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.

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 the total thrust of 1000 tons at the surface of Earth. (84)

The proposal was reportedly supported by Marshall Mitrofan Nedelin, who oversaw the development of ICBM for the Soviet Ministry of Defense. At the same time, OKB-1, the R-7 developer strongly opposed the R-8 proposal. (74)

As Korolev's leadership in rocket industry was largely uncontested at the time, the R-8 never went beyond the paper stage.

R-8 at a glance:

Type
Multistage ICBM with a single warhead
Weight at launch 650 tons
The propellants UDMH (Unsymmetrical Dimethyl Hydrazine)
The 1st stage propulsion unit 4 liquid-fuel engines
Thrust 800-1000 tons