空间科学学报

2001 Vol. 21, No. 1

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SOME DISCUSSIONS ON THE INFLUENCE OF MAGNETOSPHERIC ENVIRONMENT CAUSED FROM THE TRANSIT OF COMETS

LI Zhongyuan, DUAN Suping, CHEN Yao, MA Boli

2001, 21(1): 1-8. doi: 10.11728/cjss2001.01.20010101

Abstract(2155) PDF 706KB(1073)

Abstract:
During the transit of comets （Halley, Hyakutake and Hale-Bopp）, some data analysis and statistical research have been made and the possible influence of magnetospheric environment resulted from the 5 times transit of the 3 comets have been discussed. According to the feature of cometary plasmas, the possibility is pointed out in this paper that cometary tail is able to cause the magnetospheric disturbance. However, the disturbance is restricted by some rigorous condition, and it is not essay for the comets to possess such condition during their transit.

DISTRIBUTION OF IMPULSIVE ELECTRIC FIELD IN THE NEAR EARTH PLASMA SHEET DURING STORM AND NON-STORM TIME

TU Jiannan, WAN Weixing, NING Baiqi, PU Zuyin

2001, 21(1): 9-16. doi: 10.11728/cjss2001.01.20010102

Abstract(2270) PDF 727KB(835)

Abstract:
The electric field data obtained by the Geotail satellite in the near earth plasma sheet were used to analyze the spatial distribution of the impulsive electric field during storm （Dst ＜ -25nT) and non-storm （Dst ＞ -25 nT） time. It is shown that the strong electric field （up to 5-8mV/m） associated with the earthward fast ion flow is produced in the region earthward of -16 Re. The electric field during the storm time is stronger and occurs in the region closer to the Earth. The stronger electric field that is located closer to the Earth is in association with the thinner plasma sheet and the closer distance of the plasma sheet inner edge to the Earth. It is inferred that the substorm injection during the storm time is more efficient to inject energetic particles into the ring current.

A NUMERICAL SOLUTION METHOD OF NONLINEAR PROPAGATION OF GRAVITY-WAVE PACKET IN A 3-DIMENSIONAL SPHERICAL COORDINATE SYSTEM

ZHANG Shaodong, YI Fan, XIONG Donghui

2001, 21(1): 17-28. doi: 10.11728/cjss2001.01.20010103

Abstract(2079) PDF 868KB(760)

Abstract:
By using FICE scheme and taking the atmospheric basic motion equations as the governing equations, a full-nonlinear numerical model in 3-dimensional spheric coordination is established, and a reasonable polar boundary is specified, the examination of this model is also presented. The calculation result exhibits the essential characteristics of the nonlinear propagation of gravity-wave packet in atmosphere: the whole wave packet propagates upward, the wave-associated disturbance velocity increases with the increasing height.

THE NONLINEAR PROPAGATION OF DOWNGOING GRAVITY-WAVE PACKET IN A COMPRESSIBLE ATMOSPHERE

YUE Xianchang, YI Fan

2001, 21(1): 29-35. doi: 10.11728/cjss2001.01.20010104

Abstract(2010) PDF 564KB(1018)

Abstract:
By using an ADI scheme, the nonlinear propagation of downgoing gravitywave packet in a two-dimensional compressible atmosphere is simulated. Results of numerical simulation suggest that the wave-associate energy moves downward and the velocity perturbation amplitude decreased rapidly. Comparing with the numerical results of linearized equations, we find that under nonlinear condition, a gravity wave packet is still able to keep some characterizations as under linear propagation. The impact of nonlinear effect on the propagation velocity of gravitywave packet weakens rapidly with decreasing velocity perturbation amplitude.

PETROGRAPHIC AND MINERAL CHEMICAL STUDY OF THE ZHUANGHE AND GUANGMINGSHAN METEORITES

LIN Yangting, WANG Daode, LIU Jinyuan, Makoto Kimura, WANG Zhiyan

2001, 21(1): 36-41. doi: 10.11728/cjss2001.01.20010105

Abstract(2344) PDF 512KB(685)

Abstract:
The Zhuanghe and Guangmingshan meteorites fell in 1976 and 1996, respectively. Both of them fell in Zhuanghe city, Liaoning province, within a distance about 20 km apart. These two meteorites are similar in texture, mineral modal composition and mineral chemistry) and are classified as H5 chondrites. Their final equilibrium temperatures are lower than 500℃ according to the two-pyroxene thermometer. Cooling rate of Guangmingshan in its asteroidal body is 10-100℃/Ma, based on the correlation between the band width and composition of taenite; Zhuanghe probably cooled slower, as indicated by common occurrence of tetrataenite. Guang-mingshan was weakly shocked, showing only fracturing of silicates; it is classified into S1 of shock grade. Undulant distinction of silicates is common in Zhuanghe, and there are also fine-grained impact-induced melt veins, suggesting a shock grade of S2.

CALCULATE AND APPLICATION OF THE GPS SATELLITE CLOCK OFFSET

JI Shanbiao, ZHU Wenyao, XIONG Yongqing

2001, 21(1): 42-48. doi: 10.11728/cjss2001.01.20010106

Abstract(2484) PDF 558KB(1291)

Abstract:
The characteristics of GPS satellite clock is analysed, and a method to calculate the satellite clock offset is given based on ground GPS station in this paper. With developed algorithm and software, one meter accuracy for low orbit satellite determination is achieved from data of ground tracking station.

ANALYTICAL SOLUTION OF MOTION EQUATIONS AND EQUATION OF SPECIFIC KINETIC ENERGY FOR RELATIVE MOTION OF TWO CLOSE SPACECRAFTS

LI Dayao

2001, 21(1): 49-54. doi: 10.11728/cjss2001.01.20010107

Abstract(2170) PDF 441KB(927)

Abstract:
When an objective spacecraft （OS） moves along a near circular orbit in unpowered flight, the relative motion of a controlled spacecraft （CS） relatively to the OS is described approximately by the Hill equations on condition that the CS is near to the OS. The Hill equations are solved on the assumption that the thrust acceleration of the CS is the linear function of time. The equation of specific kinetic energy （ESKE） for the relative motion of the two close spacecrafts is deduced from the Hill equations. The applications of ESKE to orbit meet and orbit rendezvous are discussed.

COMPUTER SIMULATION RESEARCH FOR THE CONTROL OF SPACICRAFT CHARGING

GONG Bin, GU Shifen, HUANG Wengeng

2001, 21(1): 55-60. doi: 10.11728/cjss2001.01.20010108

Abstract(2131) PDF 454KB(1003)

Abstract:
This paper uses a set of equations for the spacecraft charging with the equivalent circuit model to make up the corresponding computer simulation. With this simulation, the paper analyses the charging of spacecraft under the worst conditions of substorm time, finally, discusses the feasibility of the control of spacecraft charging by ejecting electrons with an electron gun.

STUDY OF SATALLITE SURFACE COMTAMINATION OF REMAINDER PROPELLANT EXHAUSTED FROM AN ENGINE

CHENG Xiaoli, MAO Mingfang, YAN Xiqin

2001, 21(1): 61-67. doi: 10.11728/cjss2001.01.20010109

Abstract(2145) PDF 610KB(823)

Abstract:
The physical processes of exhausting propellant and its migrating in space before the secondary startup of an engine in the high altitude and super-vacuum environment have been analyzed by using the vacuum physical theory. The assumptions used in the model and equations are given. An appropriate numerical method is developed to solve the equations and to conduct the computer simulation related to the physical process at the condition of vacuum. The contamination on satellite caused by the exhausting propellant is calculated. The unsteady process of concentration variation as well as the maximum contamination on satellite surface at different time is obtained. The theoretical criterion is provided for performing the propellant exhausting scheme desired.

A LARGE DEPLOYABLE HEXAPOD PARABOLOID ANTENNA

CHEN Xiangyang, GUAN Fuling

2001, 21(1): 68-72. doi: 10.11728/cjss2001.01.20010110

Abstract(2476) PDF 406KB(1012)

Abstract:
Deployable structures are increasingly interested for engineers in the aerospace field. A deployable hexapod truss is developed for space application in this paper. The most significant feature is no mechanism to be locked during the deployment, compared with previous varied deployable units. It’s packaging ratio is shown to be good too. A large paraboloid truss antenna is designed by using the deployable hexapod truss, the geometric condition and structural precision are also studied. An aluminium alloy model is made in the last two years. The details of the movable parts, such as diagonal retractable bars and initial perturbation constructions are intruduced in detail in this paper. It is proved by numerical results of structure analysis that the stiffness of antenna is high enough for space application.

DYNAMIC CONTROL SMCE-ROBOT ARM WITH PASSIVE JOINTS

HE Guangping, LU Zhen, WANG Fengxiang

2001, 21(1): 73-80. doi: 10.11728/cjss2001.01.20010111

Abstract(2092) PDF 651KB(970)

Abstract:
The dynamic control problems of under-actuated redundant space station robots were studied, which include the kinematics path planing and the stable dynamic control algorithm of non-holomic redundant robot system. In the dynamic algorithm, the kinematics path planing method was utilized. The dynamic control algorithm can guarantee the end-effector trajectory tracking error to converges asymptotically to zero. Three joints plan robot was used to simulate the algorithm, and the conclusions were verified by the simulation results.

CHAOTIC ATTITUDE MOTION OF A MAGNETIC RIGID SPACECRAFT IN A COMPLEX FORCE FIELD

CHEN Liqun, LIU Yanzhu

2001, 21(1): 81-85. doi: 10.11728/cjss2001.01.20010112

Abstract(1965) PDF 326KB(776)

Abstract:
Chaotic attitude motion of a magnetic rigid spacecraft with internal damping in a circular orbit near the equatorial plane of the earth is investigated. The Melnikov method is applied to establish the condition of the existence of a transversal heteroclinic cycle. The numerical tools such as power spectrum and Lyapunov exponents are used to identify the dynamical behaviors. The numerical results indicate that periodic motion and chaos appear for different parameters.

SIMULATION OF SINS/GPS INTEGRATED NAVIGATION SYSTEM

CAO Fuxiang, BAO Zheng

2001, 21(1): 86-91. doi: 10.11728/cjss2001.01.20010113

Abstract(2160) PDF 506KB(981)

Abstract:
The main aim using SINS/GPS integrated system in navigation is to improve long-term accuracy. For remote sensing application, both long-term accuracy and short-term accuracy are important. The SINS/GPS pseudo-range and pseudo-range rate integrated navigation system are studied based on the precise model of pseudorange rate in which position error is concerned in this paper. Simulation results show that the long-term position error of integrated system is within 5 meters. If the middling accuracy inertial instrument is used, the relative change of position error in the time interval of GPS measurement is centimeter level.

PLANETARY TIDE FORCE TRIGGERING SOLAR FLARES

DONG Shihua, ZHENG Leping

2001, 21(1): 92-94. doi: 10.11728/cjss2001.01.20010114

Abstract(1861) PDF 257KB(882)

Abstract:
In this paper, solar tide dynamics is briefly reviewed and it is pointed out that the effect of plantary tide force on triggering solar flares is more obvious for flares with stronger intensity, and that the ratio of outputs of strong planetary tide force triggering flares with Imp≥ 3 to weak ones is as high as 9.33. This fact revealed in this paper is significant in prediction of disturbances in solar-terrestrial space.