Methods are discussed for studying the variability in space of the substance composition of the surface of Mars in experiments on gamma-ray spectroscopy on board a mobile vehicle—“Mars rover”. It is shown that data on the elemental composition of the substance in local volumes of the matter with a characteristic linear size of the order of several meters along the rover travers can be obtained using the method of “tagged charged particles” (TCP). This method allows to exclude from consideration both the counts caused by gamma-ray radiation from the surrounding surface outside the tested local area and radiation from the spacecraft itself. The method of identifying the composition of the substance in the tested volume with the known types of Martian regolith according to the APXS experiment is also discussed. This method is based on the comparison of measured intensities of the main characteristic nuclear lines with the values corresponding to these lines for known regolith types. It is underlined that the proposed method allows to experimentally detect new types of regolith, the composition of which differs from the composition of all previously known types of Martian matter.

The paper considers the most significant relativistic effects in the rotational dynamics of Neptune’s satellites (Triton (N1), Naiad (N3), Thalassa (N4), Despina (N5), Galatea (N6), Larissa (N7), and Proteus (N8)). For the first time, the most significant secular and periodic terms of the geodetic rotation of Triton and six inner satellites of Neptune are determined in the angles of their rotation relative to the fixed equator of the Earth of the J2000.0 epoch, defined in the international coordinate system (ICRF), and the vernal equinox of the J2000.0 epoch and in the Euler angles relative to their own coordinate systems. The study showed that the value of geodetic rotation can be significant not only for bodies that revolve around supermassive central bodies, but also for close satellites of giant planets. The values obtained of the geodetic rotation for the system of satellites under study can be used for a numerical study of their rotation in the relativistic approximation, and also used to estimate the influence of relativistic effects on the orbital–rotational dynamics like heavenly bodies of exoplanetary systems.

The results are presented of a numerical simulation for the motion of a group of geosynchronous objects from positional observations obtained with the unique Zeiss-2000 research facility at the Terskol Observatory, Institute of Astronomy, Russian Academy of Sciences. A description is given of improved high-precision mathematical software designed to work with positional observations of satellites. The results are discussed of testing the software for observations of near-Earth objects obtained with the above-mentioned Zeiss-2000 facility. The modified software helps determine the dynamic state vector of a near-Earth object and its windage parameter. The testing has used observations of geosynchronous objects 90008, 90031, 90214, and 97149 (the object numbers are given in accordance with the numbering in the dynamic database of space objects maintained by the Keldysh Institute of Applied Mathematics, Russian Academy of Sciences). The resulting parameters are used to study the long-term orbital evolution of the objects. It is shown that three objects (90008, 90031, and 90214) are captured in a 1 : 1 resonance with the Earth’s rotation velocity and have a stable motion in a rotating coordinate system close to a harmonic oscillator over a 10-year time interval. Object 97149 is not resonant, but its motion remains regular over a time interval of 10 years.

The paper presents a description of the numerical model of motion of artificial Moon satellites (AMS), developed by the authors, and the results of studying the features of the dynamics of objects in the circumlunar space. A numerical modeling of motion of 5180 objects uniformly distributed in the circumlunar space was carried out. It is shown that in a number of regions of the circumlunar space, the orbital lifetime of AMS is very short, depending on the choice of the initial value of the semi-major axis and inclination. The reasons for this phenomenon are elucidated. These results can be used in choosing a strategy of arrangement of satellite systems for long-term use in the circumlunar orbital space.

In this paper, we summarize the experimental data on the features of the mineral, chemical, and isotopic compositions of minor bodies of the Solar System—asteroids, Saturn’s satellites, and nuclei of comets of different dynamic types—which suggest that the formation of these bodies was significantly influenced by the mixing of different-genesis matter: presolar and nebular. The latter was formed in the circumsolar gas–dust protoplanetary accretion disk that is also called the nebula. The matter of presolar origin includes amorphous iron–magnesium silicates, refractory organic compounds, volatile organic compounds, amorphous water ice, as well as ices of СО2, NH3, CH3OH, CO, etc. The species of nebular origin are aluminum-, calcium-, and titanium-rich refractory inclusions (known as CAls), microcrystalline magnesium silicates, as well as crystalline water ice, the hydrogen isotopic composition of which is several times lower than that of water ice of the protosolar nebula. The presolar- and nebular-origin matter could be mixed because, in the circumsolar disk at the early stages of its evolution, in addition to the main accretion flux of the gas–dust matter passing through the disk toward the Sun, there was a flux moving in the opposite direction, from the Sun, from the inner hot regions of the circumsolar disk outward to its external regions. There, the nebular matter was mixed with the protosolar matter, which had been precipitating onto the disk from its accretion envelope, mainly onto its edge, during the first million years of its evolution. The currently available package of the experimental data allows us to suppose that it is exactly the mixing of the matter from two regions of the circumsolar disk, within which the P–T conditions significantly differed, that may explain the presence of chemically and isotopically heterogeneous ice–rock bodies in the outer Solar System.

An algorithm for finding a solution for determining a preliminary orbit in the noncoplanar case, when the plane of the desired orbit does not coincide with the plane of motion of an observer, is proposed using a method based on solving a system of transcendental equations for two dimensionless variables. Solutions to the system are found by searching for the minima of the goal function by the Nelder–Mead method using the simplex. As examples, the results of determining the orbit of comet Borisov are given.

At present, the task of selecting landing sites for the Luna 27 spacecraft is provided with alarge amount of actual data, often with a higher spatial resolution compared to the data used to select of the Luna 25 landing sites. In addition, more data about the lunar surface with a spatial resolution comparable to the size of a spacecraft can be further obtained using the Luna 26 orbiter. Preliminary estimates of the lunar surface conditions in the south polar region, south of 80° S, for the landing of Luna 27 spacecraft have revealed the need to seriously improve the landing accuracy in comparison with the Luna 25 landing ellipse. The size of such landing ellipse south of 80° S makes a safe landing almost impossible since the surface near the Moon’s south pole does not have a single smooth and illuminated area of that size. Increasing the landing accuracy up to 5 km opens up the possibility of choosing a landing site among six candidates. A further increase in landing accuracy up to 3 km can provide a wide choice among 15 candidate sites, each allowing both a safe landing and the accomplishment of the Luna 27 scientific mission. Finally, with a landing accuracy of about 500 m, one can outline vast areas in the vicinity of the south pole with numerous sites offering favorable conditions both for a safe landing and for carrying out an extensive scientific program.

In this paper, we develop previous studies that considered a free molecular gas flow through a dust porous mantle of a cometary nucleus. Before, we considered various types of both homogeneous and heterogeneous layers built of nonintersecting spheres, including the layers containing microscopic cracks and inner cavities. At the same time, data from the Rosetta space mission provide convincing evidence that the near-surface layer is composed of porous aggregates rather than homogeneous solids. In this study, we propose models, in which the layer is constructed of porous aggregates formed by ballistic agglomeration. The effective porosity of the model layers is in a range of the values resulting from the analysis of observations of comet Churyumov–Gerasimenko. With the test-particle method, we quantitatively estimated the distribution functions for the free paths, the layer's permeability, and the other effective kinetic characteristics of sublimation products that passed through a nonisothermal porous layer. In addition, we estimated the volume adsorption of the visible solar light in the near-surface absorbing layer. For all of the considered transport characteristics, we present approximating expressions that may effectively be used in nonstationary thermophysical models of the physics of a cometary nucleus.

Within the framework of this work, using a three-dimensional numerical model of the general circulation of the Martian atmosphere MAOAM (Martian Atmosphere: Observation and Modeling), also known as MPI-MGCM (Max Planck Institute Martian General Circulation Model), we simulated the planet’s hydrological cycle during the 28 and 34 Martian years (MY28 and MY34) dust storm seasons. A quantitative assessment of the photodissociation of water vapor under the influence of solar radiation at the Lyman-alpha wavelength has been carried out. The simulation results are compared with individual profiles obtained with the Atmospheric Chemistry Suite (ACS) spectrometer installed on the ExoMars Trace Gas Orbiter (TGO) spacecraft. The MAOAM model has a spectral dynamical core and successfully predicts the temperature regime of Mars through the use of physical parameterizations that are characteristic of both Earth and Martian models. The hydrodynamic block of the model includes the transfer scheme, microphysics of water vapor and ice, heterogeneous nucleation, sedimentation, photodissociation, and exchange of water with the surface. Studies show the effect of dust storms on both the total water vapor content in the atmosphere and its vertical distribution. More intense pumping of water vapor into the upper atmosphere during dust storms provides more intense photodissociation of water vapor (in some seasons up to 6.5 tons per second in total in the entire atmosphere). The strongest photodissociation is observed at heights of 50 to 80 km for MY34 and 70 to 80 km for MY28. The dissociated water vapor can then potentially become a source of hydrogen dissipation into space, followed by a decrease in the mass of water on the planet.

Abstract—The technology of multilevel distributed automated processing of visual information in automated optoelectronic systems for ground–space monitoring based on a problem-oriented version of a comprehensive “information-cybernetic-didactic” approach has been considered. The results are of theoretical and practical value in solving problems of information efficiency ensuring in various fields of activity requiring the processing of visual information. The results of simulation and field modeling have been given.