Kosmičeskie issledovaniâ

Using a numerical model, the influence of intermittency on the acceleration of particles in the equatorial plane of the Earth's magnetotail was studied. For comparison with observational data, we selected the event of July 17, 2001, when plasma flows with velocities of up to 400 km/s and an amplitude of the turbulent magnetic field of the order of ten nT were observed in the plasma layer of the magnetotail for more than 10 minutes. Modeling of the electromagnetic field is carried out using a superposition of wavelets, which are distributed uniformly throughout the computational domain. By means of a special distribution of amplitudes, we ensure that the resulting field is multifractal and intermittent. It is shown that when accelerated in an intermittent field, the energy spectra of particles rise and flatten, which means that particles are able to gain more energy than when accelerated in a turbulent plasma layer without taking into account intermittency.

The paper presents the results of the space experiments “Test”, “BTN-Neutron”, “UV-atmosphere” and “Matryoshka R” carried out on board the Russian Segment of the International Space Station (RS ISS). Various aspects of the micrometeorite environment are described: sources of fine sediment on the ISS surface, its biochemical composition, physical characteristics of particles, factors affecting structural elements and equipment of the ISS. The study is based on the results of space experiments conducted on board the RS ISS. Basing on consideration of ways to account for meteor hazard and the data obtained in the considered space experiments, it is proposed to form a unified interdisciplinary model of the environment of a manned spacecraft. Taking samples of fine sediment from the surface of objects in near-Earth space is an effective alternative to launching expensive specialized missions to study the Universe.

The paper presents possible options for changing the orbit of the spacecraft operating near the Sun-Earth libration point for the purpose of the close passage of asteroids approaching the Earth. Two methods of constructing transfer trajectories to one or more celestial bodies are proposed: transferring the spacecraft from the initial bounded orbit in the vicinity of the L₂ Sun – Earth libration point to the required one in the same vicinity and taking it to the Earth along the trajectory of an unstable manifold. Examples are provided in which the asteroids Apophis and 1997 XF₁₁ are chosen as targets, whose trajectories will pass near the spacecraft in 2029 and 2028, respectively. It is shown that under the existing fuel cost restrictions, the spacecraft can be redirected to the targeted asteroids by the proposed methods. According to the calculations, in all cases the spacecraft does not leave the near-Earth space and therefore, during or after the passage of the asteroid, it can be used in solving other scientific problems.

The problem of autonomous control of the translational motion of the spacecraft in the vicinity of the focus of the gravitational lens of the Sun is formulated. The problem is solved by a reinforcement machine learning method using contemporary stochastic numerical methods. The costs of the characteristic velocity for targeting the focal line of a remote extended source, the final accuracy of targeting and the quality of the control function are investigated. The results of the study are given for various forms of state and observation: 1) position and velocity, 2) noisy position and velocity, 3) image of the Einstein ring. The efficiency of control strategies when using recurrent layers and fully connected layers with an input in the form of a measurement stack is compared. The training of control models accounting for execution errors of maneuvers is also being explored.