- Family: Molniya
- Length: 43.44 m
- Diameter: 3 m
- Launch Mass: 305 T
- Low Earth Orbit Capacity: 1900 kg
The Molniya 8K78 was manufactured by Strategic Rocket Forces with the first launch on 1960-10-10. Molniya 8K78 has 20 successful launches and 20 failed launches with a total of 40 launches. The Molniya was a modification of the well-known R-7 Semyorka rocket and had four stages.
The 8K78 resulted from a crash program by the Korolev Bureau to develop a booster for launching planetary probes. A larger third stage was added along with a fourth stage (Blok L) that was designed to fire in-orbit to send the payload out of LEO. The basic R-7 core was also structurally strengthened and given more powerful engines. A rushed development produced multiple malfunctions of the upper stages, which led to its being replaced by the improved Molniya-M in 1964, but there were enough 8K78s left to continue flying them into 1967.