Proposed Russian version of RL10A-4-1 by Pratt & Whitney. Main modification are new turbopumps. May be derivative of RD-0128 project. Pratt & Whitney signed a preliminary marketing agreement on 7 April 2000 with Russia’s Chemical Automatics Design Bureau giving Pratt & Whitney exclusive international marketing rights to the RD-0146 which CADB had been developing for the new Angara rocket family. The RD-0146 thrust level fell between those of Pratt & Whitney’s workhorse RL-10 and the cancelled Euro-American SPW-2000. As of 2007 the engine was being marketed for use in future high performance upper stages for the Onega (improved Soyuz), Proton, or Angara launch vehicles. Performance here is from KBKhA web site, 2007. Original quoted performance was 100 kN thrust / 470 sec specific impulse.