The Kuznetsov NK -33 (internal 11D111 ) was a Soviet liquid rocket engine of the design office Kuznetsov from Samara, which was originally developed for the N1 moon rocket.


The engine was developed in the late 1960s from the upcoming all flight tests of the N1 used NK -15 engine and should provide a higher thrust and greater reliability than this and be up to 15 times wiederzündbar part. When N1 program 30 engines NK - 33 in the first stage and eight NK -43 should be used in the second stage. The engines were ready for use in 1974, but were never used because of the program was terminated. A total of 208 NK -33 and NK -43 built 42 engines, of which about 150 were mothballed.

The engines are still very progressive, as they had to reach the maximum thrust for the N1. They work with a very high combustion chamber pressure, regenerative cooling and in the main stream method in which the propellant feed turbines by a signal generated in a pre-combustion chamber working gas ( staged combustion cycle) are driven. This procedure is only rarely (for example, in the main engines of the Space Shuttle ) applied because the hot oxygen-rich exhaust gases from the combustion prechamber metal attack and damage as the main combustion chamber and the nozzle. This problem was solved, however, by Soviet engineers, as tests with a long burn time showed in the late 1970s. The engines are in the range of 55 to 104% of nominal thrust controlled by the excess oxygen is changed during combustion. The variant NK -43 ( 11D112 and AJ26 -60) was (similar to the NK -15W ) as modified upper variant with significantly extended nozzle ( adaptation to the vacuum) and thus projected higher thrust and better specific impulse.


The engines are used in the first stage of the commercial U.S. launcher Antares as AJ26 -61. The successful maiden flight of the Antares rocket took place on 21 April 2013. After the development of the N1 rocket in the Soviet Union was canceled before it came to a flight of the NK -33 engines in the N1F, this represents the first use of these engines dar.

Planned operations

Nikolai Dmitrievich Kuznetsov suggested the engines mid-1970s before the first stage of the Proton and later also for the Zenit rocket. However, this was never realized.

In the late 1990s, the decades intercalated engines U.S. companies were offered for sale since been exported to the USA and also been used. Originally they were to be used in the Kistler K -1. The Kistler bought 58 of the remaining engines NK - 33 and NK - 18 43 for 440 million U.S. dollars, and let this be modified by the company Aerojet (swiveling part, replacement of rubber parts, new electronics). The modified engines hot AJ26 -58 or 59 (NK - 33) and AJ26 -60 ( NK -43 ). At a use of the engines, it did not come at Kistler due to the insolvency of the company in 2010, however.

In Russia there been efforts, the NK -33 engines in the modernized Soyuz rocket ( Soyuz -2- 1w, Soyuz -2-3 and Soyuz -3) to use. It is envisaged that the first Soyuz -2- 1v deliver end of 2013.