Vol 57, No 3 (2019)

The event on January 27, 2012 is an example of the features of the dynamics of formation of a shock, excited by a fast coronal mass ejection (CME) at a velocity higher than 2000 km/s, are investigated. The following data were used: (a) images of the Sun in the UV channel of 13.1 nm from the AIA instrument at distances of 1.0–1.4 solar radii from the Sun’s center, (b) the images of the white corona from the LASCO C2 and C3 coronographs at R ≈ 2.1–30 solar radii. Investigations indicated the validity of regularities, established earlier for the cases of relatively slow CMEs (at velocities <1500 km/s): (1) The shock front is formed, when the velocity of a leading part of a CME relative to the undisturbed solar wind becomes greater than the local Alfven velocity of wind, which corresponds to the phenomenon of “transition through the sound velocity” for magnetized plasma. (2) The change in the width of a shock front and, accordingly, in the energy dissipation mechanism occurs in a shock front from a “collisional” one, at distances from the Sun’s center lower than 10 solar radii, to a “collisionless” one, at distances greater than ten solar radii. During the event of January 27, 2012, it was possible to investigate in more detail the process of transition from the collisional to collisionless shock front. It was found that the longitudinal length of a shock front, excited by a fast CME at distances lower than 6 solar radii, increased almost 10 times as compared to a slower CME. One of the main causes for this increase, along with a high velocity, is the fact that the motion of CME has occurred in the plane of the belt of coronal streamers. It is concluded that, at distances lower than 6 solar radii, the shock front structure ahead of the CME is of “parallel” type; that is, the angle between the vector of an undisturbed magnetic field and the normal to the front was close to 0°.

The role of altitude models of Earth’s magnetic field for solving geophysical problems using spacecraft is considered. The results of studying the features of the deep structure of Earth’s crust in the structure of magnetic anomalies according to the data of satellite altitude measurements on the CHAMP mission are presented. The informativity of the components of the magnetic anomalies in near-Earth space calculated by the component model of Earth’s magnetic field is presented for searching for minerals in the geothermal regions of Central Europe and North America, in the zone of deposits of ferruginous quartzites of the Baltic shield, and hydrocarbon deposits in the oil and gas basins of Tatarstan, Siberia, the Barents, Mediterranean, and North seas.

The problem of reentry vehicle control during its descent from a near-Earth orbit is considered under conditions of “enhanced” disturbances. The earlier developed terminal descent control algorithm is considerably improved to satisfy constraints on landing accuracy, load factor, and propellant consumption. A method for automatically shifting the deorbit point, adaptating to actual motion conditions, and modifying the reference bank function is proposed, which ensured the satisfaction of the specified constraints under action of an aggregate of enhanced disturbing factors.

An analytical technique for designing satellite constellations for operational global monitoring of Earth’s surface is presented. This technique makes it possible to calculate the rational shift from the argument of latitude and longitude of the right ascension of the ascending node between satellites in the system. The orbital parameters of spacecraft and the characteristics of its field of view should be taken from basic solutions for satellite constellations of operational global monitoring, considered by authors in earlier studies. The resulting basic solutions make it possible to find the maximal break in the observation of any point on Earth’s surface for a single satellite, and the technique described here makes it possible to determine the rational location of several satellites in the system and minimize the peak revisit time for the entire satellite constellation. The technique has been developed for spacecraft with a daily repeat of flight track and makes it possible to determine the minimum number of satellites in the system that can provide a break in observation to be limited by a given value. This study presents several families of solutions for satellite constellations with a daily repeat of flight track on low circular orbits at heights below 2000 km.