Semianalytic estimations of boundaries of a corridor of spacecraft entry into the planetary atmosphere at considerable values of permissible maximum overload

Trajectories of spacecraft entry into the planetary atmosphere with a velocity essentially exceeding the first cosmic velocity are considered. An estimation of the minimum permissible value of the altitude of conditional pericenter (perigee in the case of the Earth), at which extreme permissible value of maximum overload is reached, is of the main interest. Semianalytic formulas including the cases of considerable values of the maximum overload are suggested.