|Country of origin||Soviet Union|
|Designer||Kuznetsov Design Bureau|
|Propellant||LOX / kerosene|
|Thrust (vac.)||1,753 kN (394,000 lbf)|
|Thrust (SL)||1,505 kN (338,000 lbf)|
|Chamber pressure||14.50 MPa (2,103 psi)|
|Isp (vac.)||331 seconds (3.25 km/s)|
|Isp (SL)||297 seconds (2.91 km/s)|
|Length||3.7 m (12 ft)|
|Diameter||2 m (6 ft 7 in)|
|Dry weight||1,247 kg (2,749 lb)|
The NK-15 (GRAU index 11D51) is a rocket engine designed and built in the late 1960s by the Kuznetsov Design Bureau. The NK designation is derived from the initials of chief designer Nikolay Kuznetsov. The NK-15 was among the most powerful LOX/RP-1 rocket engines when it was built, with a high specific impulse and low structural mass. It was intended for the ill-fated Soviet N-1 Moon rocket.
The engine equipped the N1 rocket which had four consecutive launch failures all due to this engine. Its successor the NK-33 allowing multiple fire resistance tests and increased life service was to be used on the N1F, a new version of the N1, but the program was canceled.