Energia (rocket)

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Energia (officially designated 11K25, Russian: Энергия) was a super-heavy lift launch vehicle developed by the Soviet Union. Built primarily to support the Buran space shuttle program, it was the most powerful launch vehicle in Soviet and Russian space history, with a low Earth orbit payload capacity comparable to the U.S. Saturn V rocket.

Key moments

  • 1974-05Soviet Union scraps the failed N1 lunar rocket program and begins conceptual design of Energia as its replacement
  • 1976OKB-1 (later renamed RKK Energia) starts formal development of the Energia launch system
  • 1987-05-15First test launch of the Energia rocket
  • 1988-11-15Second and final launch, carrying the uncrewed Buran space shuttle on its only orbital test flight
  • Early 1990sEnergia program is officially retired following the dissolution of the Soviet Union

Development Background and Strategic Goals

Energia was developed to replace the unsuccessful N1 lunar rocket, which suffered multiple catastrophic test failures in the early 1970s. The program was primarily driven by the Soviet Union's desire to match the United States' Space Shuttle program capabilities, with core objectives including launching large space station modules, heavy satellites, and reusable orbital vehicles. It served as the centerpiece of a broader Soviet space infrastructure project that included advanced rocket engines and companion launch vehicles like the Zenit.

Design and Performance Capabilities

The baseline Energia was a "one-and-a-half-stage" launch vehicle, paired with kerosene-liquid oxygen strap-on boosters and a liquid hydrogen-liquid oxygen core stage. It could carry up to 100 tons to a 200km low Earth orbit (51.6-degree inclination), with reduced payload capacities for geosynchronous transfer orbit, lunar transfer, and deep space missions. At the time of its development, it held the record for the highest launch thrust among operational rockets worldwide.

Legacy and Impact

The Energia program only conducted two official launches before being discontinued. Despite its short operational life, key technologies from the program—especially the RD-170 high-pressure combustion-cycle engine—were later adapted for use in modern Russian launch vehicles such as the Soyuz-5 and Angara series. The rocket remains an important symbol of Soviet heavy-lift space technology, and its design principles influenced subsequent super-heavy launch vehicle development globally.

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".[4][5] 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.[6]

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,[7] 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.[3] 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.[7] 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.

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,[7] 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".[8] This configuration required the addition of an upper stage to perform the final orbital insertion.[8] The first launch of the Energia was in the configuration of a heavy launch vehicle, with the large Polyus military satellite as a payload, however Polyus failed to correctly perform the orbital insertion.

Due to the termination of the Buran program the Energia program was concluded after only two launches. The legacy of Energia/Buran project manifests itself in the RD-170 family of rocket engines, and the Zenit launcher, with the first stage roughly the same as one of the Energia first-stage boosters.

Stages/Components

Block A first stage

The first stage, Block A was four strap-on boosters weighing in at 340 tons with fuel included. The boosters had a burn time of 156 seconds from takeoff. They used one RD-170 engine for each booster, four in total. Each booster was 40 meters (131.2 ft) tall and 3.9 meters (12.7 ft) wide. The stage used kerosene as fuel.[6]

The boosters' thrust was 7,906.100 kN in a vacuum.[9]

Block Ts second stage

The second stage, Block Ts was the core/center stage of the rocket weighing in at about 50 tons with fuel included. The stage had a burn time of 470 seconds from takeoff. They had used 4 one-chamber RD-O120 engines. The stage was 59 meters (193.5 ft) tall and 7.75 meters (24.4 ft) wide. The center used liquid hydrogen as fuel instead of the kerosene used in the boosters.[6]

The core stage had 7,848.124 kN of thrust in a vacuum.[9]

Launch history

First launch (Energia–Polyus)

The Energia was first test-launched on 15 May 1987, with the Polyus spacecraft as the payload. An FGB ("functional cargo block") engine section originally built as a cancelled Mir module was incorporated into the upper stage used to insert the payload into orbit, similarly to Buran and the US Space Shuttle performing the final orbital insertion, since the planned "Buran-T" upper stage had not yet progressed beyond the planning stage.[8] The intended orbit had 280 km (170 mi) altitude and 64.6° inclination.[10]

The Soviets had originally announced that the launch was a successful sub-orbital test of the new Energia booster with a dummy payload, but sometime later it was revealed that in fact the flight had been intended to bring the Polyus into orbit. The two stages of the Energia launcher functioned as designed, but due to a software error in its attitude control system, Polyus's orbital insertion motor failed to inject the payload into orbit. Instead, the Polyus reentered the atmosphere over the Pacific Ocean.[11]

Second launch (Energia–Buran)

The second flight, and the first one where payload successfully reached orbit, was launched on 15 November 1988. This mission launched the uncrewed Soviet Shuttle vehicle Buran. At apogee, the Buran spacecraft made a 66.7 m/s burn to reach a final orbit of 251 km × 263 km.[7][12]

Discontinuation and potential revival

Production of Energia rockets ended with the end of the Buran shuttle project in the late 1980s, and more certainly, with the fall of the Soviet Union in 1991. Since that time, there have been persistent rumors of the renewal of production, but given the political realities, that is highly unlikely.[17]

While the Energia is no longer in production, the Zenit boosters were in use until 2017. The four strap-on liquid-fuel boosters, which burned kerosene and liquid oxygen, were the basis of the Zenit rocket which used the same engines. The engine is the four combustion chamber RD-170. Its derivative, the RD-171, was used on the Zenit rocket. A half-sized derivative of the engine, the two-chamber RD-180, powered the American Lockheed Martin Atlas III vehicle,[18] and still powers the Atlas V rocket, while the single-chamber derivative, the RD-191, has been used to launch the Korean Naro-1 (as a reduced-thrust variant named the RD-151) and the Russian Angara rocket. The RD-181, based on the RD-191, was used on the Antares 200 series rocket.[19]

In August 2016, Roscosmos announced conceptual plans to develop a super heavy-lift launch vehicle from existing Energia components (particularly the RD-171 engine for side boosters)[20] instead of pushing the less-powerful Angara A5V project.[21] This would allow Russia to launch missions towards establishing a permanent Moon base with simpler logistics, launching just one or two 80–160-ton super-heavy rockets instead of four 40-ton Angara A5Vs implying quick-sequence launches and multiple in-orbit rendezvous.[22] Tests of RD-171MV engine, an updated version of the engine used in Energia, were completed in September 2021 and may potentially be used in the successor Soyuz-5 rocket.[23]

Proposed variants

Three major design variants were conceptualized after the original configuration, each with vastly different payloads.

Energia-M

The Energia-M was an early-1990s design configuration and the smallest of the three. The number of boosters was reduced from four to two, the core stage was shortened and fitted with just one RD-0120 engine. It was designed to replace the Proton rocket, but lost a 1993 competition to the Angara rocket.[24][25]

A non-functional prototype ("structural test vehicle") of the Energia M still exists in the Dynamic Test Stand facility at Baikonur Cosmodrome.[26]

Energia-2 (GK-175)

Energia-2 was an evolution of the Energia studied in the 1980s. Unlike the Energia-Buran, which was planned to be semi-reusable (like the U.S. Space Shuttle), the GK-175 concept was to have allowed the recovery and reuse of all elements of the vehicle, similarly to the original, fully reusable Orbiter/Booster concept of the U.S. Shuttle.[27][28] The Energia-2 core as proposed would be capable of re-entering and gliding to a landing.[27]

Vulkan

The final never-built design concept was also the largest. With eight Zenit booster rockets and an Energia-M core as the upper stage, the Vulkan (which shared the name with another Soviet heavy lift rocket that was cancelled years earlier) configuration was initially projected to launch up to 200 metric tonnes into 200 km orbit with inclination 50.7°.[29]

The development of the Vulkan and the refurbishment of Universal Test Stand and Launch Pad at site 250 for its launches was in progress between 1990–1993 and abandoned soon after due to a lack of funds and the collapse of the Soviet Union.[30]

Comparison with the Space Shuttle

The Energia rocket was created as a response to the Americans building the Space Shuttle and was heavily based on the already designed Space Shuttle. While the Shuttle was made as a cheaper alternative for spaceflight, the Russians were paranoid about its use as a military weapon and responded by designing and building Energia-Buran.[31]

The Space Shuttle could only bring a maximum 30 tonnes to LEO[32], but the Energia could bring a maximum 100 tonnes to LEO. This makes the Space Shuttle a heavy-lift launch vehicle and the Energia a super-heavy lift launch vehicle.

The Space Shuttle program lasted 30 years, operating from 1981 to 2011. The Energia program began in 1976 and after its only two launches officially ended in 1993 and in total operated for 17 years.[6]

See also

  • Comparison of orbital launchers families
  • Comparison of orbital launch systems

References

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  2. Energia Characteristics^
  3. Launch vehicle "Energia" Official Site^
  4. Krivonosov, Khartron: Computers for rocket guidance systems^
  5. Control systems for intercontinental ballistic missiles and launch vehicles^
  6. Energia www.russianspaceweb.com, retrieved 2025-10-18^
  7. Energiya-Buran: The Soviet Space Shuttle Springer Science & Business Media, 2007^
  8. B. Hendrickx, "The Origins and Evolution of the Energiya Rocket Family," J. British Interplanetary Soc., Vol. 55, pp. 242-278 (2002).^
  9. Mark Wade. Energia www.astronautix.com^
  10. Vassili Petrovitch, Polyus (accessed 21 September 2010).^
  11. Polyus Astronautix, retrieved September 25, 2017^
  12. Mark Wade, Encyclopedia Astronautics, Buran. (accessed 21 September 2010).^
  13. Vadim Lukashevich. Manufacturing History of the Energia Launch Vehicle buran.ru, retrieved 25 January 2018^
  14. Vadim Lukashevich. The Polyus Spacecraft buran.ru, retrieved 25 January 2018^
  15. Dwayne A. Day, Robert G. III Kennedy. Soviet Star Wars: The launch that saved the world from orbiting laser battle stations Air & Space/Smithsonian, January 2010, retrieved 25 January 2018^
  16. Vadim Lukashevich. Timeline of the flight of Buran on 15 November 1988 buran.ru, retrieved 25 January 2018^
  17. Russia plans to revive super Soviet Energia missiles scienceinfo.net, 12 December 2018^
  18. Atlas Launch System Payload Planner's Guide Lockheed Martin, December 1998, retrieved 12 July 2022^
  19. First Angara rocket launched on suborbital test flight Spaceflight Now, July 9, 2014, retrieved July 9, 2014^
  20. Roscosmos To Develop New Super-heavy Rocket Russian Space News, August 22, 2016^
  21. http://izvestia.ru/news/628028 Izvestia, August 22, 2016^
  22. Anatoly Zak. Russia's New Rocket Project Might Resurrect a Soviet-Era Colossus Popular Mechanics, Hearst Digital Media, 24 July 2018, retrieved 24 October 2019^
  23. Eric Berger. Rocket Report: Next Falcon Heavy launch date set, Soyuz 5 engines clear tests Ars Technica, 9 October 2021^
  24. This Immense Russian Rocket Was Abandoned For Decades Popular Mechanics, 2015-07-06, retrieved 2017-05-28^
  25. Origin of the Angara project www.russianspaceweb.com, retrieved 2021-07-15^
  26. John Wenz. This Immense Russian Rocket Was Abandoned For Decades Popular Mechanics, 2015-07-06, retrieved 2021-03-24^
  27. Б.И.Губанов. Триумф и трагедия «Энергии» глава 41^
  28. The Space Shuttle – NASA Technical Reports Server (NTRS) nasa.gov, 2011^
  29. Boris Gubanov. Триум и трагедия "Энергии" NIER, 1998^
  30. Robert Godwin. Russian Spacecraft Apogee Books, 2006^
  31. Why Did the Soviets 'Copy' the Space Shuttle? Flite Test, February 20, 2019^
  32. JoAnne Calhoun. The Space Shuttle - Description, operation, and evolution nasa.gov, January 1, 1982^