On the stability of stationary motions of a system of coaxial bodies

We consider the stability of stationary motions of a model of a spacecraft as a system of coaxial bodies with small asymmetry caused by the shift of the axes of dynamic symmetry of bodies relative to the axis of rotation. We determine the stationary motions of the system; their stability is studied with respect to both the projections of angular velocity and the position of the axis of rotation. The sufficient conditions for the stability of these stationary motions are obtained by constructing a Lyapunov function, and the necessary conditions are obtained by analyzing the corresponding linearized equations of perturbed motion.     

Influence of the interplanetary magnetic field on ULF oscillations of the ionospheric resonator

A weak but statistically reliable dependence of the diurnal activity of oscillations in the ionospheric Alfvén resonator on orientation of the interplanetary magnetic field ahead of the magnetospheric front has been detected based on observations of ULF oscillations at Sayan solar observatory Mondy of the Institute of Solar–Terrestrial Physics. The interpretation of the result has been proposed. The essence is that the electromagnetic fluctuations penetrate into the magnetosphere from the interplanetary environment and influence the ionospheric resonator. The formulation of the problem and the method of solving it are part of the broad program of the experimental and theoretical study of the influence of the interplanetary magnetic field on the oscillation regime of ULF oscillations of the magnetosphere.     

Safety Analysis of Helicopter Autorotation Landing Execution on Conditions of Providing Skid Landing Gear Static Strength

The requirements for skid landing gear static strength ensuring are examined based on the comparative analysis of the Airworthiness Standards requirements. Probabilistic principle of determining the safety factor of the skid landing gear is presented. The analysis of the experimental data on bench and flight tests is performed for calculating the actual value of this factor.     

Nonlinear deforming of laminated composite shells of revolution under finite deflections and normal’s rotation angles

The discretization of the boundary value problem for laminated composite shells is based on the finite difference approach using the regular mesh with the constant grid step and the difference operators of the second order of accuracy. The dynamic relaxation method is proposed for the solution of the nonlinear problem. The evolutionary equations of the dynamic relaxation are constructed, and the optimum parameters of the converging linear iterative process are estimated.     

Analytical construction of interception trajectories in atmosphere

For an interception strategy of a removable target by a return space vehicle (RSV), we propose a structure of the control law by the aerodynamic efficiency that determines a chain of the three standard trajectories: nosing-up–free flight–nosing-down. A solution of the terminal problem is to determine numerical values of the control parameters that define moments to switch the RSV flight from one standard trajectory to another.     

Flow between finite and infinite disks with consideration of surface mobility

A problem of modeling the incompressible viscous flow between two disks taking into account the rotation of one of them is considered. We study the effect of the disk angular velocity (flow regimes) in the interdisk spacing, finiteness (infiniteness) of disk radiuses, calculation region configuration as well as distances between disks on the flow characteristics, particularly, on the resistance moment coefficient. Numerical simulation is performed with the aid of Maple and ANSYS Fluent software.     

Calculations of shock wave energy parameters in the presence of high-voltage electrical discharge in water for the transition region

A technique for calculating the energy parameters of shock waves at electrical discharge in water is presented for the transition region of discharge channel expansion using as the base the predetermined characteristics of discharge circuit. The technique is based on the solution of energy transport equation that is similar in form to that of radiative transfer. The validity of the presented approach was experimentally verified.     

Systems for the indication and display of secondary information in avionics and autobasing complexes

We consider the peculiarities of application for the cabin indicating systems of secondary information display, formulate and systematize the compositional and technical requirements for display systems and their elements. The tendencies and lines in the development of head-up displays for avionics and autobasing complexes were determined. The technique of calculating optics of such display systems with the use of electronic distortion compensation is presented.     

Integrated acoustic monitoring system for jet fuel tanks

The paper describes a device and a technique of forming the information processing algorithms used in the integrated acoustic monitoring system for jet fuel tanks, intended for monitoring the level, density and mass of liquid products.     

Determination of characteristic frequencies of elastic oscillations of the <Emphasis Type="Italic">International Space Station</Emphasis> construction

The results of investigating free oscillations of the International Space Station construction appearing during spacecraft docking and undocking are described. The study is carried out using the measurement data of the low-frequency MAMS accelerometer. Several intervals of measurements performed in 2005 and 2006 were chosen to be studied. For chosen intervals, only the data intervals corresponding to the process of free attenuation of the oscillations construction elements were analyzed. Characteristic frequencies of elastic oscillations of the station construction and attenuation coefficients corresponding to them are found. The comparative analysis of the results obtained for various docking ports (nodes) is carried out. The described study is performed as a part of the technical experiment “The ISS Environment” carried out onboard the station in accordance with the Russian program of scientific and engineering experiments.