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Previous chapter: R-7 ICBM

In 1956, in the course of the development of the first Soviet ICBM R-7 led by Sergei Korolev, his old colleague and rival Valentin Glushko, the head of OKB-456 engine-development center, proposed a competing design. According to the leading historian at NPO Energomash, R-8 would actually be a follow-on rocket to R-7. It would increase a flight range from 7,000-8,000 kilometers for R-7 to 10,000-12,000 kilometers for R-8, thus placing the entire US territory within the range of the existing Soviet nuclear weapons. The new missile could carry a 10-ton warhead.

On August 22, 1956, Glushko sent an official technical proposal to develop R-8, which would use engines with the thrust of 100 tons. The engines would develop a total thrust of 1,000 tons on the surface of Earth (84) (apparently when combined in a cluster). Glushko planned to design the main version of the engine with a pair of combustion chambers, with a possibility of its upgrade to a four-chamber model. In further upgrades, the engine's kerosene fuel could be replaced with unsymmetrical demethil hydrazine, promising further increase the specific impulse. Glushko later wrote to Korolev that only a 200-ton four-chamber engine designated RD-109 would make sense according to the latest studies. He asked Korolev to provide a preliminary technical assignment for RD-109 in two-three weeks and start drafting a government decree, which would set the completion of the preliminary design for the project in the 4th quarter of 1957. (552)

Marshall Mitrofan Nedelin, who oversaw the development of ICBM for the Soviet Ministry of Defense reportedly support the R-8 concept. At the same time, OKB-1, the R-7 developer, strongly opposed the project. (74) Korolev argued that all upgrades of R-7 had had to be put off until the completion of R-7's flight tests. (552)

As Korolev's leadership in rocket industry was largely uncontested at the time, the R-8 never went beyond the paper stage. Still, during 1957, Glushko assigned his OKB-456 to conduct pre-preliminary studies of the RD-109 engine.


Known specifications of the R-8 ballistic missile:

Multi-stage ICBM with a single warhead
Fueled mass at launch 650 tons
The propellant UDMH (Unsymmetrical dimethil hydrazine)
The 1st stage propulsion unit 4 liquid-fuel engines
Thrust 800-1,000 tons
Flight range 10,000-12,000 kilometers (552)
Warhead mass 10 tons (552)


Next chapter: N1 launch vehicle


Page author: Anatoly Zak; Last update: February 13, 2012

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The RD-109 engine. Credit: 552