production with Yuzhmash. In February, 1977, the preliminary design of the RD-120 was finished. And on January 31, 1979 the first fire test of the RD-120 was performed. The RD-120 had a complicated debut, with the second stage failing on its first (April 13, 1985), second (June 21, 1985) and fourth (December 28, 1985) flights. While only the first failure could be attributed to the RD-120 —the propellant flow regulator had a leak and the stage ran out of propellant before being orbital—, the program initial performance was quite troubling. Eventually it proved its worth, and by December 1987 the RD-120 (and the Zenit) were considered commissioned. But in the years of the Soviet dissolution, the second stage failed twice in a row on August 30, 1991 and February 5, 1992. Zenit had other second stage failures, but only the first one has ever been attributed directly to the RD-120 itself. During 1990, the NPO Energomash Head of the Propulsion Department, and leading designer, V.K.Chvanov, was awarded the State Prize for the creation of RD-120. In October 1992, Pratt & Whitney signed an agreement with NPO Energomash to sale and represent their line of engine in the United States. During the initial version of the X-34 program, the one trying to develop a reusable launch vehicle for small payloads through a public/private association, the RD-120 was seriously considered for the 747 air-launched first stage. The RD-120 offered the best price and performance, and was the preferred choice of Orbital Sciences. In fact, on October 11, 1995, the RD-120 was fired on the U.S. and thus became the first Russian rocket engine actively in production to be fired in American soil. This version of the engine, would mainly differ from the Zenit in the addition of a gimbal mount that would enable it to offer TVC. This version would be known as the RD-120M. The second private partner in the X-34 program, Rockwell International, wanted to use their own engine, the RS-27. And given the constrained schedule and budget of the program, the engine selection was not able to be resolved and the program cancelled and reimplemented as the pure NASA research program that the X-34 was later known for. Also during the 1990s, the Chinese acquired two or three models of the RD-120, and possibly some documentation. This enabled them to bootstrap their indigenous kerosene staged combustion engine program, the