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30 December 1987, Volume 7 Issue Z1 Previous Issue    Next Issue

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A COMMENT ON THE DEVELOPMENT OF SPACE STATION Wang Xiji 1987, 7 (Z1):  1-9.  Abstract ( 1761 )   Save In this paper the space station activities of the main developed countries during the last sixteen years are described. The major issues about space station and transportation system are analysed and some configurations of space station proposed recently are evaluated. Related Articles | Metrics

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THE ASPECTS FOR DESIGNING A SPACEBORNE SAR SYSTEM Zhang Chengbo 1987, 7 (Z1):  10-19.  Abstract ( 1748 )   Save The spaceborne synthetic aperture radar is an useful microwave remote sensor. It takes its advantage of high resolution and all weather, day and night mapping capability. So it is being getting wider and wider applications.In this paper, some aspects for designing a spaceborne SAR system, such as special mapping geometry, motion compensation, optimum ambiguity design and range cell migration correction are described and analized. Related Articles | Metrics

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METHODS OF DETECTING EDGES FROM A GREY-LEVEL PICTURE Wang Ji-fen 1987, 7 (Z1):  20-26.  Abstract ( 1824 )   Save Metods of detecting edges from a grey-level picture are reviewed. The proposed algorithms are applied to several different pictures and get results of computer practice. Algorithm and parameter suitable for different pictures are noted. Related Articles | Metrics

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EXPERIMENT STUDY OF ELECTRICAL CONDUCTIVITY ABOUT TWO COMMON THERMAL CONTROL COATINGS OF SPACECRAFT Lu Yu-sun 1987, 7 (Z1):  27-33.  Abstract ( 1721 )   Save The phenomenon of Space Charge Accumulation (SGA)of spacecraft will exhibit if it operates at its orbit-especially at high altitude orbit. Improving the conductivity of spacecraft surface is one of the most useful ways to solve the problem. The surface conductivity changes and the regularities of two common thermal control paints have been studied in simulated substorm condition. Several significant results have been obtained. Related Articles | Metrics

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FAILURE DETECTION IN SENSOR SYSTEMS OF A SATELLITE USING PATTERN RECOGNITION TECHNIQUE Du Heqing 1987, 7 (Z1):  34-41.  Abstract ( 1749 )   Save The failure detection in sensor systems of a long life satellite is needed because of the increasing demands on reliability and safety. Since the life of components which compose the system has its limitaion, we use redundant technique. The component (such as sensor) in the system has two or more redundant parts. If any of them fails, it will be replaced by another one. So the problem is how to detect the failure. A method which was called WALD SEQUENTIAL ANALYSIS in pattern recognition is presented in the paper. The use of microcomputers permits the application of the method in real time processing. The result of simulation of the method in a satellite control system shows that it is feasible to detect failure in the system. Related Articles | Metrics

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TWO IMPORTANT MATHEMATICAL PROBLEMS OF SPACECRAFT Huang Lei-de(Tongji University, Shanghai) 1987, 7 (Z1):  42-49.  Abstract ( 1790 )   Save In this note, we consider some initial-boundary value problems of partial differential equations for instability and fracture problems of escape vehicle. Then, we show that the singgular integral equation methods, J-integral (of 3-D) methods and boundary element methods etc are fine techniques for the treatment of the fracture problems of spacecraft. Related Articles | Metrics

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A METHOD OF VELOCITY-HEIGHT RATIO CALCULATION FOR IMAGE-MOVING COMPENSATION OF A SATELLITE PHOTOGRAPH SYSTEM Fan Qinhong Ou Zixin 1987, 7 (Z1):  50-57.  Abstract ( 3060 )   Save A calculating method of velocity-height ratio for image-moving compensation of a satellite photograph system is presented. When the scene on the ground is photographed from an aircraft, the velocity in the velocity- height ratio for the image-moving compensation is one of the ground relative to the aircraft, i. e. so called ground velocity. However, when the scene on the ground is photographed from a satellite, if the velocity was taken as one of the ground relative to the satellite, then the great error would be made. So, the authors have modified the definition of the velocityheight ratio. Such a new definition is suitable to be used for the photographing from aircraft as well as from satellite.Having considered the globe as a spheroid and the orbit of the satellite as elliptic, this paper derived the equations for calculation of the sub-sate llite point and the velocity-height ratio, finally compared such results with those under considering the globe as a sphere and neglecting the eccentricity of the orbit, the relative error of velocity-height ratio is less than 0.5%. Related Articles | Metrics

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The Development and Current Status of International Space Insurance Industry Han Lianchao 1987, 7 (Z1):  61-67.  Abstract ( 1916 )   Save This article is a general introduction to the newly-developed international space insurance industry, It examines how the underwriting originates and grows, It also examines what space insurable risks are and what problems this industry is now seriously facing. This article holds that the space insurance is playing a more fundamental role in the activities of peacefur explorations and uses of outer space, for it provides a reliable financial guanrantee for space enterpises. However, the problems of space insurance risk management differ from that of ordinary insurance risk management and require a good deal knowledge of space techology and thorough risk analysis to tackle them. It also depends on improvement of reliability of spacecraft. In recent years, severar major space losses have frustrated the underwriting. The present capability to insure is temporarily lower before, But there are reasons to believe that the space insurance market will recover in the coming years if proper measures are taken. Related Articles | Metrics

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THE SHORT PERIOD TERMS CAUSED BY AIR DRAG PERTURBATION OF ARTIFICIAL EARTH SATELLITE IN ORBIT WITH ARBITRARY-ECCENTRICITY Lu Benkui Rong Pengzhi 1987, 7 (Z1):  68-83.  Abstract ( 1690 )   Save Using the calculating method and the analytical model of air density of CIRA 1972 at the height between 160 and 2000 km proposed by the authors, a new set of formulae for computing the short period terms caused by air drag perturbation of artificial earth satellite have been deduced. They are with simple form, good convergence, and are applicable to compute the orbit with arbitraryeccentricity. Related Articles | Metrics