Liquid hydrogen R-7 version
Varfolomeyev T., Shlyadinsky A.

The original specification of 1962 did require for the 8K78L vehicle a payload capability of about 9.51 for LEO and 2.81 for escape trajectory. All payloads for this version were being aimed at these values of payload weight.
Although LH2 is the most energetic fuel than any other, serious problem arose from its low density, - hydrogen stages required very large fuel tanks. So, as the project progressed, weight of the hydrogen upper stages had become so heavy that the "hydrogen" R-7 rocket would not meet the original requirements. To reach a desired payload capability, the total loaded weight of the entire R-7-based vehicle was to be about 3401 [6]. In that variant, it would possibly have put a payload of up to 9.5t in LEO [7]. But this meant that it was necessary to improve essentially a basic packet of Stage 1/2 , first of all to uprate a total thrust of its engine units.
During 1963 project of hydrogen R-7, i.e. the R-7 rocket with hydrogen upper stages, was revised and in early 1964 took definitive shape. Because at that time Chief Designer of rocket engines Glushko had stopped all work on LOX- kerosene engines, Korolev had to give up the idea to uprate the existing engines 8D728/727 (RD-107/108) of Stages 1/2. He proposed to power the central sustainer Block A (Stage 2) by a cluster consisting of four engines 8D717 (NK-9), designed at that time by Nikolai D. Kuznetsov's OKB-276. Thus the basic package of Stage 1/2 was to be uprated from 413.3 to about 470 tonnes of lift off thrust. All LOX tanks would be loaded with super-cooled LOX.
Two versions of hydrogen R-7 launcher were being developed during 1963-1965. The four- stage launcher received the initial designation 8K78L, was to have hydrogen Stages 3 and 4 and could possibly launch both interplanetary and orbital payloads in parking orbit. The three-stage launcher designated 11A58 was to have modified hydrogen Stage 3 and was intended to launch orbital payloads. Stage 3 of the 11A58 was to have its own inertia! control system whereas the control system of the 8K78L's upper stages was to be placed onboard hydrogen escape Stage 4, Block M.

на основе статьи Soviet Rocketry which conqured space из журнала Spaceflight
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