Smith  Howard A. 《Space Science Reviews》2003,105(1-2):493-505

Astronomy and space science, including their associated basic research activities, enjoy broad popular backing. People generally support them, and say that they follow their results with interest. This article summarizes some of the detailed results of public surveys in the United States, focusing on popular opinions and attitudes, and the somewhat paradoxical finding that despite being interested and supportive, people are often ignorant about the basic facts. I explore some of the reasons for the popularity of space science, and suggest ways of justifying space science research in the broader context of science research. I argue that vigorous and innovative education and outreach programs are important, and can be made even more effective. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

    

Moore  T.E.  Collier  M.R.  Fok  M.-C.  Fuselier  S.A.  Khan  H.  Lennartsson  W.  Simpson  D.G.  Wilson  G.R.  Chandler  M.O. 《Space Science Reviews》2003,109(1-4):351-371

Development of the low energy neutral atom (LENA) imager was originally motivated by a need to remotely sense plasma heating in the topside ionosphere, with the goal of greatly enhanced temporal resolution of an otherwise familiar phenomenon. During ground test and calibration, the LENA imager was found to respond to neutral atoms with energies well above its nominal energy range of 10–750 eV, up to at least 3–4 keV, owing to sputtering interactions with its conversion surface. On orbit, LENA has been found to respond to a ubiquitous neutral atom component of the solar wind, to the neutral atoms formed by magnetosheath interactions with the geocorona during periods of high solar wind pressure, and to the interstellar neutral atoms flowing through the heliosphere during the season of maximal relative wind velocity between spacecraft and interstellar medium. LENA imaging has thus emerged as a promising new tool for studying the interplanetary medium and its interaction with the magnetosphere, in addition to the ionospheric heating and outflow that result from this interaction. LENA emissions from the ionosphere consist of a fast component that can be observed at high altitudes, and slower components that evidently create a quasi-trapped extended superthermal exosphere. The more energetic emissions are responsive to solar wind energy inputs on time scales of a few minutes.  相似文献   

    

Vadher  V.V. Smith  I.R. Fanthome  B.A. 《IEEE transactions on aerospace and electronic systems》1986,(1):64-70

Permanent magnet generators are often used as the pilot exciters of three-stage generating units to provide an efficient and reliable source of electrical power. No external power supply is then necessary, and the problems associated with brushwear and with arcing at the rubbing contacts are eliminated. A technique is presented here by which the performance of a permanent magnet generator, when combined with a rectifier-fed d.c. load at its output terminals, may be accurately and efficiently computed. The machine model takes into account the magnetization characteristic of the permanent magnet rotor and involves only parameters which can be determined from terminal measurements on the machine at standstill. Both computed and measured characteristics for an experimental machine are presented, and a comparison of these characteristics shows that the model can predict accurately all the major characteristics of the machine, as well as its detailed internal performance, when supplying a typical resistiveinductive load.  相似文献   

    

V. A. Grigoriev 《Space Science Reviews》1989,49(1-2):151-155

The scintillation time-of-flight triggering system of the Gamma-1 gamma-ray telescope provides for both the time-of-flight discrimination and the pulse height discrimination of the secondary particles. The paper gives some experimental results for energy dependence of the instrument efficiency in 30–300 MeV energy range for different trigger logics.  相似文献   

    

Iyer  A. Singh  S.N. 《IEEE transactions on aerospace and electronic systems》1989,25(5):611-620

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  总被引：1，自引：0，他引：1  

Houles  A. Bar-Shalom  Y. 《IEEE transactions on aerospace and electronic systems》1989,25(2):176-189

An algorithm is presented for tracking a highly maneuvering target using two different sensors, a radar and an infrared sensor, assumed to operate in a cluttered environment. The nonparametric probabilist data association filter (PDAF) has been adapted for the multisensor (MS) case, yielding the MSPDAF. To accommodate the fact that the target can be highly maneuvering, the interacting multiple model (IMM) approach is used. The results of single-model-based filters and of the IMM/MSPDAF algorithm with two and three models are presented and compared. The IMM has been shown to be able to adapt itself to the type of motion exhibited by the target in the presence of heavy clutter. It yielded high accuracy in the absence of acceleration and kept the target in track during the high acceleration periods  相似文献   

    

K. Marubashi 《Space Science Reviews》1989,51(1-2):197-214

This paper describes the Space Weather Forecast Program managed by the Communications Research Laboratory of Japan. It is a long-range program consisting of three phases of five years each. This program emerged after an effort to investigate future needs for space environment prediction. We conclude that solar flares and magnetic storms are two main critical phenomena which will affect human's space activities in the 21st century. The core of the program is to set up a Space Weather Forecast Center which has core facilities: (1) a computer network system; (2) ground facilities for continuous observation of the Sun; and (3) a satellite-based space environment monitoring system. Emphasis is placed upon the necessity of internal cooperation for efficient operation of the Forecast Center.  相似文献   

    

P. P. Eggleton  C. A. Tout 《Space Science Reviews》1989,50(1-2):165-177

We discuss evolutionary processes in binaries where the primary becomes a red giant with a deep convective envelope before it fills its Roche lobe. Such binaries (late Case B or late Case C, if they evolve conservatively) ought to suffer drastic mass transfer, on a hydrodynamic timescale. In some circumstances this may lead to a common envelope, spiral-in, and finally either a very short-period binary or coalescence. But there appear to be other circumstances in which the outcome is an ordinary Algol, or a wide binary with a white dwarf companion as in Barium stars and some symbiotics. We try to demonstrate that stellar-wind mass loss, enhanced one or two orders of magnitude by tidal interaction with a companion, can vitally affect the approach to RLOF, and indeed may prevent RLOF in binaries with periods over 1000 d. Such mass loss is probably accompanied by angular momentum loss, by magnetic braking combined with tidal friction. The result is that it will not be easy to predict definitively the outcome of evolution in a given zero-age binary.  相似文献   

    

R. H. D. Corbet  A. P. Smale  J. W. Menzies  G. Branduardi-Raymont  P. A. Charles  K. O. Mason 《Space Science Reviews》1985,40(3-4):415-419

We present optical spectroscopy and photometry of 4U 1258-61 obtained over the course of six years. Evidence for the evolution of a circumstellar envelope throughout the course of the observations is presented.  相似文献   

    

M. Pakull  H. Brunner  W. Pietsch  A. Staubert  K. Beuermann  M. van der Klis  J. M. Bonnet-Bidaud 《Space Science Reviews》1985,40(3-4):379-382

Repeated observations of LMC X-4 with EXOSAT were carried out in 1983/84 in order to study its 30.5 day cycle and to cover the expected outbursts of the recurrent LMC transient A0538-66. The latter source was inactive during our campaign although a variable circumstellar envelope was still present around the optical counterpart.At least ten further X-ray sources are detected in the CMA field of view around LMC X-4 including the SNR N49 which is the possible site for the March 5, 1979 -ray burster and N63A which appears to be variable in X-ray luminosity. We furthermore discuss the strongest sources that were not present in a previous EINSTEIN survey of the LMC.  相似文献