Attached payloads on SPACEHAB, growing from the Space Shuttle to the Space Station

Although NASA's Space Shuttle is largely dedicated in the near term to Space Station assembly, 10–16 day flight opportunities still abound for spacecraft technology demonstration payloads, and experiments for the established earth and space science communities. This paper will present the latest developments of SPACEHAB flight systems in order to accommodate the flight needs of these communities on the Space Shuttle today and the Space Station tomorrow. In particular, some examples of payloads from these disciplines will be introduced together with the accommodation and experiment objectives.     

Plasmaspheric Density Structures and Dynamics: Properties Observed by the CLUSTER and IMAGE Missions

Plasmaspheric density structures have been studied since the discovery of the plasmasphere in the late 1950s. But the advent of the Cluster and Image missions in 2000 has added substantially to our knowledge of density structures, thanks to the new capabilities of those missions: global imaging with Image and four-point in situ measurements with Cluster. The study of plasma sources and losses has given new results on refilling rates and erosion processes. Two-dimensional density images of the plasmasphere have been obtained. The spatial gradient of plasmaspheric density has been computed. The ratios between H⁺, He⁺ and O⁺ have been deduced from different ion measurements. Plasmaspheric plumes have been studied in detail with new tools, which provide information on their morphology, dynamics and occurrence. Density structures at smaller scales have been revealed with those missions, structures that could not be clearly distinguished before the global images from Image and the four-point measurements by Cluster became available. New terms have been given to these structures, like “shoulders”, “channels”, “fingers” and “crenulations”. This paper reviews the most relevant new results about the plasmaspheric plasma obtained since the start of the Cluster and Image missions.     

CLUSTER and IMAGE: New Ways to Study the Earth’s Plasmasphere

Ground-based instruments and a number of space missions have contributed to our knowledge of the plasmasphere since its discovery half a century ago, but it is fair to say that many questions have remained unanswered. Recently, NASA’s Image and ESA’s Cluster probes have introduced new observational concepts, thereby providing a non-local view of the plasmasphere. Image carried an extreme ultraviolet imager producing global pictures of the plasmasphere. Its instrumentation also included a radio sounder for remotely sensing the spacecraft environment. The Cluster mission provides observations at four nearby points as the four-spacecraft configuration crosses the outer plasmasphere on every perigee pass, thereby giving an idea of field and plasma gradients and of electric current density. This paper starts with a historical overview of classical single-spacecraft data interpretation, discusses the non-local nature of the Image and Cluster measurements, and emphasizes the importance of the new data interpretation tools that have been developed to extract non-local information from these observations. The paper reviews these innovative techniques and highlights some of them to give an idea of the flavor of these methods. In doing so, it is shown how the non-local perspective opens new avenues for plasmaspheric research.     

复合材料炭化速率实验研究

为了解炭化材料内部的炭化过程,用四种配方的复合材料,采用石英灯组辐射加热的方法,在材料不同厚度位置敷设测温热电偶,根据测量的材料不同厚度位置的背面温度以及已确定的炭化速率求解公式算出材料的炭化速率,给出四种不同材料的炭化速率沿厚度方向的变化曲线,初步反映材料内部的炭化过程.     

基于Flowmaster的运输机供氧系统仿真

研究运输机供氧系统,建立相应的系统仿真模型,对整个管网系统中氧气的流动及分配进行仿真分析.系统由高压氧源、机组供氧点和座舱乘员供氧点3部分组成,各部分分别建模,然后集成系统;为了方便设计者针对不同的管路布置进行系统仿真分析,利用Flowmaster的外部元件模块开发出了氧气系统特有的元件,包括氧气调节器、减压器和快戴式氧气面罩;在某任务航程下利用此仿真模型对氧气系统进行了仿真计算,得到各气瓶耗氧量和各供氧点氧气流量的变化情况,验证了系统是否满足设计需求.     

基于直接配点法的月球软着陆轨道快速优化

介绍了直接配点法在月球探测器软着陆轨道快速优化问题中的应用.首先给出了软着陆最优化控制问题模型,其中状态方程为量纲为1的三自由度模型,性能指标选为燃料消耗最小,控制变量则为推力攻角和推力.终端状态受到速度和高度的约束.然后,应用直接配点法将最优控制问题离散化为非线性规划问题,即将动态优化问题转化为静态参数最优化问题.选取各节点和配点上的状态量和控制量作为优化参数.最后应用基于Matlab语言的SNOPT软件包对参数最优化问题进行求解,该软件包对于求解大型非线性规划问题具有很好的收敛性.仿真结果表明直接配点法对于月球探测器软着陆轨道初始状态量和控制量的取值不敏感,且求解过程具有一定的实时性.因此,直接配点法对于再入轨迹优化问题的求解是可行的.     

民用机场停机位优化配置

停机位配置指为到港或离港航班指定适宜的登机口,确保航班正点。航班停机位的高效、合理安排是机场地面作业中的一项核心任务。本文在系统分析国内繁忙机场停机位配置情况的基础上,提出以旅客登转机时间(旅客满意度)、机型与停机位类型匹配(机场效益)为优化目标,同时考虑航班类型(国内短途、国际长途)、航班数量与密度(忙时、闲时)、停机时间的停机位配置的数学模型,并设计求解模型的禁忌搜索(TS)算法。数值仿真证明了模型和算法的有效性。     

航天器复合材料胶接连接工艺分析

文章叙述了航天器复合材料胶接工艺应具备的条件,航天器产品常用胶粘剂及其特性,研制航天器复合材料耐久型胶接结构基本要素及复合材料胶接连接工艺特性和品质控制等内容。     

西工大低湍流度风洞的变湍流度技术

西工大低湍流度风洞实现宽范围变湍流度能力的技术途径：适当的变湍流度格栅位置；宽范围变化的变湍流度格栅结构尺寸；恰当处理好变湍流度格栅装置与风洞试验段上游气动轮廓的干扰问题。文中给出了变湍流度时对功率损失的影响及该风洞的变湍流度能力，综述了变湍流度时对部分试验结果影响的规律性。     

Committee on the peaceful uses of outer space

The first artificial earth satellite, Sputnik 1, was launched on 14 October 1957 and proceeded to orbit the Earth blithely unconcerned with the political boundaries below. It was apparent that space activities had international implications. In the United Nations, the question of space activities was first raised in 1957 in the context of the debate on disarmament. In 1958, the ‘Question on the Peaceful Uses of Outer Space’ was placed on the agenda of the General Assembly, which adopted a resolution establishing an Ad Hoc Committee on the Peaceful Uses of Outer Space (COPUOS).