共查询到20条相似文献,搜索用时 31 毫秒
1.
B. I. Rabinovich 《Cosmic Research》2010,48(2):139-149
Some new results are presented concerning quantization of observed parameters of the Solar System and exo-planet systems,
as well as some functions of these parameters. General adiabatic invariants are introduced including (for the Solar System)
orbital quantum numbers of planets and quantum numbers characterizing their proper rotation (spin). The quantization of parameters
relating to satellite and exo-planetary systems is considered. Some arguments are presented about the influence of nonlinear
disturbances of Alfvenic plasma proto-ring of the type of Frenkel-Kontorova (FK) and Russell-Korteweg-de Vries (KdV) solitons
on formation of elite rings and their evolution with conservation of corresponding invariants. A mechanical model is synthesized
that describes nonlinear FK soliton type disturbances of magnetized plasma. 相似文献
2.
On the basis of an invariant representation of ion spectra with > 0.1 keV/nT, new methods of separation and quantitative analysis of the adiabatic component of storm-associated variations of fluxes of ions in the geomagnetic trap from the satellite data are developed. The regularities of adiabatic variations of flux ratios for different ion components, associated with their spectra scaling laws, are considered. 相似文献
3.
深空探测技术已经被列入国家发展计划,由于空间环境的特殊性,对空间低温制冷技术提出了更高的要求。文章介绍了美国、日本和欧空局用于深空探测的深低温制冷技术的发展状况,包括超流氦制冷技术、多级机械制冷技术、吸附式制冷技术、绝热去磁制冷技术和氦稀释制冷技术,并介绍了在天文卫星和空间望远镜上的应用;综述了中国空间低温制冷技术的发展现状,提出了中国开展深低温制冷技术研究的启示和建议。 相似文献
4.
The problem of the construction of a satellite broadcasting system whose capabilities are supplemented and expanded in comparison with geosynchronous satellites is considered. The optimal orbit of a high-elliptic satellite of the Earth, which provides for a maximal duration of stay of the satellite sighting line within the directional pattern of an antenna motionlessly installed on the Earth's surface, is determined. The advantages of using a satellite system with such orbits are shown. 相似文献
5.
A. A. Zlenko 《Cosmic Research》2006,44(1):69-73
The stationary motions of a synchronous axisymmetric satellite are studied in the field of attraction by the Earth and a third body whose parameters are close to those of the Moon. Equations of motion are written in canonical variables that take into account the resonance character of the problem. The plots characterizing the dependence of the rotation parameters of the satellite relative to the center of mass on the elements of satellite’s translational motion are presented. A picture is given that represents the initial configuration of the system for implementing stationary motions. 相似文献
6.
Two techniques are able to permit a significant progress in the global measurement of the Earth gravity field: satellite to satellite tracking and gradiometry. The preliminary results concerning the study of a gradiometric satellite to be launched by Ariane are presented.After stating the scientific objectives and the mission specifications, one focuses on the definition of the gradiometer and the gradiometric satellite. After analysis of the problems associated with gradiometry based upon differential accelerometry, one presents the Cactus accelerometer design evolution and the implications on the satellite configuration and interfaces with the gradiometer. Finally a short mission analysis is presented. 相似文献
7.
A satellite equipped with a magnetic attitude control system and a pitch flywheel has been considered. The system performance in the transient mode has been investigated. The characteristic exponent of the system have been approximated for a satellite on a circumpolar orbit. In the steady-state mode of gravitational attitude, small motions are considered in the vicinity of equilibrium. The attitude accuracy has been analyzed. The algorithm of an arbitrary but given attitude of the satellite in the orbital plane has been investigated. A numerical simulation has been performed. 相似文献
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9.
We consider the angular motion of an axi-symmetrical satellite equipped with an active magnetic attitude control system. Dynamics of the satellite is studied on the entire control loop, consisting of a bunch of three successively used algorithms. The control cycle includes the stages of nutation damping, spinning up the satellite about its symmetry axis, and reorienting the symmetry axis into a preset direction in the inertial space. The results are confirmed by numerical simulations. 相似文献
10.
The mode of spinning up a low-orbit satellite in the plane of its orbit is studied. In this mode, the satellite rotates around its longitudinal axis (principal central axis of the minimum moment of inertia), which executes small oscillations with respect to the normal to the orbit plane; the angular velocity of the rotation around the longitudinal axis is several tenths of a degree per second. Gravitational and restoring aerodynamic moments were taken into account in the equations of satellite’s motion, as well as a dissipative moment from eddy currents induced in the shell of the satellite by the Earth’s magnetic field. A small parameter characterizing deviation of the satellite from a dynamically symmetric shape and nongravitational external moments are introduced into the equations. A two-dimensional integral surface of the equations of motion, describing quasistationary rotations of the satellite close to cylindrical precession of the corresponding symmetrical satellite in a gravitational field, has been studied by the method of small parameter and numerically. We propose to consider such quasistationary rotations as unperturbed motions of the satellite in the spin-up mode. 相似文献
11.
The problem of planar motions of a dumbbell-like body of variable length in a central field of Newtonian attraction is considered
both in the exact formulation and in satellite approximation. In the satellite approximation the true anomaly of the center
of mass is used as an independent variable, which has allowed us to represent the equation of planar oscillations of the dumbbell
in the form similar to the Beletskii equation. Some exact solutions to the inverse problem are given both in the complete
formulation and in satellite approximation. Under an assumption of small orbit eccentricity and amplitude of the dumbbell
vibrations the conditions of existence are found for families of almost periodic motions and splitting separatrices. The phenomena
of alternation of regular and chaotic motions are established numerically, as well as chaos suppression with increasing frequency
of vibrations. Using the method of averaging the stabilization of tangent equilibria is proved to be impossible. 相似文献
12.
Attitude stabilization of a satellite by magnetic coils 总被引:1,自引:0,他引:1
Vladimir A. Bushenkov Michael Yu. Ovchinnikov Georgi V. Smirnov 《Acta Astronautica》2002,50(12):721-728
Stabilization problem for a satellite is considered. The only measurement is of the geomagnetic field in the satellite coordinates. The control is carried out by a magnetic moment of current coils (magnetorquers) mounted on the satellite body. The stabilizer constructed in this work solves the problems of magnetic and gravitational stabilization. Qualitative analysis and results of numerical simulation are presented. The results of simulation show that the proposed stabilization system is reliable, and has an appropriate accuracy and does not need powerful sources of energy, and therefore can be used for attitude control of small satellites. 相似文献
13.
V. V. Sazonov 《Cosmic Research》2013,51(2):133-146
We investigated periodic motions of the axis of symmetry of a model satellite of the Earth, which are similar to the motions of the longitudinal axes of the Mir orbital station in 1999–2001 and the Foton-M3 satellite in 2007. The motions of these spacecraft represented weakly disturbed regular Euler precession with the angular momentum vector of motion relative to the center of mass close to the orbital plane. The direction of this vector during the motion was not practically changed. The model satellite represents an axisymmetric gyrostat with gyrostatic moment directed along the axis of symmetry. The satellite moves in a circular orbit and undergoes the action of the gravitational torque. The motion of the axis of symmetry of this satellite relative to the absolute space is described by fourth-order differential equations with periodic coefficients. The periodic solutions to this system with special symmetry properties are constructed using analytical and numerical methods. 相似文献
14.
The attitude stability of an Earth-orbiting satellite experiencing aerodynamic torque is studied. This is accomplished by applying the theory of total stability (or, stability under constantly acting disturbances) to the equations of motion. The satellite is gravity-gradient stabilized and a damping torque is incorporated. The aerodynamic torque results from the presence of two flat panels attached to the cylindrical body of the vehicle. This perturbing torque is treated as an additive disturbance in Euler's equations of motion. A Lyapunov function is constructed and then used in an appropriate theorem on stability under constantly acting disturbances. Explicit expressions are thereby found for bounds on a hypothetical initial condition (a rotation from the Earth-pointing equilibrium) and on the aerodynamic torque, so that if these disturbances are less than their respective bounds then the resulting attitude motion of the satellite will not exceed a pre-assigned value. These bounds depend on that pre-assigned value, and on the physical parameters of the satellite. The design implications of these bounds are then discussed. 相似文献
15.
L. D. Akulenko Ya. S. Zinkevich D. D. Leshchenko A. L. Rachinskaya 《Cosmic Research》2011,49(5):440-451
Rapid rotational motion of a dynamically asymmetric satellite relative to the center of mass is studied. The satellite has
a cavity filled with viscous fluid at low Reynolds numbers, and it moves under the action of moments of gravity and light
pressure forces. Orbital motions with an arbitrary eccentricity are supposed to be specified. The system, obtained after averaging
over the Euler-Poinsot motion and applying the modified averaging method, is analyzed. The numerical analysis in the general
case is performed, and the analytical study in the axial rotation vicinity is carried out. The motion in the specific case
of a dynamically symmetric satellite is considered. 相似文献
16.
We consider the issues of modeling the moments of aerodynamic forces acting upon a satellite with gravitational system of
stabilization. It is assumed that satellite orbits are almost circular with heights in the range 550–750 km. Simplified analytical
expressions are suggested for the aerodynamic moment in the case when a satellite moves in the regime of gravitational orientation.
Accuracy of the obtained expressions is estimated to be compared with that of expressions derived under the assumption of
constant coefficient of frontal resistance. An analysis is made of short-periodic variations of the atmosphere density occurring
due to orbital motion of a satellite. It is demonstrated that these variations can result in a substantial change of the aerodynamic
moment, and their approximation by a truncated Fourier series is suggested. Estimates of the accuracy of the suggested approximation
are given. 相似文献
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18.
针对空间绳系机器人抓捕非合作目标/空间垃圾后需要对其进行回收/拖曳的精确控制问题,提出了一种利用抓捕后保持阶段的振动特性辨识目标参数的方法。首先,根据质量特性参数辨识的需要,推导了系统的动力学模型。不同于以往将本体卫星和被抓捕目标简化为质点的动力学模型,本文针对任意的目标抓捕位置,在考虑重力梯度影响的基础上,利用拉格朗日法获得系统各广义坐标的动力学公式。然后,分析非合作目标和系绳在后抓捕保持阶段的姿态运动。最后,在非合作目标与本体卫星没有任何信息交互的情况下,利用后抓捕阶段目标卫星和系绳特有的振动,并使用具有鲁棒性可遗忘因子的递推最小二乘法,提出了包括转动惯量和质心到任意抓捕点距离在内的质量特性参数辨识算法。 相似文献
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20.
某型卫星有效载荷支架振动抑制 总被引:6,自引:1,他引:6
某型号卫星的有效载荷支架结构在验收级振动试验时振动超标。在对结构不做大的修改的前提下,采用约束阻尼层用对原结构进行处理。对不同的约束阻尼层方案采用有限元方法进行计算,综合考虑各种影响因素,如阻尼比和附加质量等,得到合理的约束阻尼减振方案,并在结构星上进行试验,确定最终实施方案。实施方案后,正样星在0.1g振动条件下,最大振动幅值下降了22.3%,保证了卫星的顺利发射。该卫星已经成功发射,并且在轨运行正常。该问题的成功解决和解决问题的方法与过程为今后解决类似问题提供了经验。 相似文献