Analysis of synchronization of satellite communication systems at combined methods of multi -station access to repeater

Spatially-frequency, spatially-time, and spatially-frequency-time multi-station access to the re-translator is a characteristic feature of modern satellite communication systems. The article analyzes the ways of synchronization of satellite communication systems with combined methods of multi-station access to a repeater located on an artificial earth satellite. The analysis will allow us to organize and conduct high-quality research to identify the most optimal method experimentally, taking into account the advantages and disadvantages of each of them.

Spacecraft pulsed flights trajectories with the stages jettison into the atmosphere and phase restriction (part II)

The paper considers the idea of reducing near-Earth space debris by discarding expended stages into the Earth’s atmosphere. The problem of optimizing the pulsed flight between the reference circular orbit of an artificial Earth satellite and the target elliptical orbit with a phase restriction on the maximum distance of the spacecraft from the Earth has been solved. Derivatives under the transversality of Lagrange principle in the process of solving are calculated by means of a specially developed technology of numerical-analytical differentiation. The first part of the paper introduces the statement and formalization of the problem. The second part of the paper studies the conditions for the optimality of Lagrange principle, analyses them and compares the findings obtained with the previously known results.