Molniya-M

Molniya-M (R-7 8K78M)

Drawing of the Molniya-M carrier rocket
Function	Medium carrier rocket
Manufacturer	TsSKB-Progress
Country of origin	Russia/Soviet Union
Size
Height	43.4 m (142.3 ft)
Diameter	2.95 m (9.67 ft)
Mass	305,000 kg (672,000 lb)
Stages	3
Associated rockets
Family	R-7
Comparable	Soyuz-2/Fregat
Launch history
Status	Retired
Launch sites	Baikonur 1/5, 31/6 Plesetsk 16/2, 41/1, 43
Total launches	297
Successes	276
Failures	21
First flight	19 February 1964
Last flight	30 September 2010

The Molniya-M (Russian: Молния, meaning "lightning"), designation 8K78M, was a Russian (previously Soviet) carrier rocket derived from the R-7 Semyorka 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 1958-60. As 1962 ended, there had been 12 launches of 8K78s, 10 of which failed (five Blok L failures, four Blok I failures, and one failure caused by the Blok A core stage). 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 engines were enhanced still further and the Kosberg Bureau completely redesigned the Blok I stage. The Blok L engine was also slightly enhanced. The first six 8K78Ms built used RD-108 engines in the Blok I stage, which was also used in the two manned Voskhod boosters, all subsequent 8K78Ms using RD-110 engines which were shared with the Soyuz booster.

The 8K78M was first launched in 1964; however, the existing stock of 8K78s had not been used up yet and they continued to fly until 1967. During 1967, the improved core stage and strap-ons from the Soyuz 11A57 were adopted and made standard on all R-7 based vehicles. It made 297 launches and experienced 21 failures. There were no failures of 8K78Ms caused by the core and strap-ons, and after 1968, all failures were caused by the Blok L stage until 2005 when one of the last boosters flown suffered a Blok I engine failure. The final flight of a Molniya-M lofted an Oko early warning satellite from Plesetsk on 30 September 2010 despite some apprehension that the launch vehicle, manufactured in 2005, had exceeded its storage life. It will be replaced by the Soyuz-2/Fregat.

Although originally developed for planetary probes, those had switched to the larger Proton booster by the 1970s due to increasing mass and complexity. For most of its operational life, the Molniya-M was used to launch its namesake Molniya and also Oko satellites into Molniya orbits, orbits of high eccentricity that allow satellites to dwell over polar regions.