The RD-250 (, GRAU index: 8D518) is the base version of a dual-nozzle family of liquid-fuel rocket engines, burning a hypergolic mixture of unsymmetrical dimethylhydrazine (UDMH) fuel with dinitrogen tetroxide oxidizer in a gas-generator open cycle.[1] The RD-250 was developed by OKB-456 for Yangel's PA Yuzhmash ICBM, the R-36 (8K67). Its variations were also used on the Tsyklon-2 and Tsyklon-3 launch vehicles. It was supposed to be used on the Tsyklon-4, but since the cancellation of the project it should be considered as out of production. Three engines from this family bundled together make the corresponding RD-251 propulsion module.
Versions
The engine has seen different versions made:
- RD-250 (GRAU index: 8D518): Base engine of the family. Used on the R-36. A bundle of three RD-250 form the RD-251 cluster.
- RD-250P (GRAU index: 8D518P): Improved version of the RD-250. Used on the R-36P. A bundle of three RD-250P form the RD-251P cluster.
- RD-250M (GRAU index: 8D518M): Improved version of the RD-250P. Used on the R-36-O. A bundle of three RD-250M form the RD-251M cluster.
- RD-250PM (GRAU index: 8D518PM): Improved version of the RD-250M. Used on the Tsyklon-3. A bundle of three RD-250PM form the RD-261 cluster.
- RD-252 (GRAU index: 8D724): Vacuum optimized version of the RD-250. Used on the R-36 and Tsyklon-2 second stages.
- RD-262 (GRAU index: 11D26): Improved version of the RD-252. Used on the Tsyklon-3 second stages.
Modules
Some of these engines were bundled into modules of multiple engines. The relevant modules and auxiliary engines are:
- RD-251 (GRAU index: 8D723): A module comprising three RD-250. Propulsion module of the R-36 (8K67) first stage.
- RD-251P (GRAU index: 8D723P): A module comprising three RD-250P. Propulsion module of the R-36P (8K68) first stage.
- RD-251M (GRAU index: 8D723M): A module comprising three RD-250M. Propulsion module of the R-36-O (8K69) and Tsyklon-2 first stage.
- RD-261 (GRAU index: 11D69): A module comprising three RD-250PM. Propulsion module of the Tsyklon-3 first stage.
Comparison
Possible technological transfer to North Korea
Several experts think that technology from the RD-250 engine could have been transferred to North Korea from Russia. This transfer would explain the rapid progress of North Korea in the development of two new missiles: the intermediate-range Hwasong-12 and the intercontinental ballistic missile (ICBM), Hwasong-14. Due to complexity of the technology involved in this type of engine, modifications or reverse engineering seem difficult to achieve. Thus it is believable that complete hardware could have been bought on black market and directly shipped to North Korea, by Russia or Ukraine.[2] Conversely, there is analysis[3] (made by two Ukrainian authors) suggesting an alternative mechanism for North Korea to receive R-36 missile engines, or an entire missile, from USSR or Russia.
See also
- R-36 (missile) - ICBM for which this engine was originally developed.
- Tsyklon-2 - launch vehicle based on the R-36.
- Tsyklon-3 - Three stage launch vehicle developed from the Tsyklon-2.
- Cyclone-4M - launch vehicle based on the R-36
- Rocket engine using liquid fuel
External links
References
- The RD-250 engine at the center of an international storm www.russianspaceweb.com, retrieved 2023-01-03^
- The secret to North Korea’s ICBM success www.iiss.org, retrieved 2017-08-15^
- North Korean Missile Engines: Not from Ukraine, Mariana Budjeryn & Andrew Zhalko-Tytarenko, Atlantic Council, 2017-09-12^
- RD-250 Encyclopedia Astronautica, retrieved 2015-06-20^
- RD-251 Encyclopedia Astronautica, retrieved 2015-06-20^
- RD-252 Encyclopedia Astronautica, retrieved 2015-06-20^
- RD-261 Encyclopedia Astronautica, retrieved 2015-06-20^
- RD-262 Encyclopedia Astronautica, retrieved 2015-06-20^
- Nicolas Pillet. Tsiklone - Le premier étage Kosmonavtika.com, retrieved 2016-07-04^
- Nicolas Pillet. Tsiklone - Le deuxième étage Kosmonavtika.com, retrieved 2016-07-04^
- NPO Energomash list of engines NPO Energomash^