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25 October 2009, Volume 29 Issue 05 Previous Issue    Next Issue

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Design and On-orbit Performance Evaluation of Thermal Control System for SHENZHOU-7 Spaceship Huang Jiarong Fan Yufeng Liu Bingqing Lu Wei(Beijing Institute of Spacecraft System Engineering,Beijing 100094) 2009, 29 (05):  1-7.  Abstract ( 1798 )   Save The on-orbit flight data were analyzed and the operation performance was evaluated.Flight test shows that TCS has excellent temperature adjust and adapt abilities during prelaunch and ascent stages,orbit flight,EVA and reentry phases,and all apparatus temperature,air temperature and air relative humidity meet the technology requirements. Related Articles | Metrics

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Development and Test Results of Dual Compensation Chamber Loop Heat Pipe Zhang Hongxing Miao Jianyin Shao Xingguo(Beijing Institute of Spacecraft System Engineering,Beijing 100094) 2009, 29 (05):  8-14+41.  Abstract ( 1921 )   Save A dual compensation chamber loop heat pipe(DCCLHP) was developed to solve the problem of the relative orientation limit between the evaporator and the compensation chambers. The construction of the evaporator and the compensation chambers was presented.The concurrent design method of the working fluid charge mass and the compensation chambers volumes was introduced.Within a certain temperature range,the DCCLHP can not only start up and operate normally at any orientation,but also can avoid the most difficult startup situation.The operation and the thermal control characteristics of the DCCLHP were investigated.Test results indicate that in some heat load regions,the operating temperatures vary with the relative orientation between the evaporator and the compensation chambers.It was explained by the thermal equilibrium of the compensation chambers and the usage efficiency of the return liquid subcooling.The test results and discussion of the DCCLHP suggest that part of the return liquid subcooling that cools the liquid to be locally subcooled must be considered in the mathematical modeling of the LHP.Another suggestion is that an effective method to decrease the operating temperature or thermal resistance of the DCCLHP is to enhance the heat transfer between the return liquid and the fluid in the saturated compensation chambers is to increase the usage efficiency of the return liquid subcooling. Related Articles | Metrics

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Investigation of Temperature Oscillation in Miniature Loop Heat Pipe with Flat Evaporator Gai Dongxing Liu Wei Liu Zhichun Yang Jinguo(School of Energy and Power Engineering,Huazhong University of Science and Technology,Wuhan 430074) 2009, 29 (05):  15-20+32.  Abstract ( 2208 )   Save Loop heat pipes are heat transfer devices based on the evaporation and condensation of a working fluid,and using capillary pumping forces to ensure the fluid circulation.A series of tests have been carried out with a miniature loop heat pipe(MLHP) with flat evaporator and a fin-and-tube type condenser.The loop was made of pure copper with stainless mesh wick and acetone was used as the working fluid.At low heat loads,temperature oscillations were observed throughout the loop.The characteristics of temperature oscillation of the flat MLHP at heat fluxes from 2W/cm2 to 3W/cm2were studied.The compensation chamber was considered as the most critical component of the MLHP and its hydrodynamic state dictated the extent and the characteristics of the temperature oscillations for the input heat load.The heat leaks from the evaporator to the compensation chamber,the heat loss to ambient and subcooled liquid temperature dictated the vapor condition inside the compensation chamber,and the rate of vapor growth or dissipation dictated the nature of the temperature oscillation.The effects of different liquid charging ratio and the tilt angle to the temperature oscillations were studied in detail. Related Articles | Metrics

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Monte Carlo Method for Thermal Model of Spacecraft Parametric Analysis and Robustness Determination Yang Huning Zhong Qi(Beijing Institute of Spacecraft System Engineering,Beijing 100094) 2009, 29 (05):  21-27.  Abstract ( 1715 )   Save Based on the development demand of spacecraft thermal parametric analysis and robustness determination,Monte Carlo(MC) design schemes were developed.First,the satellite equipment′s temperature was assumed as dependent variables,and stochastic parameters were assumed as independent variables.Then Monte Carlo method was applied to generate dynamic responds of the thermal model.By analyzing the statistical results,formulas for parametric analysis and robustness calculation were deduced.At last,a numerical simulation example was given to correlate stochastic parameters and calculate robustness for a satellite instrument.Simulation results show that MC scenario streamlines parametric sensibility and margin estimation,and produces numerical results.Furthermore,the results can be used to instruct the engineering design. Related Articles | Metrics

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Research on Thermal Test Methods for Extravehicular Mobility Unit Fan Hanlin1 Sun Meng1 Li Tanqiu2 Wu Zhiqiang2 Zhang Kan1 Pan Wei1(1 Beijing Institute of Spacecraft System Engineering,Beijing 100094)(2 Astronaut Center of China,Beijing 100094) 2009, 29 (05):  28-32.  Abstract ( 1796 )   Save Active thermal control technologies were used in extravehicular mobility unit(EMU).The configuration of EMU is complicated and there are many influence factors on reaching heat flux.The thermal test for EMU had the different characters with that of traditional space probe.Different simulation methods of EMU thermal test were presented,based on the characteristics of the thermal design.It′s feasible to validate the thermal design by equivalently simulating the space heat flux as the test thermal boundary and measuring the heat leakage of the EMU and heat dissipation ability. Related Articles | Metrics

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Real-time Algorithm for Formation Satellite Fuel-optimal Maneuvers in Elliptic Orbits Zhao Yu Zhang Honghua(National Laboratory of Space Intelligent Control,Bejing Institute of Control Engineering,Beijing 100190) 2009, 29 (05):  33-41.  Abstract ( 1656 )   Save The LGL pseudo-spectral method was applied to the rapid computation.Since a large number of discrete nodes were needed to realize the high precise formation flying control due to the non-continuity in the fuel-optimal control method,which would influence the computation efficiency,a new real-time algorithm for formation maneuvers was presented combining the time-scaling strategy with the recursive optimization method in model predictive control.The algorithm improved the local precision of results with the global optimization of results preserved.Numerical simulation results demonstrate the effectiveness of the proposed algorithm. Related Articles | Metrics

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Comparison of IAU1976,1980 and IAU2000A Precession-nutation Model Wang Mingming Luo Jianjun Ma Weihua(College of Astronautics,Northwestern Polytechnical University,Xi′an 710072) 2009, 29 (05):  42-47+53.  Abstract ( 2898 )   Save For precise satellite orbit determination,the transformation should be done between the Celestial Reference Frame(CRF) and the Terrestrial Reference Frame(TRF).Precession and nutation should be considered during coordinate transformation from the CRF to the TRF.IAU1976 precession model,IAU1980 nutation model and IAU2000A precession-nutation model were presented,the differences were compared with IAU2000A precession-nutation model.The results indicate that IAU2000A model is more precise. Related Articles | Metrics

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Study on Relative Radiometric Calibration of the Spatially Modulated Imaging Fourier Transform Spectrometer Yao Lele Zhao Wei Fan Shiming(Beijing Institute of Satellite Information Engineering,Beijing 100086) 2009, 29 (05):  48-53.  Abstract ( 1816 )   Save The spatially modulated imaging Fourier transform spectrometer(SMIFTS) is different from other spectrometers.Its interference data cube consists of one dimensional spatial information and one dimensional spectral information of land.Because of its special theory,the on-board data calibration of SMIFTS is imperfect.A method of relative radiometric calibration was introduced to generate CCD models of the detectors,which was based on statistics method,and the real on board data of HJ-1A was used to validate it.The results indicate that the method can correct the difference of CCD response and the difference of the imported light field,reduce the nonlinear offsetting of phase,and can raise the precision of spectrum reproduction. Related Articles | Metrics

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Approach for DRS Link Configuration Decision Using Physical Programming Hu Dan Yan Zhongwen(China Academy of Space Technology,Beijing 100094) 2009, 29 (05):  54-60.  Abstract ( 1985 )   Save Physical programming(PP) was used to develop a decision making method for highly flexible Data Relay Satellite(DRS) configurations.DRS provides numerous communications links such as KSA forward/return link,SMA forward/return link,etc.that results in the complexity of DRS link parameters configuration.Using specific methodology,a multi-objective model was simplified to tri-objective model to configure DRS link parameters.A PP based decision approach was proposed and the procedure of the approach was given.The results demonstrate the effectiveness of the PP based approach for DRS configuration decision. Related Articles | Metrics

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Analysis and Simulation for Countermeasures of Maneuver Failures in Homing Phase of Rendezvous Docking Wu Shenggang Li Jiutian Li Haiyang Luo Yazhong Huang Haibing(College of Aerospace and Material Engineering,National University of Defense Technology,Changsha 410073) 2009, 29 (05):  61-66+83.  Abstract ( 1905 )   Save First,according to the type of maneuver failure and the various constraints,the model of planning control strategies after maneuver failure in homing phase of rendezvous docking(RVD) was given.Then,the countermeasures of maneuver failure were given.Finally,based on the high-precision orbit model,the maneuver failures in homing phase of RVD were simulated and analyzed.The simulation result shows that these countermeasures can deal with the maneuver failures in the homing phase well. Related Articles | Metrics

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Autonomous Determination of Relative Orbit for Satellite Formation Flying Using Radio-only Measurement Wang Hui Gu Xuemai(Harbin Institute of Technology,Harbin 150001) 2009, 29 (05):  67-74.  Abstract ( 1897 )   Save The mathematical programming method was used to research the collision avoidance rules,evasion and control strategies,in two moving conditions,including formation of satellite configuration reconstruction and configuration failure reorganization.The system controllable matrix shows that the target phase can also be achieved without radial thrust,just consuming much more fuel compared with the whole thrust under the condition of configuration failure reorganization,the issues regarding the backup satellite′s parking location before moving,the location and moment selection of accessing into formation of satellite,and the failure satellite′s target orbit were discussed.The simulation results show that the proposed method is true,simple and effective. Related Articles | Metrics

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Research on the Implementation of CCSDS-RS(255,223) High Speed Decoder Zhang Zhengning1 Li Jilin1 Zhan Yongjie1 Liu Changzhu2(1 Space Star Technology Co.,Ltd,Beijing 100086)(2 Beijing Remote Sensing Information Institute,Beijing 100086) 2009, 29 (05):  75-83.  Abstract ( 2468 )   Save Reed-Solomon(RS) code is a linear block code which has very strong capability of correcting random or burst errors.It has been widely used in various communication systems.A FPGA implementation of high speed RS(255,223) decoder used for space communication was presented and a new high speed error-correct architecture which using RiBM algorithm to solve the key equation for decoding Reed-Solomon codes was given.Moreover,high speed bit parallel Galois field multiplier and pipelining methods were used to achieve maximum decoding speed.Synthesis and experiments results show that the FPGA implementation of the decoder achieves a throughput of 1.7Gbit/s and decode delay of 296 clocks,the performance is multiple times higher than conventional design′s. Related Articles | Metrics