Loading...

Table of Content

    25 June 2001, Volume 21 Issue 03 Previous Issue    Next Issue
    For Selected: Toggle Thumbnails
    Analysis of the Effect of Weightlessness on Astronaut's Thermoregulation
    Pang Cheng Gu Dingliang (Institute of Space Medico Engineering,Beijing 100094)
    2001, 21 (03):  . 
    Abstract ( 1650 )   Save
    The phenomena of changes of astronaut's thermoregulatory functions and inter relations between them caused by the effect of weightlessness in both spaceflight and simulated space environment on the earth are systematically analyzed and summarized.It is pointed out that in weightlessness environment the spontaneous convection disappears ,the body fluid shifts toward head and torso,the body water loses by urinating,the function of cardiovascular system weakens and the maximal oxygen intake reduces.All above will disable thermoregulatory function and finally disturb the heat tolerance of astronauts significantly.Furthermore,within the thermoregulatory mechanism,behavioral regulation acts as a supplement and extension related to the physiological regulation.The former can,however,play a role only on the latter.Thus,in design of the cabin thermal control system and space suit ventilation-liquid-cooling system,the effect of weightlessness should be considered.
    Related Articles | Metrics
    Investigation into Material State Characterization of Debris Cloud Created by Cylindrical Projectile Impact on Bumper
    Zhang Wei Pang Baojun Luo Dekun Zhang Zehua (Harbin Institute of Technology,Harbin 150001)
    2001, 21 (03):  . 
    Abstract ( 1495 )   Save
    High velocity impact on long duration and large size spacecraft by meteoroid and space debris is a threat to its safety operation,that can in turn lead to significant damage and catastrophic failure.In order to conduct an accurate assessment of spacecraft module wall damage impacted by debris cloud created by meteoroids and space debris high velocity impact on bumper,the three state material characterization of debris cloud must be known.The analysis model of debris cloud material characterization is presented.The mass distribution of the three states of material in the debris cloud created by a cylindrical projectile impact on bumper is calculated.The mass distribution of the three states of material of projectile and bumper in the debris cloud is also calculated.The mass distribution of the three states of material of debris cloud is different when projectile high velocity impact on bumper with different velocity.As the impact velocity increases,the amount of the debris cloud material subjected to melting and/or vaporization is increase,the damage to module wall is small.When velocity is smaller than 7km/s,the debris cloud is in the state of solid,it has large damage to the module wall.
    Related Articles | Metrics
    A New Optimized Method for Quantitative Analysis of Fault Tree
    Jin Xing Wu Jiangtao Hong Yanji (Institute of Command and Technology of Equipment,Beijing 101416)
    2001, 21 (03):  . 
    Abstract ( 1917 )   Save
    Based on the method of Boolean manipulation and disjoint method,a new optimized method is presented for quantitative analysis of s coherent fault tree.The reliability,probability of failure,minimal cut sets,minimal path sets and critical importance factor can easily obtained by the method.
    Related Articles | Metrics
    An Calculation Method for Frequency Interference Involving Non-GSO Telecommunication Satellite Constellation
    Zhou Aosong (Chinese Academy of Space Technology,Beijing 100081)
    2001, 21 (03):  . 
    Abstract ( 1736 )   Save
    Two properties involving non-GSO telecommunication satellite constellation,non-fixed and time-varied characteristics and aggregate characteristics are studied.An calculation method for frequency interference involving non-GSO telecommunication satellite constellation is proposed.By introducing the concepts of time discrete simulation and equivalent power flux density,this method can resolve the desiderative problem that how to calculate the interference involving non-GSO telecommunication satellite constellation in China.
    Related Articles | Metrics
    Variable Structure Control for Space Rendezvous and Berthing
    Wang Ying Wu Hongxin Xie Yongchun (Beijing Institute of Control Engineering,Beijing 100080)
    2001, 21 (03):  . 
    Abstract ( 1612 )   Save
    The variable structure control method for the closing phase of the space rendezvous and berthing is introduced.The sliding mode is very important in the variable structure control but often designed to the linear relationship of the state variable.In items of the characteristic of the relative motion equations,the nonlinear sliding mode is designed and the stability of the system is proved.Compared with the PID control method,the control accuracy of the variable structure control method is lower than that of PID control method,but the consumption less than that of the PID control method.
    Related Articles | Metrics
    Study on Automatic Planning Technology of EMR System Robot
    Huang Xianglong Liang Bin Chen Jianxin (Beijing Institute of Control Engineering,Beijing 100080)
    2001, 21 (03):  . 
    Abstract ( 1570 )   Save
    The automatically operating scheme and hardware composition of EMR system robot are briefly introduced.Based on this,automatic planning of walking node with heuristic search algorithm,task planning,and sub-task cooperated are discussed in detail.The results of simulation and experiment prove this approach proposed in this paper is successful.
    Related Articles | Metrics
    A GPS Receiving Antenna on Satellite
    Ye Yunshang Yang Xiaoyong (Beijing Institute of Spacecraft System Engineering,Beijing 100086)
    2001, 21 (03):  . 
    Abstract ( 1604 )   Save
    According to the main technical requirements of GPS receiving antenna on satellite,the design and the test results for resonant quadrifilar helical antenna are given.The results show that the antenna possesses excellent circular hemispherical beam with wideangle circular polarization and better impedance match.This antenna has a compact structure and high integration.It has been used for some low orbit satellites.
    Related Articles | Metrics
    Optimization Calculation of Shaped Beam in Satellite Multiple-Beam Antennas
    Zhang Yixi Fu Junmei Wang Wenbing (Electromagnetic and Communication Laboratory, Xi'an Jiaotong University,Xi'an 710049)
    2001, 21 (03):  . 
    Abstract ( 1681 )   Save
    The principle and mathematical model of satellite multiple-beam antenna are introduced.Then it is proved that pattern synthesis is essentially an optimizationproblem and the two feasible optimization algorithms,the least pth algorithm and Minimax algorithm ,are used to synthesize patterns for a square area and Chinese map respectively.Finally the simulation results of these two algorithms are presented and discussed in detail.
    Related Articles | Metrics
    Study on Addition Type Silicone Thermal Control Coatings
    Tan Bien (Beijing Institute of Aeronautic Materials,Beijing 100095) Hao Zhiyong (China Beijing Materials Academy,Beijing 100024) Zeng Yibing Zhang Lianzheng (Institute of Aeronautic Materials and Processing,Beijing 100076)
    2001, 21 (03):  . 
    Abstract ( 1602 )   Save
    The white control coatings with low ratios of solar absorptance to emittance are successfully prepared.The factors (resin type,filler type,ratio of resin to pigment etc.) that affect the property are discussed.The results indicate that coatings made with addition type rubber has lower α s value (<0 20).Increasing ratio of filler to adhesives value,the α s/ ε h value will decrease.In order to made low α s/ ε h value,the more content filler should be added into adhesive without giving up the art.The ratio of [Si H] to [CH=CH 2] has no obvious effect on α s value.But the type of vinyl silicone rubber has effect on α s value.The coating made with higher content vinyl group silicone rubber has larger α s value.For both of spraying and brushing method,brushing is preferred way although coatings made with them has similar α s value.
    Related Articles | Metrics
    CCSDS Downlink Virtual Channel Schedule and Performance Analysis
    Gu Yingqi Tan Weichi (Beijing Institute of Spacecraft System Engineering,Beijing 100086)
    2001, 21 (03):  . 
    Abstract ( 1625 )   Save
    The characteristics of multiple application processes onboard in packet telemetry system are represented.The distribution and the utilization of transfer layer virtual channels are suggested and the schedule model is developed by using polling systems.System performance is evaluated by average delay,maximum delay and buffer usage resulted from different schedules under the condition of different combinations of data sources.Appropriate strategies for various data source conditions are also suggested.The results would be useful in the initial design of data system onboard.
    Related Articles | Metrics
    A Study on Singularity Analysis of Large Spacecraft SGCMG System
    Zhang Jinjiang Li Jisu Wu Hongxin Zhou Guangrui (Beijing Institute of Control Engineering,Beijing 100080)
    2001, 21 (03):  . 
    Abstract ( 1628 )   Save
    Single Gimbal Control Moment Gyro (SGCMG) system is the best choose of large spacecraft attitude control system.But the phenomenon of singularity exists in this system,this increases difficulty in designing steering law.The singularity states of SGCMG system on the base of singularity analysis are studied.The criterion of singularity avoidance is proposed.According to this criterion,singularity states are classified per fectly.At the same time,singularity of SGCMG system at all kinds of frames is discussed in common.
    Related Articles | Metrics
    A Calibration Study of Leakage Detecting With Mass-spectrometry Under Non-vacuum Environment
    Yan Zhiping Huang Shuying (Beijing Spacecraft,Beijing 100080)
    2001, 21 (03):  . 
    Abstract ( 1554 )   Save
    The calibration formulas of leakage detecting with mass spectrometry under nonvacuum environment are derived.The strengths and weaknesses of various existing leakage calibration method are analyed respectively.The analysis results show that in order to fast perform leakage calibration of high accuracy,the injection method of standard gas quantity is agreeable to leakage calibration.
    Related Articles | Metrics