Attractive forces inside a thin nonuniform meteor ring

Attractive forces inside a thin nonuniform meteor ring are found and their features are revealed.     

Stochastic motion of geosynchronous satellites

Long-period evolution of the orbital elements of geosynchronous objects moving in the neighborhood of separatrices of the region of libration resonance is studied. At the phase plane “the longitude of the subsatellite point-semi-major axis” the regions of migration of separatrices where the separatrices can move due to the influence of perturbations are isolated. The dimensions of these regions and the distances between them have the same order of magnitude, several kilometers along the semi-major axis. The regions of migration do not overlap at the initial value of the orbit inclination 0°. When inclination increases, gradual overlapping of these regions takes place. On average, the width of the zones of stochasticity increases when the area to mass ratio increases and decreases when inclination of the orbit increases. The zones of stochasticity corresponding to different separatrices are separated from each other. A catalog of the passive geosynchronous objects moving in the neighborhood of separatrices is compiled. The evolution of the objects of the catalog is studied.     

Variational equations in parametric variables and transformation of their solutions

An analytical relationship is derived which connects the matrix of partial derivatives of the current state vector with respect to the initial conditions with the matrix of solutions to variational equations in parametric variables. These equations correspond to the equations of motion obtained using the generalized coordinate-time transformation admitting an increase of the number of unknown parameters. Particular cases of transformations leading to the variational equations in regularizing variables of Sperling-Burdet and Kustaancheimo-Stiefel are considered. All formulas necessary in these cases for determination of the matrix of isochronous derivatives are obtained.     

Navigation of a space bunch under conditions of its rotary motion

The properties of a tethered space system (bunch) in the mode of rotational motion are used in determination of the parameters of the location and orientation of the end vehicles of the bunch by the method with the simplest possible instrumental implementation.     

The motion of a particle in perturbed field of an attracting center

The integrable case of the perturbed two-body problem is considered. The perturbation is determined by the potential of a special form. The L-matrix is chosen in such a way that partial separation of variables should take place in regular coordinates. Integration of the equations of motion of the problem under consideration is made. The solutions are expressed through elliptic functions. The orbits for various cases are constructed. The results of numerical calculations are given.     

On the planar inertial motion of a system of three coupled bodies

Numerous papers are devoted to studying the motion of a system (coupling) of two bodies in the Earth’s satellite orbit ([1–4] and others). The problem on the planar inertial motion of three bodies, coupled by a non-extensible weightless string having the form of an unfastened chain, is considered in the paper. Such a configuration can be represented, for example, by a system of two coupled spacecraft rotating around their common center of mass (in order to simulate the gravity force) in long-term space missions, when the third body (the lift) is located on a connecting cable. The bodies are considered to be the material points (particles).     

Malfunction of satellite navigation systems GPS and GLONASS caused by powerful radio emission of the Sun during solar flares on December 6 and 13, 2006, and October 28, 2003

Poor quality of functioning of GPS during solar flares on December 6 and 13, 2006 is analyzed in this paper. These flares were accompanied by extremely high (unexampled) level of the solar radio emission flux. A comparison is made of these events with the solar flare on October 28, 2003. Statistically reliable experimental evidence is obtained that GPS positioning was partially paralyzed on the sunlit side of the Earth during the strongest bursts of solar radio emission. The obtained results give a serious ground to revise the role played by space weather factors in operation of modern satellite systems and to take these factors into account more carefully, when such systems are designed and exploited.     

Some new applications of the generalized problem of two fixed centers

A generalized problem of two fixed centers and its limiting version is considered. New possible applications of this problem are obtained. Using a symmetric version of the problem, the external field of gravitation is approximated. The limiting version approximates the inner field.     

Specific features of motion of geosynchronous satellites in the neighborhood of unstable stationary points

A study of peculiarities of the motion of equatorial circular geosynchronous satellites is performed in the neighborhoods of unstable stationary points with longitudes of 165° and 345°. The maps of initial conditions are constructed on the phase plane “longitude of subsatellite point-semi-major axis of orbit” corresponding to various types of regular motions and to quasi-random solutions. The dimensions of zones of the quasi-random solutions are within the limits from decimal fractions of a degree to a few degrees (in longitude) and from hundreds of meters up to several kilometers (along the semi-major axis).     

The family of potentials admitting integration of the perturbed two-body problem in regular coordinates

An infinite system of potentials is presented that admits separation of regular variables in the perturbed two-body problem. The regular coordinates are constructed using a specially selected L-matrix. An explicit solution to the problem in the elliptical case is constructed. In the general case the solution is reduced to inversion of hyper-elliptic integrals. The cases of motion with and without constraints are considered. The results of numerical experiments are presented.     

Planar inertial motion of an elastic cluster of three bodies

A problem of planar inertial motion of three bodies connected in the form of a triangle by an elastic imponderable filament is considered, as well as a particular case of the problem of motion of a closed chain of n bodies. This configuration can be a basis for extended planar constructions in deep space.The bodies are considered as material points. The paper elaborates a subject of [1]     

Determination of two Satellites’ relative motion using tracking measurements

A technique to determine the initial relative velocity of two satellites at the initial time instant, based on the results of NORAD system’s measurements, is presented. The determination of a relative initial position is shown to result in the unsatisfactory accuracy. This technique is applied to determining the initial velocity of separation of the first Russian nanosatellite TNS-0 from the International Space Station.     

航天器爪型对接机构对接过程动力学仿真分析

航天器对接机构是完成空间在轨对接任务的核心机构,要保证成功完成对接任务,必须清楚掌握其对接过程动力学作用机理与表现。文章针对爪型对接机构的对接过程开展动力学研究,建立了考虑对接过程中的接触、摩擦及碰撞等非线性因素的对接机构动力学模型,进行对接过程的全程动力学仿真模拟,详细分析了对接过程的影响因素与作用机理,并从能量角度分析了缓冲器的工作性能,可为爪型对接机构的设计、对接初始条件确定和控制策略的制定提供参考。     

柔性锥-杆式对接机构碰撞过程仿真研究

以中小型航天器普遍采用的锥-杆式对接机构为研究对象,提出一种柔性对接锥作为缓冲系统的方案,用柔性锥变形吸收撞击能量作为缓冲。用有限元法对碰撞过程进行仿真,讨论了柔性对接锥作为缓冲系统的性能对对接过程的影响。仿真结果表明:与普通对接锥相比,柔性锥能减小碰撞力峰值50%多。     

空间对接过程的仿真研究

分析了内翻式异体同构周边式对接机构的接触形式，控制模型和力学模型，建立了对接过程的动力学仿真模型。利用试验数据对该模型进行了验证，并在此基础上进行对接过程的仿真研究。     

周边式对接机构对接捕获阶段的三体力元动力学模型

在空间交会对接过程中，从首次接触碰撞到完成捕获这一阶段称为对接捕获阶段，对对接捕获阶段动力学性态的研究是空间交会对接技术的关键，建立动力学模型进行仿真是研究的一个有效途径。以有内导向瓣异体同构周边式对接机构为研究对象，从机构的物理模型出发建立了对接捕获阶段的三体力元模型。该模型考虑了缓冲系统六个方向之间的耦合和缓冲系统中齿轮等转动部件惯量的影响。并在动力学仿真软件DADS的接口上开发相应的用户模块。在DADS平台上完成对接过程的动力学仿真。     

交会对接系统的递阶控制

本文从大规模动态系统观点出发,研究空间站自主对接过程的递阶控制问题.仿真结果表明,递阶控制为自主对接过程的优化提供了一条新的途径.     

对接过程中捕获锁质量和锁合面间隙影响分析

采用弹性接触动力学有限元和多刚体动力学方法分别对航天器对接接触碰撞过程和对接机构捕获、缓冲与校正过程进行了数值模拟,对比分析了捕获锁质量对捕获过程的影响及捕获锁锁合面间隙对捕获后对接过程的影响。从仿真结果可以看出,附加质量有利于主、被动对接环之间形成接触滑移,捕获后锁合面间隙引起两飞行器间相对速度震荡,并延迟了碰撞力和缓冲时间。     

主动控制式对接机构对接预捕获阶段的仿真

介绍了主动控制式对接机构对接的基本操作过程，并以具有六个作动阻尼器的主动接制式对接机构为例，对对接预捕获阶段作了详细的研究。 该阶段两对接飞行器的运动方程，给出了作动／阻尼器为满足捕获条件所需达到的长度的计算方法，设计了控制回路，在此基础上作了数值仿真。仿真结果表明，建立的数学模型是正确的，设计的控制系统控制效果良好。