|Function||Medium launch vehicle|
|Country of origin||Soviet Union|
|Launch sites||Baikonur, Plesetsk|
The Molniya (Russian: Молния, meaning "lightning"), GRAU Index 8K78, 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. The Molniya also carried early Venera probes to Venus.
Molniya (E6) was a minor revision adapted for launch of some Luna series space probes.
"Molniya-M Carrier Rocket". РКЦ Прогресс. Retrieved 7 October 2014.