A brief review of theoretical studies of circumlunar dusty plasma, the important factors in the formation of which are electrostatic processes and impacts of micrometeoroids on the lunar surface, is given. Observation data of dust particles in the vicinity of the Moon, obtained within the “Luna-25” mission, are described for the first time. It is shown that there is at least one reliable observation of a dust particle either of lunar origin or associated with the high-speed Perseid stream. The need to improve the Lunar Dust Monitor device on the “Luna-27” lander is discussed. The improvement is associated with the need to install a rod for placing electrostatic sensors at a sufficient distance from the device, which is desirable to reduce disturbances of the surrounding plasma and the near-surface electrostatic field because of the influence of the lander.

The program of scientific research of the Luna-25 lunar lander includes the experiment "Dust monitoring of the Moon" (in Russian, "Pylevoi monitoring Luny" (PmL)), which provides for the study of the dynamics of lunar microparticles and parameters of the near-surface dusty plasma. Using the PmL instrument, it is planned to record for a long time individual microparticles above the lunar surface, to measure and evaluate their physical characteristics (momentum, velocity, charge, mass, and concentration), as well as to monitor the dynamics of the parameters of the near-surface dusty plasma environment (density, temperature, and potential). The instrument has passed successfully the entire range of ground tests.

Fluxes of mass and dust particles are calculated, which appear in orbit around Mars due to collisions of meteoroids with Phobos and Deimos. Size distributions of dust particles captured in orbit around Mars are determined. Knowledge of parameters of these particles is important when planning the experimental studies on dust in the system of Mars within the framework of the future space missions.

We have calculated the mass fluxes and dust particle fluxes the presence of which in orbits around Mars is due to collisions between meteoroids with Phobos and Deimos. The size distributions of dust particles captured in orbits around Mars are determined. Knowledge of the parameters of these particles is important when planning experiments to dust study in the system of Mars as part of future space missions.

The possibility of the separation of dust particles owing to impacts of micrometeoroids on the surface of the Moon has been discussed. It has been shown that this effect is significant and should be taken into account when determining the number of particles rising over the surface of the Moon at the formation of a plasma–dust system. The average number of regolith particles leaving the surface of the Moon owing to the impacts of fast meteoroids has been determined for various altitudes over the Moon. The size distribution function of particles leaving the surface of the Moon because of impacts of meteoroids has been determined. It has been shown that impacts of meteoroids constitute an important source of dust microparticles in the plasma–dust system over the surface of the Moon.

A dusty plasma layer formed near the illuminated part of the surface of the Moon under the action of ultraviolet radiation, as well as fast and slow solar wind, has been numerically simulated. The numerical calculations including the photoemission properties of lunar regolith samples delivered to the Earth have been compared to estimates within known theoretical models. It has been shown that the flux of solar wind particles plays an important role in the formation of the surface photoelectron layer. The conditions of the charging and stable levitation of dust particles in the surface plasma layer of the Moon have been analyzed.

Представлена теоретическая модель для самосогласованного описания концентраций фотоэлектронов и пылевых частиц над поверхностью освещенной части Луны. Модель учитывает положение места наблюдения, а также эффекты образования фотоэлектронов на поверхности Луны и поверхностях пылевых частиц, динамики пылевых частиц в электрическом и гравитационном полях, зарядки пылевых частиц за счет их взаимодействия с фотонами солнечного излучения, электронами и ионами солнечного ветра, фотоэлектронами и т.д. Получено выражение, описывающее распределение фотоэлектронов над поверхностью освещенной части Луны. Выполнен расчет распределений по размерам и высотам подъема заряженных пылевых частиц над освещенными участками поверхности Луны для различных значений угла между местной нормалью и направлением на Солнце. Показано, что не существует существенных ограничений на место посадки аппаратов будущих лунных миссий, изучающих пыль в приповерхностном слое Луны.

A theoretical and experimental feasibility study of possible determination of the hydrogen and deuterium concentrations in the surface layers of planetary bodies is presented. The method under study is the recoil proton and deuteron spectrometry of forward scattering in the course of elastic interaction of alpha particles with the nuclei of hydrogen isotopes. The spectra of recoil protons and deuterons were recorded using a prototype model of a hydrogen spectrometer, and these spectra were used to determine the hydrogen concentrations in the samples of different compositions.