Energia (; GRAU 11K25) was a 1980s super-heavy lift launch vehicle. It was designed by NPO Energia of the Soviet Union as part of the Buran program for a variety of payloads including the Buran spacecraft. Control system main developer enterprise was the Khartron NPO "Electropribor". The Energia used four strap-on boosters each powered by a four-chamber RD-170 engine burning kerosene/LOX, and a central core stage with four single-chamber RD-0120 (11D122) engines fueled by liquid hydrogen/LOX. The launch vehicle had two functionally different operational variants: Energia-Polyus, the initial test configuration, in which the Polyus system was used as a final stage intended to put the payload into orbit, and Energia-Buran, in which the Buran orbiter was the payload and the source of the orbit insertion impulse. The launch vehicle had the capacity to place about 100 tonnes in Low Earth orbit, up to 20 tonnes to geostationary orbit and up to 32 tonnes by translunar trajectory into lunar orbit. The launch vehicle made just two flights before being discontinued. Since 2016, there have been attempts to revive the launch vehicle, reusing an updated version of its booster engine in the Soyuz-5 rocket. Development history Work on the Energia/Buran system began in 1976 after the decision was made to cancel the unsuccessful N1 rocket. The facilities and infrastructure built for the N1 were reused for Energia (notably the huge horizontal assembly building), just as NASA reused infrastructure designed for the Saturn V in the Space Shuttle program. Energia also replaced the "Vulkan" concept, which was a design based on the Proton and using the same hypergolic propellants, but much larger and more powerful. The "Vulkan" designation was later given to a variation of the Energia which has eight boosters and multiple stages. The Energia was designed to launch the Soviet "Buran" reusable shuttle, and for that reason was designed to carry its payload mounted on the side of the stack, rather than on the top, as is done with other launch vehicles. Design of the Energia-Buran system assumed that the booster could be used without the Buran orbiter, as a heavy-lift cargo launch vehicle; this configuration was originally given the name "Buran-T". This configuration required the addition of an upper stage to perform the final orbital insertion. The first launch of the Energia was in the configuration of a heavy launch vehicle, with the large Polyus military satellite as a payload,