Vol 12, No 4 (2013)

The paper is devoted to up-to-date onboard computing systems of the «Malachite» family, created at the Center. The structure and architectural features of this computing system generation that provide high reliability of the equipment in terms of external destabilizing factors. The paper also addresses issues of further development of onboard digital computer systems produced by the Center.

Aspects of Earth remote sensing data processing for the detection and identification of natural and anthropogenic objects are examined in the paper. The results of research carried out on multi- and hyperspectral images of Samara region obtained from EO-1 and Landsat-8 spacecraft are presented.

The paper presents mathematical models, an algorithm and software for the assessment of the relative time spent by navigation satellites (NS) and Earth remote sensing (ERS) satellites under mutual visibility conditions. A method of choosing the place for the installation of navigation system aerials on the spacecraft body is proposed based on the criterion of maximum relative time of mutual visibility no less than a specified number of the NSs.

The paper analyses a nanosatellite’s uncontrolled motion relative to its mass center after separation from the upper stage of «Soyuz» carrier rocket. Stochastic models of the initial conditions of the nanosatelite attitude motion are formulated. The possibility of successful solutions of navigation and communication problems using satellite navigation systems and low-altitude communications networks for LEO nanosatellites is shown.

Eddy-current transducers with single-coil sensitive elements are discussed in the paper. Embodiment modifications are presented and examples of using the transducers for measuring mechanical parameters are demonstrated.

Spatial motion of an uncontrolled nanosatellite around its center of mass on low circular orbits is considered. The aerodynamic characteristics of nanosatellites CubeSat-2U and CubeSat-3U are determined. The distribution functions of the maximum angle of attack of nanosatellites for various flight altitudes depending on the dispersion of the components of the initial angular velocity are obtained.

The paper is devoted to problems of constructing software and algorithmic support for a ground-based complex for determining the attitude of small satellites. The kinematic attitude determination algorithms based on the integration of diverse information form the software basis.

The paper deals with the problems of using transport spacecraft based on a nuclear power supply system and electric rocket engines for the transportation of payload to the near-earth orbits and exploring the Solar system in the nearest perspective. A method of calculating the parameters of a transport spacecraft power supply complex is presented. The problems of using this type of transport spacecraft at the current stage of space engineering are identified.

The paper deals with the development of methods of testing onboard equipment incorporated in automatic spacecraft. Considerable difference in methods of assessing the technical state of the object under investigation in normal operation during the tests is shown. A way of testing using the pattern for the modification of onboard equipment control programmes with the aim of increasing its controllability is discussed.

The paper presents some issues related to on-stand emergency protection and control systems developed by the center (FKP NITs RKP) in support of propulsion tests of the new Russian «Soyuz-2-1в» launch vehicle.

The paper outlines the foundations of a self-consistent theory of antennas. It is shown that the incorrectness of the physical model of the antenna leads to the incorrectness of its mathematical model. Integral representations of the electromagnetic field that become a system of integral equations in relation to the unknown surface current distributions on the emitting area under boundary conditions are proposed as the main instrument of self-consistent analysis. The results of self-consistent electrodynamic analysis for certain types of antennas are presented.

Digital half-tone images (DHI) represented by g-digit binary numbers often possess great statistical redundancy which can contribute to increasing DHI reception noise immunity. The paper presents algorithms of DHI non-linear filtration based on Markovian networks with several states that make it possible to reduce the time of image transmission. The filtration algorithms are investigated in the presence of white Gaussian noise. The results of the investigation confirm the theoretical assumptions of the possibility of improving DHI reception quality without the increase in energy resources on the transmitting side of the communication channel.

To clause the problem of a choice of design characteristics low-orbit space vehicle, incorporating Electric Rocket Propulsion System (ERPS) for correction of parameters of an orbit is considered. The mathematical models describing interrelation of factors of an environment, design parameters of onboard systems (including ERPS) and design characteristics low-orbit space vehicle as a whole are considered.

The paper presents a design of a sensor for studying micrometeoroids and space debris.

The article discusses technological capabilities of increasing the lifetime of power gyroscopes and momentum wheels due to the improvements in the technology of assembling them. It is shown that the axial preload on the main bearings of power gyroscopes and momentum wheels has a considerable influence on their lifetime. It is necessary to control the magnitude of the axial preload in conditions close to operating ones.