Molniya (-M)

TsSKB Progress
 

The Semyorka version Molniya 8K78(M) is beside the Voskhod and the Soyuz the third with an upper stage Block-I and was the first version with an additional fourth stage Block-L. The Molniya was used for a interplanetary and lunar transfer of payloads, still before the Voskhod and Soyuz went in service.

Base for the Molniya launcher was a further variant of the Semyorka, the R-7 (8K74). The necessary third stage Block-I was taken over from the ICBM R-9A (8K75) and then improved. The fourth (escape) stage Block-L was new. A particularity was the installation of a BOZ (Blok Obespechenya Zapuska = Unit for Ensuring Ignition). The engine S1.54000 was developed by the OKB-1 (Korolov).

Already in 1959, December the prototype from the Molniya launcher with a third stage and a dummy of the fourth stage accomplished a first suborbital flight. In the summer 1960 began the development of the fourth stage.
Then in the fall 1960 the qualification of the four-stage Molniya was under proof. Planned was the launch of two Mars -probes. A long series of failures began at 10.10.1960 and ended in 1965 finally.

In the year 1962 the Molniya 8K78 launcher was modified in first time. The sustainer received the more powerful engines RD-108 (8D727K). Between Fairing (6.74 m length) and Block-I was inserted an adapter of 2.30 m length, which the fourth stage should take in. Up to now the Block-L was placed in the payload bay and has limited very the free area.
Between 1962 and 1965 was launched this variant in 20 times, 11 of it were failures. Payloads were Venus-, Mars- and Luna-probes as well as 4 Molniya-satellites.

Since 1963 was worked for the launcher's improvement. In the new production plant of the 11A57 Voskhod in Kuibyshev (now Samara) were developed more modern variants of the engines RD-107 and RD-108 (8D727 and 8D728) and new kerosene- fuel (RG-1). The engine S.5400A of the Block-L was replaced by the improved 11D33. A new engine RD-0108 for Block-I did not prove and was exchanged again by the old RD-0107 engine after 6 launches of the new launcher 8K78M. The first launch of the new variant with a new fairing of 7.14 m length and with a Venus-probe at 19.02.1964 was however again a failure.

Then between 1966 and 1967 resulted a further modernization of the Molniya launcher. The entire base packet of the R-7 (8K74) in favor of the base packet 11S59 was exchanged, which was developed for the Soyuz 11A511. For the third stage the new engine RD-0110 was taken over. Some configured variants of the fourth stage were developed then in the course of time for different missions.

                            MVL         = IP, LTO
                            SO-L         = Prognoz 1- 10
                            2BL          = OKO, Molniya-1 , -2
                            2BL-M      = OKO, Molniya-1 , -3
                            2BL-SM    = Prognoz-M

The 4 solid-fuel motors of the BOZ-unit were replaced by two new (0.371 t). The last version Block 2BL-M has a powerful engine 11D33M. The fairing was extended to 7.81 m length and later for the launches of OKO and Molniya-3 to 8.28 m length. Thereby the 2.30 m long adapter to the Block-I could taken away.
The first launch of the new 8K78M resulted at 07.02.1968 with a equipment of the manned moon program N1-L3. The last attempt to start a interplanetary mission with the Molniya failed at 31.03.1972 (Kosmos 482). Currently the Molniya 8K78M is used almost exclusively still for the launches of Molniya- and OK-satellites. They are started with the Soyuz 11A511U, which has the new changed upper tank - conclusion of the core.