VESTNIK of Samara University. Aerospace and Mechanical Engineering

The design of a vitamin space greenhouse for the Vitacycle-T space experiment on the Russian segment of the ISS is described. The preproduction model of Vitacycle-T successfully passed autonomous tests at the IMBP RAS in 2024. The total area of crops illuminated by LEDs in the vegetation module is 0.4 m², and its volume is 0.09 m³. The power consumption of the installation is about 870 watts. The average daily yield of cabbage leaves in the space greenhouse was 84 g, and the labor costs for the maintenance of the space experiment during ground tests did not exceed 5.5 minutes per day. The space greenhouse will be able to meet the needs of one astronaut in vitamins A and C. The test results allow us to consider the Vitacycle-T vitamin greenhouse as a promising element for future biological and technical life support systems for space crews.

Studies have been conducted on the influence of the following uncertain operational factors on the linear resolution of spacecraft for optical-electronic observation of the Earth’s surface: deviations from the nadir of the optical axis of the spacecraft observation equipment, the wavelength in the panchromatic spectrum, and the normalized spatial frequency of optical systems. It is shown that all these factors significantly affect the terrain linear resolution index. A methodology is proposed for design assessment of terrain linear resolution, taking into account uncertain operational factors that can be used to determine the probabilistic indicators of terrain linear resolution, namely, the probability of obtaining terrain linear resolution of not less than a given value, and the value of terrain linear resolution with a given probabilistic guarantee. It is shown that the type of distribution laws of the input quantities significantly affects the resulting laws of spacecraft terrain linear resolution, obtained by calculated dependence. In the area of small probabilities, the worst values of terrain linear resolution are obtained under the normal laws of input values, and in the area of medium and high probabilities, the worst values are obtained with uniform distributions. It is shown that the values of terrain linear resolution for spacecraft with a lens optical system are better than those with a mirror optical system, all other things being equal. For real optical systems, there are limitations on the range of operating spatial frequencies transmitted by the optical system that lead to the fact that the terrain linear resolution cannot be better than pixel resolution.

A conceptual design of an experimental demonstration model of three-layer structure of a launch vehicle body is proposed, based on the replacement of aluminum honeycomb filler with an energy-related material, in particular, based on composite solid rocket propellants. When energy-related material is burned under vacuum conditions, pyrolysis occurs in the experimental demonstration model material, including thermal destruction of the experimental demonstration model material. The efficiency criterion for the heat and mass exchange process during the energy-related material combustion inside the experimental demonstrator and, accordingly, the design concept of the experimental demonstrator, is the skin temperature. After the thermal destruction process is completed in the experimental demonstrator pyrolysis process, in accordance with the proposed concept of creating the experimental demonstrator aerodynamic loading is carried out to assess the degree of dispersion of the experimental demonstrator. The conducted numerical experiments showed the fundamental possibility of significant influence of the design concept of the experimental demonstrator on the skin temperature and, accordingly, an increase in the degree of thermal destruction of the skin material and the possibility of dispersion of the experimental demonstrator under aerodynamic influence. Comparisons were made with the results of physical modeling of burning the experimental demonstrator with specific energy material, which were close to the results of numerical experiments.

The article presents an algorithm for optimizing targeted operation of spacecraft by including in the planning algorithm the requirements for distinguishing consumers, clouds and dynamics of changing the priority of survey areas. The article also presents the results of statistical simulation of the developed algorithm and highlights the key conclusions necessary for the organization of work on the development of commercial remote sensing of the Earth from space, as well as the development of spacecraft based on constellations of small spacecraft.

One of the ways of improving the characteristics of technological and analytical equipment is an application of “smart” materials, among which dielectric elastomers are promising due to their low elastic modulus and its high effect of internal vibration protection. The article focuses on a theoretical analysis of the studied materials and identifies the key parameters that influence the dielectric elastomer actuator’s deformation, including the manufacturing technology, geometric parameters and composition of dielectric elastomers. A manufacturing technology of dielectric elastomer actuators was developed successfully. Samples with different thicknesses of the dielectric layer were made by the research group. The results of the research suggest dependence of deformation on the effective layer thickness.

An analysis of the existing mathematical models allowing thermogasdynamic calculations of gas turbine engines of various thermogasdynamic cycles is carried out. It was found that most models do not allow calculation with solid oxide fuel cells or in case methane is used as fuel, with subsequent production of hydrogen as a result of steam-water conversion. Therefore, a mathematical model of a solid oxide fuel cell has been developed that considers internal electrochemical reactions followed by the determination of the main electrochemical parameters with hydrogen used as fuel. Computational studies have been carried out on the basis of the developed mathematical model, and the results of evaluating its adequacy are presented that demonstrate a high correlation with the experimental data, which confirms the accuracy of the description of work processes and the applicability of the developed mathematical model of a solid oxide fuel cell. The developed mathematical model is implemented as a module in the DVIGwT software package. The application of the developed mathematical model of a solid oxide fuel cell and its software implementation will allow performing thermogasodynamic calculations of advanced schemes of gas turbine engines, including solid oxide fuel cells, and will also reduce time costs and technical risks when performing a large complex of design calculations.

One of the urgent tasks when establishing the endurance limits of steel is limiting the time of the experiment. The main purpose of this work is to compare several accelerated methods for determining the fatigue strength: the Locati method, the method of measuring electrical resistance and the calculation method taking into account the microstructures of steel. The study was carried out on 09G2S steel in the as-delivered condition which has a ferrite-pearlite structure. As a result of the comparison, it was found that the Locati method and the method for determining the fatigue strength of low-carbon and low-alloy steels give almost identical results. The method of measuring electrical resistance gives the range of stresses in which the desired fatigue strength is located. It is shown that the first sharp jump in the change in electrical resistivity of the sample may indicate the beginning of the stage of cyclic microflow or the beginning of irreversible softening of the steel. In addition, the method of measuring electrical resistance can be useful in combination with the Locati method, when there is no data on the slope of the left branch of the fatigue curve; then using this method it is possible to determine the interval in which 3 samples need to be tested to construct this branch.

An experimental method has been developed that makes it possible to obtain the kinematic parameters of a particle moving in an air stream, while colliding with the surface of an airfield. The experimental setup and methodology of the experiment are described, and the main results are presented in the form of the density and distribution function of the angles of incidence and reflection for the case of collision of granite particles with a fragment of an airfield slab. The obtained statistical characteristics are the initial data for modeling the process of ingress of foreign objects into the entrance to the power plant.