International space station: : Ready to fly

The International Space Station (ISS) is no longer a paper program, focused on design, development and planning. It is an operational program, with hardware soon to be launched and ground systems in place. Additional modules, components and elements are now under construction in almost all of the 16 ISS International Partner and Participant countries, with metal being bent, software being written, and testing ongoing. Crew members for the first four crews are in training in the U.S. and Russia, with the first crew launching in mid 1999. Mission control centers are fully functioning in Houston and Moscow, with operations centers in St. Hubert, Darmstadt, Tsukuba, Turino, and Huntsville going on line as they are required.

The International Space Station, as the largest international civil program in history, features unprecedented technical, managerial, and international complexity. Seven international partners and participants encompassing 15 countries are involved in the ISS. Each partner is contributing and will be operating separate pieces of hardware, to be integrated on-orbit into a single orbital station. Mission control centers, launch vehicles, astronauts/cosmonauts, and support services will be provided by partners across the globe, but must function in a coordinated, integrated fashion. This paper will review the accomplishments of the ISS Program and each of the Partners and Participants over the past year, focusing on completed milestones and hardware. It will also give a status report on the development of the remainder of the ISS modules and components by each Partner and Participant, and discuss upcoming challenges.     

EnDat2.2接口的新一代角度编码器

海德汉公司中心轴和内置轴承角度编码器已成为小至数角秒的小角度测量的标准设备.特别适用于机床旋转轴,例如回转工作台和铣床摆头,是位置控制和速度控制的最佳选择.     

未来机载雷达中具有高精度测距能力的新HPRF模式

已研究了一种新的雷达模式，它可以不模糊地估算目标速度并能通过IPRF模式中的脉冲时间延迟估算距离。要实现这点，距离门宽度要减至近乎机载目标（比如战斗机）的距离向长度。与普通HPRF模式不同的是，在不模糊距离中要有多个可辨别的距离门。距离模糊的分辨则由脉冲串至脉冲串间的脉冲重复频率变化来进行。模糊分辨的算法要考虑到这样一个事实，即在PRF变化期间，目标能移至下一个距离门或跨过一个或更多的相邻距离门。此外，可以在算法中采用不模糊速度测量来补偿目标距离徙动以减少虚警率。     

Orbiting spies—opportunities and challenges

The great improvement in civil observation satellite capabilities over the past two decades—such that the image quality of civil and military satellites is now converging—is demonstrated with the aid of illustrations. The advantages of such progress, eg. new tools for treaty verification, are discussed. Potential problems, including censorship and denial of access to images of one's own country, which may conflict with the UN Remote Sensing Principles, are also highlighted. It is suggested that work on an ASAT treaty should be made a priority for the future.     

Arms control and conflict observation satellites

Dr Jasani argues the urgent case for establishing an international satellite monitoring agency, with an arms control and conflict observation satellite (ACCOS). He gives examples of recent technology advances and cites the imminent major development of space weapons by the USA and the USSR as a pressing reason for setting up a verification and crisis control mechanism. Both Europe and the non-aligned nations are in a position to participate in orbiting an ACCOS.     

US national missile defence and international security: blessing or blight?

With the revival of the US national missile defence, there is a danger of jeopardising not only the existing arms control and disarmament process, but also some of the measures that are on the table in the United Nations for negotiations. Examples of these are the prevention of an arms race in outer space and the nuclear fissile materials cut-off agreement. In this paper, the missile defence issues are examined. It is suggested that, if the US builds a missile defence system that is allowed by the 1972 Anti-Ballistic Missile Treaty between the USA and Russia, it could achieve its goal of defending itself against a limited missile attack. With this kind of approach, it may be possible to save many of the long-standing bilateral and multilateral treaties and prevent the beginning of a new and much wider nuclear arms race.     

Particle Scattering by Magnetic Fields

The need for a correct quantitative treatment of the interactions between cosmic rays and turbulent magnetic fields continues to be one of the fundamental problems of modern astrophysics. It is the aim of this paper to review new developments in the understanding of mechanisms involved in the scattering of charged particles by magnetic field fluctuations. Special emphasis is given to a comparison of transport parameters determined from the modeling of spacecraft and neutron monitor observation of solar particle events, with theoretical predictions derived from a spectral analysis of simultaneously measured fluctuation spectra. It appears that the traditional quasi-linear theory of particle scattering requires only a slight modification, and the major problem still is our lack of knowledge of the three-dimensional structure of the magnetic turbulence. Possibilities to better reconcile the theory with observations by properly taking into account the microphysics of wave and turbulence aspects of the fluctuations, and to use energetic particles as probes to study certain properties of the magnetic turbulence, are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Could civil satellites monitor nuclear tests?

As the momentum for further cuts in nuclear weapons grows and fears of nuclear proliferation increase, the need to monitor nuclear testing is becoming more pressing. While military observation satellites are already used for this purpose, this article argues that greater independence and impartiality could be achieved through the use of civilian remote sensing satellites, whose images could be made available to the International Atomic Energy Agency (IAEA). How images from space are processed and interpreted is described, as is how civil satellites might be used to verify a comprehensive test ban treaty. Four options open to the IAEA for utilizing remotely sensed images are discussed.