航天飞机动力系统方案探讨

本文简要介绍以美国为代表的第一代航天飞机动力装置情况,还介绍了英国霍托尔、西德桑格尔航天飞机动力装置的性能和方案特点,最后提到了发展高性能、低成本运载火箭是一次性使用运载火箭的发展方向.     

国外航天飞机介绍(一)

一 美国航天飞机轨道器示意图③’、 法冈Hermes轨道器示意图 苏联肮天飞机示意图 卜而为航天飞机 下而为?宁o航天飞饥门“米亚-1”丁仰轰炸机苏联航天飞机示意图上面为航天飞机下面为背负航天飞机的“米亚-4”重型轰炸机国外航天飞机介绍(一)     

美国航天飞机固体火箭助推器

固体火箭助推器是航天飞机动力系统的主要组成部分之一,是当今各国在发展航天飞机时所选的通用助推方案.美、日、西欧都已发展了或正在发展航天飞机用的大型固体助推器.本文重点介绍美国航天飞机固体助推器性能及其设计特点.     

NASA将建造新型火箭将人类送入太空

北京时间7月21日17时51分,美国＂亚特兰蒂斯＂号航天飞机在佛罗里达州肯尼迪航天中心安全着陆,意味着美国为期30年的航天飞机时代宣告终结。虽然＂亚特兰蒂斯＂号航天飞机完成了太空之旅的绝唱,但美国宇航局将宇航员送进太空的计划并未停止。日前,     

航天飞机再入航迹初步设计的一种计算方法

本文给出一种由航天飞机质心位置和飞行速度随高度的变化值计算再入航迹其它运动参数的方法。用美国“哥伦比亚”号航天飞机轨道器的飞行数据验算表明,该方法不失为一种可供再入航迹初步设计中选用的简便算法。     

美国“阿特兰蒂斯”号航天飞机升空开始绝唱之旅

北京时间7月8日23时30分,美国＂亚特兰蒂斯＂号航天飞机成功启动其太空之旅,这也是美国航天飞机的绝唱,标志着美国航天飞机时代的终结。此前,＂发现＂号和＂奋进＂号已分别于今年3月和6月退役。＂阿特兰蒂斯＂号从佛罗里达州肯尼迪航天中心升空,执行美国航天飞机项目第135次也是最后一次飞行,其任务期为12天,主要任务是为空间站运送一年的给养。     

美国军方拟研发新飞行器4小时可抵达全球各地

美国军方正在制定一项新的计划，拟设计一种类似于航天飞机的新型飞行器，其飞行速度超过目前任何一种飞机，几乎可以与航天飞机相媲美，能够在4小时之内将美国全幅武装的海军陆战队士兵运抵全球各热点冲突地区。     

“发现”号航天飞机重返太空

北京时间2005年7月26日晚10时39分，美国“发现”号航天飞机从位于佛罗里达州肯尼迪航天中心发射升空，大约9分钟后“发现”号航天飞机成功进人预定轨道。北京时间8月9日20时11分22秒．“发现”号航天飞机在推迟一天着陆后，安全降落在爱德华兹空军基地，标志着历时13天2l小时32分钟48秒代号为STS-114的航天飞机重返太空任务取得圆满成功。     

焊接技术在航天飞机上的应用

焊接技术是制造航天飞机的主要工艺技术,它对确保航天飞机零、部件的轻重量、高可靠性和长寿命有着十分重要的作用。本文简述了先进的焊接术在国外航天飞机轨道器、主发动机、反作用控制发动机、轨道机动发动机、固体火箭发动机壳体和外贮箱等主要部件上的应用情况。此外,对我国航天飞机焊接技术的发展提出了建议。     

“奋进”号航天飞机顺利完成STS-118任务

介绍了美国"奋进"号航天飞机发射的基本情况、先期的准备工作、主飞行任务及其意义。     

Concepts of turbulence and C.F.D. applications

The article's main theme is the ‘turbulence modelling’ used in present days' computational schemes. This modelling is an effort to account for the influence of turbulent motion on diffusion processes, and reflects our efforts to bridge what is generally recognized as the ‘closure gap’, i.e. to replace a needed phenomenological relation(s) with hypotheses of some kind. In this way one tries to remedy our lack of knowledge of turbulent motion. For that purpose a number of ideas and concepts over the past 60 years is mentioned and their incorporation in numerical analysis is discussed. The main emphasis is placed on the physical concepts and their consequences.     

R. Buccheri, J. van Paradijs, M. A. Alpar, The Many of Neutron Stars

We see neutron stars principally by their radio and X-ray emission. Their appearance in these different bands depends on whether the emission comes from the surface or its magnetosphere. New phenomena continue to be found from neutron stars, which makes it an exciting and topical research area. This volume is a collection of the papers from a NATO Advanced Study Institute held in Italy in October 1996. Many, and for me the most interesting ones, are substantial reviews on topics such as Pulsar magnetic fields and glitches (M. Ruderman), Radio pulsar population properties (D. Lorimer), Gamma-ray emission from CGRO pulsars (G. Kanbach), Neutron stars and black holes in X-ray binaries (J. van Paradijs), Kilohertz quasi-periodic oscillations in low-mass X-ray binaries (M. van der Klis), Thermonuclear burning on rapidly accreting neutron stars (L. Bildsten), On the X-ray emission properties of rotation powered pulsars (W. Becker and J. Truemper). It will serve as a useful reference and source book for students in high energy astrophysics and related fields. The high price may deter its purchase by individuals, but it will be a good volume for a library needing recent coverage on neutron stars. It does not of course include the most recent developments on anomalous X-ray pulsars or magnetars. This revised version was published online in August 2006 with corrections to the Cover Date.     

Comments on `Existence and uniqueness of GPS solutions' by J.S.Abel and J.W. Chaffee

The commenter points out that a direct Global Positioning System (GPS) algorithm together with discussions on the existence and uniqueness of the solution appeared in his paper (J. Guidance, Control, and Dynamics, vol.9, p.715-17, Nov./Dec. 1986). Since the GPS solution is reduced to solving a quadratic equation, the existence and uniqueness can be easily tested. J.S. Abel and J.W. Chaffee, in the above-titled paper (ibid., vol.26, no.6, p.748-53, Sept. 1990), show that the GPS solution problem is similar to the hyperbolic-fix problem. The commenter notes that it can be inferred from his later work (ibid., vol.26. no.5, p.748-53, Sept. 1990) that the two solutions exist if and only if the four GPS satellites are coplanar, in which case the two solutions are mirror-symmetric with respect to the GPS plane     

R. Burkhardt, U. Esser, H. Hefele, I. Heinrich, W. Hoffmann, V. R. Matas, L. D. Schmadel, R. Wielen and G. Zech (eds.), Astronomy and Astrophysics Abstracts, Volumes 69A and 69B, Literature 1998, Part 1, published for Astronomisches Rechen-Institut

The reviewed Volumes of the AAA series record, summarize and index nearly 12 000 papers covering all aspects of astronomy and space sciences, published throughout the world during the first half of the year 1998. The AAA series is the most important source of information on progress in the scientific disciplines. They have become an indispensable source of information for scientists and students involved in the Universe research. This revised version was published online in August 2006 with corrections to the Cover Date.     

Newton迭代法的P．C．格式

基于Newton迭代法 ,提出了一种有效的预估校正 (P .C .)迭代格式。本方法把牛顿法中的微分以差商替代 ,因而 ,既可求解具离散根的方程 ,也适用于有重根的方程求解 ,大量的试验结果表明 ,本文算法不仅可有效解决重根问题 ,而且有较高的收敛速度。     

U.S. Army battery needs-present and future

The purpose of this paper is to describe the needs of the U.S. Army for silent portable power sources, both in the near and longer term future. As a means of doing this, the programs of the Power Sources Division of the Army Research Laboratory are discussed. In carrying out these programs, the personnel of the Power Sources Division work closely with the Battery Management Office of the Army Materiel Command, which is located in the Logistics and Readiness Directorate of the Communication-Electronics Command (CECOM). We are also closely integrated with the Army Research Office, and the fuel cell personnel of the CECOM Research Development and Engineering Center (RDEC), and the battery personnel of the RDECs for the Tank and Automotive Command and the Missile Command. The six program areas discussed in which the Power Sources Division is engaged are: primary batteries, rechargeable batteries, reserve/fuze batteries, pulse batteries and capacitors, fuel cells, and thermophotovoltaic power generation     

Ocean Engineering in the U. S. Navy

This paper is the complete text of an address given at the IEEE meeting in New York on March 23, 1966, in ?Undersea Technology Session,? covering the U. S. Navy's furtherance of the development of Ocean Engineering and some plans for the future. The items covered include the deep submergence systems project, SEALAB III, salvage work packages circa 1967, and additions to the Marine Engineering Laboratory.     

Comments on `Detector relative efficiencies in the presence ofLaplace noise' by M.I. Dadi and J.R. Marks II

In the above-titled paper (see ibid., vol.AES-23, p.568-82, July 1987) M.I. Dadi and J.R. Marks II studied the relative efficiencies of the Neyman-Pearson optimal detector with respect to the linear and sign detectors, for the detection of a constant signal in additive Laplace noise. By applying the central limit theorem, they derived expressions for three types of asymptotic relative efficiencies (AREs). However, as noted in the above paper, the Gaussian approximation to the sign detector fails to yield the correct asymptotic efficiency. The commenter derives the correct ARE of the optimal detector with respect to the sign detector for the Laplace noise     

A. M. Hubert and C. Jaschek (eds.), B[e] Stars

The B[e] stars are early type stars with hydrogen emission lines, forbidden [FeII] and [OI] emission lines, and with an IR excess due to circumstellar dust. These properties may occur in stars of quite different evolutionary stages. In fact, the group of B[e] stars is very inhomogeneous, and contains pre-main sequence stars, supergiants with disks, compact planetary nebulae, symbiotic stars, and a group of stars with unclear evolutionary phase. The book gives the proceedings of a workshop in Paris in 1997 in which the properties and evolutionary phases of the B[e] stars are discussed. It contains chapters on: (1) the definition of B[e] stars, (2) distances, kinematics and the distribution in our Galaxy, (3) spectroscopy, (4) infrared properties, (5) photometry, polarimetry and variability, (6) models for winds and disks, (7) evolutionary stages, (8) revised classification of B[e] stars. The book ends with an object list of all B[e] stars. The book is very useful for students and researchers of hot star winds and gives nice overviews of the observations and theories and remaining puzzles of these strange objects with winds and outflowing dust-forming disks. This revised version was published online in August 2006 with corrections to the Cover Date.