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The paper considers the possibility of cargo relocation without fuel costs along a tether connecting two heavy space stations by a spacecraft with a controlled solar sail. The spacecraft's relative motion dynamics is studied within the context of a model problem that assumes that the stations describe one heliocentric orbit, the solar sail is a perfect reflective flat panel, and the tether realizes an ideal unilateral handrail constraint that restricts the spacecraft relative motion to an ellipsoid. It is noted that, if the distance between stations is sufficiently small and the ratio of the sail area to the spacecraft mass is on the same order of magnitude as in already-implemented space missions, solar radiation is the main factor that influences the spacecraft's motion in the orbital frame of reference. The problem of searching a set of pairs of points, between which relocation with a permanently oriented sail is possible, is solved for the pairs that belong to the intersection of the ellipsoid boundary and the plane of the stations' orbit. The duration of the spacecraft relocation between the ellipsoid poles is estimated for the case of the sail oriented orthogonally to the solar rays. Also, the duration of the fastest relocation between poles is computed using special sail orientation control laws, including the case of zero initial and final velocities. [ABSTRACT FROM AUTHOR]

The structure and evolution of the passive continental margins of the Arctic Ocean are considered on the example of the South Kara Basin. Its development is associated with the evolution of the West Siberian Plate and the formation of the Arctic Ocean. Until the Late Cretaceous, the South Kara Basin was the north margin of the West Siberian Plate, whose formation is related to the Permian-Triassic processes of riftogenesis accompanied by the eruptions of traps. In the Mesozoic, due to the opening of the Arctic Ocean, the South Kara basin became a part of the continental margin, where the accumulation of marine sandy-clayey rocks continued. [ABSTRACT FROM AUTHOR]

Abstract: The northern part of Sakhalin Island is an area of recent intensive tectonic movements and hydrothermal processes, as well as a place of accumulation of useful minerals. The deep structure of the lithosphere beneath the region of the Neftegorsk earthquake of May 27, 1995 in North Sakhalin, which killed residents and caused significant destruction, is examined in this paper. Our geodynamic model shows that North Sakhalin consists of the North Sakhalin Basin, Deryugin Basin and an ophiolite complex located between them. The Deryugin Basin was formed in place of an ancient deep trench after subducting the Okhotsk Sea Plate under Sakhalin in the Late Cretaceous–Paleogene. The North Sakhalin Basin was formed on the side of the back-arc basin at that time. The ophiolite complex is fixed in the position of ancient subduction zone that was active in the Late Cretaceous–Paleogene. Approximately in the Miocene, the subduction of the Okhotsk lithosphere apparently ceased. The remains of the subduction zone in the form of an ophiolite complex have been identified from geological and geophysical data. On the surface, the subduction zone is manifested as deep faults stretched along Sakhalin. It is probable that the Neftegorsk earthquake was a result of activation of this ancient subduction zone. [Copyright &y& Elsevier]

We consider a special space tethered system consisting of a dumbbell-shaped rigid body and a particle. The particle coast along on the cable. The cable ends are placed in the dumbbell endpoints. We call such system 'the system with leier constraint (the Dutch term 'leier' means the rope with both fixed ends). We assume that the system mass center moves along the circular orbit in the Newtonian Central Force Field. We study the dumbbell's relative motion caused by the particle of small mass in the orbital frame of reference. We deduce a sufficient condition for librations of the dumbbell about its stable equilibrium. We find a family of the dumbbell's asymptotic motions tending to librations about unstable equilibrium. The surface of such asymptotic motions is an interstream separating the areas of the dumbbell's right-hand and left-hand rotations. We deduce an equation of this surface. [ABSTRACT FROM AUTHOR]

The binary asteroids are of current interest in the modern dynamics as there have been up to 50 discoveries of binaries. Estimates are that about 20% of near-Earth asteroids may be binary asteroids. Nevertheless the known asteroids pairs are rather rare objects in the Solar System. There are a number of papers studying the various aspects of asteroid pair dynamics. In this paper we study some stationary motions in the system of binary asteroid. Using the model for the first time suggested in [1], we approximate the bigger asteroid by the dumbbell-shaped rigid body. Moreover we assume that the smaller asteroid has mass close to zero. It was shown in [1] that the motion equations for the considered system have the stationary solutions corresponding to the smaller asteroid's equilibria relative to the axis of the regular precession and the dumbbell rod These equilibria similar to the libration points in the Restricted Circular Problem of Three Bodies (RCP3B). There are two types of such equilibria. The equal distances from the dumbbell endpoints characterize the equilibria of the first type, therefore we shall name them 'the libration points similar to Lagrangian' or 'the triangular libration points' (TLPs) by analogy to a classical problem. At difference with RCP3B there are two or one TLPs or they do not exist. Equilibria of the second type in something are similar to the Eulerian libration points. They belong to the plane containing the bigger asteroid's angular momentum and the dumbbell rod. Moreover, these equilibria belong to the strip bounded by straight lines crossing the dumbbell endpoints and being perpendicular to angular momentum. Therefore we shall name them 'the coplanar libration points'(CLP). The CLPs coordinates are computed by following procedure. Two algebraic equations are deduced. One of these equations determines the curve containing all CLPs. We say that this curve is 'the Geometrical locus of CLPs' (GL). The second equation allows to locate CLPs in GL. Studying evolution of CLPs in GL it can be proved that the number of CLPs varies from 3 up to 7, but if the dumbbell consist of equal spheres then only the odd number of CLPs is possible. However, if the dumbbell is asymmetric then the number of CLPs can be equal 4 or 6 for some rare situations. [ABSTRACT FROM AUTHOR]

Equilibrium positions of a small-mass body are considered with respect to a precessing dumbbell. The dumbbell represents two rigidly fixed spherical gravitating bodies. Such a system can be considered as a model of a binary asteroid. Stability of relative equilibrium positions with equal distances from the small mass to the attracting centers is studied. By analogy with the classical restricted three-body problem, these positions are referred to as triangle libration points. It is shown that the character of stability of these libration points is determined by three constant parameters: nutation angle and angular velocity of precession, as well as the ratio of masses at the ends of the dumbbell. Stability conditions are derived in the linear approximation, and the regions of stability and instability in the space of problem parameters are constructed. The paper is a continuation of [1]. [ABSTRACT FROM AUTHOR]

The paper demonstrates that in computing a linear form (g, x) on the solution of a system of linear equations Ax = f, the round-off error depends on the quantities ‖A−1f‖ and ‖AT−1g‖ rather than on the condition number of the coefficient matrix A. Estimates of the inherent and round-off errors in solving the above problem by the orthogonalization method are provided. Numerical results confirming theoretical conclusions are presented. Bibliography: 8 titles. [ABSTRACT FROM AUTHOR]

The possibility of nonimpact tension of a cable after its weakening when a small load moves along the cable whose ends are fixed on a massive dumbbell-like spacecraft which is moving in a steady-state manner along a circular orbit is considered. The conditions of existence and classification of the trajectories of nonimpact motion, including periodic ones, are presented. [ABSTRACT FROM AUTHOR]

The motion of a space object in the gravitational field of the Earth is considered. The object consists of an extended space station and a weight, which is free to move along the cable fixed to the ends of the station. It is assumed that the station is composed of two masses coupled by a weightless rod, while the cable is weightless and non-stretched. The equations of motion of such a system are derived for the case when the motion proceeds in a single plane, while the center of mass of the system moves along a circular geocentric orbit. The conditions of the cable tension (conditions of being on tie) are derived. The phase portrait of the weight motion along the cable is constructed when the station is oriented to the attracting center or is perpendicular to this position. The possibility to leave the tie in this case is analyzed. Equilibrium configurations of the system are found, i.e., such motions of the object under consideration at which the weight does not change its position relative to the station. Lyapunov stability of such configurations is analyzed for two situations: when the station is composed of equal masses and when masses at the ends of the station are different. In particular, for the case of different masses it is established that there exist such positions of equilibrium at which the dumbbell is located at an angle to the direction to the attracting center. In some cases these positions can be stabilized (if the weight is fixed on the cable). [ABSTRACT FROM AUTHOR]

Examines the motion of a system that represents an elongated space station considered as a system of two material points connected by a weightless rod and load hat can freely move along a cable. Effect of gravitation on the relative motion of the load; Points to consider if the inhomogeneity of the of the gravitational field is neglected; Establishment of the differentiating formulas with respect to time; Determination of the phase portrait of relative motion.

It is proposed to estimate the effects of hydrogen on alloy degradation from the total specific energy Wc of limiting deformation. Data are given on estimating the degradation from Wc for various alloys given various treatments (hydrogenation, heat treatment). [ABSTRACT FROM AUTHOR]