YF-100 and YF-115. According to a WikiLeaks cable dated, September 28, 2007, the Ukrainian government denies any involvement of Ukrainian industry in that transfer, and states that no involvement, at least until 2007, had happened with the Chinese 11th nor 4th Academy regarding the transfer of RD-120 technology. The RD-120 had significant margins built in, which allowed between 2001 and 2003 to develop a modernized 'Uprated' or 'Forced' version of the engine for Sea Launch which increased thrust 10% to . It also incorporated many improvements, which allowed it to increase chamber pressure and thrust without additional weight gain. It still has a 5% extra margin, extended the design life to 4260 seconds, the number of ignitions to 19 and allows to consider it as a base for a reusable rocket, the engine is still not capable of restarting inflight. After a program that used 4 test engines and performed 28 hot fire tests with an accumulated running time of 8,135 seconds, the engine was qualified for flight. Testing started in March 2004 and it had its debut flight on February 15, 2006 where it successfully orbited EchoStar X. Versions This engine has had two operative versions and some proposed variations: RD-120 (GRAU Index 11D123): Original version developed for the Zenit-2 second stage. The main characteristics is that it uses a vertical turbopump, since the fuel tank is a torus and the engine has to fit in the center hole. RD-120 (augmented thrust) (GRAU Index 11D123): Thrust augmented version developed for the Zenit-3SL second stage. Some authors identified it as the RD-120M (GRAU Index 11D123M). RD-120K: Project of unknown first stage project. Had reduced expansion area and the subsystem arrangements was done to reduce total length. It had enough development done that it actually performed some fire tests. RD-120M: Version proposed for the X-34 program. It added a gimbaled mount, and was test fired in the USA. RD-120U: Version proposed for the ULV-22. RD-146 RD-182: Methane / LOX version of the RD-120K. Proposed for the Riksha launch vehicle project for the Makeyev Rocket Design Bureau. RD-182M: LNG / LOX version of the RD-182. Proposed for the Vozdushnyy Start launch vehicle project. RD-870: Ukrainian version of RD-120K with Russian-produced combustion chamber replaced with modified RD-263 engines from stocks, being developed by Yuzhnoye Design Bureau for use in the first stage of Cyclone-4M SLV. Technological derivatives Not considering straight variations of the