The NK-9 was a rocket engine designed and built in 1959 by the Kuznetsov Design Bureau. The NK designation was derived from the initials of chief designer Nikolay Kuznetsov. It was intended for the R-9 Desna, but lost this bid to the RD-111. It was the world's first oxygen-kerosene engine in the 1 MN+ thrust class to use a closed-cycle design with staged combustion of generator gas in the combustion chamber. For the second stage of this missile, the NK-9V engine was developed, with testing starting in September 1962. In the early 1960s, the NK-19 was created, for use on an upgraded R-9 first stage, along with the NK-21. Both were cancelled. It was later developed into the NK-31, which was intended to be used on variants of the N-1, which were also cancelled.
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External links Information of NK-9 More info on NK-9