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Soviet copy of the US Space Shuttle. Unlike the Shuttle, the main engines were not mounted on Buran and were not reused. Representing a huge leap in Soviet space technology and project management - it involved the work of 1206 subcontractors and 100 government ministries. Buran flew only once in 1988. The cost of Buran - 14.5 billion rubles, a significant part of the effort to maintain strategic and technical parity with the United States - contributed to the collapse of the Soviet system and the demise of the spacecraft. In June 1974 a decision was made to start work on an Reusable Space System (MKS) and in October 1974 NPO Energia was given responsibility for the project. The target payload at that time was 80 metric tons. The Energia-Buran Reusable Space System (MKS) had its origins in NPO Energia studies of 1974 to 1975 for a 'Space Rocket Complex Program'. In 1974 the N1-L3 heavy lunar launch vehicle project was cancelled and Glushko was appointed chief designer of the new NPO Energia enterprise, replacing Mishin as the head of the former OKB-1. At the same time in the United States development work was underway on the space shuttle. The US Defense Department planned to use the shuttle for a range of military missions. The Soviet leadership, seeking strategic parity, wished development in the Soviet Union of a reusable manned spacecraft with analogous tactical-technical characteristics. The success of Apollo and the failure of the N1-L3 program pointed to serious deficiencies in the technology base of the Soviet Union. The time-honored Soviet method of rectifying such situations was to copy the foreign technology. To reduce development cost and risk, NASA and USAF shuttle trade studies had settled on a partially reusable design. While the solid propellant booster rockets were recovered, the cryogenic main propellant tank of the shuttle core was expendable. The main engines and guidance system were recovered with the orbiter. The American shuttle design was studied intensively by Russian rocket scientists, but important aspects of it were rejected based on Soviet engineering analysis and technology: The Soviet Union at this point had no experience in production of large solid rocket motors, especially segmented solid rocket motors of the type used on the shuttle. Glushko favored a launch vehicle with parallel liquid propellant boosters. These would use a 700 metric ton thrust four-chamber Lox/Kerosene engine already under development. The high chamber pressure, closed-cycle, reusable 230 metric ton thrust Lox/LH2 main engine being developed for the shuttle was well outside engineering experience in the Soviet Union. No engine using these cryogenic propellants had ever been used in Russian rockets, and the largest such engine under development was the 40 metric ton thrust 11D57. Glushko believed that while a Soviet cryogenic engine of 200 metric tons thrust could be developed in the required time, to develop a reusable engine would be impossible due to limited experience with the propellants. This conclusion led to other important design decisions. If only expendable engines were to be used, there was no need to house them in the re-entry vehicle for recovery. This meant that the orbiter itself could be moved from the lateral mounting of the space shuttle to an on-axis position at the top of the rocket core. The result was the Vulkan - a classic Soviet launch vehicle design: booster stages arranged around a core vehicle, with the payload mounted on top. The elimination of the lateral loads resulted in a lighter booster, and one that was much more flexible. The vehicle could be customized for a wide range of payloads by the use of from two to eight booster stages around a core equipped with from one to four modular main engines. Either a payload container for heavy payloads (Glushko's LEK lunar base) or the military's required spaceplane could be placed on the nose as the payload. As far as the manned orbital vehicle itself, three different primary configurations were studied extensively, as well as a range of more radical proposals. The obvious choice was a straight aerodynamic copy of the US shuttle. The shuttle's form had been selected by NASA and the US Air Force only after painstaking iterative analysis of over 64 alternate configurations from 1968 to 1972. It would obviously benefit the Soviet engineers to take advantage of this tremendous amount of work. However the NPO Energia specialists who had developed the Soyuz capsule disapproved of the winged US shuttle design. They knew from the extensive aerodynamic studies undertaken to develop Soyuz that there were large weight penalties and thermal control problems in any winged design. Their studies indicated that a lifting body shape capable of high angles of bank at hypersonic speed could nearly match winged designs in cross range. Therefore their preferred 1974 design was an unwinged spacecraft, consisting of a crew cabin in the forward conical section, a cylindrical payload section, and a final cylindrical section with the engines for maneuvering in orbit. This unwinged MTKVA would glide to the landing zone at low subsonic speed. The final landing maneuver would use parachutes for initial braking, followed by a soft vertical landing on skid gear using retrorockets. After a great deal of detailed analysis the definitive MTKVA design proposed in May 1976 had a refined aerodynamic shape with a rounded triangular cross section. The 200 metric ton vehicle had over twice the shuttle's mass and nearly three times the shuttle's payload. The third configuration was a smaller spaceplane launched by a Proton-class booster. OKB MiG had been developing the Spiral lifting body spaceplane since 1965, but the project was underfunded and years behind schedule. Spiral was an ambitious concept that was to be launched by a hypersonic air breathing first stage. But the spaceplane itself had been refined in form as a result of years of analysis, wind tunnel, and sub-orbital sub-scale model tests. Chelomei's OKB, whose Raketoplan spaceplane had been cancelled in 1965 in preference to Spiral, also had a contender, the LKS. Evidently owing nothing to earlier Raketoplan designs, this used a shuttle-type wing on a smaller 20 metric ton spacecraft. The government decree 132-51 authorizing development of the Energia-Buran system was issued on 12 February 1976 with the title 'On development of an MKS (reusable space system) consisting of rocket stages, orbiter aircraft, inter-orbital tug, guidance systems, launch and landing facilities, assembly and repair facilities, and other associated facilities, with the objective of placing in a 200 km Northeast orbit a payload of 30 metric tons and returning a payload of 20 metric tons'. The Ministry of Defense was named the Program Manager, with NPO Energia as the prime contractor. The official military specification (TTZ) was issued at the same time with the code name Buran. A declaration of the Presidium on 18 December 1976 directed co-operation between all concerned user, research, and factory organizations in realizing the project. Chief Constructor within NPO Energia was I N Sadovskiy. Chief Designer for the launch vehicle was Y P Kolyako and for the orbiter P V Tsybin. NPO Yuzhnoye in the Ukraine would build the booster rockets. While NPO Energia would build the booster engines, the core Lox/LH2 engines would be built by Kosberg. Chelomei and MiG were to continue, at a modest level, design and test of their LKS and Spiral smaller spaceplanes as backups. The specification of the TTZ set forth payload requirements a bit greater than those set for the US shuttle. It required that the OK orbiter be accomplish the following:
Therefore a straight aerodynamic copy of the US space shuttle, was selected as the orbiter configuration on 11 June 1976. MiG was selected as subcontractor to build the orbiter. For this purpose MiG spun off a new design bureau, Molniya, with G E Lozino-Lozinskiy as chief designer. Wind tunnel tests were conducted on a wide range of possible arrangements of rocket stages and orbiter positions. In the end, Buran was moved to the lateral position, as with the US space shuttle. The main engines, for the reasons given earlier, remained in the core vehicle. The liquid boosters were retained, but reduced to four in number. After being re-stressed for the lateral launch loads, the resulting Energia launch vehicle had half the lift-off mass and payload of the Vulkan. This was sufficient to carry the Buran with its required internal payload of 30 metric tons. The MKS draft project was completed on 12 December 1976. The military assigned the system the index number 1K11K25 and the launch vehicle the article number 11K25. The draft project was reviewed by the expert commission in July 1977, leading to a government decree 1006-323 of 21 November 1977 setting out the development plan. The technical project was completed in May 1978. The flight test plan at the beginning of the project foresaw first launch of the booster in 1983, with the payload being an unmanned OK-ML-1 mock-up of the orbiter. This would not have a heat shield and remain attached to the booster. A second mock-up, OK-ML-2, would be used on the second launch, but be separated from the vehicle after burnout. However it would also be without heat shield, and be expended. The first flight Buran was to fly unpiloted in 1984. Manned flights were to be routine by the 1987 seventieth anniversary of the Soviet Union. The approved launch vehicle layout consisted of the core Block Ts stage, surrounded by 4 Block A liquid propellant boosters and the Buran orbiter or a payload canister. During assembly, transport, and on the pad these were attached to a Block Ya launch services module, which provided all pneumatic, electrical, hydraulic, and other services to the vehicle prior to launch. The modular Energia design could be used for payloads of from 10 to 200 metric tons using various combinations of booster stages, numbers of modular main engines in the core stage, and upper stages. The version with two booster stages was code-named Groza; with four booster stages, Buran; and the six-booster stage version retained the Vulkan name. The 7.7 meter diameter of the core was determined by the maximum size that could be handled by existing stage handling equipment developed for the N1 program. The 3.9 meter diameter of the booster stages was dictated by the maximum size for rail transport from the Ukraine. Propellant selection was a big controversy. Use of solid propellants in the booster stages, as used in the space shuttle, was considered again. But Soviet production of solid fuel motors had been limited to small unitary motors for ICBM's and SLBM's. There was no technological base for production of segmented solid fuel motors, and transport of the motor sections also presented problems. The final decision was to use the familiar Lox/Kerosene liquid propellants for the boosters. In the 1960's Glushko had favored use of toxic but storable chemical propellants in launch vehicles and had fought bitterly against Korolev over the issue. It was surprising that he now accepted use of Lox/Kerosene. But Korolev was dead, and the N1 a failure. Glushko's position had been vindicated, perhaps he now had to agree objectively that use of the expensive and toxic propellants in a launch vehicle of this size was not rational. Another factor may have been that the propellants of the core were going to be cryogenic anyway. Lox/Kerosene propellants for the core were considered, but a primary objective of the project was to seek technological parity with the United States by exploiting technologies developed there. Chief among these in the field of liquid fuel rocketry was the use of Lox/LH2 propellants. Therefore the engines of the core were based on the Space Shuttle Main Engine (SSME) of the USA, with the same thrust rating and specific impulse specifications. Although the SSME may have been the starting point, Soviet engine technology led that of the United States in many other detailed points of liquid rocket design. By the mid-1960's the USA had practically abandoned development of liquid fuel engines, with the sole exception of the SSME. The US military preferred to use solid rocket motors for missile and booster stage applications. Russian rocket engineers had spent their entire lives perfecting military liquid fuel rockets and had never favored solid fuel. Therefore Russian Liquid Oxygen/Kerosene and N2O4/UDMH engines were of much higher performance than those in the US. The contribution of unique Soviet technology and the inevitable changes that occurred during development resulted in the MKS RD-0120 main engine being different in detail from the SSME while retaining the same performance. Drawing on this blend of mature American technology and Soviet innovation, the RD-0120 had a relatively trouble-free development program. The final engine represented for the Soviet Union new technical solutions in engine reliability, control, throttleability, and performance. These were the first fully throttleable Soviet engines, and their first production Lox/LH2 engines. By contrast the RD-170 engine for the booster stage was a purely Soviet design and experienced a slow and difficult development program. These were exactly the kind of closed-cycle liquid oxygen/kerosene engines that Glushko had opposed developing in the 1960's. In addition the TTZ required that they be reusable for ten missions. Glushko fell back on his old solution when being unable to handle combustion stability problems: an engine unit consisting of four chambers fed by common turbopumps. Providing adequate wall cooling for the high temperature / high pressure combustion chambers seemed at times insoluble. One problem followed another and finally the RD-170 became the pacing item, with rocket stages completed but lacking engines. As costs reached the project ceiling, Glushko and Minister Afanasyev had to escalate the fight to the highest levels of the Soviet leadership. But Glushko defended his people, retained his job, and the problems were eventually solved. The Block A 11S25 booster stages were the responsibility of KB Yuzhnoye in the Ukraine, F Utkin, General Constructor. They were to be reused ten times, and were therefore fitted with parachute containers. Solid fuel soft landing rockets in the parachute lines provided a soft landing downrange. It's not clear how the 35 metric ton boosters were to be transported back to base for reuse. In 1979 the EUK13 dimensional model of the launch vehicle was delivered to Baikonur for handling demonstrations and production of tooling. Continued development problems with the booster rockets led to a management shake-up at Yuzhnoye in January 1982. By this time the project was several years behind schedule. The originally planned first flight in 1983 was obviously unattainable. Also in 1982 the 3M-T transport aircraft was completed and began delivery of central block propellant tanks and structural elements for construction of a realistic mock-up of the booster. The 3M-T was a heavily modified M-4 bomber, and was limited to 50 metric tons loads carried on the top of the fuselage. By December 1982 the 4M Energia mock-up was completed, leading to dynamic/vertical/load tests in May-October 1983. The 4M was then returned to the shop for fitting of complete functional propellant systems. The OK-KS Buran systems test stand was built at NPO Energia to conduct tests not possible on other stands. These included electrical layout, pneumo-hydraulic tests in abort conditions, EMI tests, failure mode response, telemetry, interface with the launch vehicle, software systems test. The test stand was completed in August 1983 and the test series was completed in March 1984. 77% of the tests of the OK were automated, compared with only 5% for the Soyuz-TM. The 50 metric ton payload limitation of the 3M-T transport meant that the Buran orbiters had to be delivered in a severely incomplete and stripped-down condition to the cosmodrome. They were delivered without orbital systems, engine section, crew cabin, vertical stabilizer, landing gear, and with only 70% of the heat shield tiles. This meant that complex final assembly operations had to conducted at the MIK-OK at Baikonur. The OK-ML-1 orbiter mock-up arrived atop the 3M-T at Baikonur in December 1983 (This action seems to have been in the fine Soviet tradition of individual enterprises proving they have met the plan, even if the method of doing it was useless. OK-ML-1 was to have been used in the first launch of the Energia, by the end of 1983. By delivering it to Baikonur by December 31, the spacecraft builders could claim, "well, we met OUR part of the plan..."). OK-ML-1 was used for handling and pad compatibility tests. It was followed by the OK-MT in August 1984. This functional mock-up was used for systems integration tests, and was to be expended on the second test flight. From March-October 1985 the Ts core stage was back on the UKSS for cold flow tests. A total of nine cryogenic fuelling cycle were completed with the 4M Energia mock-up, representing the first operational use in the world of super-chilled hydrogen. The OK-GLI Buran analogue flight vehicle, for horizontal subsonic approach and landing tests, was delivered to Zhukovskiy test flight centre near Moscow, followed by its first flight with Cosmonaut Igor Volk at the controls on 10 November 1985. Two flying labs, based on Tu-154 transports, were used to prior to this to duplicate anticipated Buran handling and test systems software. They conducted 140 flights before Buran's first flight, including 69 automatic landings at Zhukovskiy and at the Jubilee airfield at Baikonur. In December 1985 the wings of the first flight OK arrived at Baikonur. This was followed by what was to be the first 20 second Energia main engine firing test. This was terminated at 2.58 seconds when the automatic control system detected a slow spool up of an engine turbine. In a the first attempt at a full-duration test helium leaks contaminated electro-hydraulic systems, leading to a situation where the tanks could not be drained. An engineering brigade had to work on the fuelled booster for 55 minutes, attach another helium tank, which led to successful de-fuelling of the vehicle. The second engine test was a complete success, the engine running for 390 seconds. This test required the entire city of Leninsk to be without water for ten days in order to accumulate enough water for the UKSS cooling system. By January 1986 it was clear that the project, now three years behind schedule, had no prospect of completion due to problems in obtaining deliveries of equipment for Buran, numerous problems in assembling the orbiters and lack of manpower at Baikonur, and a general loss of management focus. Minister O D Bakhnov called large group of industry leaders to the cosmodrome to review measures to concentrate and accelerate the remaining work. Three 'Tiger Teams' were set up. The first, led by Semenov, was to finish the flight Buran orbiter and associated facilities in time for a third quarter 1987 launch. The second, led by B I Gubanov, was to finish the Energia launch vehicle and fly it, without the Buran mock-ups if necessary, at the earliest possible date. The third group, led by S S Banin, was to complete the assembly and launch facilities. These groups were given unlimited authority to obtain necessary resources to complete their missions. As was usual on crash programs, working in parallel meant that there was some duplication of effort and some work had to be repeated to take into account changes made by the other groups. But the results were immediate. Facility 211 at Baikonur alone increased from 60 to 1800 staff by March 1986. The first Buran payload, 37KB module s/n 37070, arrived in Baikonur in February 1986. The 37KB modules, similar to the Kvant module of the Mir space station, were to be standard on the early Buran flights. 37KB-37070 itself primarily contained instrumentation to measure the performance of the orbiter and its structure on its first flight. As with the American shuttle, tile installation was a big problem. However once adequate manpower was provided the work was completed in three months. Electrical tests of the Buran flight vehicle began in May 1986. Tests of the orbiter's ODU engine unit uncovered an apparent defect in gaseous oxygen valves of the reaction control system. Although it threatened to delay flight of the Buran, it was eventually discovered to be a software problem and remedied within days. In August-September 1986 further UKSS tests of Energia were conducted in preparation of a test launch without Buran. These were conducted using a dummy payload and solid rocket motors to simulate loads from the booster rockets. Following this vehicle 6SL was selected for the first actual launch. The launch vehicle used by itself without Buran was named Energia by Glushko only just before the launch. Energia was to deliver the military Skif-DM Polyus battle station into orbit. This was to be followed by ten flights of Energia-Buran, only the first of which was to be unpiloted. Due to delays in completion of the enormous static test facility at Baikonur, which could test the entire Energia vehicle stack, it was decided to launch the vehicle without the verification the tests would provide. The launch of 6SL was planned for 11 May 1987 at 21:30 Moscow time. It was delayed five hours when a leak was detected in the Block 3A electrical distribution section, then by another hour due to a fault LH2 thermostat. The launch vehicle performed successfully, but the payload failed to inject itself into orbit due to a guidance system failure. With the launch vehicle finally proven, the focus moved to clearing Buran for flight. Two variants of the first unmanned mission were considered: a three day flight, or a two orbit flight. The three day flight would represent a complete shakedown of the orbiter's systems, but would require that most of the orbiter's systems be completed and certified for flight. The two orbit flight could be done without fuel cells, opening the payload bay doors, deploying the radiators, etc. It could be accomplished earlier and would prove the essential automated launch, orbital maneuver, and landing systems. While this debate was underway a collective letter was sent to the Soviet government by workers on the project, including the cosmonauts Volk and Leonov. This letter argued that the first flight should be piloted, as was the American space shuttle. In order to resolve the issue, a special commission was appointed to study the alternatives. The commission decided in favor of the two orbit automated flight. Buran was first moved to the launch pad on 23 October 1988. The launch commission met on 26 October 1988 and set 29 October 06:23 Moscow time for the first flight of the first Buran orbiter (Flight 1K1). 51 seconds before the launch, when control of the countdown switched to automated systems, a software problem led the computer program to abort the lift-off. The problem was found to be due to late separation of a gyro update umbilical. The software problem was rectified and the next attempt was set for 15 November at 06:00 (03:00 GMT). Came the morning, the weather was snow flurries with 20 m/s winds. Launch abort criteria were 15 m/s. The launch director decided to press ahead anyway. After 12 years of development everything went perfectly. Buran, with a mass of 79.4 metric tons, separated from the Block Ts core and entered a temporary orbit with a perigee of -11.2 km and apogee of 154.2 km. At apogee Burn executed a 66.6 m/s maneuver and entered a 251 km x 263 km orbit of the earth. In the payload bay was the 7150 kg module 37KB s/n 37071. 140 minutes into the flight retrofire was accomplished with a total delta-v of 175 m/s. 206 minutes after launch, accompanied by Igor Volk in a MiG-25 chase plane, Buran touched down at 260 km/hr in a 17 m/s crosswind at the Jubilee runway, with a 1620 m landing rollout. The completely automatic launch, orbital maneuver, deorbit, and precision landing of an airliner-sized spaceplane on its very first flight was an unprecedented accomplishment of which the Soviets were justifiably proud. It completely vindicated the years of exhaustive ground and flight test that had debugged the systems before they flew. But this triumph was also the last hurrah. Buran would never fly again. The Soviet Union was crumbling, and the ambitious plans to use Buran to build an orbiting defense shield, to renew the ozone layer, dispose of nuclear waste, illuminate polar cities, colonize the moon and Mars, were not to be. Although never officially cancelled, funding dried up and completely disappeared from the government's budget after 1993. Originally three flight orbiters were to be built, but this was increased to 5 in 1983. Structurally the first three orbiters were essentially completed, while the extra two remained unbuilt except for the engine units The final Buran test flight plan at the beginning of 1989 was as follows:
Development of the launch vehicle cost 1.3 billion rubles, with an estimated total economic effect of 6 billion rubles. Total cost of the Energia-Buran project was put at 14,5 billion rubles. It involved the work of 1206 subcontractors and 100 government ministries. The cost of Buran - a significant part of the effort to maintain strategic and technical parity with the United States - contributed to the collapse of the Soviet system and its own demise. Today the flight orbiters sit in their assembly halls in Baikonur, covered in dust. The Energia core stages sit in the MIK assembly hall, immense exhibits. The booster stages are in forlorn rows, their engines stripped for more lucrative use on Zenit and Atlas boosters launched by American companies. The orbiter mock-up stands in the safing area, quietly crumbling in the desert. The apartment buildings are vacant. The rest is silence. Buran Technical Description Although of the same aerodynamic shape and size as the shuttle, Buran differs in detail. The following table compares the two spaceplanes:
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