A security space capability for Europe? Implications for US policy

As the European Union takes tentative steps towards creating a “rapid reaction force” able to operate independently of NATO, an important question is what capabilities that force must have in order to operate effectively. Among those capabilities is the use of space systems for communications and intelligence applications. This article examines the prospects for an independent security space capability in Europe, and the implications of the emerging European interest in space autonomy for US policy.     

Building and maintaining the constituency for long-term space exploration

The exploration of space is a long-term endeavor that will require strong public support to weather societal and political changes over the period of its implementation. In August 2006, George Mason University's Center for Aerospace Policy Research organized a workshop to address this issue. The sustainability of space exploration was investigated from a variety of perspectives by invited experts from the space sector as well as from the market research and public relations fields. This paper summarizes the results of the workshop. It presents market research data along with recommendations for an active strategic communications effort as well as public engagement to enhance public support for space exploration, especially among the younger age groups which tend to be uninterested in space activities.     

Strategies for telecommunications and navigation in support of Mars exploration

The planned exploration of Mars will pose new and unique telecommunications and navigation challenges. The full range of orbital, atmospheric, and surface exploration will drive requirements on data return, energy-efficient communications, connectivity, and positioning. In this paper we will summarize the needs of the currently planned Mars exploration mission set, outline design trades and options for meeting these needs, and quantify the specific telecommunications and navigation capabilities of an evolving infrastructure.     

Integrated RF-optical TT&C for interplanetary telecomms

Science return and high bandwidth communications are one of the key issues to support the foreseen endeavours on next generation missions [J.L. Gerner, Telemetry, tracking and command of satellites—a perspective, TT&C 2004 Workshop, 7–9 September 2004]. Interplanetary telecommunication systems are required that support the foreseen endeavours. Given the same constraints in terms of mass, power and volume a laser communications terminal can offer an increase in telemetry bandwidth over classical RF technology allowing for a variety of new options, specifically to missions that require large distances, such as to the Moon, to liberation points L1 and L2, ultimately aiming at deep space missions. An increase in telemetry data rate allows the mission to consider the processing of raw scientific data to take place on ground, making use of latest technology further developed during the cruise phase of the probe, rather than applying data pre-processing on-board the satellite. Enhanced sensing techniques that generate more science data return could be used and access to data during flight could be faster. Results of on-going activities will be presented, comprising PPM laser communications and advanced tracking concepts. An overview will be given of the system concept for an integrated RF-optical TT&C transponder. Results will be shown from hardware tests on communications performance in inter-island test campaigns.     

Integrated RF-optical TT&C for interplanetary telecomms

Science return and high bandwidth communications are one of the key issues to support the foreseen endeavours on next generation missions [J.L. Gerner, Telemetry, tracking and command of satellites—a perspective, TT&C 2004 Workshop, 7–9 September 2004]. Interplanetary telecommunication systems are required that support the foreseen endeavours. Given the same constraints in terms of mass, power and volume a laser communications terminal can offer an increase in telemetry bandwidth over classical RF technology allowing for a variety of new options, specifically to missions that require large distances, such as to the Moon, to liberation points L1 and L2, ultimately aiming at deep space missions. An increase in telemetry data rate allows the mission to consider the processing of raw scientific data to take place on ground, making use of latest technology further developed during the cruise phase of the probe, rather than applying data pre-processing on-board the satellite. Enhanced sensing techniques that generate more science data return could be used and access to data during flight could be faster. Results of on-going activities will be presented, comprising PPM laser communications and advanced tracking concepts. An overview will be given of the system concept for an integrated RF-optical TT&C transponder. Results will be shown from hardware tests on communications performance in inter-island test campaigns.     

弱太阳闪烁中深空探测信道的自适应控制

为提高探测器发射机功率利用率,在探测器和地球间建立可靠的传输链路,弱太阳闪烁中的深空信道的自适应控制十分重要。根据CCSDS规范,提出了一种基于连续功率控制和离散速率控制策略的深空信道自适应控制方法。数学分析和计算机仿真表明,(1) 太阳闪烁越强,自适应功率控制效果越明显;(2) 当太阳闪烁引起的信号衰减不大,小于9.4dB时,MPSK自适应控制信道容量高于非自适应控制信道容量。
     

Canadian space policy

Canada's geography made it an early leader in the development of space technology, and generated a civilian-oriented, terrestrially focused space programme with a strong focus on communications and an increasing emphasis on transferring space technology and activity from the government to the private sector. During the 1980s Canada's space programme has strengthened and broadened measurably; its now contains major projects in Earth observation and robotics as well as communications, and has diversified its international partnerships from the USA to Europe. However, persisting weaknesses in launch capability, space science and military space programmes, and the dependence of all three current major projects (Msat, Radarsat, and the International Space Station's Mobile Servicing System) on the USA represent potential vulnerabilities which require national investments and expanded international affiliations if they are to be offset.     

发展X-37B空间飞机的背后动因分析

文章通过对X-37B飞行器的飞行试验任务分析,指出了X-37B飞行器不是空天飞机,也不是全球快速打击平台,而是一种低成本太空进入能力的飞行验证器,它的作用定位在空间而不是在空中。通过飞行试验和验证试验,旨在打造一个可重复使用的轨道转移运载器。将美国2010年航天战略的重大调整、国际空间站的运行延期和航天飞机退役等事件结合起来,对X-37B发展的背后动因进行分析,有助于了解美国航天发展的未来趋势。经过动因的详尽分析,指出要特别关注美国航天战略调整的两个重心转向,尤其是两个转向背后的动机。如何正确地认识国际空间站的作用定位,对于审视载人航天的未来发展有重要意义。美国航天战略的调整使载人航天的重心回到近地轨道上。基于中国目前的能力现实,建议中国的载人航天重心放在地球轨道上,做好各种能力的建设,并利用这些能力把地球轨道上的事做得更好。     

Space for celestial symphonies? Towards the establishment of international radio quiet zones

The growth of low- and medium-Earth orbit mobile satellite communications poses a threat to radio astronomers which could be mitigated by the establishment of international radio quiet zones (IRQZs), where communications traffic is managed (not eliminated) to allow radio astronomy to continue. Using the prototype of national such zones in the USA, this article explains how the system would work and discusses the international legal parameters that would bound it, drawing on current aerospace, outer space and high seas legislation. Precedents for an IRQZ—Exclusive Economic Zones, denuclearised zones and the Antarctic regime—are also examined.     

Space technology in developing nations: an assessment

Space technology can make an immense contribution to solving the problems of the world as a whole, and the developing nations in particular. This report summarizes the use of satellites by developing countries in the fields of communications, remote sensing, disaster management and space science. India and China, in particular, have built up impressive capabilities in several of these areas, but the great majority of developing countries still do not have access to this technology. The author addresses a number of proposals to the international community for bringing the satellite revolution to the developing world.     

Current status of the Russian space programme

This paper surveys the status of Russian space activities in terms of budget, operational satellite systems, workforce and industrial capabilities. There is inequality between companies and particularly between various tiers of cooperation in production. In the current situation international cooperation, both in the form of joint non-commercial ventures and integration into the global space market, is considered vital for sustaining national space capabilities.     

Convergence and technology acceleration in non-safety aeronautical mobile-satellite communications: Policy for the 21st century

Commercial activities from outer space have largely consisted of satellite communications. Whilst the maritime and land-mobile services can now be regarded as mature, the next growth area is anticipated in the provision of non-safety aeronautical mobile-satellite services, a service which is now poised to expand significantly in an era marked by competition and convergence of communications technologies. This article highlights and analyses pertinent institutional, legal and regulatory issues, describing what the law is, while making recommendations relating to what the current law should become if the rules were changed to accord with good policy.     

Dream project: Applications of earth observations to disaster risk management

The field of disaster risk management is relatively new and takes a structured approach to managing uncertainty related to the threat of natural and man-made disasters. Disaster risk management consists primarily of risk assessment and the development of strategies to mitigate disaster risk. This paper will discuss how increasing both Earth observation data and information technology capabilities can contribute to disaster risk management, particularly in Belize. The paper presents the results and recommendations of a project conducted by an international and interdisciplinary team of experts at the 2009 session of the International Space University in NASA Ames Research Center (California, USA). The aim is to explore the combination of current, planned and potential space-aided, airborne, and ground-based Earth observation tools, the emergence of powerful new web-based and mobile data management tools, and how this combination can support and improve the emerging field of disaster risk management. The starting point of the project was the World Bank’s Comprehensive Approach to Probabilistic Risk Assessment (CAPRA) program, focused in Central America. This program was used as a test bed to analyze current space technologies used in risk management and develop new strategies and tools to be applied in other regions around the world.     

Technical and economical comparison between a modular geostationary space platform and a cluster of satellites

In recent years, the identification of a large number of telecommunication missions reflects a growing demand for the provision of a large variety of communications and data transmission services performed by a space segment.

At present, communication space segment use a single operational satellite per orbit position. However, the expected increase of communication channels per space segment will lead to a corresponding increase of satellite mass and size which could exceed the capabilities of existing launch vehicles in terms of mass and volume requirements. Those considerations, coupled with the threatening saturation of the geostationary orbit, lead to the conclusion that an optimal space segment concept must be defined on a technical as well as economical point of view.

Two main concepts may be envisaged: one is a large platform, which can be assembled either in geostationary orbit (resulting in several launches, rendez-vous and docking), or in low earth orbit by using the STS; the other concept is a cluster of satellites.

These candidate concepts are designed to meet the requirements of a reference mission. They are characterized by the required number of modules to be launched, the type of launcher, the new subsystems or equipments to be developed. The concepts are evaluated following technical criteria such as adaptability to other missions, flexibility, growth potential. A cost/benefit evaluation of each solution is presented. A comparison between the different concepts is then made on the basis of the technical/economical attractiveness of each solution.     

Ukrainian space policy — contributing to national economic development

Following Ukraine's 1991 declaration of independence and the disintegration of the USSR, Ukraine inherited a third of the Soviet Union's space industry. This paper presents an overview of the main features of Ukraine's current policy on the exploitation of this capability as a factor in the transformation of its economy. It illustrates how the policy is being realized in the areas of launch systems, Earth observation, satellite communications and international relations, and concludes that Ukraine's strengths in the space field are counterbalanced by obstacles which must be faced, both within the country and externally.     

Tracking and data relay satellite system: NASA's new spacecraft data acquisition system

The growth in NASA's ground network complexity and cost triggered a search for an alternative. Through a lease service contract, Western Union will provide to NASA 10 years of space communications services with a Tracking and Data Relay Satellite System (TDRSS). A constellation of four operating satellites in geostationary orbit and a single ground terminal will provide complete tracking, telemetry and command service for all of NASA's Earth orbital satellites below an altitude of 12,000 km. The system is shared: two satellites will be dedicated to NASA service; a third will provide backup as a shared spare; the fourth satellite will be dedicated to Western Union's Advanced Westar commercial service. Western Union will operate the ground terminal and provide operational satellite control. NASA's Network Control Center will provide the focal point for scheduling user services and controlling the interface between TDRSS and the rest of the NASA communications network, project control centers and data processing facilities. TDRSS single access user spacecraft data systems should be designed for efficient time shared data relay support. Reimbursement policy and rate structure for non-NASA users are currently being developed.     

Developing the next phase in NASAs satellite communications program

NASAs early efforts in satellite communications development brought confidence in space technology use for improved telecommunications. New, worldwide satellite communications systems have resulted, and are now on a commercial, self-sustaining operational basis. Since 1973, NASA has conducted hundreds of user experiments and demonstrated newer technology using ATS-1, -3, -6 and CTS. Now, projections show that the commercial demand will continue to increase, soon exceeding the current technology's capacity.As a result, U.S. Space Policy affirmed in 1978 that NASA should embark again on a research and development program for satellite communications with specific, characterized goals. The resulting plan's elements include $\text{30}\text{20}\text{GHz}$ Ka-band technology, extending the current work in advanced multi-beam antennas; a narrowband system and technology study that could lead to mobile and transportable communications developments; and studies of future uses of technology in communications. The program plan and its evolution are described, followed by a report of current progress and future expectations.     

空间目标可见光相机探测能力理论计算方法研究

空间目标可见光相机的探测能力主要与相机自身收集目标信号的能力、相机本身的背景噪声以及探测器组件的噪声水平有关。衡量空间目标可见光相机探测能力的主要技术指标是信噪比。在国内外相关资料比较缺乏的情况下，文章通过原理研究和理论推导，得到了空间目标可见光相机探测能力理论计算公式，并用实例进行了例证，表明该方法正确可取，为空间目标可见光相机设计时对探测能力的分析和预估提供了理论计算方法。     

空间目标可见光相机探测能力理论计算方法研究

空间目标可见光相机的探测能力主要与相机自身收集目标信号的能力、相机本身的背景噪声以及探测器组件的噪声水平有关。衡量空间目标可见光相机探测能力的主要技术指标是信噪比。在国内外相关资料比较缺乏的情况下,文章通过原理研究和理论推导,得到了空间目标可见光相机探测能力理论计算公式,并用实例进行了例证,表明该方法正确可取,为空间目标可见光相机设计时对探测能力的分析和预估提供了理论计算方法。     

舱外活动系统述评

舱外活动（EVA）系统可分为3部分：1）航天员装备系统,包括舱外航天服（EVA航天服）、安全系绳和机动装置;2）空间支持系统,包括气闸、约束装置、EVA工具、在轨训练设施、遥控自动操作装置,以及表面运输工具;3）地面试验、训练与保障系统,包括减重／失重设施、热／真空试验舱、虚拟现实模拟系统、星体表面模拟场地,以及任务保障设施。文章阐述EVA系统的组成与功能,评述EVA技术现状及发展趋势。