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Abstract: In 2016–2017, dosimetric studies were carried out on the Lomonosov satellite of the radiation environment in a circular orbit with an altitude of about 500 km and an inclination of 98°. The studies were carried out using a DEPRON device, in which two semiconductor detectors were located behind shielding of 0.54 and 0.81 g/cm2 of aluminum. The planetary distribution of the radiation absorbed dose rate at the altitude of the Lomonosov was obtained, which was separated into four characteristic regions: the zone of low and middle latitudes, the zone of the South Atlantic anomaly, the zone of the outer radiation belt of the Earth, and the high-latitude zone of the polar caps. The average daily values of the dose rates measured during the day in each of these areas have been determined. The strongest variations (up to an order of magnitude) are experienced by the daily dose in the outer zone. The existence of the relationship between dose-rate variations in the outer belt and the level of geomagnetic disturbance was confirmed. PubDate: 2022-04-01
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Abstract: The results of repeated processing of magnetic measurements carried out on the Photon-12 satellite (which was in orbit from September 9 to 24, 1999) are described. The processing was performed in order to reconstruct the uncontrolled rotational motion of this satellite. In re-processing, the simplified mathematical model of rotational motion was used. The actual orbit of a satellite (the apogee height is 380 km, the perigee height is 220 km) is replaced by a circular orbit; the expression for the aerodynamic moment acting on a satellite is simplified. The system of differential equations underlying the new model is autonomous and proved to be sufficiently accurate to reconstruct the satellite motion based on magnetic measurements in the case in which the satellite angular velocity was not very low and grew gradually. In the last third of the flight, when the satellite motion became virtually stable and had a sufficiently high angular velocity, this system could be reduced to a generalized-conservative system. Such a reduction makes more definite the set of its solutions suitable for approximate description of the actual motion of a satellite. In some segments of motion, the combining of which covers about 3 days, it was possible to use, for this purpose, the periodic solutions continued from the Lyapunov periodic solutions. PubDate: 2022-04-01
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Abstract: This study is devoted to the possibility of creating artificial halo orbits in the circular restricted three-body problem of the Earth–Moon system due to the small acceleration from low-thrust engines acting on a spacecraft for a long time in situations, where the natural halo orbit cannot meet the mission requirements or is busy. In this paper, using collocation and parameter-continuation methods, two classes of artificial halo orbits in the Earth–Moon system are obtained. The first class is generated due to additional constant in magnitude and direction acceleration. A complete family of orbits of this class was obtained, which significantly differ from the traditional ones in terms of period and shape. The second class of orbits is generated by variable electric propulsion. This class of orbits was obtained as a solution to the problem of the optimal consumption of the working substance for orbit formation with a given period using the Pontryagin maximum principle and the method of continuation in parameter. It was shown that there are significant differences in orbital periods between artificial halo orbits—descendants of the same halo orbit. The calculation results confirm the possibility of using low-thrust engines to vary the parameters of natural halo orbits suitable for ballistic design of future lunar missions. PubDate: 2022-04-01
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Abstract: In extreme events of space weather, very large fluxes of “storm” particles are formed preceding the arrival of a shock wave into the Earth’s orbit. They are the ones that pose the greatest danger to life-support systems in the upper atmosphere, in space, and on the Earth. The results have been checked of the prediction of “storm” particles accelerated by shock waves from variations in high-energy cosmic rays by measurements on the ACE spacecraft (United States). The forecast reliability is assessed at P ≥ 80%. PubDate: 2022-04-01
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Abstract: The irradiation of surfaces of high-altitude levels from the upper troposphere to the lower mesosphere is considered. Previously not performed calculations of the characteristics of transit irradiation of latitudinal zones of surfaces in tropical years and their parts from 3000 BCE to 2999 CE have been carried out. Energy characteristics (J) are calculated for all years and specific energy characteristics (J/m2) are calculated as average of many years and for individual years. For each pair (latitudinal zone and part of the tropical year), the specific entering (through this zone into a body bounded by the surface) transit energy, the specific outgoing (from a body bounded by the surface) transit energy and their difference (balance) are calculated. For the whole surface, the balance for any period of time is equal to zero (in the absence of the atmosphere); for the half-surface and 5° latitude zone in the presence of transit irradiation, the balance is nonzero. On the surfaces of all altitude levels, the most significant spread between the balances for 5° zones is noted among the semiannual balances in the polar regions. For 5° zones of each semisurface from the equator to the pole in the summer half of the year, the semiannual balance to the 65th parallel is negative, then positive, and vice versa in the winter half of the year. The semiannual balance for the semisurface in the summer half of the year is positive and negative in the winter half of the year at all altitude levels. In the considered range of years, the modulus of the semiannual balance for the semisurface decreases in both summer and winter halves of the year. PubDate: 2022-04-01
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Abstract: This paper presents typical examples of the appearance of singular points in the proximity of optimal trajectories in different interorbital low-thrust missions. As a rule, the occurrence of singular points is accompanied by the appearance of computational difficulties in solving boundary-value problems. PubDate: 2022-04-01
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Abstract: Based on the OMNI2 database for the period from 1976 to 2019, the behavior of the relative abundance of helium ions Nα/Np is investigated inside interplanetary coronal mass ejections (ICMEs). It is shown that the previously discovered anticorrelation between Nα/Np and the parameter β inside ICMEs is due to the dependence on magnetic pressure (or the magnitude of the interplanetary magnetic field), while the dependence of Nα/Np on the magnitude of the thermal pressure weakly falling in a magnetic cloud and increases in EJECTA. The data obtained are consistent with the previously suggested hypothesis that an electric current enriched with helium ions flows inside an ICME [1–3]. PubDate: 2022-04-01
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Abstract: In this paper, we consider disturbances in the airglow of the Earth’s upper atmosphere caused by a launch of the Yamal-601 satellite on May 30, 2019. For this purpose, we used the data acquired with an optical system of the Institute of Solar−Terrestrial Physics, Siberian Branch, Russian Academy of Sciences (ISTP SB RAS). The measurements were carried out at the Geophysical Observatory (GPO) of the ISTP SB RAS (~52° N, ~103° E) with a complex of optical instruments—a whole-sky camera, a spectrograph, and a Fabry–Pérot interferometer. According to the data of the KЕО Sentinel camera, an extensive area of airglow was observed along the flightpath; it appeared approximately 2−4 min after the spacecraft’s passage over the GPO and existed for ~20 min. A transversal scale of the spacecraft’s flightpath is estimated approximately as 95–110 km if the spontaneous-emission altitude is assumed to be at ~150 km (and it is about 190–220 km if the spontaneous-emission altitude is ~300 km). We discuss the mechanisms that may result in forming the observed area of airglow, including the mechanisms connected with the physical and chemical interaction of fuel products with atmospheric components and the influence of propagation of a shock wave or short-period internal gravitational waves. Probable causes of the delay observed in appearing the airglow after the spacecraft’s flyby are analyzed. PubDate: 2022-04-01
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Abstract: Calculations were made of the volume and integral emission intensities of the Lyman–Birge–Hopfield (LBH) bands of molecular nitrogen at 146.4, 138.4, 135.4, and 132.5 nm in the upper atmosphere of Titan during the precipitation of electrons with energies of 30–1000 eV from the magnetosphere of Saturn, taking into account the kinetic processes for singlet excited states of N2 molecules. Calculations showed that the ratios of the calculated integral emission intensities of the LBH bands to the emission intensity of the 337-nm band of the second positive system for the entire interval of the considered energies of magnetospheric electrons take on constant values. The results obtained are in good agreement with the calculations performed for auroral electrons precipitating into the Earth’s polar ionosphere. PubDate: 2022-02-01 DOI: 10.1134/S0010952522010051
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Abstract: The technology of guiding scientific equipment to objects under study using a steerable platform onboard the Russian segment of the International Space Station (ISS) is presented. The problem of optimizing the guidance of scientific equipment using several guidance platforms that will be delivered to the ISS is discussed, and ways of solving it based on the analogy with the problem of several traveling salesmen are proposed. PubDate: 2022-02-01 DOI: 10.1134/S0010952522010014
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Abstract: Features of the implementation of a beam-pulse amplifier (BPA) of whistler waves in magnetospheriс enhanced and depleted ducts with refraction reflection are considered. Extended along the magnetic field, ducts with a width of about 100–300 km often occur after magnetic disturbances in the morning and daytime magnetospheres beyond the plasmapause, where the excitation of chorus emissions occurs under the same conditions. The dispersion characteristics of whistler emissions in a planar duct are analyzed under the conditions of the Wentzel–Kramers–Brillouin (WKB) approximation and refractive reflection from the “walls.” For enhanced (depleted) ducts, it is shown that, for the first ten modes at frequencies below (above) half of the electron-cyclotron frequency, the conditions for exciting discrete spectral elements with wave normal angles to the magnetic field less than 20° can be satisfied. The magnitude of the amplification of noise pulses with the indicated angles of the wave normal is only 20% less than in homogeneous plasma at an optimal angle of about 39°. The proposed model explains the possibility of excitation of chorus emissions with relatively small angles of the wave normal by means of the BPA mechanism. It was found that both the intensities and the typical angles of the wave normal can differ significantly in the lower and upper bands of excitation of the choruses. PubDate: 2022-02-01 DOI: 10.1134/S0010952522010026
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Abstract: — Low-frequency microaccelerations are studied onboard an artificial Earth satellite designed for microgravity investigations in a low, near-circular orbit. The satellite has the shape of a cylinder with two solar-battery panels located in the same plane symmetrically relative to the longitudinal axis of a cylinder. The satellite moves relative to its center of mass in the solar orientation mode: the normal to the plane of solar-battery panels is directed toward the Sun, the angular velocity around this normal is low, and the longitudinal axis makes small oscillations with respect to the plane of the orbit. This mode is implemented with using the system of four controlling reaction wheels. A version of this mode is proposed with a limitation on the accumulation of the total angular momentum of a system of reaction wheels by means of controlling the satellite’s angle of rotation around the normal to the plane of solar-battery panels. The satellite motion relative to the center of mass in the mode of combination of gravitational and solar orientation is considered. PubDate: 2022-02-01 DOI: 10.1134/S001095252201004X
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Abstract: The problem of calculating the direction of the braking impulse to bring the reusable returnable first stage of a launch vehicle into the desired landing region is considered. A mathematical model and a method for solving the problem are proposed, taking into account a number of features of the motion of the returnable stage in the Earth’s atmosphere, as well as the specifics of setting some design parameters. Examples of numerical calculations are given. PubDate: 2022-02-01 DOI: 10.1134/S0010952522010038
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Abstract: To describe the processes of acceleration and transfer of charged particles in turbulent magnetospheric and solar plasmas, a two-dimensional model of a turbulent electromagnetic field with a controlled intermittency level is proposed. In the model, the electromagnetic field has two components: a turbulent electromagnetic field obtained in the form of a superposition of plane waves, and an electromagnetic field created by oscillating magnetoplasma structures—plasmoids. Within the framework of the model, the role of intermittency in the acceleration of charged particles is investigated. It is shown that, the larger the parameter characterizing the level of intermittency, the higher the energy values that the charged particles are able to reach. The use of the model for describing observations of high-energy particle fluxes in the Earth’s magnetosphere and in the solar wind is discussed. PubDate: 2022-02-01 DOI: 10.1134/S0010952522010087
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Abstract: — The article presents results of ground calibrations of the FREND neutron telescope installed onboard the TGO spacecraft of the Russian-European ExoMars project. The main goal of the FREND space experiment is to measure hydrogen content in the subsurface layer of Mars to a depth of 1 m. High resolution maps of water mass fraction in the regolith are constructed based on these measurements. During ground physical calibrations, assessments of effective areas and measurements of angular sensitivity functions were obtained for each of the five FREND detectors. We demonstrate that FREND measurement characteristics correspond to its declared scientific goals and allow detecting and investigating local areas with enhanced water/water ice concertation on the subsurface of Mars with high spatial resolution of up to 60–200 km. PubDate: 2022-02-01 DOI: 10.1134/S0010952522010099
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Abstract: An Erratum to this paper has been published: https://doi.org/10.1134/S0010952521120017 PubDate: 2021-11-01 DOI: 10.1134/S0010952521120017
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Abstract: An Erratum to this paper has been published: https://doi.org/10.1134/S0010952521120029 PubDate: 2021-11-01 DOI: 10.1134/S0010952521120029
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Abstract: An Erratum to this paper has been published: https://doi.org/10.1134/S0010952521120030 PubDate: 2021-11-01 DOI: 10.1134/S0010952521120030
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Abstract: We investigated variations on scales of 104–105 km and local spatial inhomogeneities in the density of protons Np, doubly ionized helium ions (α-particles) Nα, and the relative abundance of helium Nα/Np in the solar wind. Measurements taken by two spacecraft, SPEKTR-R and WIND, separated in space by a distance of more than 1 million km, are analyzed, and the correlation coefficient between measurements of the corresponding parameters at different time intervals is determined. For intervals with a generally high level of correlation of plasma parameters, variations in the level of local (over shorter subintervals) correlation were analyzed. We showed that a low level of local correlation of all studied parameters is relatively common. The level of local correlation depends on the type of large-scale solar wind stream, as well as on the bulk velocity of the flow and the degree of flux variability. In addition, a low level of local correlation is often characterized by a negative component Bx of the interplanetary magnetic field. The regions of local spatial inhomogeneities in the densities of protons and helium and the relative abundance of helium are identified and their size is estimated. PubDate: 2021-11-01 DOI: 10.1134/S0010952521060022
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Abstract: All reliable information on the long-term characteristics of the interplanetary medium, such as the spectrum of variations and the anisotropy and gradients of cosmic rays, have been obtained from the data of a ground-based network of detectors since its inception. However, to solve the inverse problem, it was required to know the shape of the spectrum of variations, which until now was only given empirically. In this work, we have studied and experimentally determined the spectrum of variations of protons and helium nuclei based on precision measurements of particle fluxes up to a hardness of 60 GV outside the atmosphere on an AMS-02 magnetic spectrometer, in addition to establishing the transformation of the form of this spectrum when the polarity of the solar magnetic field is reversed. The found form of the spectrum of cosmic-ray variations will allow increasing the accuracy of the reconstructed parameters of the spectrum of variations and will form a solid basis for further studies of modulation effects in the heliosphere and related applications. PubDate: 2021-11-01 DOI: 10.1134/S0010952521060101
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