一种适用于卫星数据传输的高效编解码算法

提出了一种喷泉编解码方法,又称为快速速龙码（RRC）,该编码方法能实现与传统速龙码相同的差错控制效率的同时,时间复杂度相对更低。相对传统速龙码,在编码过程中无需计算中间节点,直接通过生成矩阵计算校验节点;其解码方法是先通过置信传播（BP）算法对校验节点进行降度之后,再对校验节点降度之后组成的矩阵进行高斯消元法解码,从而降低矩阵规模。改进后的算法更加高效和简单,适用于航天器空间通信中的应用层数据传输、存储保护和深空探测信号传输。     

基于地面分布式数据中心的天地一体化网络

天地一体化网络通常具有覆盖范围广、数据传输量大等特点。现有的一体化网络研究侧重于网络间传输协议,以及如何有效管理网络资源等。但考虑到当前卫星网络数据处理能力相对较差,而地面网络发展已非常成熟,因此将一体化网络与数据中心网络融合,把数据中心网分布式地接入骨干光网络中,卫星作为网络的传输节点与地面分布式数据中心网络构成统一整体;以中国电信骨干网为基础,针对一体化网络的内部传输代价和外部请求代价等多种因素,进行折中,使用整数线性规划得到网络的最优化部署。所提出的网络架构能很好地满足一体化网络的要求,提供了一种具有竞争力的信息平台设计架构。     

Transforming solar system exploration: The origins of the Discovery Program, 1989–1993

The Discovery Program is a rarity in the history of NASA solar system exploration: a reform program that has survived and continued to be influential. This article examines its emergence between 1989 and 1993, largely as the result of the intervention of two people: Stamatios “Tom” Krimigis of the Johns Hopkins University Applied Physics Laboratory (APL), and Wesley Huntress of NASA, who was Division Director of Solar System Exploration 1990–92 and the Associate Administrator for Space Science 1992–98. Krimigis drew on his leadership experience in the space physics community and his knowledge of its Explorer program to propose that it was possible to create new missions to the inner solar system for a fraction of the existing costs. He continued to push that idea for the next two years, but it took the influence of Huntress at NASA Headquarters to push it on to the agenda. Huntress explicitly decided to use APL to force change on the Jet Propulsion Laboratory and the planetary science community. He succeeded in moving the JPL Mars Pathfinder and APL Near Earth Asteroid Rendezvous (NEAR) mission proposals forward as the opening missions for Discovery. But it took Krimigis's political skill and access to Sen. Barbara Mikulski in 1993 to get the NEAR into the NASA budget, thereby likely ensuring that Discovery would not become another one-mission program.     

Space debris and the need for space traffic control

This report summarises the presentations which took place at the ‘Space Traffic Control – Is the Space Debris Problem Solvable?’ conference hosted by the Royal Aeronautical Society on the 2nd July 2013. The conference sought to promote discussion over methods to deal with the issue of space debris in particular and speakers included representatives from the European Space Agency, the United Kingdom Space Agency, practitioners and academia. Themes which emerged during the conference included the urgency of the problem of space debris, the need for short-term and long-term solutions, the necessity for the development and implementation of space debris remediation technologies to complement existing mitigation efforts and, last but not least, the wider applications of space traffic control. Regarding the sub-title of the conference, ‘is the space debris problem solvable?’, it would appear from the presentations that while there is the potential for future management of the issue through debris remediation and harmonised mitigation efforts, no comprehensive solutions exist at the time of writing.     

Portfolios of promise: A review of R&D investment techniques and how they apply to technology development in space agencies

Despite a rich legacy of impressive technological accomplishments, the government acquisition of advanced space systems is increasingly synonymous with schedule slips and cost overruns. Program reviews have suggested that investing more in centralized and strategic research and development outside particular programs will reduce technical uncertainties and improve cost and schedule outcomes. This paper suggests roles for a centralized technology office by examining the methods available in the literature for managing portfolios of research projects.     

ESA strategic planning for space exploration

The European Space Agency (ESA) is pursuing an independent strategic planning process for consolidating a destination driven (LEO, Moon, Mars) space exploration strategy. ESA's space exploration strategy is driven by the goals to maximise knowledge gain and to contribute to economic growth. International cooperation is a key pillar of ESA's strategy as it is considered both, an enabler for achieving common goals and a benefit, opening new perspective for addressing future challenges. The achievement of ESA's space exploration strategy is enabled through international partnerships. The interagency coordination process conducted within the framework of the International Space Exploration Coordination Group (ISECG) plays an important role in laying the foundations for future partnerships. It has achieved so far the development of a common vision for space exploration, a common plan for implementing the vision in the form of the Global Exploration Roadmap, as well as a common approach for articulating the value of global space exploration. ESA has been a strong promoter and supporter of the interagency coordination process conducted within ISECG and thanks to its unique expertise in international cooperation the Agency has contributed to its success.     

地球同步轨道区域电磁频谱监视效能分析

地球同步轨道区域电磁频谱的监视效能进行了分析和仿真。首先针对目标卫星主瓣,进行了频谱监视的目标覆盖率与监视概率分析,结果表明通过主瓣方式实现频谱监视的可行性较差;进而提出基于目标卫星副瓣进行频谱监视的方法。理论分析得到了实现同步轨道目标卫星全覆盖的轨道高度差、监视角及监视距离之间的关系;最后以实际在轨的同步轨道卫星作为目标样本库,进行目标覆盖率仿真分析,结果验证了基于目标卫星副瓣进行地球同步轨道区域电磁频谱监视是可行的。     

弱撞击对接机构捕获系统运动空间研究

以弱撞击对接机构（LIDM）捕获系统的运动空间为研究对象,提出了影响运动空间的主要因素如驱动臂长度、转动副转角、结构框内径等对运动空间的限制。在此基础上,对捕获系统运动空间及其各截面进行了分析,并详细讨论了结构框内径对运动空间的影响,对LIDM的设计和优化具有重要意义。