Rocket stage - Trans-orbit booster Fregat

This paper discusses a proposal for increasing the payload-carrying capability of a launch vehicle by using the Fregat booster stage (as the fourth stage for the R-7A launcher and as the fifth stage for the Proton launch vehicle). Particular attention is given to the tasks which the Fregat booster stage is designed to fulfill, the systems which are part of the Fregat, and the launch vehicles which will use Fregat as the upper stage. The main performance parameters of the Fregat stage are presented, as well as diagrams illustrating the performance of the Fregat booster stage.