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Vol 63, No 5 (2025)
Articles
Bayesian meteor reconstruction using the PAIP-V data
Abstract
The paper considers the reconstruction problem of events registered by orbital and ground-based detectors with low angular but high temporal resolution. It is shown that in such a situation it is still possible to obtain highly accurate spatiotemporal reconstruction if one combines information on both the geometry and kinematics of the motion and its dynamics (luminescence curve) within a single algorithm. This is especially important in the presence of multiple structural gaps between photodetector channels when only a portion of the event is recorded. In this paper, a Bayesian method implemented by means of the PyMC library is proposed for the reconstruction of track events (tracks of meteors, satellites, etc.): the parametric model takes into account both the features of the event itself and the process of its registration, and the posterior distribution of the parameters is constructed using MCMC sampling. The method is tested on the example of a small sample of meteors of the Geminid-2022 meteor shower recorded by the PAIP-V ground-based detector installed in the Murmansk region.
453-470
Methods of a satellite formation orbital motion control based on consensus algorithms
Abstract
Methods for synthesizing control of the relative motion of a group of spacecraft are considered. The main goal is to develop a control strategy that compensates for the disintegration of the group caused by relative orbital drift. The control design employs techniques based on various types of graphs to describe satellite interactions. A proof is provided demonstrating the feasibility of eliminating relative satellite drift using a method based on directed graphs. The resulting algorithm is adapted to scenarios where one or more spacecraft in the group may malfunction. To derive the control in such cases, a modified version of the Raft protocol for achieving consensus in multi-agent systems is used. In addition to analytical derivations and the general methodology, the work presents results from numerical simulations.
471-481
Analysis of low-thrust satellite tour strategy in the Jupiter system
Abstract
A new method for designing a Tisserand graph with low-thrust between gravity assists is proposed. The motion of a spacecraft is considered in the context of the circular restricted three-body problem and the zero-radius sphere of influence model, based on conjugate conic sections. Simple control algorithms for changing the semi-major axis and eccentricity are used for low-thrust maneuvers. The analysis of the proposed control algorithms is carried out. The effectiveness of the proposed technique is shown. Examples of effective low-thrust spacecraft maneuvering strategies in the Jupiter satellite system for transfer to the orbits of Europa, Ganymede, and Calisto have been obtained.
482-500
Time of Flight Estimation in Low-thrust Transfers Between Asteroids Using Deep Neural Networks
Abstract
This paper focuses on optimizing the transfer time for multiple asteroid rendezvous missions utilizing low-thrust propulsion. An indirect method based on Pontryagin’s maximum principle is employed to generate training data by optimizing low-thrust trajectories for minimal time of flight. A deep neural network (DNN) is subsequently trained to estimate the minimum time of flight (TOF) between each pair of asteroids. To enhance the accuracy of predictions for rapid transfers (less than 150 days), the dataset is augmented with additional trajectory simulations. Leveraging the trained neural network, a Beam Search (BS) algorithm is implemented to efficiently determine the fastest sequence of rendezvous with multiple asteroids, starting from an arbitrary initial asteroid. The results demonstrate that an optimal rendezvous sequence involving 15 asteroids is achieved, with an average time of flight of 107.5 days per segment.
501-514
Providing a special thermal environment of the ART-XC mirror X-ray telescope as a necessary condition for obtaining significant scientific results
Abstract
The article presents the main significant scientific results obtained by the first Russian reflecting X-ray telescope ART-XC named M.N. Pavlinsky. This telescope has been operating as part of the observatory Spektr-RG since 2019. It is shown that the prerequisite for obtaining these results was to maintain a special thermal regime of telescope components with high accuracy and stability. The problems of telescope thermal control are presented. The engineering solutions and control algorithms that allowed solving these problems in ART-XC are described. Experimental, including flight data, illustrating the implementation of these solutions are presented. Recommendations on thermal control systems for similar telescopes are given.
515-530
Orbiting dumbbell with a variable mass distribution: dynamics and control
Abstract
The plane orbital motion of a dumbbell-shaped body of variable length in the central field of attraction is considered. It is assumed that the mass of the dumbbell is concentrated at its end points. The attitude motion is considered Within the so-called satellite approximation, when the center of mass of the dumbbell moves in an unperturbed elliptical Keplerian orbit. The laws of changing the length of the dumbbell have been found, which make it possible to implement certain prescribed classes of its motion around the center of mass. In the general case, the chaotic nature of motion is detected numerically using the Poincare map for the period.
531-540
On the additivity of changes in optical properties during simultaneous and separate irradiation of ZnO powder modified with SiO2 nanoparticles by protons and quanta of the solar spectrum
Abstract
The results of a study of the spectra of diffuse reflection (ρλ) and integral absorption coefficient (as) of ZnO powders, used as one of the best pigments for temperature-control coatings of spacecraft, are presented. To increase the photo- and radiation resistance of micron-sized mZnO powder, one of the effective methods was used – modification with nSiO2 silicon dioxide nanoparticles. The change in the optical properties of the modified mZnO/nSiO2 powder was studied under separate and simultaneous irradiation with protons with an energy of 5 keV and solar spectrum quanta (SSP) with an intensity three times higher than the solar one. The ρλ spectra were recorded after each irradiation period in a vacuum at the irradiation site (in situ), which made it possible to avoid the interaction of defects formed during irradiation with atmospheric gases. Calculations were carried out for the additivity coefficient, determined by the ratio of the sum of changes in the absorption coefficient as under separate irradiation to changes under simultaneous exposure to radiation. It was found that, depending on the irradiation time, it varies from 1.30 to 1.39. The results of the study allow us to conclude that if in outer space the pigment is simultaneously affected by protons of the Solar wind and SSP, then ground-based tests must be carried out with their simultaneous action. If tests are carried out under separate irradiation, then in order to obtain reliable changes in the performance characteristics of the pigment it is necessary to introduce coefficients that take into account synergistic effects – additivity coefficients.
541-550
The results of experimental studies conducted in 2018-2023 in the framework of the SURA-CSES program
Abstract
The results of experiments conducted in 2018–2023 to study the characteristics of plasma perturbations, that were generated in the Earth’s outer ionosphere when ionospheric F2 layer was modified by powerful HF radio waves radiated by the mid-latitude SURA heating facility, are discussed. Measurements were taken during the daytime and evening (night) hours at low and high levels of solar activity. Plasma perturbations were registered by the onboard instruments of the Chinese low-orbit satellite CSES (ZH-1) both above the SURA heating facility and in the magnetically conjugate ionosphere. The characteristics of a powerful radio wave penetrating into the outer ionosphere, the influence of ionospheric disturbances of natural and artificial origins on the propagation of a powerful radio wave through the ionosphere, the conditions of VLF radio wave generation due to nonlinear demodulation of a powerful radio wave, etc. were studied. In the paper, it is considered the influence of the main ionospheric trough on the development of interaction of powerful HF radio waves with the ionospheric plasma and on the generation of artificial ionospheric turbulence in the trough.
551-576