最先进的攻击型核潜艇技术发展美国V.S.俄罗斯

攻击型核潜艇是建立强大海军不可或缺的重要武器装备，也是冷战时期美苏相互比拼的重要筹码。随着冷战结束，美，俄两个超级大国的海军所承担的战略任务发生了很大改变．即从重视海洋作战转移到局部战争的近海作战．但攻击型核潜艇的地位和作用并来降低。伊拉克战争中，美英联军共向战区派遣了12艘攻击型核潜艇．发射了约300枚“战斧”巡航导弹．对加速战争的进程起到了重要的作用。为了应对新型威胁，新型攻击核潜艇在设计思想上强调以多功能．多用途为主．除继续强调反潜、反舰功能外．还要求具有较强的对陆攻击．监视，情报收集，特种部队输送、局部海上控制能力等。[编者按]     

世界导弹武器试比高

如今的导弹武器已不是过去那种以简简单单的打得远、威力大为目标了,而是不仅要求打得远、狠、准,还要求能作出机动、快速反应。针锋相对有矛必有盾1942年10月,由德国研制的世界上第一枚导弹——V-2导弹成功升空,射程190千米。第二次世界大战结束后,苏联和美国在V-2导弹的基础上相继研制发展了自己的导弹。从第一枚导弹诞生至今只     

深度阅读:一个“美国疯子”的太空梦

人类失去梦想,世界将会怎样?没有梦想,人类就不可能挣脱地球的束缚,也不可能在航天领域取得今天这样的辉煌成就。在纪念人类首次进入太空50周年的日子里,这里要讲述一个号称美国疯子艾伦·马斯克(Elon Musk)创建美国太空探索技术(SpaceX)公司的故事。他的太空梦想、他的创业道路,以及这个公司发展运载火箭和载人飞船的理念和技术途径,都会对我们有所启示。     

美国成功发射移动用户目标系统-4

2015年9月2日,美国成功发射移动用户目标系统-4(MUOS-4)卫星,这是美国在2015年发射的第2颗MUOS卫星。目前,这一5星星座已完成4星发射,构成了海军所谓的"初始星座",基本实现了全球覆盖。经过数月在轨测试之后,MUOS-4卫星将投入使用。配合地面站的建设和大系统联合测试,整个系统将于2017年实现"全面运行能力"(FOC)。届时,MUOS卫星的数字化载荷将为战术部队卫星通信能力带来质的飞跃。     

美国内部争论:航天部队是否独立成军

正2017年6月,由众议员罗杰斯和库珀领导的众议院军事战略力量小组委员会提出了一项法律草案,决定设立太空部队(类似海军陆战队),将太空军事行动与空军其他军事行动分开。罗杰斯和库珀希望尽快促成此事。如果这一草案成为法律,空军将在2019年1月1日之前建立新的军种,司令官将在国防部参谋长联席会议上得到席位,并直接向空军部长汇报。2017年3月以来,美国空军部长希瑟·威尔逊和空军参谋长大卫·古德芬已在参议院拨款委员会、众议院     

美国用探空火箭发射学生卫星

<正>美国东部时间2010年3月27日10点09分,美国航宇局(NASA)从沃洛普斯飞行基地发射了一枚用于试验的探空火箭。火箭进入亚轨道之后,成功释放了两颗由学生建造的立方体卫星。     

Planetary Protection Policy (U.S.A.).

Through existing treaty obligations of the United States, NASA is committed to exploring space while avoiding biological contamination of the planets, and to the protection of the Earth against harm from materials returned from space. Because of the similarities between Mars and Earth, plans for the exploration of Mars evoke discussions of these Planetary Protection issues. US Planetary Protection Policy will be focused on the preservation of these goals in an arena that will change with the growth of scientific knowledge about the martian environment. Early opportunities to gain the appropriate data will be used to guide later policy implementation. Because human presence on Mars will result in the end of Earth's separation from the martian environment, it is expected that precursor robotic missions will address critical planetary protection concerns before humans arrive.     

U.S. operational space program for climate observations

Satellites provide two important characteristics to earth climate studies not available from other, conventional sources: (1) full global coverage, and (2) consistency within the data set. This latter arises from the fact that the satellite data are usually derived from one instrument (or at least from a small number) whereas other sources involve large numbers of separate instruments and hence exhibit a substantial standard deviation. Satellite data, of course, are more subject to bias and must therefore be carefully validated, usually via ground truth.The ISCCP and ISLSCP are examples of the increasing reliance on satellite data for climate studies. In addition to the multispectral images, quantitative products of importance are: (1) atmospheric temperature structure, (2) snow cover, (3) precipitation, (4) vegetation index, (5) maximum/minimum temperature, (6) insolation, and (7) earth radiation balance. The U.S. civil space program is presently committed to its current geostationary (GOES) and polar (NOAA) programs through this decade and to continue both programs into the next decade with spacecraft carrying improved and augmented instrumentation. GOES VISSR Atmospheric Sounder (VAS) data, presently in research status and available only for special observation periods, will become available operationally in 1987 from the current spacecraft series. GOES-Next will provide additional spectral channels, simultaneous imaging, atmospheric soundings, and possibly increased resolution starting in 1990. The NOAA follow-on spacecraft, in the same time frame, is expected to provide additional spectral channels, improved passive microwave radiometry, and possibly increased spatial resolution. The Landsat program is expected to be continued by a commercial operator following the useful life of Landsat-5. All three follow-on programs are presently at various stages of definition and procurement. Final definition may not be completed until late in 1984. However, their status as of the time of this presentation will be reviewed in detail.     

U.S. planetary protection program: Implementation highlights

The implementation of planetary protection in the United States space program has reflected the trend in policy from an absolute to a probabilistic prohibition of the contamination of the celestial bodies of the solar system. The early emphasis on spacecraft sterilization (e.g. Ranger) was replaced by the imposition of contamination control procedures on later missions such as Pioneer, Viking, and Voyager. Similarly, analytical and laboratory techniques were developed to demonstrate compliance with probabilistic requirements. Microbial burden reduction methods that are not hazardous for spacecraft reliability supplanted the abstract concept of sterilization. The United States implementation of planetary protection has been completely successful. In an exploration program that has included Mercury, Venus, Mars, the Jovian system, and the Saturnian system, there have been no accidental impacts or detection of false positives (terrestrial microbes). Further, the contamination control and microbial burden procedures have proved beneficial to spacecraft systems and on-board science instruments. We review in this paper the implementation of planetary protection procedures by the Pioneer (10 and 11), Viking and Voyager projects.     

美国载人太空探索的艰难进程

正奥巴马政府中止了重返月球的载人航天计划以后,其提出的载人登火星构想给美国载人航天出了一个大难题。虽然咬住了低地球轨道以远的大方向未曾放松,但遥远的火星如何去,美国经历了关于未来载人航天的争论和艰难抉择。现在,以载人登火星为背景的小行星探索计划又遇到了新问题—2016年4月提出的"太空复兴"法案对该计划提出了质疑,特朗普政府的决策仍很艰难。1"灵活性途径"显示美国低地球轨道以远载人航天的无奈过渡     

美国GPS系统及其国际合作进展

当前世界各卫星导航系统竞相发展。为适应新的发展局面,全球导航卫星系统(GNSS)供应商纷纷利用各类多双边平台开展国际协调,围绕卫星导航领域的国际合作不断加深。美国GPS自20世纪90年代建成以来,一方面不断优化星座结构,进行系统升级,保持技术领先;另一方面也针对国际形势不断调整对外合作战略,加强与其他系统间的对话与交流,通过各类多双边平台积极扩大国际合作范围,从而维护其在卫星导航领域的主导地位。     

美国“天基太空监视”系统卫星投入运行

据美国空军太空司令部网站2011年3月14日报道,经过5个多月的在轨试验与评估,美国空军最近已把首颗"天基太空监视"系统卫星的控制权移交给了位于施里弗空军基地的第50作战大队第1太空作战中队。它具有里程碑的意义,是美国为提高空间目标和活动监视能力,完全掌握空间战场态势研制的天军武器系统。该卫星投入正式运行后,能按照     

梦想从这里开始——2010年赴美太空营训练夏令营

<正>2010年8月10日～23日,由中国宇航学会组织承办的赴美国太空营训练夏令营在美国举行,来自北京、上海、西安、苏州、无锡的56位师生参加了本次活动。在阿拉巴马太空营训练中心,营员们按年龄分成4组,由教官带领分别进