An infrared detection range model for near space craft application

Aimed at the problem that it is hard to detect near space hypersonic target for conventional radar because of its high flight speed, flight height, and flight distance and so on, the detection performance of space-based radar to near space hypersonic target was analyzed. The characteristics of near space hypersonic target and the advantages of space-based radar was introducted, and then, the detection performances of space-based radar to near space hypersonic target from detection range, searching and tracking mode were studied. It has certain guiding significance for space-based radar development and perfection of near space detection system.

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Stellar Evolution

Transactions of the International Astronomical Union ◽

10.1017/s0251107x00022343 ◽

1962 ◽

Vol 11 (02) ◽

pp. 137-143

Author(s):

M. Schwarzschild

Keyword(s):

Solar System ◽

Stellar Evolution ◽

Space Craft ◽

New Techniques ◽

Substantial Body ◽

Individual Stars ◽

The Past ◽

Evolution Of Galaxies ◽

History Of ◽

Fast Flow

It is perhaps one of the most important characteristics of the past decade in astronomy that the evolution of some major classes of astronomical objects has become accessible to detailed research. The theory of the evolution of individual stars has developed into a substantial body of quantitative investigations. The evolution of galaxies, particularly of our own, has clearly become a subject for serious research. Even the history of the solar system, this close-by intriguing puzzle, may soon make the transition from being a subject of speculation to being a subject of detailed study in view of the fast flow of new data obtained with new techniques, including space-craft.

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Seti Figure of Merit

International Astronomical Union Colloquium ◽

10.1017/s0252921100015293 ◽

1997 ◽

Vol 161 ◽

pp. 711-717 ◽

Cited By ~ 1

Author(s):

John W. Dreher ◽

D. Kent Cullers

Keyword(s):

Figure Of Merit ◽

Qualitative Difference ◽

Current Generation ◽

Detection Range ◽

Sky Surveys ◽

Independent Observations ◽

Good For

AbstractWe develop a figure of merit for SETI observations which is anexplicitfunction of the EIRP of the transmitters, which allows us to treat sky surveys and targeted searches on the same footing. For each EIRP, we calculate the product of terms measuring the number of stars within detection range, the range of frequencies searched, and the number of independent observations for each star. For a given set of SETI observations, the result is a graph of merit versus transmitter EIRP. We apply this technique to several completed and ongoing SETI programs. The results provide a quantitative confirmation of the expected qualitative difference between sky surveys and targeted searches: the Project Phoenix targeted search is good for finding transmitters in the 109to 1014W range, while the sky surveys do their best at higher powers. Current generation optical SETI is not yet competitive with microwave SETI.

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The effect of back-melting on the continuity of crystallographic orientation and composition in HgZnTe

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133114 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1696-1697

Author(s):

H.J. Zuo ◽

M.W. Price ◽

R.D. Griffin ◽

R.A. Andrews ◽

G.M. Janowski

Keyword(s):

Directional Solidification ◽

Space Shuttle ◽

Solidification Process ◽

Space Experiment ◽

Infrared Detection ◽

Directionally Solidified ◽

Crystallographic Defects ◽

Semiconducting Alloys ◽

Uniform Composition ◽

Growth Experiments

The II-VI semiconducting alloys, such as mercury zinc telluride (MZT), have become the materials of choice for numerous infrared detection applications. However, compositional inhomogeneities and crystallographic imperfections adversly affect the performance of MZT infrared detectors. One source of imperfections in MZT is gravity-induced convection during directional solidification. Crystal growth experiments conducted in space should minimize gravity-induced convection and thereby the density of related crystallographic defects. The limited amount of time available during Space Shuttle experiments and the need for a sample of uniform composition requires the elimination of the initial composition transient which occurs in directionally solidified alloys. One method of eluding this initial transient involves directionally solidifying a portion of the sample and then quenching the remainder prior to the space experiment. During the space experiment, the MZT sample is back-melted to exactly the point at which directional solidification was stopped on earth. The directional solidification process then continues.

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