Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 124 journals)
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 Cosmic ResearchJournal Prestige (SJR): 0.246 Citation Impact (citeScore): 1Number of Followers: 5      Hybrid journal (It can contain Open Access articles) ISSN (Print) 1608-3075 - ISSN (Online) 0010-9525 Published by Springer-Verlag  [2467 journals]
• Analysis of Phases of Quasi-Biennial Variations of Cosmic-Ray Fluxes and
Solar-Activity and Interplanetary-Medium Parameters

Abstract: The phases of quasi-biennial variations (QBVs) in cosmic-ray fluxes and solar-activity and interplanetary-medium parameters are investigated. A spectral analysis of QBVs of listed data was carried out. For the data used, the spectral components with a maximum amplitude (the sinusoidal component with a period of about 1.7 years (about 20.5 months)) are identified. A comparison of phases of QBVs with the phases of these sinusoids in those time intervals, where the QBVs were reliably identified unambiguously, is performed. It is shown that, according to all data, the phases of quasi-biennial variations persisted for many decades with minor deviations. This testifies to the longitudinal stability of the regions on the Sun, which are responsible for a quasi-biennial variation.
PubDate: 2022-10-01

• Spectral Characteristics of Self-Emission from Electric Thrusters with

Abstract: We have considered procedure and results of the experimental study for spectral characteristics of self emission from laboratory models of electric thrusters with closed electron drift, with special reference to a thruster with an anode layer (TAL) and stationary plasma thruster (SPT), for a discharge power of 600, 800, and 1000 W, vertical and horizontal polarizations, and various propellants (krypton, xenon). The study allowed us to reveal a number of specific features of radio-frequency emission from thrusters with closed electron drift in the spectral domain. In particular, it was determined that the TAL has a broadband spectrum recorded in the frequency band from 1 to 4 GHz. Vertical polarization dominated in the studied modes, and the level of radio-frequency emission from TAL operating with krypton was 5–10 dB higher than in the case of its operation with xenon. In turn, the SPT has a broadband spectrum recorded in the frequency band from 1 to 3 GHz. Horizontal polarization slightly dominated in the studied modes. For the SPT, the maximum emission level excess in krypton operation compared to xenon was about 10 dB in the frequency range from 1 to 2 GHz for horizontal polarization. The results allow us to solve the problem of quantitative assessment for the effect of emission from thrusters with closed electron drift on the noise immunity of space communication systems.
PubDate: 2022-10-01

• Electrodynamic Control with Distributed Delay for AES Stabilization in an
Equatorial Orbit

Abstract: A satellite with an electrodynamic stabilization system is considered. To solve the problem of triaxial stabilization of an artificial satellite in an arbitrary position in the orbital coordinate system, the question is raised of the possibility of creating an electrodynamic control system for the angular motion of an artificial satellite according to the type of PID controller, which differs from the classical PID controller in that the restoring component of the control moment contains a distributed delay. A theorem concerning the asymptotic stability of the stabilized equilibrium position of an artificial satellite is proved, which confirms that it is possible to create the indicated system of electrodynamic control. The effectiveness of the proposed control system and the feasibility of its application for smoothing transient processes is confirmed by numerical simulation.
PubDate: 2022-10-01

• Dynamics of the Nightside Boundaries of the Auroral Oval during Magnetic
Storm on May 27–29, 2017

Abstract: Using the Meteor M2 low-orbit satellite, the dynamics of the boundaries of the auroral oval on the nightside during the magnetic storm observed from May 27 to 29, 2017, was studied. The dependence of the position of the boundaries during different phases of the storm on the state of the magnetosphere as well as interplanetary medium was studied. The experimentally obtained data on the boundaries of the auroral electron precipitation region were compared with data calculated using a statistical model developed independently and determining the position of the oval depending on the magnitude of the AL index. It was found that, during the initial phase of the storm, the main factor that influenced the further dynamics of the oval was a powerful prolonged pulse of solar wind pressure, which, in combination with a stable southward interplanetary magnetic field (IMF), led to compression of the magnetosphere and a decrease in the area of the polar cap and expansion of the equatorial oval boundaries. During the main and recovery phases of the storm, the solar wind pressure returned to prestorm levels, and the dynamics of the oval boundaries was associated with substorm activity and changes in the Bz components of the interplanetary magnetic field: the southward direction of the IMF during the main phase led to a shift of the oval to lower latitudes, and a gradual decrease in the modulus of the southward component caused a poleward shift of the oval in the recovery phase. It is shown that the polar boundary of the oval directly responds to changes in the solar wind, while the dynamics of the equatorial boundary contains features associated with geomagnetic activity and with the development of magnetospheric current systems indirectly controlled by the parameters of the interplanetary medium, in particular, by the intensity of large-scale convection.
PubDate: 2022-10-01

• The Dynamics of Arranging a Spacecraft Tether Group as a Triangular
Constellation

Abstract: The method of arranging a tether group of four spacecraft as triangular beam constellation is considered in this paper. The group consists of a central spacecraft, from which the tethers are released, and three small spacecraft (satellites). After arrangement, the group is a triangular beam symmetric constellation of spacecraft stabilized by rotation with a certain specified angular velocity. When arranging the group, it is proposed to use a combined control method, which consists in the joint use of low-thrust engines located on satellites and tether release devices that ensure their smooth braking at the final stage of system arrangement after the engines are turned off. To select the control laws for the arrangement of the system, a mathematical model of the plane motion of the system constructed using the Lagrange equations is developed and used. To check the feasibility of the proposed control laws, a more complete spatial mathematical model of the system motion is used, which takes into account the motion of the spacecraft and satellites relative to their centers of mass, the extensibility and one-sidedness of mechanical links (tethers), disturbances during separation of spacecraft, inaccuracy in knowing the initial angular velocity of rotation of the system before separation, etc.
PubDate: 2022-10-01

• Analysis of 630.0-nm Emission Sources in Auroras

Abstract: The role is considered of all known potential sources of excitation of the 1D term of atomic oxygen in auroras and the value of their relative contributions to the emission intensity of 630.0-nm emission in the height interval of 100−300 km. The main attention is paid to the role of weak excitation sources of 1D terms, such as collisional interactions between the components of atmospheric gases N(2D) + O, N(2D) + O2,N(2P) + O2, and N+ + O2; direct electron impact O2 + e*; and the radiative transition O(1S) → O(1D) + hν557.7. It is shown that, despite the small partial contributions of these sources to the intensity of the 630.0-nm emission, their total contribution can be quite significant. The total efficiency of these sources varies from 66 to 6% with an increase in altitude from 100 to 300 km and is significant at altitudes below 200 km. It is shown that the influence of the decontamination process $${\text{O}}_{{\text{2}}}^{ + } + {\text{NO}}$$ leads to the fact that, in the region of heights of ∼110−150 km, the set of reactions of collisional interactions of ionospheric plasma components N(2D) + O, N(2D) + O2,N(2P) + O2, and N+ + O2 becomes the second most efficient source contributing to the intensity of the 630.0-nm emission.
PubDate: 2022-10-01

• An Algorithm for Safe Landing of a Spacecraft during Descent from a
Circumlunar Orbit

Abstract: The problem of safe landing of a spacecraft with a combined propulsion system from a circumlunar orbit to a given place on the lunar surface is considered. Landing safety is ensured by the implementation of restrictions on the motion parameters at the time of landing, as well as the possibility of horizontal displacement of the spacecraft relative to the lunar surface to correct the landing place, taking into account the slope, the absence of large stones, and deep pits. The descent-control algorithm uses the solution to the free fall‑braking model problem. The proportional guidance algorithm is used to correct the landing place. Adaptation to the actual magnitude of the apparent acceleration is carried out. Statistical tests have shown the efficiency of the algorithm, an estimate of the accuracy of lending and propellant consumption has been obtained, taking into account all restrictions on the operation of the propulsion system under the conditions of a safe lunar landing.
PubDate: 2022-10-01

• The Second Stage of BTN Neutron Space Experiment onboard the Russian
Section of the International Space Station: the BTN-M2 Instrument

Abstract: As recent studies onboard various spacecraft have shown, one unresolved technical problem of manned interplanetary flights at the moment is the high radiation background of interplanetary space, which, as in the case of a manned mission to Mars, can be critically dangerous for the crew. Work on this topic is being carried out by all space agencies. One such space experiment is represented by the BTN-Neutron experiment onboard the Russian section of the International Space Station (ISS). The main result of the work was the construction of the BTN-M2 instrument for creating effective radiation protection onboard prospective manned spacecraft, creating an engineering model of the radiation background both inside and outside the ISS, and for registration of γ rays and neutrons during solar flares and cosmic γ-ray bursts.
PubDate: 2022-10-01

• Features of the Motion of the Earth’s Geographic North Pole and Jumping
in the Geomagnetic Field

Abstract: The results of an analysis and comparison of times of appearance of the features of the long-term displacement of the geographic North Pole over the Earth’s surface and the components of the angular momentum of the atmosphere and global jumps in the geomagnetic field are presented. The calculations used long-term data on the motion of the geographic North Pole with intervals between readings of 0.05 years, data on the components of the angular momentum of the atmosphere, and information on the appearance of global jumps observed at all magnetic observatories of the globe. The following methods were used in the study: wavelet analysis, approximation of nonlinear trends by smooth functions, and two-channel spectral analysis. Based on the results of the analysis, a conclusion was drawn about a possible connection between the features in the nonlinear trends of the motion of the geographic North Pole over the Earth’s surface and the components of the angular momentum of the atmosphere, as well as global jumps in the secular variations of the geomagnetic field in the interval of 1964–1980 with global energy rearrangements in the adjacent shells of the Earth’s system. Coherence was established between variations with a period of 35.3 years in data on the variation in the position of the North Pole relative to the conditional beginning and in data on the variation in the dipole moment. The possibility of the process of their synchronization with an advance of 6 years of fluctuations in data on the variation in the dipole moment is allowed.
PubDate: 2022-08-01
DOI: 10.1134/S0010952522040086

• Features of the Artificial Injection of Energetic Electrons from the
Earth’s Radiation Belt into the Midlatitude Ionosphere and Their
Dependence on Geophysical Conditions

Abstract: — This paper presents the results of studies of the features of the injection of energetic electrons from the Earth’s radiation belt into the midlatitude ionosphere when the F2 region of the ionosphere is modified by powerful HF radio waves emitted by the SURA heating facility. The measurements discussed in this paper were performed in 2019 using low-orbit (h ≈ 850 km) NOAA-series satellites in the electron-energy range of 40–612 keV. The measurements were carried out in various geophysical conditions both above the SURA facility and in the magnetically conjugated ionosphere. In comparison with the previously obtained data from the DEMETER satellite, the performed studies made it possible to establish that, in a magnetic-flux tube with L ≈ 2.7, the most effective stimulation of the injection of energetic electrons takes place in the late evening and night hours, while the lower effective takes place in daytime conditions. The intensity of injection strongly depends on the degree of filling the radiation belt with energetic electrons. The energy introduced into the ionosphere by the injected energetic electrons is estimated. Examples of their possible influence on both generation of artificial ionospheric turbulence and atmospheric processes are given.
PubDate: 2022-08-01
DOI: 10.1134/S0010952522040049

• Times of Existence of Technogenic Microparticles Injected into Near-Earth
Space in a Geostationary Orbit

Abstract: Based on results of numerical modeling, this paper shows for the first time the possibility of a long-term orbital existence of technogenic aluminum-oxide particles separating from the surface of an active geostationary satellite or a “debris” object “buried” in the vicinity of a geostationary orbit. It is shown that, under the conditions of low solar and geomagnetic activity, particles with radii exceeding a threshold value close to 1.1 μm have long orbital times of existence (more than 1 month). The times of orbital existence of technogenic particles with radii greater than the indicated threshold value virtually do not depend on the initial position of an injection point in a geostationary orbit and grow rapidly with increasing radius of a technogenic particle. So, the time of orbital existence of a particle with a radius of 3 μm is equal to 130 days, while for a particle with radius of 3.52 μm, this time is more than 2 years (!). The results of numerical experiments have shown that, under conditions of low solar and geomagnetic activity, submicron technogenic particles with radii less than 0.1 μm can also have long orbital existence times. The analysis of calculated data has shown that the long-lived particles with radii in the range from 0.01 to 0.1 μm have moved in the so-called “Keplerian” mode of motion. In addition, the possibility of long-term (more than 2 years) orbital existence of ultrasmall technogenic particles with radii less than 0.01 μm injected in a geostationary orbit was demonstrated. The analysis has shown that, in this case, the technogenic particle has moved in the “so-called magnetic–gravitational capture mode.”
PubDate: 2022-08-01
DOI: 10.1134/S0010952522040050

• Analysis of Fast Variations in Electron Fluxes in the Gap Region Using the
Normalized Range Method Based on Measurement Data on the SiriusSat-1
Satellite

Abstract: The use of the normalized range method for an analysis of the fast variability of electron fluxes in near-Earth space is proposed. This method makes it possible to conclude whether a uniform time series corresponds to a random process, or whether there are memory effects or excessive variability. This study analyzes the SiriusSat experiment data. We used data on the time of each particle interaction in the detector with an accuracy of ~20 μs, which makes it possible to study variations in electron fluxes of subrelativistic energies on subsecond time scales. In some cases, the value of the Hurst exponent indicates excessive flux variability in the gap region ( $$L\sim 2.3$$ ) east of the South Atlantic anomaly at characteristic times of 0.6–0.9 s.
PubDate: 2022-08-01
DOI: 10.1134/S0010952522040062

• Nuclear Defense Against Kilometer-Long Asteroids

Abstract: The possibility of correcting the trajectory of kilometer-long chondrite asteroids threatening the Earth with the help of nuclear explosions in near-Earth and distant outer space is assessed. It is shown that to put such asteroids on a safe trajectory requires nuclear explosions with a power of more than 100 Mt at distances of more than 100 million km from the Earth. It is also shown that at the found power it is impossible to preserve the integrity of kilometer-long asteroids because of their fragmentation. The latter circumstance makes the task of correcting the trajectories of such asteroids using nuclear explosions difficult to achieve because of the difficulties in predicting the trajectories of the fragments formed.
PubDate: 2022-08-01
DOI: 10.1134/S0010952522040025

• A Physical and Mathematical Model of the Pressure Dynamics of Residue Gas
inside a Nonpressurized Instrument Compartment of a High-Orbital
Spacecraft

Abstract: This paper presents a physical and mathematical model and the results of evaluation calculations of the process of gas release from structural materials located inside a nonpressurized instrument compartment (NPIC) of a high-orbital spacecraft. Also presented is a model of the dynamics of the pressure drop of the residual gas inside the NPIC, after passing through the active phase of the flight and entering the calculated orbit. It is shown that the main reason for the significant (2–3 week) duration of the process of gas-pressure reduction of an NPIC to a value that allows the inclusion of high-frequency and -voltage equipment is the process of gas evolution from structural and paintwork materials located inside the NPIC. The intensity of outgassing, in turn, depends on the diffusion processes of outgassing substances within the materials themselves. An analysis of the influence of the geometry of the ventilation openings on the duration of the decrease in pressure inside the NPIC to the required level indicated the insignificance of this influence. The physical and mathematical models presented in the paper make it possible to estimate the characteristic time for reducing the pressure inside the NPIC to the required level and, thereby, select the materials inside the NPIC in order to reduce the period of reaching the allowable pressure inside the NPIC.
PubDate: 2022-08-01
DOI: 10.1134/S0010952522040037

• Deep Structure of the Arctic and Antarctic according to Component Magnetic
and Gravitational Anomalies

Abstract: The results of a study of the deep structure of the Earth’s polar regions based on the interpretation of gravitational anomalies, geomagnetic-field anomalies, and seismological data are presented. Based on measurements on the CHAMP and Swarm satellites, vector models of the magnetic field of the Arctic and Antarctic have been verified. To study the magnetically active zones and roots of the lithosphere observed in near-Earth space, deep sections were constructed. Density sections were obtained from gravitational anomalies, and magnetic sections were obtained from anomalies in the modulus and components of the geomagnetic field. To estimate climate risks, a joint analysis of deep sections with satellite data on variations in the ice cover of the polar regions was carried out. It showed that vertical thermofluid channels play a significant role in the process of ice melting. Distinctive features of melting centers caused by endogenous factors are revealed. The migration paths of fluid flows destroying the ice cover are visualized in sections in the form of channels with reduced magnetic and density properties. The conducted studies allows to understand the possible reasons for the localization of centers of ice and permafrost destruction. It was shown that in the permafrost zones of ancient basement blocks, thermal areas of through taliks arise under the influence of heat flows of fluid-supply channels. Melting areas can be represented by hot spots of ore clusters, within which mineral deposits are concentrated under the influence of hydrothermal flows of mineralized fluids. Studies of the deep structure of the Arctic and Antarctic are of scientific and applied importance for solving exploratory geological and geophysical problems and estimating climate risks.
PubDate: 2022-08-01
DOI: 10.1134/S0010952522030078

• Erratum to: A Flight of the Proton-M Launch Vehicle Carrying the Yamal-601
Satellite: Optical Effects Observed in a Distant Zone of the Launch Site

Abstract: An Erratum to this paper has been published: https://doi.org/10.1134/S0010952522130020
PubDate: 2022-06-01
DOI: 10.1134/S0010952522130020

• Erratum to: Periodic Approximation of the Rotational Motion of the
Photon-12 Satellite

Abstract: An Erratum to this paper has been published: https://doi.org/10.1134/S0010952522130019
PubDate: 2022-06-01
DOI: 10.1134/S0010952522130019

• A Method for Assessing the Robustness of the Autonomous Navigation System
of a Spacecraft Based on the Theory of Experiment Planning

Abstract: A method for estimating the robustness of an autonomous spacecraft navigation system to the impact of perturbing factors of various physical nature is proposed. The methodology is based on the methodology of G. Taguti and the theory of experiment planning, in accordance with which the calculated ratios are obtained for estimating the robustness of the autonomous navigation system of a spacecraft to various perturbations of the orbital flight. The adequacy of the methodology is confirmed by the example of an autonomous spacecraft navigation system, including on-board optical-electronic, radio engineering and computing facilities. The proposed technique is universal and can be applied to navigation systems of other moving objects.
PubDate: 2022-06-01
DOI: 10.1134/S0010952522030030

• Analysis of Trajectories of Spacecraft Launching into High Circular Orbits
of the Moon Artificial Satellite

Abstract: The launch of a spacecraft into the stable, high polar orbits of a Moon artificial satellite is considered. These orbits can be used to construct a lunar multifunctional satellite system, as well as a near-Moon orbital spaceport. Analysis and comparison of three schemes of direct spacecraft transfer from the Earth to the Moon—with a one-, two-. and three-impulse maneuver of transition into the final orbit—are performed. In particular, the energy, geometrical, and temporal characteristics of a two-impulse transfer obtained under significant influence of gravitational perturbations are compared with their one- and three-impulse analogues.
PubDate: 2022-06-01
DOI: 10.1134/S0010952522030042

• The Method of Determination of the Gravitational Field Model of an
Asteroid Using a Group of Small Spacecrafts

Abstract: This paper proposes a method for determining the parameters of the gravitational field of an asteroid using a group of spacecrafts. The gravitational field of an asteroid is described by the model of spherical harmonics and is characterized by the Stokes coefficients and the gravitational parameter of the body. The group of vehicles consists of the chief and deputy spacecrafts. The observed measurements are of the distance and radial velocity between the chief and each deputy vehicle. The proposed method is applied to the already studied asteroids Eros and Itokawa. The accuracy of the gravitational field parameters determination depends on errors of observed measurements. The possibility of improving the parameters accuracy by increasing the number of deputy satellites in the group is investigated.
PubDate: 2022-06-01
DOI: 10.1134/S0010952522030091

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