RD-0233
The RD-0233 and RD-0234 are liquid rocket engines, burning N2O4 and UDMH in the oxidizer rich staged combustion cycle. The only difference between the RD-0233 and the RD-0234 is that the latter has a heat exchanger to heat the pressuring gasses for the tanks. Three RD-0233 and one RD-0234 are used on the first stage of the UR-100UTTKh ICBM. While the engine is out of production, the ICBM as well as Rokot and Strela remain operational as of 2015.
