--- title: "Buran programme" chunk: 2/5 source: "https://en.wikipedia.org/wiki/Buran_programme" category: "reference" tags: "science, encyclopedia" date_saved: "2026-05-05T12:39:22.205241+00:00" instance: "kb-cron" --- === Programme development === The development of the Buran began in the early 1970s as a response to the U.S. Space Shuttle program. Soviet officials were concerned about a perceived military threat posed by the U.S. Space Shuttle. In their opinion, the Shuttle's 30-ton payload-to-orbit capacity and, more significantly, its 15-ton payload return capacity, were a clear indication that one of its main objectives would be to place massive experimental laser weapons into orbit that could destroy enemy missiles from a distance of several thousands of kilometres. Their reasoning was that such weapons could only be effectively tested in actual space conditions and that to cut their development time and save costs it would be necessary to regularly bring them back to Earth for modifications and fine-tuning. Soviet officials were also concerned that the U.S. Space Shuttle could make a sudden dive into the atmosphere to drop nuclear bombs on Moscow. In 1974, Valentin Glushko's design bureau, OKB-1 (later NPO Energiya), proposed a new family of heavy-lift rockets called RLA (Russian: РЛА, «Ракетные Летательные Аппараты», romanized: Raketnyye Letatel'niye Apparaty, lit. 'Rocket Flying Apparatus'). The RLA concept included the use of kerosene and liquid hydrogen as fuel, and liquid oxygen as oxidizer (both new technologies in the Soviet space programme), with the shuttle orbiter being one possible payload. While NPO Molniya conducted development under the lead of Gleb Lozino-Lozinskiy, the Soviet Union's Military-Industrial Commission, or VPK, was tasked with collecting all data it could on the U.S. Space Shuttle. Under the auspices of the KGB, the VPK was able to amass documentation on the American shuttle's airframe designs, design analysis software, materials, flight computer systems and propulsion systems. The KGB targeted many university research project documents and databases, including Caltech, MIT, Princeton, Stanford and others. The thoroughness of the acquisition of data was made much easier as the U.S. shuttle development was unclassified. By 1975, NPO Energiya had come up with two competing designs for the orbiter vehicle: the MTKVP (Russian: МТКВП, «Многоразовый Транспортный Корабль Вертикальной Посадки», romanized: Mnogorazoviy Transportniy Korabl' Vertikal'noy Posadki, lit. 'Reusable Vertical Landing Transport Ship'), a 34-meter-long lifting body spaceplane launched on top of a stack of kerosene-fuelled strap on boosters; and the OS-120 (Russian: ОС-120, «Орбитальный Самолет», romanized: Orbital'niy Samolet, lit. 'Orbital Spaceplane–120 tons'), a close copy of the US Space Shuttle based on US Space Shuttle documentation and designs obtained through the VPK and KGB. The OS-120 was a delta-winged spaceplane based heavily on the US Space Shuttle design, equipped with three liquid hydrogen engines, strapped to a detachable external tank and four liquid fuel boosters (NPO Energiya even considered the use of solid propellant rocket boosters, further imitating the US Shuttle's configuration). A compromise between these two proposals was achieved by NPO Energiya in January 1976 with the OK-92 (Russian: ОК-92, «Орбитальный Корабль», romanized: Orbital'niy Korabl', lit. 'Orbital Ship–92 tons'), a delta-winged orbiter equipped with two Soloviev D-30 turbofan jet engines for autonomous atmospheric flight, launched to space from a rocket stack made of a core stage with three cryogenic engines, and four kerosene-fuelled boosters, each with four engines. By 1978, the OK-92 design was further refined, with its final configuration completed in June 1979. Soviet engineers were initially reluctant to implement a spacecraft design with so many similarities to the US Space Shuttle. Although it has been commented that wind tunnel testing showed that NASA's design was already ideal, the shape requirements were mandated by its potential military capabilities to transport large payloads to low Earth orbit, themselves a counterpart to the Pentagon's initially projected missions for the Shuttle. Even though the Molniya Scientific Production Association proposed its Spiral programme design (halted 13 years earlier), it was rejected as being altogether dissimilar from the American shuttle design. The construction of the shuttles began in 1980, and by 1984 the first full-scale Buran was rolled out. The first suborbital test flight of a scale-model (BOR-5) took place as early as July 1983. As the project progressed, five additional scale-model flights were performed. A test vehicle was constructed with four jet engines mounted at the rear; this vehicle is usually referred to as OK-GLI, or as the "Buran aerodynamic analogue". The jets were used to take off from a normal landing strip, and once it reached a designated point, the engines were cut and OK-GLI glided back to land. This provided invaluable information about the handling characteristics of the Buran design, and significantly differed from the carrier plane/air drop method used by the United States and the Enterprise test craft. Twenty-four test flights of OK-GLI were performed by the Gromov Flight Research Institute test pilots and researchers after which the shuttle was "worn out". The developers considered using a couple of Mil Mi-26 helicopters to "bundle" lift the Buran, but test flights with a mock-up showed how risky and impractical that was. The VM-T ferried components and the Antonov An-225 Mriya (the heaviest airplane ever) was designed and used to ferry the shuttle. The flight and ground-testing software also required research. In 1983 the Buran developers estimated that the software development would require several thousand programmers if done with their existing methodology (in assembly language), and they appealed to Keldysh Institute of Applied Mathematics for assistance. It was decided to develop a new high-level "problem-oriented" programming language. Researchers at Keldysh developed two languages: PROL2 (used for real-time programming of onboard systems) and DIPOL (used for the ground-based test systems), as well as the development and debugging environment SAPO PROLOGUE. There was also an operating system known as Prolog Manager. Work on these languages continued beyond the end of the Buran programme, with PROL2 being extended into SIPROL, and eventually all three languages developed into DRAKON which is still in use in the Russian space industry. A declassified May 1990 CIA report citing open-source intelligence material states that the software for the Buran spacecraft was written in "the French-developed programming language known as Prolog", possibly due to confusion with the name PROLOGUE.