Energia (rocket)

Energia (Russian: Энергия, romanized: Energiya, lit.'Energy'; GRAU: 11K25, Sheldon: K-1, DoD: SL-17) 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 program was launched in 1976, following the cancellation of the unsuccessful N1 rocket designed for Soviet crewed lunar missions. Energia was the Soviet Union's first successful super-heavy lift launch vehicle, and the world's second, after the US Saturn V.

The launch vehicle made just two flights before being discontinued, carrying Polyus in 1987 and the Buran orbiter in 1988. Since 2016, there have been attempts to revive the launch vehicle. Its RD-170 booster engine was at the time the most powerful rocket engine to use liquid fuel, and scaled-down versions of the RD-170 have been used, with a dual-chamber derivative on the US Atlas III and Atlas V, and single-chamber derivatives on the Russian Angara rockets, US Antares 200, and South Korean Naro-1.