Versions of the low Earth orbit satellite communication systems design

The different variants of system structure and parameter choice depending on system requests are considered in the article. On the basis of selected groups, which consist of 24 or 36 spacecraft with a symmetrical structure and orbit altitude 1600 km, it is demonstrated that one can have a high communication provision probability (0.98...1.0) in regional and regional-global communication systems. Such systems cover entire continents, where the connectivity is provided only by restricted Earth transponders, and in global systems-by a communication provision combined method, i.e. by usage of intersatellite communication links for two directions in each spacecraft and some Earth transponders