The Molniya (Russian: Молния, meaning "lightning"), GRAU Index 8K78, was a modification of the well-known R-7 Semyorka rocket and had four stages.[1][2] The rocket was given the name Molniya due to the large number of Molniya communication satellites the rockets launched.[3]
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 (replacing the inaccurate direct ascent of the first generation Luna probes launched on the 8K72) and the core and strap-ons had the new uprated 8D74K first stage engines. The first couple of 8K78s flown used an 8K74 core however vehicles flown in 1962-63 used the older 8K71 core. The 8K74 core returned for vehicles flown in 1964 and later.
The initial 8K78s had a faulty Blok I design that was prone to vibration issues and pump cavitation. The Blok I was redesigned afterward and the improved version was first flown on 11 November 1963. The uprated 8K78M booster was introduced in 1965 but 8K78s continued to fly into 1967.[4][5][6][7] The Molniya also carried early Venera probes to Venus.[2]
Molniya (E6) was a minor revision adapted for Luna E-6 series space probes where the guidance system for the entire launch vehicle was moved to the probe itself.[2]
This Template lists historical, current, and future space rockets that at least once attempted (but not necessarily succeeded in) an orbital launch or that are planned to attempt such a launch in the future
Symbol † indicates past or current rockets that attempted orbital launches but never succeeded (never did or has yet to perform a successful orbital launch)
