Korolev completed the design of the gigantic N-1 on December 25, 1964. It was almost exactly as tall as the Saturn V, but it used only traditional fuels—liquid oxygen and kerosene—with modestly powered engines and several nozzles. It was intended first for EOR, but then for LOR, like the Apollo rockets. Its competitors were Yangel’s R-56 (OKB-586) and Chelomei’s Proton UR-700 (OKB-52), which instead used gigantic UDMH engines (RD-270) developed by Glushko (OKB-456). The UR-700 (for a direct mission to the Moon) had eight in the first stage, four in the second, and an RD-210 in the third, which could launch 30 tons of payload to the Moon. In the USSR, contrary to expectations, there was fierce competition between rival design bureaus (until September 1966 when Mstistlav Keldysh finally chose N-1 for the lunar landing and UR-500K for the translunar mission), even after a project had been chosen, while in the USA, several private companies participated in a tender, but then a design was chosen (1961-62) and continued with that one.
