The NK-33 and NK-43 engines were designed during the height of the US / Soviet Space Race to place a man on the moon.  Built by the renowned gas turbine design bureau, ND Kuznetsov Joint Stock Company Scientific-Technical Complex of Samara Russia, the NK-33 and NK-43 engines are upgraded versions of the NK-15 and NK-15B engines which flew on the first four flights of the Russian N-1 moon launcher.  The NK-33 and NK-43 engines were designed to provide improved thrust, reliability, and to provide a restart capability which would allow all engines to be acceptance tested before being flown.

Today, the NK-33 and NK-43 engines are being marketed commercially by GenCorp Aerojet of Sacramento, CA.  Despite being developed in the late 1960's, the NK family is still the highest performing LOX / RP (kerosene) set of rocket engines ever produced.  Aerojet has contracted with Kistler Aerospace to provide updated versions of the NK-33 and NK-43 engines for the K-1 RLV.  Currently, Aerojet is in discussions with NASDA to provide the NK-33 engine as the first stage of an upgraded J-class ELV.  Kelly Space and Technology of San Bernardino, CA has stated that they would like to use NK-33 engines for the first stage of their Astroliner RLV.