Category Energiya-Buran

None of these preparatory activities were reported by the Soviet media as they happened. Although Buran was no longer a state secret, Soviet space officials adopted a carefully limited posture concerning their plans. As the new policy of openness came into effect, some space officials and cosmonauts had begun confirming the existence of a shuttle in interviews and informal conversations in the mid-1980s. The official disclosure of the Soviet shuttle was left to Glavkosmos, an organization often described in the West as a Soviet equivalent to NASA, although it was actually the international relations arm of the Ministry of General Machine Building. Speak­ing at a Moscow press conference on 8 April 1987, Glavkosmos official Stepan Bogodyazh finally acknowledged that the Soviet Union was developing a reusable spacecraft and would announce the launch in advance. Bogodyazh’s statement was confirmed on 13 May 1987, when the TASS news agency reported the imminent launch of the first Energiya rocket and added it would be used in the future to orbit reusable spacecraft. In January 1988 Glavkosmos chief Aleksandr Dunayev told another Moscow news conference the first Soviet shuttle would be launched soon. Two months later he said the mission was still expected shortly, although engineers were encountering problems daily. He also promised that (unlike the maiden Energiya launch) the shuttle launch would be broadcast live on Soviet television.

Despite these occasional statements, Soviet officials provided little if any tech­nical details on their shuttle system. All this changed with the release of a government decree in early July 1988 that officially declassified the Energiya-Buran program [39]. By the end of that month the newspaper Pravda published an in-depth article on the Energiya-Buran system by chief designer Boris Gubanov, who confirmed earlier statements that Buran’s first flight would be unmanned:

“The role of manned flights on such carriers is not yet fully clear, such is the opinion of many specialists. A blind imitation of air travel is not relevant here. Space technology has gone its own way. Automatic ships were the first to enter space and humans followed only later. In the future, space will mainly be the working field of automatic spacecraft and transportation systems. The role of humans will probably be linked to research and specific maintenance and repair work… Today’s task is to accomplish the landing of an orbital ship in auto­matic mode without the involvement of pilots, and later that of separate units and stages. Nowadays, automatic flights from take-off to touchdown are also performed with aircraft, such as the Tu-204.’’

Almost certainly, the flight had originally been timed to upstage the return to flight of the US Space Shuttle (mission STS-26), but the ODU problems and several other issues had thwarted those plans. However, unaware of those developments, Western media speculated the Soviet shuttle might still blast off before Discovery. On 20 September the Washington Times reported US spy satellites had photographed the Soviet shuttle on the pad earlier that month and that some US officials expected a launch within a week. This clearly was a mistake, because the stack had been inside the Energiya assembly building since late August. However, the newspaper also quoted Soviet space expert Saunders Kramer as saying the odds of that happening were all but zero. Kramer correctly stated the vehicle had been wheeled out to the pad in the spring and “then inexplicably removed”, attributing the delay to problems with the computer software [40].

On 29 September 1988 all eyes were turned to Cape Canaveral in Florida, where the Space Shuttle Discovery was poised to return America to space 2.5 years after the January 1986 Challenger disaster. Lift-off occurred at 15: 37 gmt, and eight minutes later Discovery safely entered orbit. However, the Russians were intent on stealing at least some of the thunder from NASA’s success, taking advantage of the occasion to finally unveil their counterpart of the Space Shuttle to the world. Television viewers around the Soviet Union were surprised when the evening news program Vremya opened by showing a shot of the Energiya-Buran stack on the launch pad (taken during the May-June pad tests). The name Buran, painted on the side of the vehicle, had been carefully retouched so as not to be visible to the television audience, although it had leaked to the West several years earlier. The picture was accompanied by a terse TASS statement saying preparations for the launch were underway and that the mission would be unmanned. The Buran lead story was followed by footage of a conversation between the orbiting Mir crew and East German leader Erich Honecker. Vremya completely downplayed the news from Cape Canaveral by show­ing a brief clip of the Discovery launch just before going off the air. Interestingly, the following day some Soviet newspapers published exactly the same photograph with the name Buran erased altogether.

The next comment on launch preparations came from LII lead test pilot Igor Volk. Speaking at a meeting of the Association of Space Explorers in Bulgaria in early October, he revealed that 23 October was the target date for the launch when he left the Soviet Union. The Soviet shuttle moved into the background again until 23 October, when the TASS news agency once again repeated that final launch preparations were underway and revealed that the orbiter was called Buran. That same day Vremya showed the first ever footage of Energiya-Buran, including spectacular shots inside the MZK, during the roll-out and on the launch pad.

Although Buran figured prominently in plans for both Mir and Mir-2, there are no indications it was ever supposed to replace traditional transportation systems such as Soyuz and Progress. The idea was that it would be used in parallel with those systems for missions requiring its unique capabilities, such as assembly of large structures, swapping out of modules and delivery and return of large pieces of equipment. While Buran could have made it possible to reduce the number of Soyuz and Progress missions, these vehicles would have continued to play a crucial role in Soviet space station operations. This also explains why the Russians never stopped improving Soyuz and Progress during the development of Buran.

In fact, the International Space Station (ISS) is now pretty much operated as the Russians had set out to do with Mir and Mir-2, being serviced by a combination of large shuttles and smaller capsule-type vehicles. The ISS itself is clear proof that it is impossible to operate a space station with large shuttle vehicles alone. Although such vehicles can deliver larger crews and more supplies than capsule-type spacecraft, it is not economically justified to use them for dedicated crew rotation and resupply missions. Ideally, these tasks should be combined with shuttle-unique assignments and not be seen as mission objectives in themselves.

The biggest problem with Shuttle/Buran-type vehicles is that they can only stay docked to a space station for several weeks at most until their consumables run out. Vehicles like Soyuz and Progress can be largely deactivated after docking to a station and remain attached to it for months on end. This means they are always available for reboost and refueling operations when needed and—crucially for crew safety—can always immediately return a resident crew back home if an emergency situation arises. NASA had originally planned to service Space Station Freedom solely with

the Space Shuttle and leave crews on board in between Shuttle missions. Only after the 1986 Challenger disaster did it dawn on the agency that it would be dangerous to have crews on the station without a lifeboat attached. NASA then found itself scrambling to find a US contractor capable of building a station lifeboat at short notice. Fortunately enough for NASA, political changes in the USSR allowed the agency to adopt Soyuz as a lifeboat for Freedom in 1992 and the vehicle continued to serve in that role as part of the ISS.

The simultaneous operation of large shuttles and capsules also provides redun­dancy. One vehicle can continue to service the station in case the other is grounded. This was vividly demonstrated by the 2003 Columbia accident, after which Soyuz and Progress vehicles served as a lifeline for the station. One can only imagine what things would have been like if both the Space Shuttle and Buran had been around for ISS operations. Having been built to the same specifications as the Shuttle, Buran could have continued ISS assembly work during the Shuttle’s standdown. Of course, this is no more than wishful thinking, because the very conditions that lay at the foundation of Buran’s downfall enabled the creation of the ISS.

As had been Valentin Glushko’s original intention with the RLA rockets, the modular design of the Energiya rocket allowed it to be transformed into a wide variety of lighter and heavier launch vehicles. If all had gone according to plan, Russia could now have had an entire family of heavy-lift launch vehicles capable of orbiting payloads from just 30 tons to a mind-boggling 500 tons.

Vulkan

The Energiya version with eight strap-on boosters was known as Vulkan (“Vol­cano”). With the lower section of the core stage completely surrounded by strap – ons, the payload and upper stage were mounted atop the core stage as on a conventional rocket. The tanks of the strap-on boosters and core stage were stretched and the strap-ons did not have the parachute recovery systems of the standard Energiya. Vulkan would have required the development of a new adapter platform to place it on the launch table. Launches would only have taken place from the UKSS pad, which was built from the beginning with a view to supporting Vulkan launches in the future.

Two slightly different versions of Vulkan have been described in Russian litera­ture. One used the same RD-0120 and RD-170 engines as the standard Energiya and was capable of placing 170 tons into a low 50.7° orbit. Equipped with an 11D57M cryogenic upper-stage engine of the KB Saturn “Lyulka” design bureau (vacuum thrust 42 tons, specific impulse 460 s), it could inject a 28-ton payload into geostationary orbit [64].

The other version carried upgraded first and second-stage engines and the Vezuviy cryogenic upper stage, probably outfitted with the RO-95 engine of KBKhA. The upgraded first-stage engines were known as RD-172 or 14D20 and had a sea – level thrust of 784 tons (as compared with 740 tons for the RD-170). Also mentioned has been an even more powerful version called RD-179 with a reported sea-level thrust of 860 tons. The core stage engines retained the RD-0120 designator and had a vacuum thrust of 200 tons (as compared with 190 tons for the standard RD-0120). The following payload capacities are given: 200 tons to a low 50.7° orbit, 172 tons to a 97° orbit, 36 tons to geostationary orbit, 43 tons into lunar orbit, and 52 tons to Mars. Possibly, the first version was an early proposal that was later superseded by the more capable one [65].

The development of Vulkan seems to have been set in motion by a government decree released in July 1981, which called for making “technical proposals” for the rocket within the next five years. The “technical requirements” that formed the basis for these proposals were issued in July 1982. With a payload capacity of around 200 tons, Vulkan was seen by the Russians as a rocket that could play a crucial role in future manned missions to Mars and other planets of the solar system. It was the subject of further government decrees between 1983 and 1986, but timelines for its development remained vague as no concrete payloads were ever defined for it.

Studies of new air-launched systems began at NPO Molniya in 1977 under a research program known as Rosa (“Dew”) and initially focused on the use of the Antonov-124 Ruslan as the carrier aircraft. By 1981 this resulted in the so-called System 49, in which the Ruslan would carry a single-person 13-ton spaceplane attached in tandem to a two-stage rocket. The rocket had two Kuznetsov NK-43 LOX/kerosene engines in the first stage and a single Lyulka 11D57M LOX/LH2 engine in the second stage. With an overall take-off mass of 430 tons, System 49 allowed the spaceplane to place about 4 tons into a low 51° inclination orbit. Payloads could be launched into orbits with altitudes between 120 and 1,000 km and with inclinations between 45° and 94°.

In 1982 System 49 was superseded by a modified system called Bizan (“Mizzen”). Having the same performance as System 49, it differed from the latter in that the spaceplane was placed on top of a single-stage rocket and had main engines itself. The advantage of the single-stage rocket was that it would burn up over the ocean across the world from the launch point. In the two-stage System 49 the first stage would have crashed in a zone about 2,000 km from the launch point, requiring that area to be cleared for impact. Bizan’s rocket was fitted with a single NK – 43A, while the spaceplane itself had two 11D57M engines, which could now be reused on subsequent missions. Also considered was a cargo version known as Bizan-T, where the spaceplane was replaced by an unmanned cargo canister [4]. Bizan was also

the name of an unmanned rocket system launched from the An-225 Mriya that was studied by the Volga Branch of NPO Energiya in 1984-1988 [5].

Glushko’s initial position was to use only hydrocarbon fuels in the RLA family and introduce liquid hydrogen (LH2) at a later stage, when the technology was ripe.

Glushko had always disliked liquid hydrogen. In the 1960s he had opposed the use of liquid hydrogen on the upper stages of the N-1 rocket, arguing that the low density of hydrogen required large tanks and worsened the rocket’s mass characteristics. At an August 1974 meeting where Glushko outlined his plans for the RLA rocket family, several participants urged him to move to liquid hydrogen straightaway, but Glushko remained adamant [38]. At another meeting he reportedly said:

“The person who can find a way of building a rocket suited for the orbiter but

with the use of oxygen-kerosene will become my deputy’’ [39].

However, by the end of the year Glushko had to yield to the pressure. On 30 Novem­ber 1974 MOM minister Sergey Afanasyev signed an order to start the development of powerful cryogenic engines [40].

Despite Glushko’s wariness, Energomash had already performed some initial research on LOX/LH2 engines. In 1967 Glushko had tabled a proposal for a 200 to 250-ton cryogenic engine for the N-1 and a similar proposal had come from the Kuznetsov bureau [41]. Then there were studies at Energomash of two cryogenic engines for the RLA family, namely the RD-130 (200-ton vacuum thrust) in 1973 and the RD-135 (250-ton vacuum thrust) in 1974 [42]. Actually, the original idea was that Energomash would go on to build the engine, but the bureau was too preoccupied with the development of the powerful LOX/kerosene engines. Therefore, the task was entrusted to the Chemical Automatics Design Bureau (KB Khimavtomatiki or KBKhA) in Voronezh (the former “Kosberg bureau’’). The deal was that KBKhA in turn would hand over to Energomash the development of a 85-ton thrust LOX/ kerosene engine for the second stage of the medium-lift 11K77 (“Zenit”) rocket [43].

KBKhA was not the most obvious choice. First, the only space-related engines developed by KBKhA before this had been LOX/kerosene upper stages for R-7 derived launch vehicles and engines burning storable propellants for the second and third stages of the Proton rocket. Second, there were two design bureaus in the Soviet Union that had already pushed research on LOX/LH2 engines beyond the drawing board. These were KB Khimmash (the “Isayev bureau’’) and KB Saturn (the “Lyulka bureau’’), both of which had developed cryogenic engines for the upper stages of the N-1 (the 7.5-ton thrust 11D56 of KB Khimmash and the 40-ton thrust 11D54 and 11D57 of KB Saturn). One can only speculate that Glushko had second thoughts about relying on design bureaus that had been involved in the N-1, a rocket he wanted to erase from history.

Not only was KBKhA a newcomer to the field of LOX/LH2, it was now supposed to build from scratch a cryogenic engine several times more powerful than any developed in the Soviet Union before. With an anticipated vacuum thrust of 250 tons, the engine (called RD-0120) would even outperform the Space Shuttle Main Engine, which was related to the fact that the Russians had to compensate for the higher latitude of the Baykonur cosmodrome. Not surprisingly, KBKhA engineers began their work on the RD-0120 by consulting specialists from KB Khimmash and KB Saturn. They also extensively analysed the data available on the Space Shuttle Main Engines [44]. They almost certainly also benefited from the preliminary

research done by Energomash on the RD-135, which had exactly the same perform­ance characteristics as the original version of the RD-0120.

The RD-0120 (also labelled 11D122), developed at the Chemical Automatics Design Bureau (KBKhA) in Voronezh, was a LOX/LH2 engine with a vacuum thrust of 190 tons and a vacuum specific impulse of 454 s. It was a staged combustion cycle engine in which the gases from the gas generator are cycled back into the main combustion chamber for complete combustion. The propellants first passed through low-pressure turbopumps (“boost pumps’’) that boosted the pressure significantly to prevent cavitation of the main turbopump assembly. The low-pressure hydrogen pump used a gas turbine driven by gaseous hydrogen from the main chamber cooling loop. The low-pressure oxygen pump had a hydraulic turbine powered by liquid oxygen.

Each RD-0120 had a single-shaft turbopump consisting of a two-stage axial turbine, a three-stage hydrogen pump, and two oxygen pumps. One of the oxidizer pumps was intended to feed the main combustion chamber and the other to feed the gas generator and the hydraulic turbine of the low-pressure oxygen pump. The 32,500 rpm turbopump was driven by a single fuel-rich preburner operating at 530°C.

During ascent the RD-0120 could be gimbaled plus or minus 11 degrees in pitch and yaw to help steer the rocket. Each engine was gimbaled with the help of two hydraulic servoactuators developed by KB Saturn (the “Lyulka bureau”), with hydraulic pressure being provided by pumps driven by high-pressure hydrogen gas from the engine itself. The engine could be throttled over a range of 45 to 100 percent, a significantly higher throttlability than the Space Shuttle Main Engine (SSME) (67-104%). The pneumatic control system included pressure helium bottles, pneumatic and electro-pneumatic valves, and system piping.

Nominal burn duration was between 450 and 500 seconds, although this could be significantly extended in case one engine had to compensate for the loss of another. The RD-0120 engines for the first three flightworthy Energiya rockets (6SL, 1L, and 2L) were certified for a total burn time of 1,670 seconds (230 seconds for test firings, 480 seconds for the launch, and 960 seconds back-up capability). This was increased to 2,000 seconds for flight vehicle 3L. Theoretically, this meant the engine could be reused for about three to four missions, although they were of course destroyed on re-entry together with the core stage. However, there were plans to certify the engines for 10 to 20 missions for reusable versions of Energiya and for possible use on foreign reusable launch vehicles. It was also planned to gradually uprate the engine, increas­ing the vacuum thrust to 230 tons and the vacuum specific impulse to 460.5 s. One of the modifications would have been the inclusion of an extendable nozzle to prevent loss of specific impulse in vacuum conditions.

Although the RD-0120 was built to the same overall performance specifications as the SSME, it certainly was not a copy of the SSME, differing from it in several important aspects. Also, the Russians could draw on their extensive experience with staged-combustion cycle engines used on the Proton rocket and various inter­continental missiles. While the RD-0120 had a single turbopump assembly both for liquid oxygen and hydrogen, the SSME has separate turbopumps for each propellant. Soviet engineers did consider a similar scheme, but opted for the single turbopump system because it simplified the computer control system and the ignition sequence. The RD-0120 had a channel-wall nozzle with fewer parts and welds than the SSME nozzle and was therefore easier to manufacture. In the late 1990s NASA even considered building a similar nozzle for the SSME, eliminating the tubular construction as a potential source of nozzle leaks. The new nozzle was also expected to have a higher degree of reusability [2].

The Thermal Control System (STR) had two internal and two external loops. Each loop operated completely independently, with pumps circulating cooling agents through it. The cooling agents were substances known as “Antifreeze-20” for the internal loops and “PMS-1.5” for the external loops. The internal loops maintained proper temperature (18-28°C) and humidity (30-70%) in the crew compartment, collected excess heat from equipment inside and just outside the crew compartment, and then transferred that heat to the external loops via liquid-to-liquid heat ex­changers. The external loops removed heat from systems in the unpressurized part of Buran (including the fuel cells, the hydraulic system, the payload, the maneuvering and attitude control engines) and finally delivered the excess heat to three types of

“heat sinks”: the radiator panels on the payload bay doors, flash evaporators, and ammonia boilers.

The eight radiator panels (one on each payload bay door) were the primary means of heat rejection in orbit. Just as on the Shuttle Orbiter, the two forward panels on each side could be unlatched and tilted to allow heat to be radiated from both sides of the panel. The fixed aft panels only dissipated heat from the outer side. When the payload bay doors were closed, heat loads from the external coolant loops were rejected by the flash evaporators or ammonia boilers, which cooled the loops by evaporating water and ammonia, respectively, and venting the resulting gases overboard. Water for this purpose was produced by the fuel cells and stored in the tanks of the Process Water System, whereas the ammonia was loaded in two small tanks prior to launch. The flash evaporators were apparently used during launch and the initial part of re-entry, but since water evaporation becomes ineffec­tive under higher atmospheric pressure, the ammonia boilers took over at an altitude of 35 km [19].

For space station missions Buran would have carried a Docking Module (SM) in the forward part of the payload bay. It consisted of a spherical section (2.55 m in diameter) topped by a cylindrical tunnel (2.2 m in diameter) with an APAS-89 androgynous docking port, a modified version of the APAS-75 system developed by NPO Energiya for the 1975 Apollo-Soyuz Test Project. The spherical section, bolted to the floor of the cargo bay, had two side hatches, one connecting it to Buran’s mid-deck and the other providing access to the payload bay for spacewalking cosmonauts or to a Spacelab-type module. The tunnel provided the actual interface between the Docking Module and the target vehicle and would be extended to its full length after opening of the payload bay doors. With the tunnel fully extended, the adapter was 5.7 m high. If the extendible part of the tunnel became stuck in its

deployed position, it could be pyrotechnically separated to allow the crew to close the payload bay doors.

At least one flightworthy SM was built for the first mission of flight vehicle nr. 2, which would have featured a docking with Mir and a Soyuz TM spacecraft. The Buran Docking Module served as the basis for a small module that was supposed to be attached to the Mir-2 space station to act as a berthing place for Soyuz, Progress, and Buran vehicles and as an airlock for spacewalks. It would be towed to the station by a detachable Progress-M propulsion compartment. The module was eventually launched as Pirs to the International Space Station in September 2001 (see Chapter 8).

During missions not involving dockings, Buran would have flown with an internal airlock in the mid-deck. The EVA spacesuit used by the cosmonauts would have been a modified version of the semi-rigid Orlan spacesuit, originally developed in the 1960s for the Soviet piloted lunar program. Developed by the Zvezda organ­ization in Tumilino, it would have been worn by the cosmonaut who was supposed to stay behind in lunar orbit aboard the LOK mother ship to assist his colleague in spacewalking to the lunar lander before landing and back to the LOK after ascent from the lunar surface. The Orlan was a simplified, lighter version of the moon – walker’s Krechet suit. Unlike the Krechet, it was not completely self-contained (being connected to the spacecraft’s power systems with an umbilical) and designed for relatively short spacewalks.

After cancellation of the lunar program a modified version of the suit known as Orlan-D was developed for EVAs from the Salyut-6 space station, launched in 1977. The modifications were mainly related to the fact that the suit had to remain in orbit for a long time, be serviceable, and be worn by different cosmonauts. In October 1980 NPO Energiya and Zvezda reached agreement on using the same Orlan-D for space­walks from Buran. The suit and airlock could support up to three 5-hour EVAs during a 7-day Buran mission and from six to eight EVAs during a 30-day mission.

In March 1984 Zvezda was ordered by MOM and MAP to start development of a jet-powered backpack, giving cosmonauts more flexibility during spacewalks. Interestingly, the order came just one month after the first use of the analogous Manned Maneuvering Unit (MMU) on Space Shuttle mission 41-B. Called 21KS or SPK (“Cosmonaut Maoeuvering Unit’’), the device was intended for spacewalks both from the Mir space station and Buran. One of the main functions that the Russians had in mind for the unit was to allow spacewalking cosmonauts to inspect Buran’s heat shield in orbit. Two of the units could be installed aboard Buran, one on the starboard side of the cargo bay, the other on the port side.

The development of the 21KS also required Zvezda engineers to design a compatible, fully self-contained spacesuit called Orlan-DMA. This no longer had an electrical umbilical connecting it to on-board systems and was equipped instead with a special unit containing power supply, radio communications, and telemetry systems. In 1987 the final decision was made to use this suit in the Buran program instead of the Orlan-D.

Although the Orlan-DMA saw extensive use by Mir spacewalkers between 1988 and 1997, the 21KS was flown only twice by cosmonaut Aleksandr Serebrov from

Mir in early 1990. Since the station could not maneuver to retrieve him if he became stranded, Serebrov remained attached to the station by a 60 m long safety tether. Untethered spacewalks with the 21KS would probably have been authorized only for the Buran program, with the cosmonaut being able to venture 100 m from the vehicle.

In 1992 Zvezda and the German Dornier company studied the feasibility of jointly developing a European-Russian spacesuit for the European Hermes space – plane, Buran, and the then still planned Mir-2 space station. The work on the joint suit (“EVA Suit 2000”) continued after cancellation of those programs in 1993, but

ESA backed out the following year because of financial constraints. The Russian suit now used on ISS is the Orlan-M, a further modification of the Orlan-DMA [27].

KB Energomash, situated in the Moscow suburb of Khimki, was responsible for the design of the RD-170 engines of the Blok-A strap-on boosters. The bureau originated as OKB-456 in 1946 and was headed from the beginning by Valentin P. Glushko, who had begun his career as a rocket engine designer at the Gas Dynamics Laboratory in Leningrad in 1929. OKB-456 developed all the engines for the Soviet Union’s early ballistic missiles and derived space launch vehicles. In January 1967 OKB-456 was renamed KB Energomash (KBEM). In May 1974 it was united with the old Korolyov bureau (then named TsKBEM) to form the giant conglomerate NPO Energiya. While Glushko became the new head of Korolyov’s former empire, he appointed Viktor P. Radovskiy as chief designer of the Energomash subdivision. On 19 January 1990, one year after Glushko’s death, Energomash again separated from NPO Energiya and

became known as NPO Energomash. The following year Radovskiy was replaced by Boris I. Katorgin, who led the organization until 2005.

KB Energomash had a so-called “Experimental Factory”, originally known as “Experimental Factory 456” and renamed OZEM in 1967. It produced test models and the first flightworthy versions of new rocket engines. However, since the factory’s production capabilities were relatively limited, serial production of engines was usually farmed out to other organizations. Being the most complex engines designed yet, the RD-170 and its Zenit cousin (the RD-171) were no exception. Even for the experimental engines the manufacture of the combustion chamber was entrusted to the “Metallist” factory in Kuybyshev, which had already built combustion chambers for the N-1 rocket. The production of the chambers was overseen by the “Volga Branch’’ of Energomash in Kuybyshev.

In 1978 it was decided that serial production of the RD-170 and RD-171 would eventually be transferred to PO Polyot in the Siberian city of Omsk, which until then had specialized in building small satellites and the 65S3/Kosmos-3M launch vehicle. Polyot’s task was dual. It delivered components to the KB Energomash factory for the engines manufactured there and at the same time produced complete engines itself. PO Polyot’s first RD-170 rolled off the assembly line in 1983 and during that same year KB Energomash set up a branch in Omsk, mainly to produce the blueprints necessary for serial production of the engines. Between 1983 and 1992 PO Polyot manufactured eleven RD-170 and about forty RD-171 engines. While many of those were used in test firings, none of them was ever completely installed on an Energiya or Zenit rocket. However, virtually all individual components of these engines were later used in the assembly of RD-171 engines for the Sea Launch version of Zenit. Energomash’s Experimental Factory produced its last RD-170 in 1990. Its director during the Buran years was Stanislav P. Bogdanovskiy (1968-1992) [4].

Buran had two back-up landing sites, an “eastern” site not far from the Soviet Pacific coast and a “western” site in the Crimea. The eastern site was situated south of Lake Khanka very close to the small town of Khorol, a little over 100 km north of Vladivostok. The aerodrome was originally used in the 1960s as a temporary home base for the Tu-95MR bomber and later hosted Tu-95RTs Navy reconnaissance planes, Tu-16 planes belonging to the Pacific fleet, and fighter jets of the Air Defense Forces. In the 1980s it was modified for its role in the Buran program by lengthening the existing runway and installing equipment of the Vympel navigation system. The runway was 3.7 km long and 70 m wide. The western site was located near the town of Simferopol in the Crimea and featured a 3.6 km long and 60 m wide runway. There is conflicting information on whether the two sites were ready in time for Buran’s maiden mission in November 1988, but they should have been available for the first manned missions in the early 1990s [18].

Also considered was the possibility of landing Buran on ordinary runways, not specially adapted for the orbiter and not equipped with the navigation facilities needed to assist in a hands-off landing. A requirement formulated for Buran’s test pilots was to land Buran on such runways at nighttime without any illumination [19].