The US national space transportation policy: issues for congress

Below is a summary of what was to be the first in a series of reports produced by the Office of Technology Assessment (now defunct) on policy for the USA's future space transportation technology and industrial base. It examines the Clinton Administration's 1994 National Space Transportation Policy and supporting implementation plans and raises and analyses such issues as conflicts and redundancies within NASA and DoD space transportation development programs; competition and cooperation with foreign launch vehicle and component providers; US government limits on the conversion of long-range missiles to space launchers in the face of Russian activity in this area; and the effectiveness of Administration efforts to include the private sector in space transportation decision making. Some issues not covered in the Policy are also discussed.     

Microwave policy issues for solar space power

This article reviews the three major policy issues likely to arise from an SSP system: environmental safety, frequency allocation and prevention of interference with other frequency-using activities. Supporters of SSP must make sure that their case is heard clearly at the ITU, but they must also do more to promote public awareness of the technology's potential benefits in order to counter inappropriate use of the Precautionary Principle by anti-technology groups. The strengthening of standard-setting groups world-wide will also assist this process.     

Galileo系统在空间飞行器定位中的应用

欧洲的Galileo系统将在2008年建成，届时它将与美国的GPS系统相互补充。在对Galileo系统导航星座轨道和信号结构分析的基础上，结合各种不同轨道高度的空间飞行器用户的动态特点，推导了用户卫星接收天线的可见可用性模型，建立了基于Galileo坐标系统(ITRF-96)的高动态定位算法模型，针对实际航天工程任务的LEO和GEO卫星进行了定位仿真，为Galileo系统在空间领域的实际应用打下了基础。     

Driving UK space policy forward: Time for an annual conference

Despite public enthusiasm, space in the UK is perceived as lacking support from the government and policy often seems incoherent. A knock-on effect is the low number of students pursuing study or careers in science and engineering. Lately, however, space activity has been receiving greater attention from official circles and, in an effort to capitalise on this, a group of individuals has come up with a plan to hold an annual conference on UK space policy. The aims and framework of the conference are described.     

Reply policy and signal type: assumptions drawn from minimal source information

A scenario is developed under which a discovery of extraterrestrial technology is made by one of the World’s search for exterrestial intelligence (SETI) programs. The nature of the signal received gives an absolute minimum of information as to the nature of the senders. Current SETI detection and reply policy is examined under these assumptions. Current policy calls for prompt and public release of signal information and stellar coordinates upon announcement of a discovery. The SETI protocol calls for no reply until authorized by international consultations. It is argued that changes are needed in these policies to guard against the possibility of unauthorized replies that could severely complicate long-term interstellar communication.     

空地一体化信息对抗系统构架设想

首先介绍“空天一体化”作战体系概念及信息对抗系统的组成和系统特点,并基于目前信息对抗系统的现状和对未来信息战的推测,对空地一体化信息对抗系统构架做了初步的设想。重点介绍空地一体化信息对抗系统的需求、系统构架、组成、特点及关键技术。     

空间信息对抗能力与技术需求

在陆、海、空、天、电战争范畴,空间攻防对抗是战略制高点。从美军的空间对抗的发展和变化,折射出未来的空间对抗需求已由“确保摧毁”向“确保生存”的战略概念转变,由“硬杀伤”向“软能力”倾斜。从需求出发,提出未来空间信息对抗能力设想,以及实现这些能力的主要关键技术。     

Space exploration policy: Towards an operational vision

This article examines the historical and social context of space exploration policy. It seeks to reconcile a contradiction between the visionary grandeur of space and public perceptions of space exploration as the province of a narrowly-focused political interest group. The author argues that perceptions of the space age are artificially restricted by dating its origins to Sputnik and Apollo and allowing it to be dominated by science and technology objectives devoid of a more encompassing social framework. Guiding principles for developing space exploration activities in a broader conceptual and operational framework are offered.     

对地面军事电磁信息的天际防护系统

针对当前空间电子侦察、空间对抗的严峻形势,提出对地面军事电磁信息的天际防护系统。即针对有大量侦察卫星对地面防御系统所有电磁辐射信号进行侦收的现实,采取有效的反侦察措施,以适应太空作战制信息权任务的需求。明确了天际防护系统的作战使命以及应具备的主要功能,给出了系统的简要组成框图,具体分析了对地面电磁辐射信息的天际防护的相关问题,也提出了防护星组的布局问题等。最后,归纳了天际防护系统所应该专门研究的几个主要问题。     

航行情报动态信息处理系统静态数据维护技巧

航行情报动态信息处理系统(以下简称CNMS)是航行情报工作的主用系统,负责航行通告的发布、接收、处理,飞行前航行情报资料公告的提取。目前民航局空管局下属的地区空管局、空管分局、空管站情报部门均安装了CNMS。各地CNMS系统之间相互独立,配置有各自独立的数据库,系统数据管理由各地的情报员负责。对于地区空管局一级的情报部门,由于有     

Current policy issues in remote sensing: report by the International Policy Advisory Committee of ISPRS

The role of remote sensing in promoting sustainable development, its general benefits and easing access to remotely sensed images, especially for developing countries, have all been examined by the International Policy Advisory Committee of the ISPRS in 2003. This report, a slightly revised version of an article that appears in the September 2003 issue of the ISPRS's Highlights magazine, presents the committee's findings and recommendations.     

On the global geodetic observing system: Africa's preparedness and challenges

Space geodetic techniques and satellite missions play a crucial role in the determination and monitoring of geo-kinematics, Earth's rotation and gravity fields. These three pillars of geodesy provide the basis for determining the geodetic reference frames with high accuracy, spatial resolution and temporal stability. Space geodetic techniques have been used for the assessment of geo-hazards, anthropogenic hazards and in the design of early warning systems for hazard and disasters. In general, space geodesy provides products for Earth observation, science and influences many activities (e.g., building and management) in a modern society. In order to further promote the application of space geodetic methods to solving Earth science problems, the Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG) was commissioned as an important geodetic infrastructure that integrates different geodetic techniques (such as Global Navigation Satellite Systems, Very Long Baseline Interferometry, Satellite Laser Ranging, Interferometric Synthetic Aperture Radar and Doppler Orbitography and Radio-positioning Integrated by Satellite), models and analysis techniques for the purpose of ensuring long-term, precise monitoring of geodetic observables vital for monitoring Earth system processes. Since its inception, there has been considerable progress made towards setting up the infrastructure necessary for the establishment of the GGOS database. While the challenges that beleaguer the GGOS are acknowledged (at least at global level), the assessment of an attuned GGOS infrastructure in the African context is necessary, yet lacking. In the present contribution, (a) the African preparedness and response to the observing system is assessed, and (b) the specific scientific and technological challenges of establishing a regional GGOS hub for Africa are reviewed. Currently only South Africa has a fundamental geodetic observatory located at Hartebeesthoek, Pretoria. Other countries in Africa have shown interest to participate in global geodetic activities, in particular through interest in the development of a unified African geodetic reference frame (AFREF). In particular interest has been shown in the proposed African VLBI Network (AVN), which will be partially based on existing ex-telecommunication radio antennas. Several countries are investigating their participation in the AVN, including Kenya, Nigeria and Ghana.     

基于有限测点的复杂管路全局振动预示方法

基于数值模拟和实验提出和验证了一种利用有限测点振动信息进行典型管路系统约束状态及载荷参数重构识别,进而通过精细有限元建模实现管路系统动态响应评估的管路全局振动检测预示方法。主要研究内容包括：首先,建立了典型发动机管路结构随机振动响应分析正问题有限元模型,提出了针对管路振动全面预示的测点设置策略;其次,发展了激励和约束参数分别重构的振动系统参数识别方法,基于共轭梯度法建立了载荷、约束确定论反演算法,确立了基于管路系统实际结构和载荷、约束参数重构结果的高精度振动建模方法;最后,搭建了管路系统的简谐/随机振动实验系统,基于位移和应变振动测量信号进行了约束刚度和载荷的重构,建立了发动机典型管路的精细有限元模型,实现了管路结构振动位移和应力的全面检测预示,验证了所提方法的有效性。结果发现,针对仿真和实测振动信号均可实现对管路振动的有效检测预示,能够确定管路薄弱位置和最大应力状态,可为重型等新型发动机管路结构设计和完整性评价提供有效支撑。     

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.     

The need for a United Nations space policy

The international community is entering an era of shared global utilities from space and is increasingly reliant on space systems and activities that support a myriad of applications and utilities on Earth. A growing number of states are seeking to develop or extend their space capabilities. At the same time, a variety of non-state actors are also extending their involvement in space activities. The United Nations is the principal inter-governmental forum to deal with various space issues of global importance. Moreover, the United Nations system itself has become increasingly reliant on space systems for its day-to-day operations. In order for the United Nations to play its necessary role in the space arena, it will need to be supported by a space policy. A United Nations space policy would provide over-arching guidance on space activities for UN stakeholders in the space arena; it would inform UN participation in space activities and would promote improved coordination and cooperative governance of outer space activities. A world without a common UN space policy will not be able to respond to the challenges of the rapidly evolving space arena in the 21st century.     

Blended control, predictor-corrector guidance algorithm: an enabling technology for Mars aerocapture

A guidance scheme designed for coping with significant dispersion in the vehicle's state and atmospheric conditions is presented. In order to expand the flyable aerocapture envelope, control of the vehicle is realized through bank angle and angle-of-attack modulation. Thus, blended control of the vehicle is achieved, where the lateral and vertical motions of the vehicle are decoupled. The overall implementation approach is described, together with the guidance algorithm macrologic and structure. Results of guidance algorithm tests in the presence of various single and multiple off-nominal conditions are presented and discussed.     

The benefits of remote sensing for energy policy

A strong remote sensing regime is a necessary component of any contemporary national or international energy policy. Energy is essential to the functioning of modern industrial society, and as such it is the responsibility of governments to produce sound national energy policies in order to ensure stable economic growth, ecologically responsible use of energy resources and the health and safety of citizens. Comprehensive, accurate and timely remote sensing data can aid decision making on energy matters in several areas. This paper looks at the benefits that can be realized in resource exploration, weather forecasting and environmental monitoring. Improvements in the technology of remote sensing platforms would be of great value to buyers of energy, sellers of energy and the environment. Furthermore, the utility of such information could be enhanced by efforts of government agencies to communicate it more effectively to the end-user. National energy policies should thus include investments not only in satellite system hardware to collect data, but also in the services required to interpret and distribute the data.     

Space nuclear power: technology, policy, and risk considerations in human missions to Mars

There is a large discrepancy between potential needs for nuclear propulsion and power systems for the human exploration of Mars and the current status of R&D funding, public opinion, and governmental support for these technologies. Mission planners and spacecraft designers, energized by the recent claims of possible discovery of life on Mars and responding to increased public interest in the human exploration of Mars, frequently propose nuclear reactors and radioisotope thermoelectric generators (RTGs) for interplanetary spacecraft propulsion and for power supply on the surface of Mars. These plans and designs typically assume that reactors will be available "on-the-shelf," and do not take the extensive R&D costs required to develop such reactors into consideration. However, it is likely that current U.S. policies, if unchanged, will prohibit the launch of nuclear reactors and large RTGs in response to a perceived risk by the public.     

电推进系统空心阴极产品试验技术

空心阴极是电推进系统可靠性和工作寿命关键部件,空心阴极产品的研制在很大程度上依赖于阴极试验技术的支持。在介绍空心阴极试验分类和试验设备的基础上,从性能试验、验收和鉴定试验及寿命验证试验等方面讨论了电推进系统空心阴极的产品试验技术。