The RD-856 (Russian: Ракетный Двигатель-856, romanized: Raketnyy Dvigatel-856, lit. 'Rocket Engine 856', GRAU index: 8D69M), also known as the RD-69M, is a four-nozzle liquid-fuel rocket vernier engine, burning a hypergolic mixture of unsymmetrical dimethylhydrazine (UDMH) fuel with dinitrogen tetroxide (N2O4) oxidizer in a gas generator cycle.[3] It was used on the R-36, Tsyklon-2 and Tsyklon-3 second stage as thrust vector control by gimbaling of its nozzle.[3] The engine is distributed through a cylindrical structure that is integrated around the main engine RD-252 module. The structure includes aerodynamic protection for the nozzles.[2] The engine was started by a pyrotechnic ignitor.[2]

The engine was serially produced between 1965 and 1992. It was first launched on December 16, 1965 on an R-36 and its last launch was on January 30, 2009 with the last launch of the Tsyklon-3. The production capability was restarted for the Tsyklon-4 but with the apparent cancellation of the program the engine would still be out of production.[4]

See also

References

  1. ^ "RD-856". Encyclopedia Astronautica. Archived from the original on June 27, 2002. Retrieved 2016-07-06.
  2. ^ a b c Pillet, Nicolas. "Tsiklone - Le deuxième étage" [Tsyklon - The second stage] (in French). Kosmonavtika.com. Retrieved 2016-07-06.
  3. ^ a b c "RD-856". Yuzhnoye. Archived from the original on 29 May 2015.
  4. ^ Krebs, Gunter Dirk (2016-04-24). "Tsiklon". Gunter's Space Page. Retrieved 2016-07-05.


Allikas: https://en.wikipedia.org/wiki/RD-856
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