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25 June 1986, Volume 6 Issue 03 Previous Issue    Next Issue

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STUDY AND MEASUREMENT OF CONDUCTANCE OF SPACECRAFT'S SURFACE MATERIALS Lu Yu-Sun 1986, 6 (03):  1-7.  Abstract ( 1853 )   Save The charge accumulation on spacecraft surface is a threat against its own life. The condition of surface charge Accumulation (SCA) is ruled by many physical parameters. But the electric conductie capability of space materials has the most important influence to SCA. Therefore, it is necessary to attempt to improve the conductance of spacecraft's surface materials. In this article, the measuremet methods of the surface and the bulk conductance have been discussed. The measurement results of conductance about seven spacecraft's surface materials at 10~(-3)Pa and the plots that the conductance of materials changes with vacuum have been given. In the end of the paper, these experiment results have been discussed. Related Articles | Metrics

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THE SELECTIVE ANALYTICS OF ADHESIVES FOR SPACECRAFT COMPOSITE STRUCTURES Li yue ying 1986, 6 (03):  14-21.  Abstract ( 1650 )   Save The selective principles of adhesives for spacecraft Composite structures are analysised in view point of practice. On upon space working environment of spacecraft, analytics on utility of adhesives are made. These analytice are. related to design, thermal resistance and technology. Related Articles | Metrics

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CONTACT HEAT METHOD OF SATELLITE SKIN Jiang Jing shan 1986, 6 (03):  22-29.  Abstract ( 1581 )   Save Simulation of space heat flux with heater strips attached directly to the satellite skin is a technique simulating space heat flux absorped by satellite with electrical heat generated by heater strips, which were attached directly to the satellite skin in advance and in test electrical current pass through which.Using this simulate method, heat flux can adjust simply, the changes in thermal input may be simulated. It would not shield thermally satellite and not interfere thermal simulation of adjacent surface. So that, it may simulate exact heat flux distribution and earth's shadow.Design. fabrication and attach of beater strips area very important things. To obtain better test precition, must select correct attached position and space dimension of heater strip.Emittance of satellite surface would be simulated in rest. When simulate transient condition, thermal capacity would be simulated. Related Articles | Metrics

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A SLOW SCAN TV CAMERA FOR SATELLITE APPLICATION Zhao bingyi Xia jianming Tong ruilin Cui huaxian Wang mozhen Dou chunhua Yu chunfu 1986, 6 (03):  30-36.  Abstract ( 1993 )   Save The TV camera for satellite application is the core of the TV technigue in image remote—sensor. This paper presenteda slow scan TV camera. It has good performance, stable and reliable operation, and can be used for satellite. Some technical matters Occurred during the research of the camera are also discussed in this paper. Related Articles | Metrics

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STUDY OF PLANAR NEAR-FIELD MEASUREMENTS OF ANTENNAS Yie Yunshang 1986, 6 (03):  37-46.  Abstract ( 1860 )   Save This paper first describes a necessity of far-field constructed from near-field measurements for the future satellite's antennas. The first part of this paper discusses a plan-polar near-field technique. By means of the Lorentz reciprocity theorem and The Jacobi-Bessel series expansion the transform formulas from near-field to far-field have been developed. Once the phase and amplitude distributions are sampled by a scanning probe in a plane-polar configuration, the measured data may be transformed into the far radiataed field using the above formulas. Finally, an automated planar near-field measurement system program-controlled by a microcomputer is presented.In the second part of this paper we have summarized some recent results in NBS on upper-Bound errors in far-field antenna paramefers determined from planar near field measurements. Some important formulas and relationships are presented. They may be used for evaluating the maximum errors of far-field paramefers produced by planar nearsfield measurements.They also can provide useful guidelines for design of near-field measurement technique. Related Articles | Metrics

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ELECTROMAGNETIC LAUNCH TECHNOLOGY Gong Lian (Tsinghua University) 1986, 6 (03):  47-55.  Abstract ( 2216 )   Save Electromagnetic propulsion as a high-technology have been attempted by scientists for years. In the past ten years, the significant achievements in support technologies (energy storage, high velocity switching, high current density in sliding contacts and synchronization) make up the strong potential for pracitical electromagnetic launch (EML) technology.The advantages of the EML are. it can launch projectile to high velocity in a short distance, lower cost, less environmental damage and without the furel weight penalty.There are two approches. RAILGUNS, powered by low-voltage DC homopolar generators, and COAXIAL SYNCHRONOUS ACCELERATORS of drive coil configuration, which are more complex but mor flexible.Potential applications include the launching of aircraft from carriers and land bases, especially it can be used for disposing the nuclear waste to outer space, or a new generation of hypervelocity artillery for missile.Because of the evident meaning for military and civil purposes, both the U. S. Department of Defense (DOD) and a number of universities have been worked in developing EM launchers and obtained a good deal of achiermeats. Related Articles | Metrics

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AN EXPERIMENT INVESTIGATION OF “RIT15-” 15cm RF-THRUSTER Feng Huifen 1986, 6 (03):  56-67.  Abstract ( 2265 )   Save Working principle of RIT-15, its performance, parameter calculation and its experiments are presented briefly in the article. The inert gases Xenon(Xe) and Argon(Ar)have been used instead of Mercury(Hg)as the thruster propellant. Experiment results show the thruster has normal operation. Beam current of 150～220mA can be extracted from the source and the correspondent thrust is 7～14mN. Inert gas is a kind of hopeful propellant for ion propulsion because it is convenient in operation and nonpoisonous. But inert gas thruster has lower thrust level and lower mass utilization, these disadvantages could be eliminated with improving the thruster structure and increasing the coupling ability of RF generator. Related Articles | Metrics