develop RP-1/LOX engines on the scale of the Saturn F-1. When Korolev also suggested developing a liquid hydrogen engine for the N-1, Glushko said that LH2 was completely impractical as a rocket fuel. The UR-700, Glushko said, could enable a direct-ascent trajectory to the Moon which he considered safer and more reliable than the rendezvous-and-dock approach used by the Apollo program and Korolev's N-1 proposals. He also imagined the UR-700 and 900 in all sorts of applications from lunar bases to manned Mars missions to outer planet probes to orbiting battle stations. When Korolev died in January 1966, his deputy Vasily Mishin took over the OKB-1 design bureau. Mishin succeeded in getting the Kremlin to terminate the UR-700/900 project as well as the RD-270 engine Glushko planned for the launch vehicle family. His main arguments were the tremendous safety risk posed by a low-altitude launch failure of the UR-700 in addition to the waste of money by developing two HLV families at once. After the complete failure of the Soviet manned lunar effort, unmanned Mars missions, and the deaths of four cosmonauts, Mishin was fired in 1973 and the Kremlin decided to consolidate the entire Soviet space program into one organization headed by Glushko. One of Glushko's first acts was to suspend the N-1 program, which however was not formally terminated until 1976. He then began work on a completely new HLV. During this time, the US was developing the Space Shuttle. Glushko decided that the new HLV, Energia, would use entirely liquid-fueled engines, with an LH2 core stage taking the place of the Shuttle main engines, and the Shuttle's solid-propellant strap-on boosters with liquid boosters using LOX/RP-1 RD-170 engines. While the RD-120 engine used for the Energia core stage was developed quickly and with little difficulty, the RD-170 proved harder to work out. Glushko instead decided to use an engine with four combustion chambers fed from a single propellant feed line. The RD-170 powered strap-on boosters designed for Energia became the basis for the Zenit booster family which began flying in 1985. Since the Buran space shuttle was not ready for operations, Energia's maiden flight in May 1987 carried aloft a prototype space station module called Polyus. Ultimately, Buran did fly the following summer, a few months before Glushko's death. While Energia and Buran fell victim to loss of funding after the collapse of the USSR, the RD-170 engines