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Table of Content

    25 February 1995, Volume 15 Issue 01 Previous Issue    Next Issue
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    MEASURING EQUIPMENT FOR STUDYING CRYODEPOSITE OF CONDENSABLE VAPOUR ON OPTICAL SURFACES
    Guo Qing;Pei Yuntian(Shanghai Institute of Technical Physics,Chinese Academy of Science, Shanghai 200083)Lan Zengrui(Shanghai Institute of Spacecraft Engineering, Shanghai 200240)Meng Xianhua; Yang Xuemei; Wang Aibing(Shanghai Institute of Measurement, Sh
    1995, 15 (01):  . 
    Abstract ( 1759 )   Save
    his paper has introduced the basic principle, structure and operation instruction of the measuring equipment for studying cryodeposite on optical surfaces.The main performances have been obtained with experiment. System errors have been analysed. This device is simple in structure, complete in function, reliable enough in performance and convenient in use. The measuring wavelength is from near infrared to far infrared and the precision is better than 3%, which is close to the same equipment from external. It can be used for measuring all kinds of condensable vapour cryodeposite. It will be an effective device for further developing space technology.
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    GUIDANCE, CONTROL AND SIMULATION OF MANNED SPACECRAFT IN REENTRY PHASE
    Zhang Shouxin;Fong Shuxing(The Institute or Command and Technology, CONSTIND, Beijing 101407)
    1995, 15 (01):  . 
    Abstract ( 1880 )   Save
    his paper studies the reentry guidance rules and the effects of the reentry errors on the landing spot of a spacecraft. Its contents reads as follows: the study of the laws of vertical direction and side direction, to analyze the effect of each error on landing spot; simulation calculating the comprehensive effects of all of errors on the landing spot.It gives the level of the effects of the reentry errors on the landing spot and presents the accuracy levels which the reentry errors must satisfy. The results of simulation prove that the guidance laws can make satisfactory control accuracy of the landing spot.
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    FAULT DIAGNOSIS TECHNIQUES OF FOREIGN MANNED SPACECRAFT
    Ji Changwei;Huang Wenhu;Rong Jili(Harbin Institute of Technology, Harbin 150001)
    1995, 15 (01):  . 
    Abstract ( 1867 )   Save
    The Paper details the applications of fault diagnosis techniques of foreign manned spacecraft as well as its development process, and highlights the expert system techniques. The fault diagnosis for foreign manned spacecraft ranged from the 1960s' simple condition monitoring, the 1970s' algorithm-based diagnosis to the 1980s' knowledge-based intelligent diagnosis. On the other hand, the paper also presents two fault diagnosis expert systems developed by NASA for space shuttle main engine turbopump and space station freedom power system and comprehensively analyses the characteristics of fault diagnosis expert systems in space field, and then discusses the future work.
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    THE MECHANISM ANALYSIS TO SUPERPERFORMANCE OF DF USING SPATIAL SPECTRUM ESTIMATE AND REAL SYSTEMS INTRODUCTION
    Lou Lichun(P. O. Box 947-2, Postal Code 100083 Beijing, China)
    1995, 15 (01):  . 
    Abstract ( 1648 )   Save
    Difficulty in making spatial spectrum estimate direction finder has been shading the bright future of the latter. The mechanism analysis to Super-performance of DF using spatial spectrum estimate is presented. The analysis consists of physical one and mathematic one. Several real systems are introduced and reviewed. Super-performance of the new DF method has been shown by the systems.
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    AN EXPLORATION OF SOLUTION ON THE SYNTHETICAL BENEFIT MODEL
    Zhang Chengyi;Ye Zhenjie(National University of Defence Technology, Changsha 410073)
    1995, 15 (01):  . 
    Abstract ( 1595 )   Save
    The model of the synthetical benefit is a dynamic model which multieffects with various factors. It both includes general benefit model and considers optimal bencfit model for optimal investment, the former can be obtained by analyzed method, the latter is not very eagy to obtain. The paper takes it as an optimal control prolem with fixed end-points judging from analyzed characteristic of model there by satisfactory solution is obtained by using green's theorem(formula).
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    THE RESEARCH ON CROSSING DIPOLES CIRCULAR POLARIZATION ANTENNAS
    Liu Jianxin(Beijing University of post and Telecommunication, Beijing 100088)Yan ZhongWen(Beijing Institute of Spacecraft System Engineering, Beijing 100086)
    1995, 15 (01):  . 
    Abstract ( 4545 )   Save
    y the Hallen equation's solution, a method of forming crossing dipoles circular polarization antennas from choosing the length of dipoles is given in this paper.The equation is solved by moment method. The computed and measured circular polarization antennas' patterns are also given. Because of the simple and reliable structure, this sort of antennas can be used widely in spacecraft.
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    A PRACTICAL METHOD FOR CALCULATING PARACHUTE OPENING FORCES
    Gong Wenxuan(Nanjing University of Aeronautics and Astronautics, Nanjing 210016)
    1995, 15 (01):  . 
    Abstract ( 1551 )   Save
    ased on the H.G. Heinrich's theory of parachute opening dynamics,this paper considers the effects of vent, crown cloth area with large porocity, and porocity at the middle and lower portions of the canopy on parachute opening force. In continuity equation for calculation Filling time of parachute canopy the variation of drag area in process of canopy inflation is calculated by using the non-linear drag area variation curves. The initial parachute drag area during the inflation of parachute canopy is also considered. The constant inlet diameter is assumed and equals to (4(CA)0/ C(st)π)(1/2) during the initial phase of parachute inflation. The computation example shows that the results of calculation are in agreement with the measured data satisfactorily.
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    COOLED DEWARS FOR ASTRONOMICAL DETECTOR APPLICATION
    Ge Ruihong;Bi Longsheng; Cao Shencheng;Nie Yumin(Lanzhou Institute of Physics, Lanzhou 730000)
    1995, 15 (01):  . 
    Abstract ( 1519 )   Save
    his article sums up the demand of cryogenically cooled dewars for astronomical CCD detector. The general situation of the dewars in China, the characteristics of the TWD type dewar and its test are described. The test results show that Mark Ⅱ and Mark Ⅲ dewars vessel without detector achieve the technical targets as follows:effective volume 2.5L and 1.25L, mass 2.05kg and 3.02kg, preservation time of liquid nitrogen 110h and 116h respectively. Vacuum keeping for more than two years. After connecting with detector, the preservation time of Mark Ⅱ dewars for liquid nitrogen is 40h, the temperature of CCD cold plate achieves-100~-120℃.
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    DIRECTLY MEASURING ANTENNA G/T BY USING SUN AS A RADIO SOURCE
    Lu Peiye;Zhao Weiyuan(Chinese Remote Sensing Satellite Ground Station, Beijing 100086)
    1995, 15 (01):  . 
    Abstract ( 1729 )   Save
    his paper introduces direct measurement of the antenna G/ T performance in three data channels by using the sun as a radio source after the Chinese Landsat Ground receiving station is upgraded.For fixed-turned data channels, antenna G/ T~α(antenna elevation angle) performance curves of the Landsat-5 down link frequency arc measured. For tuned data channels. G/ T the performance characteristics of Landsat-6. JERS-1. ERS-1. SPOT and ZY-1 Satellites down link frequencies are measured in the case of a equal to 5°and 30°.Finally the Error analysis is presented.
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