|Country of origin||USSR|
|Designer||OKB-154, Yankel I. Guerchkovitch|
|Manufacturer||Voronezh Mechanical Plant|
|Propellant||N2O4 / UDMH|
|Thrust (vacuum)||30.9 kilonewtons (6,900 lbf)|
|Chamber pressure||5.3 megapascals (770 psi)|
|Specific impulse (vacuum)||RD-0207:297seconds|
|Length||524 millimetres (20.6 in)|
|Diameter||3,780 millimetres (149 in)|
|Dry weight||90 kilograms (200 lb)|
|Proton third stage|
The RD-0214 (GRAU Index: 8D811) is a rocket vernier engine burning N2O4 and UDMH in a gas generator cycle. It has four nozzles that can each gimbal 45 in plane to provide TVC to the RD-0212 propulsion module of Proton third stage. It is a revised version of the RD-0207.
When Chelomey's OKB-52 started their UR-200 ICBM project, they requested S. A. Kosberg's OKB-154 to develop the propulsion. For the second stage, they used a single RD-0206, a variation of the first stage RD-0203, but required a vernier engine. To this end, the RD-0207 vernier engine was designed. It also included a heat exchanger to heat the pressurant gases for the second stage tank. While the UR-200 project was in direct competition to the R-36 and was cancelled in favor of the latter, it did have a few test launches and thus was a proven design.
Then Chelomey moved his proposals to the super heavy ICBM UR-500 (8K82) and later to the Proton-K (8K82K). A heavy launch vehicle that could perform important missions for the Soviet moonshot. For this new missions, it would not need to comply with ICBM specification standards, but would need at least a third stage. For the third stage, the UR-200 second stage was adapted—with the same 4.1 m tanking as the first and second stages and the RD-0205 module with an RD-0206 and an RD-0207 vernier engine was given an overhaul. The new module—known as RD-0212—consisted of an RD-0213 and an RD-0214 vernier engine. Many reliability enhancements were done and much extra test firings were performed. Yet, even as of 2015 design issues were found to have caused failures.
The first launch test of the UR-200 was on November 5, 1963, and was unsuccessful. The second vehicle, launched on April 11, 1964, also failed. The final RD-0207 flight was on October 20, 1964.
The first RD-0214 flight was on October 3, 1967.
There are two basic versions of this engine:
These engines are actually bundled into modules. The relevant modules and auxiliary engines are: