sample return.

As scientists and mission planners develop planetary protection requirements for future Mars sample return missions, they must recognize the socio-political context in which decisions about the mission will be made and pay careful attention to public concerns about potential back contamination of Earth. To the extent that planetary protection questions are unresolved or unaddressed at the time of an actual mission, they offer convenient footholds for public challenges in both legal and decision making realms, over which NASA will have little direct control. In this paper, two particular non-scientific areas of special concern are discussed in detail: 1) legal issues and 2) the decision making process. Understanding these areas is critical for addressing legitimate public concerns as well as for fulfilling procedural requirements regardless whether sample return evokes public controversy. Legal issues with the potential to complicate future missions include: procedural review under National Environmental Policy Act (NEPA); uncertainty about institutional control and authority; conflicting regulations and overlapping jurisdictions; questions about international treaty obligations and large scale impacts; uncertanities about the nature of the organism; and constitutional and regulatory concerns about quarantine, public health and safety. In light of these important legal issues, it is critical that NASA consider the role and timing of public involvement in the decision making process as a way of anticipating problem areas and preparing for legitimate public questions and challenges to sample return missions.     

GLONASS接收机频率合成器的设计与实现

根据GLONASS系统的频率计划和GLONASS接收机的特定结构,提出用变化钟频法实现GLONASS接收机的前端.对相应的前端频率合成器部分提出了具体要求,并给出了基于集成频率锁相环的频率合成器的设计与实现.讨论了固有合成频率偏差的来源和消除办法.分析了频率合成器的性能指标.实验表明,该合成器稳定性好,精度高,能够满足GLONASS实验样机的要求.      

Recent advances in understanding stratospheric dynamics and transport processes: Application of satellite data to their interpretation

The present paper discusses the use of the transformed Eulerian (or “residual”) mean-flow formulation, the Eliassen-Palm flux, and Ertel's potential vorticity to provide an increased understanding of wave, mean-flow interactions, and constituent transport processes in the stratosphere. Temperature and ozone data retrieved from radiance profiles obtained by the LIMS instrument on the Nimbus 7 satellite are utilized in conjunction with these theoretical concepts for the interpretation of phenomena that occurred during the major and minor warmings of January-February 1979. The results illustrate the insight provided by these concepts and demonstrate that useful diagnostic quantities can be derived from global satellite temperature fields.     

Model implementation for dynamic computation of system cost for advanced life support.

Life support system designs for long-duration space missions have a multitude of requirements drivers, such as mission objectives, political considerations, cost, crew wellness, inherent mission attributes, as well as many other influences. Evaluation of requirements satisfaction can be difficult, particularly at an early stage of mission design. Because launch cost is a critical factor and relatively easy to quantify, it is a point of focus in early mission design. The method used to determine launch cost influences the accuracy of the estimate. This paper discusses the appropriateness of dynamic mission simulation in estimating the launch cost of a life support system. This paper also provides an abbreviated example of a dynamic simulation life support model and possible ways in which such a model might be utilized for design improvement.