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    25 October 2019, Volume 39 Issue 5 Previous Issue   
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    Scheme design and analysis of recoverable sounding rocket reducer
    YANG Jian-Yu, YANG Xuan
    2019, 39 (5):  1.  doi: 10.16708/j.cnki.1000-758X.2019.0034
    Abstract ( 233 )   PDF (2810KB) ( 78 )   Save
    In order to meet the requirements of the rapid recovery of sounding rocket and reduce the development cost,a new type of sounding rocket skirt reel deceleration program was proposed. It has light weight,changeable expansion angle,expanded resistance area and some other advantages. The aerodynamic characteristics of the supersonic sounding rocket reducer were analyzed, the external flow field was simulated and analyzed. The influence of different taper angles on the aerodynamic characteristics and overload was given. The stress and strain of the external flow field, the pressure field and the gear unit were presented. The results show that the pneumatic resistance of the gear unit is obviously related to its cone angle and has the nonlinear characteristics, and the maximum stress of the reducer is less than the allowable stress. This paper can provide reference for the design of sounding rocket and new reducer.
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    Thermalstructural coupling analysis of space inflatable
    membrane diffraction imaging structures
    SUN Xiang-Wei, XU Yan, WANG Pei-Dong, FANG Qin, ZHU Dong-Fang
    2019, 39 (5):  8.  doi: 10.16708/j.cnki.1000-758X.2019.0035
    Abstract ( 84 )   PDF (11565KB) ( 40 )   Save
    With the development of space optical technology, diffraction imaging system has become a research hotspot in the field of space optics. In this paper, a structural design scheme of an inflatable membrane diffraction imaging structures is presented. Thermodynamic coupling effects of inflatable structures under the space thermal environment were studied. A coupled thermalstructural sequence analysis framework for inflatable structures was developed. The thermalstructural coupling analysis of the inflatable structure was realized by IDEAS and ANSYS secondary development technology. The transient heat transfer, thermal stress and thermal deformation of the structures in orbit were investigated. The results show that there is large thermal deformation in the inflatable support structures, but the maximum thermal stress is much less than the tensile strength of the polyimide membrane,and there is no large thermal deformation response at the center of the structures. The technology support for thermal protection design of inflatable membrane diffraction imaging structures is provided.
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    Investigation of the Sband electromagnetic wave attenuation by the Hall thruster plume
    YU Bo, ZHANG Min, YU Shui-Lin, KANG Xiao-Lu
    2019, 39 (5):  19.  doi: 10.16708/j.cnki.1000-758X.2019.0036
    Abstract ( 67 )   PDF (11601KB) ( 42 )   Save
    The Hall thruster plume exerts an attenuation influence on Sband electromagnetic wave and plays an important role in the layout strategy of the thruster and antenna on the satellite. In order to study the law of the signal attenuation, an algorithm of geometric lightpath was established to numerically describe the transportation of electromagnetic wave in Hall plume. A rectification test of the algorithm accuracy was conducted, and the signalnoise ratios (SNR) were measured by the method of wave transmission in space. According to the test and calculation results at same operation cases, the maximum relative error was 26.1%, and the average relative error was 7.3%. The calculation results kept qualitatively consistent with the test results. Based on those, the 84 typical operation cases of the SNR attenuation of the Sband electromagnetic wave were computed. The calculation results show that the absorption by plume exerted a more remarkable effect than the reflection on signal attenuation, and that the max attenuation region covered the antenna position of 0.3-0.6m,the direction angle of 15°-30°, and the attenuation value of SNR between -7dB and -4dB. This paper provides a reference base for the layout strategy of the thruster and the antenna on satellites.
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    Lossless data hiding in JPEG2000 images with code stream mapping
    ZHANG Ming-Ming, ZHOU Quan, HU Yan-Lang
    2019, 39 (5):  28.  doi: 10.16708/j.cnki.1000-758X.2019.0037
    Abstract ( 78 )   PDF (11364KB) ( 33 )   Save
    Remote sensing images are compressed in JPEG2000 standard and transmitted to ground by aircraft, while some other telemetry data is needed in transmission and additional data is embedded in compressed files. The author researched JPEG2000 data structure and transformed the data part of the compressed file into an image and blocked it, and then made statistics on 256 gray values to find gray values with the most occurrences and zero occurrence. Corresponding bytes of these gray values were mapped to represent different binary secret data. Receiver extracted secret data by mapping and recovered host modified bytes. Hiding capacity has an improvement of average 500bits, PSNR of marked images are larger than 30dB,and host data can still be restored losslessly. Experimental results show that this scheme can realize lossless information carrying in JPEG2000 images and file expansion does not occur.
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    High power electrodeless electromagnetic propulsion based on high density plasma: a review
    LIU Li-Juan, WEN Xiao-Dong, SUN Xin-Feng, ZHANG Tian-Ping, GUO Ning
    2019, 39 (5):  37.  doi: 10.16708/j.cnki.1000-758X.2019.0038
    Abstract ( 59 )   PDF (4869KB) ( 63 )   Save
    High power electrodeless electromagnetic propulsion based on high density plasma has already become one of the most competitive core propulsion technologies in future space missions, such as deep space exploration, manned space flight, solar power station and onorbit maintenance and service. Based on the different acceleration mechanisms adopted in different electrodeless electromagnetic propulsion technologies, the propulsion performances of different electromagnetic propulsion technologies were compared.Then the field reversed electrodeless electromagnetic propulsion technology adopting the rotating magnetic field acceleration mechanism was analyzed,which has great advantages and potential in developing to super high power propulsion thruster. At last, the existing technical challenges confronted in developing this new conceptual thruster was presented, aiming at providing technical and theoretical supporting for the future development of the field reversed electrodeless electromagnetic propulsion technology.
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    Space microgravity combination and its control
    YU Shao-Hua
    2019, 39 (5):  49.  doi: 10.16708/j.cnki.1000-758X.2019.0039
    Abstract ( 122 )   PDF (1448KB) ( 93 )   Save
    Space microgravity combination is an upgraded version of the tethered satellite system, a more powerful and prospective version for future applications. However, both the systems are beset with the same problem: if there is no preset control,the system′s motion is unstable. Therefore, an effective control algorithm has to be developed to make the system stable. Based on a simplified dynamic model of tethered satellite,the relationship between microgravity and dynamic inertia forces was used to deduce a very unique range rate control algorithm to stabilize the system concisely and productively. This algorithm can be applied to massdistributed, elastic and other more complex cases of tethered satellite control. It can also be successfully adopted to control inorbit rendezvous and docking missions of the space microgravity combination.
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    Design of a compact satellite analog predistortion circuit
    LIU Zheng, LIU Gang, LI Qi
    2019, 39 (5):  55.  doi: 10.16708/j.cnki.1000-758X.2019.0040
    Abstract ( 60 )   PDF (2189KB) ( 34 )   Save
    A compact analog predistortion circuit used to compensate the nonlinear characteristics of solidstate power amplifier (SSPA) in the satellite tracking telemetry and command system was developed. This new predistortion circuit is simple, compact and of low cost. The fundamental principle of this linearizer was analyzed and its corresponding equivalent circuit model was shown. Then, the desired nonlinear characteristics of linearizer versus different circuit parameters were simulated and discussed. Finally, this linearizer was fabricated and measured. The comparative results of both linearized and nonlinearized amplifiers show that the linearizer can significantly improve the intermodulation distortion of amplifiers by about 6dB.
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    1553B bus communication software based on BM3803
    HAN Chun-Hui, WANG Yu, HUANG Shu-Hua, XU Quan, ZHANG Shen, LU Yue-Lin
    2019, 39 (5):  61.  doi: 10.16708/j.cnki.1000-758X.2019.0041
    Abstract ( 56 )   PDF (5113KB) ( 59 )   Save
    processor is used in a satellite ground detection equipment to simulate the bus controller in the satellite in order to detect the remote terminal, and a satellite data simulation platform with stronger realtime performance than the traditional Windows+1553B_PCI board solution is constructed. The realtime operating system μC/OSII is transplanted to BM3803, and the boardlevel support package for BM3803 is designed to ensure the onorbit software update and the task realtime. The software structure with high separation of user tasks and hardware is determined. When designing the user tasks of μC/OSII, the verification functions of BM3803 and B61580 are fully utilized to improve the software reliability. Finally, the same user task is completed with this design and the Windows+1553B_PCI board solution respectively, and the design has better realtime performance, which can meet the realtime requirements of the highlevel satellite communication protocol.
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    Thrust and specific impulse tests of miniature gallium field emission electric propulsion thruster
    XU Ming-Ming, LIU Xin-Yu, KANG Xiao-Ming, GUO Deng-Shuai, HE Wei-Guo
    2019, 39 (5):  69.  doi: 10.16708/j.cnki.1000-758X.2019.0042
    Abstract ( 70 )   PDF (3215KB) ( 43 )   Save
    The development of electric propulsion technology has promoted the research process of micro thrust measurement technology and specific impulse measurement technology. In order to evaluate the performance of the developed miniature gallium field emission electric thruster, thrust and specific impulse measurements were made. A thrust measurement platform for field emission electric thrusters was developed, the LabVIEW development was carried out and the measurement platform was calibrated and analyzed. The measured values and theoretical values of the thrust were compared through experiments. The measured values range from 3 to 28μN. In addition, using the time of flight method, the thruster′s specific impulse data under different emission currents were measured, and the specific impulse′s range is 5917-8875s.
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    Characteristics of airborne moulds from spaceflight AIT center
    ZHANG Wen-De, ZHAO Yi-Kui, YIN Hong, ZHAO Biao, XU Kan-Yan
    2019, 39 (5):  76.  doi: 10.16708/j.cnki.1000-758X.2019.0043
    Abstract ( 66 )   PDF (2800KB) ( 45 )   Save
    Understanding the species and characteristics of airborne moulds in spacecraft AIT center is of great importance for developing techniques to prevent mould contamination during the assembly and testing process of spacecraft. In this paper, the air samples were collected in three AIT centers located in different areas, and 53 purified strains of mould were acquired using traditional culturebased method. ITS sequencing result shows that these strains belong to eight mould genera. Then the characteristics of these mould strains were studied further. The growth rates measurement shows that different strains of Penicillium and Aspergillus differ greatly in their growth rates. In addition, it is found that the sensitivity of different mould strains to disinfectant PHMB is quite different. It implies that the diversity of both growth rate and disinfectant sensitivity will bring difficulties to the prevention and control of microbial contamination.
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