UR-500 rocket

One of the earliest designs of the ur500 was to use four ur200s to tie them together, but this ridiculous scheme was soon abandoned. In addition to okb-52, the units responsible for each subsystem include okb-456 (for engine) and nii-885 (for control system) of Grushko. The whole development work was completed in 1965, and the rocket made its first flight on July 16 of that year. The first launch of the rocket carries a load of proton-1 scientific satellite, so the rocket is named proton carrier rocket.

The design of the ur500 rocket is somewhat different from the Soviet Union's earliest launch vehicles derived from the R-7 intercontinental missile, such as satellite and Soyuz. Although the design of the first stage engine placed along the ring is retained, the rocket is a two-stage structure, unlike the satellite rocket, which is a bundled structure (thus actually one and a half stages). Six propellant tanks are arranged in the outer ring of the first stage of the rocket, but they are not boosters, that is, they do not separate from the rocket body after launch. The propellants used in ur500 are highly toxic hydrazine compounds. Various types of proton rockets are formed by adding several stages or upper stages to ur500.

The ur500 recorded four missions, including the launch of three proton satellites from proton 1 to Proton 3, and one launch failure. Due to the lack of the upper stage, its carrying capacity is very low, which is not much higher than that of the R-7 series of its competitors and Korolev, but its quality is much higher than that of the latter. The rocket was discontinued in 1966.