An overview of the K-1 reusable propulsion system

Modification and verification testing of a Russian NK-33 rocket engine for reusable and restartable applications

“…For the Kistler vehicle, the main combustion chamber will operate at a nominal mixture ratio of 2.59 and nominal chamber pressure (defined as 100% power level) of 2109 psia. 4 At these conditions, the preburner will operate at a nominal mixture ratio of 58 and chamber pressure of 4670 psia, with a combustion gas temperature of 670 R. Without operation of the mixture ratio valve, the mixture ratio of the engine will increase as the power level is American Institute of Aeronautics and Astronautics reduced, to about 2.75 at 75% chamber pressure level, and about 2.90 at 50% chamber pressure level. Activation of the mixture ratio control valve will provide 20% control capability in mixture ratio over the whole thrust range.…”

“…The Russian NK-33 and NK-43 engines have been modified for installation and operation on the Kistler K-l launch vehicle. 4 Modifications on the basic engine are summarized in Table II. Additional modifications required to produce a restartable NK-33 configuration are summarized in Table III. All new components have undergone qualification testing at the component level. For valves, EMAs, pyrotechnics, and sensors this testing included thermal cycling, performance verification, and vibration testing.…”

“…Requirements for the Kistler K-l vehicle call for a gimbal range of +/-6 degrees. 4 The gimbal American Institute of Aeronautics and Astronautics bearing is modified from the bearing for the space shuttle main engine (SSME). Modifications include shortening the bearing for improved integration into the Kistler vehicle, and replacing the titanium alloy used for the cryogenic environment on the SSME with a readily available and less expensive titanium alloy.…”

“…Modifications to the NK-33 engine for a Western flight vehicle were subsequently initiated for the Kistler K-l flight vehicle. 4 These modifications included new features for interface to and control by the K-l vehicle, and variations of the original Russian engine to enhance operability for use on a reusable vehicle.…”