On the S-25 anti-aircraft missile system. Part 1

The paper introduces and analyzes the results of research into the development of anti-aircraft missile systems through the example of the first Russian anti-aircraft missile system S-25. The study describes the capabilities of the anti-aircraft missile system as the implementation of the requirements specifications in the context of the development of military aviation technology and electronic warfare means and emphasizes the importance of cooperation between enterprises — developers of guided missile weapons. Although the latter issue is poorly covered in the Russian scientific, technical, and educational literature, it is an important problem in organizing the development of missile systems. The paper is the first to provide detailed data on the content and timing of the stages of modernization of the S-25 system, and also presents graphic material that clearly demonstrates the change in the capabilities of the S-25 system due to an intensive change in the characteristics of military aircraft.

Specific features of mathematical modeling of ceramic plates destruction under the influence of high-speed impactors

The paper examines the issues of mathematical modeling of ceramic armor panels’ penetration by high-speed cylindrical impactors. By means of the LS-DYNA software package, a corresponding numerical simulation methodology was developed by combining a chosen method, adjusted computational mesh cells size, appropriate Courant number, and values of linear and quadratic pseudo-viscosity coefficients. The results compared with experimental data show that Lagrangian and Eulerian numerical methods, unlike the SPH method (Smoothed Particle Hydrodynamics), improperly reproduce the process of the shock wave disintegration into an elastic precursor and a plastic wave. In addition, the common size of conical fractions dislodging from the ceramic plates was determined and the influence of the scale effect on the ceramics damage patterns was shown: an increase in the absolute value of the plate thickness leads to the increase in the dislodging cone semi-vertex angle.

A method of forming a spacecraft adapter layout to meet the requirements of dynamic compatibility by topological and parametric optimization methods

At present, the developers of launch vehicles impose a requirement for dynamic compatibility of the spacecraft with the launch vehicle, which consists in limiting the lower boundary of the first transverse and first longitudinal fundamental (primary) frequencies of the natural vibrations of the spacecraft fitted with an adapter of relatively rigid base. One of the tasks that must be solved in order to meet this requirement is the development of the spacecraft adapter layout. The traditional process of designing the adapter consists in developing its design on the basis of analogues and carrying out verification analysis with subsequent refinement of the design to meet the strength and stiffness requirements. However, this approach takes a lot of time and is not adaptable to constant changes in the input data at the initial design stage. The article presents a technique allowing the adapter layout to be quickly designed. The layout is determined to a greater extent by calculations using the topological and parametric optimization methods. The application of the developed technique is shown on the example of the development of an adapter for a promising spacecraft. It should be applied in the early stages of design. The results obtained by the method should be used as input data and recommendations for the design of the adapter.

Feasibility evaluation of using additive technologies in aerospace products

The paper studies the feasibility of using additive technologies in the manufacture of parts of complex shapes for aerospace products. The results of the structural analysis of a part helped find the directions of topological optimization and optimize the part’s design. To confirm the relevance of the design optimization, we carried out static and dynamic strength calculations in the Siemens NX software package. The paper considers technologies for manufacturing the part by 3D metal printing and traditional milling on a numerically controlled machine. In order to obtain initial data for economic calculations, we simulated manufacturing processes in various software systems. To study the feasibility of metal printing technology, we carried out its technical and economic analysis, and found that the production program, technological processing modes and the cost of materials affect the cost of the product.

Analysis of the trajectory of spacecraft return from the lunar surface to a given region of the Earth

The paper describes a method developed for designing the trajectory of a spacecraft flight from the lunar surface to a given area of the Earth’s surface and analyzes a single-pulse flight scheme, in which the trajectory of a take-off lunar rocket is approximated by a single velocity pulse. The characteristics of the spacecraft entry into the Earth’s atmosphere are chosen so as to ensure that the conditions along the entry corridor during the ballistic entry are met and to ensure the landing of the reentry vehicle at a given point on the Earth’s surface. The criterion for optimizing the trajectory of the spacecraft return to the Earth is considered to be the value of the impulse that provides the spacecraft launch from the lunar surface. The method relies on the analysis of an auxiliary problem, the solution of which makes it possible to estimate the main properties of the investigated maneuver and find an initial approximation for the selected characteristics of the optimized trajectory.

Investigation of UWB RF signal technology for solving indoor positioning problem

The article considers the process of developing a local positioning system using an ultra-wideband radio signal system and its integration with a strapdown inertial navigation system (SINS). A system based on Ultra-Wide Band (UWB) technology is used as a radio navigation system. An overview of the developed experimental integrated navigation system model is presented. Algorithms for calculating the position using the propagation time of the radio signal are used to obtain a navigation solution. An analysis of the accuracy of Single-Sided Two-Way Ranging and Double-Sided Two-Way Ranging algorithms using a UWB radio module is presented. The modeling errors of the inertial navigation system were performed. The maximum permissible parameters of the sensitive element errors were obtained for integration with the radio navigation system. The scheme of integration of the navigation solution of the UWB and SINS systems is determined.

Analysis of temperature measuring error in high-temperature ceramic samples with various methods of thermocouple fixing

The evaluation of methodological errors in measuring the temperature of nitride ceramics under unilateral heating by high-intensity heat flow was carried out. Simulation of thermal processes in the temperature sensor — sample system was performed using the Siemens PLMNX program. Various methods of fixing platinum-rhodium thermocouples with a diameter of 0.1 mm on the surface and inside the samples have been investigated. The regularities of the influence of the size of the hot junction, the presence of thermal cement, the shape of the grooves for fixing thermocouples on the methodological error of temperature measurement were investigated. Significant errors were revealed when installing thermocouples on the surface of the sample without violating its integrity. Recommendations for the installation of thermocouples were given. The results of the paper can be useful in the preparation of experimental samples for thermal tests on radiation heating stands.

Numerical study of the influence of the physicochemical liquid fuel properties on the efficiency of the low-thrust rocket engine working process

Low-thrust rocket engines are widely used in rocket and space technology for correcting the position of a spacecraft in orbit, for controlling motion along a trajectory, etc. Their number in the propulsion system can be from one to tens of units. Accordingly, the efficiency of their work significantly affects the perfection of the propulsion system as a whole. The object of the study was the low-thrust rocket engine combustion chamber operating according to the gas-liquid scheme. There were performed computational and parametric studies of various factor effects on the characteristics of the working process in the combustion chamber. The dependences of the coefficient of the consumable complex and parameters of the working process of the low-thrust rocket engine chamber on the influencing factors when using ethanol and kerosene as a fuel were calculated. A comparative analysis of the results of using these two components under similar conditions was carried out, which made it possible to reveal the influence of the physicochemical properties of the combustible component on the efficiency of the working process organization. The results obtained can be used in the design of low-thrust engines operating on the kerosene–oxygen and ethanol–oxygen propellants.

Low-orbit spacecraft for highly detailed observation with a long lifetime in working orbits with an altitude below four hundred kilometers

The paper analyzes mass-dimensional design parameters of the optical-electronic equipment for Earth’s remote sensing from heights in the range of 300...400 km. Within the research, we carried out the synthesis of a mirror-lens telescopic complex with an additional rotary mirror tilted to the optical axis of the main mirror and selected the design parameters from the conditions for ultra-high spatial resolution satellite images. Furthermore, we analyzed the mass-dimensional parameters of the spacecraft as a whole, the parameters allowing for the smaller effect of the Earth’s upper atmosphere on the evolution of the parameters of the working orbit. To maintain the radius of the low working orbit of the spacecraft for seven years, an electric propulsion system is proposed. To compensate for the aerodynamic drag force in the investigated range of heights and in any conditions of the upper atmosphere, a thrust force of no more than 18 milliNewtons is sufficient. The reserves of the mass of the working body for the operation of the electric propulsion system depend on the design-ballistic parameters of the spacecraft and the required lifetime in a given working orbit.

Application of precision chronometric technologies for monitoring deviations in the internal combustion engine operation

The article considers the main methods of internal combustion engine diagnostics. A method based on measuring the time intervals between the phases of the working cycle of the mechanism is described. An algorithm for measuring the time intervals from the formulation of the problem to the proof of the efficiency of this method on an internal combustion engine has been determined. The installation of the angle sensor on the crankshaft of the experimental bench engine VAZ 21126 is shown. The basis for the construction of a mathematical model of the crankshaft is presented and the main factors influencing its movement are identified. A criterion has been established according to which the misfire is determined most accurately. The results obtained can be used for developing diagnostic systems for internal combustion engines, as well as engines operating in extreme conditions, for example, beyond the Arctic Circle, on ships, etc.