Vol 24, No 1 (2023)

A method for designing low-energy trajectory of transfer to the Moon with the insertion of a spacecraft into a low circumlunar orbit is proposed. The analysis of this trajectory is based on the solution of a boundary value problem for the system of differential equations of the restricted four-body problem. The trajectory of the low-energy flight passes through a region of space where the gravitational attraction of the Earth, the Moon, and the Sun tend to cancel. The trajectory turns out to be very sensitive to the initial conditions of the spacecraft motion. Difficulties arise in solving the boundary value problem. Weak stability boundary issue appears. An additional difficulty in designing the trajectory of a low-energy transfer of a spacecraft is related to the multi-extremality of the optimization problem under consideration. The authors assume that the transfer trajectory passes in the vicinity of the libration point L1 or L2 of the Earth - Moon system and introduces some restrictions on the velocity vector of the spacecraft at the moment the spacecraft passes the vicinity of the libration point. This assumption and the use of enumeration in space of the two main parameters of the transfer pattern allows to find an initial approximation for the low-energy transfer trajectory.

The authors present the results of modeling the temperature drift of the resonator path length of a laser gyroscope based on a ring helium-neon laser with circular polarization of radiation and a magneto-optical frequency bias based on the Zeeman effect using the MATLAB mathematical package. The algorithm developed and implemented in the MATLAB environment makes it possible to simulate temperature deformations of the path length of a Zeeman laser gyroscope when the configuration of its structural elements changes. This allows to evaluate the quality of the supplied material for the manufacture of the ring laser resonator, as well as to evaluate the total contribution of structural elements to the resulting drift of the perimeter of the Zeeman gyroscope. The model obtained in the work is an analytical tool for additional quality control of the optical glass-ceramic SO-115M, from which the resonator is made, and optimization of the design of the Zeeman laser gyroscope, both locally and comprehensively. This is necessary to increase the efficiency of ring laser perimeter stabilization in the operating temperature range using an active perimeter adjustment system and passive thermal compensation by selecting structural elements with opposite temperature coefficients of linear expansion. The use of the developed model in the production of laser gyroscopes permits to select the structural elements of the Zeeman gyroscope, which significantly increases the time of its continuous operation in a single-mode in a wide temperature range while maintaining the re-quired accuracy for the orientation, stabilization and navigation systems of various aircraft.

Along with the rapid growth of fuel prices, the increase of car fleet in the world, including Russia, has focused on reducing fuel consumption by vehicles. One of the ways that can reduce the consumption of hydrocarbon fuels is to use vehicles with an electromechanical powertrain. The energy source for such vehicles is both an internal combustion engine and an electric motor. The results of a study of fuel consumption by a hybrid vehicle with various control algorithms are presented. The methods of mathematical and simulation modeling were used. Fuel consumption data is given when using various algorithms for turning on the gasoline internal combustion engine, depending on the vehicle speed. As a result of simulation modeling, it was found that in order to ensure the greatest fuel economy, it is necessary that the gasoline engine starts when the car reaches a speed of at least 60 km/h, then fuel consumption in the urban driving cycle is reduced by 50% compared to the gasoline engine start mode at a speed of 30 km/h.

In order to recognize and characterize the sources rocks in the BX well, samples of this well have been selected and analysed using Rock-Eval pyrolysis method and another set samples were prepared and observed through microscope for visual kerogen characterisation. The total organic carbon of BX well sediments varies between 0.41 and 3.41 wt%, with 1.29 wt% on average. These high values indicate good organic matter content in this well. The hydrogen index (HI) of the studied samples ranges from 49 to 292 mgHC/gTOC, with an average of 109 mgHC/gTOC, indicating mainly a type III kerogen. This kerogen is composed of humic material (vitrinite and inertinite) and amorphous organic matter with marine microfossils (dinoflagellate cysts and micro-foraminiferal linings). Thermal maturity parameters show that, Maastrichtian, Campanian, Early Senonian and Turonian are immature with T_max values below 435 °C. However, according to T_max values, samples reach oil window in Albian at 9840 ft while spore colour index indicate that this limit can be put at 9210 ft into Cenomanian age. The section from 7260 to 7590 ft in Campanian interval displays the best qualities of source rock. This section is composed of good quantity of type III and type II/III kerogen with moderate hydrocarbon potential, but this source rock is immature to generate hydrocarbons.

Porphyry copper deposits are accompanied by extensive aureoles of hydrothermally altered rocks which make it possible to detect them on satellite images in the absence of vegetation. The study is devoted to using the Earth’s remote sensing data, particularly, satellite images from the Japanese sensor ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer), which are used to identify areas that are promising for the discovery of porphyry copper deposits and ore occurrences within the copper belt of Kazakhstan. The analysis of numerous publications that offer various methods for processing ASTER images for the interpretation of hydrothermally altered rocks accompanying porphyry copper occurrences showed that the most effective method for this region is the Crosta technique. The Crosta technique, unlike other methods, does not use primary bands, but their combinations are obtained by the principal components analysis method. Thus, the combination of the results of the principal components analysis with the use of index images and analysis of the geological map made it possible to identify areas of hydrothermally altered rocks in the study area. The described technique helps to predict promising areas for porphyry copper mineralization of varying degrees of reliability, associated with their hydrothermal processing.