Molniya-M

The Molniya-M (, GRAU index: 8K78M) was a Soviet and Russian launch vehicle derived from the R-7 Semyorka Intercontinental ballistic missile (ICBM).

The original 8K78 booster had been the product of a rushed development program and its launch record was no better than the 8K72 Luna booster of 1958–1960. As 1962 ended, there had been 12 launches of 8K78s, ten of which failed (five Block L failures, four Block I failures, and one failure caused by the Block A core stage). left|thumb|Block L and 2MV planetary probe The two successful launches had had their probes (Venera 1 and Mars 1) fail en route to their respective planetary targets. As such, work began at the Korolev Bureau to improve the basic 8K78 vehicle. The core and strap-ons received the up-rated 8D74M engines and the Kosberg Bureau completely redesigned the Block I stage. The Block L engine was also slightly enhanced. The first six 8K78Ms built used RD-0108 engines in the Block I stage, which was also used in the two crewed Voskhod boosters, all subsequent 8K78Ms using RD-0110 engines which were shared with the Soyuz booster. Molniya boosters flown after the adaption of the new 11A511U core in 1973 used the improved 11D511 first stage engines. While 11A511U cores flown on other R-7 vehicles switched to a shorter instrument packet, the Molniya continued using the old "long" instrument packet.