Category Energiya-Buran

Between 1984 and 1993 NPO Energiya studied several relatively small spaceplanes that were primarily intended to replace Soyuz and Progress for space station support. These had the general designator OK-M (Small-Size Orbital Ship).

The basic OK-M was a 15-ton spaceplane launched by the Zenit rocket. The interface between the vehicle and the rocket was an adapter equipped with four 25-ton solid-fuel motors that could be used to either pull the ship away from the

rocket in an emergency or to provide extra thrust during launch by being activated shortly after second-stage ignition. Aerodynamically, OK-M was a mini-version of Buran, having delta wings with elevons and a vertical stabilizer with rudder/speed brake. The outer surface was covered with Buran-type heat-resistant tiles. The ship could carry a crew of two in the cabin and—if required—four more cosmonauts in a pressurized module inside its 20 m3 cargo bay. The nosecap of the vehicle would be retracted to expose an androgynous docking port. OK-M had two orbital maneuver­ing engines and 34 thrusters, all burning nitrogen tetroxide/UDMH. Power was to be provided by 16 batteries, although solar panels were also considered. Payload capacity was 3.5 tons to a 51.6°, 200 km orbit and just 2 tons to a 450 km Mir-type orbit.

Better satisfying the logistics requirements of space stations were two heavier spaceplanes called OK-M1 (31.8 tons) and OK-M2 (30 tons). Jointly developed with NPO Molniya, they were very similar to the air-launched MAKS-OS spaceplane.

However, NPO Energiya felt that such vehicles should be launched with conventional rocket systems until various mass-related and other technical issues associated with the air-launch technique were solved.

The main difference between OK-M1 and OK-M2 was the launch profile. For OK-M1 Energiya studied a rather unwieldy-looking two-stage-to-orbit configuration known as the Reusable Multipurpose Space Complex (MMKS). This consisted of a huge external fuel tank with the small spaceplane strapped to one side and a Buran look-alike vehicle to the opposite side. The external tank contained liquid oxygen, liquid hydrogen, and kerosene to power tripropellant engines in both vehicles. The Buran-sized vehicle was to act as the system’s first stage. It essentially was a Buran without a crew compartment carrying extra liquid oxygen and kerosene tanks in the cargo bay to feed four main engines in the tail section. After separating from the external tank, it would return to Earth using two jet engines mounted on either side of the mid fuselage. Next the OK-M1 would fire its two main engines to reach orbit. Safety features for OK-M1 included ejection seats for the crew and an emergency separation system.

OK-M2 was to be launched atop an Energiya-M rocket with conventional strap – on boosters or winged flyback boosters. The adapter connecting it to the rocket was virtually identical to that in the Zenit/OK-M configuration and also included solid – fuel motors that could be used either in a launch abort or for final orbit insertion. Another option was to install ejection seats in the vehicle, which would allow the use of a much simplified and lighter adapter section.

Because of the different launch technique, OK-M2 required no main engines, which translated into a higher payload capacity—namely, 10 tons to a 250 km, 51.6° inclination orbit vs. 7.2 tons for OK-M1 (6 and 5 tons, respectively, for Mir-type altitudes). Other differences were a LOX/kerosene orbital maneuvering/reaction control system for OK-M1 (2 OMS engines and 18 thrusters) vs. LOX/ethanol for OK-M2 (3 OMS engines, 27 thrusters). Both vehicles could accommodate four crew members in the crew compartment and another four in a pressurized module in the 40 m3 cargo bay. The power supply system relied on a combination of fuel cells and batteries. Just like MAKS-OS, both ships had foldable wings [13]. In 1994 a proposal was made to launch OK-M2 with a European Ariane-5 booster outfitted with Energiya strap-on boosters [14].

Concurrently with the OK-M studies, NPO Energiya worked out plans for a ballistic reusable spacecraft called Zarya (“Dawn”). This looked like an enlarged Soyuz descent capsule with a small expendable instrument section attached to it. Weighing 15 tons, it would be launched by Zenit and make a vertical landing using a cluster of 24 liquid-fuel braking engines rather than parachutes. The heat shield would be similar to that of Buran. Zarya was mainly intended for space station support, but also was to fly autonomous missions in the interests of the Ministry of Defense and the Academy of Sciences. Maximum crew capacity was eight.

Indications are that Zarya was considered a much more likely contender to replace or complement Soyuz/Progress than the OK-M spaceplanes. While OK-M was no more than a conceptual study, Zarya development was sanctioned by a government decree in January 1985 and even went beyond the “preliminary design’’ phase. Zarya was eventually canceled in January 1989 due to a lack of financing, although Valentin Glushko’s death that same month may have contributed to the decision [15].

Until the late 1950s the OKB-52 of Vladimir Chelomey was a relatively minor design bureau specializing in anti-ship cruise missiles. However, by the end of the decade Chelomey’s star began to rise, something that he owed at least partially to the fact that Khrushchov’s son Sergey began working at the design bureau in 1958. Brimming with ambition, Chelomey set his sights on intercontinental missiles and space projects. From the outset he focused his research on winged spacecraft, not just for missions in Earth orbit, but also for flights to the Moon and planets.

In 1958-1959 OKB-52 began working on two projects called Kosmoplan and Raketoplan. Kosmoplan was a rather futuristically looking family of spacecraft primarily designed to fly to the Moon, Mars, and Venus and then return to Earth. During re-entry the winged landing vehicle would be protected from thermal stresses by a jettisonable container shaped somewhat like a furled umbrella and it would land on a conventional runway using turbojet engines. One early version of the Kosmoplan was also intended for military reconnaissance missions in low Earth orbit. Initial Kosmoplan missions would be automated, with the eventual goal being to switch to piloted flights, first for the Earth-orbital version and later for the deep – space versions.

Raketoplan was initially conceived as a suborbital vehicle to carry passengers and cargo over intercontinental distances and, more importantly, to perform bomb­ing missions. Launched by a conventional rocket or a winged fly-back booster, it would perform suborbital ballistic flights with aerodynamic braking, maneuvering and landing on a runway using turbojets. Two versions were studied, one for a range of 8,000 km and the other for a range of 40,000 km.

Chelomey received official support for the projects with a government and party decree of 23 June 1960, which saw a clear shift in emphasis from civilian to military space projects compared with the space plan outlined in the December 1959 decree. It

called for the development of two unmanned deep-space versions of the Kosmoplan (“Object K”) by 1965-1966, one with a mass of 10-12 tons and the other with a mass of 25 tons. The vehicles were to be launched by a new Chelomey rocket with a launch mass of 600 tons. Raketoplan (“Object R”) was now eyed as an orbital spaceplane with a mass of 10-12 tons. An unmanned version would be ready in 1960-1961, a piloted variant in 1963-1965, and an anti-satellite version in 1962-1964 [22].

However, these goals turned out to be overly ambitious and another government decree on 13 May 1961 ordered OKB-52 to limit this work to a piloted version of the Raketoplan for military missions in Earth orbit and for deep-space missions. By 1963 engineers had completed the preliminary design for four variants of such a vehicle: two single-seat Earth-orbital versions for anti-satellite and bombing missions, a two – seat scientific spacecraft for circumlunar flight, and a seven-seat passenger ballistic spacecraft for intercontinental ranges. The first three were to be launched by the Chelomey bureau’s UR-500/Proton, the fourth by the UR-200. Despite the name Raketoplan, the circumlunar spacecraft appears to have been a wingless vehicle for a ballistic re-entry from lunar distances, one that would later evolve into a vehicle called LK-1 that had a shape reminiscent of the US Gemini capsule.

By early 1964 the Raketoplan project was left with only military goals, namely orbital reconnaissance and anti-satellite missions. At this time OKB-52 was planning two versions, the unmanned R-1 and the manned R-2, both weighing 6.3 tons. The R-1 was a model of the piloted version designed to test all essential systems in orbit. The R-2, manned by a single pilot, would fly 24-hour missions in a nominal orbit of 160 x 290 km.

Two test vehicles were developed in the framework of the Raketoplan project to test heat shield materials, flight control systems, and maneuvering characteristics at hypersonic speeds. One was a 1,750 kg model called MP-1, a cone-shaped vehicle with two graphite rudders and a set of speed brakes at the base resembling an unfurled umbrella. The MP-1 was launched by an R-12 missile from the Vladimirovka test site near Kapustin Yar (Volgograd region) on 27 December 1961. Having reached a

maximum altitude of 405 km, it successfully re-entered the atmosphere at a speed of 3,800m/s and safely landed on three parachutes 1,880 km downrange. This marked the first ever re-entry test of an aerodynamically controlled vehicle. It came about two years before the US Air Force began similar flights under the so-called START program.

The other vehicle was named M-12 and looked quite similar to its predecessor, except that the umbrella-shaped braking panels were replaced by four titanium rudders. Using the same missile and launch site as the MP-1, the 1,700 kg M-12 was launched on 21 March 1963, but was lost during re-entry, probably because of a problem with its heat shield. The data obtained during the tests were also applicable to OKB-52’s research on maneuverable warheads. This was particularly the case for the M-12, which was seen as a subscale model of the AB-200 warhead. The MP-1 and M-12 were significant in that they were the only hardware ever launched in support of the multitude of Soviet spaceplane projects conceived in the late 1950s and early 1960s.

The Raketoplan project was discontinued in 1964-1965. There appear to have been several reasons for this. First, Chelomey lost much of his political support when Khrushchov was overthrown and replaced by Brezhnev in October 1964. Second, the design bureau was heavily involved in other manned space projects such as the LK-1 circumlunar program and the Almaz military space station. Finally, many of the military objectives planned for Raketoplan were already being or about to be performed by unmanned satellites such as OKB-1’s Zenit (for photographic recon­naissance) and OKB-52’s own US (for ocean reconnaissance) and IS (for anti-satellite missions). The whole research database on Raketoplan along with a number of Chelomey’s specialists were transferred to the Mikoyan design bureau [23].

By the middle of 1975 two competing designs had emerged within NPO Energiya for a Soviet response to the Space Shuttle. In Glushko’s vision the orbiter would be just one of the payloads for his RLA rockets, mounted on top of the rocket as a conventional payload. If a winged orbiter was going to be mounted atop an RLA booster, it would place very high loads on the core stage, especially during the phase of maximum aerodynamic pressure. Therefore, the core stage would have to be strengthened, making it even heavier than it already was and decreasing the rocket’s payload capacity [52]. Therefore, the top-mounted orbiter would have to be a wing­less, vertical-landing lifting body. This configuration was backed by NPO Energiya luminaries such as Boris Chertok, Yuriy Semyonov, and Konstantin Bushuyev, who were convinced the USSR was not capable of building a reusable space transporta­tion system akin to the Space Shuttle [53]. It would also eliminate some thorny organizational problems, requiring minimal involvement from the Ministry of the Aviation Industry.

Another option under consideration was to mimic the Space Shuttle as closely as possible, namely to build a winged orbiter with main engines which would be strapped to an external fuel tank with strap-on boosters. Known as OS-120, it would enable the Russians to benefit from research and development done in the US and thereby minimize risk. While backed by Igor Sadovskiy, it was Glushko’s nightmare, since this design left no room for the family of launch vehicles he had been dreaming of for many years. The philosophy behind the OS-120 was that the Soviet Union would solely be able to match the US Shuttle’s capability to place 30 tons into orbit and return 20 tons back to Earth and nothing more. After all, the 100 to 200-ton payload capacity of the heavy RLA rockets, mainly needed for establishing lunar bases and staging manned interplanetary missions, was of little interest to the Soviet military.

With Buran being only one of many possible payloads of Energiya, flight control functions were divided between the rocket and the orbiter, each using their own set of computers. This is very different from the integrated US Space Shuttle system, where the Orbiter’s General Purpose Computers are in control of all flight events. Being the most complex rocket ever built by the Russians, flight control proved to be a daunting task, facing designers with many unprecedented problems.

Originally, the flight control systems for both Energiya and Buran were to be built at NPO AP (Scientific Production Association of Automatics and Instrument Building), a Moscow-based organization headed between 1948 and 1982 by Nikolay A. Pilyugin. However, in 1978 the development of Energiya’s control system was entrusted to NPO Elektropribor, an organization based in the Ukrainian city of Kharkov and originally founded as OKB-692 in 1959 (now called NPO Khartron). Since the early days it had been headed by Vladimir Sergeyev, replaced in 1986 by A. G. Andryushchenko. The chief designer of the Energiya control system was Andrey S. Gonchar and a leading role in its development was also played by Yakov E. Ayzenberg, who would go on to lead the organization in 1990. Production of the hardware took place at the Kiev Radio Factory. NPO AP built the orbiter flight control system and remained in overall charge of the Energiya-Buran flight control system [5].

The core stage had a primary computer (called M6M) and a computer charged with continuously monitoring the operation of all Energiya’s engines and shutting any one of them down if needed. Each Blok-A strap-on booster had a M4M computer in its nose section. There was continuous interaction between the com­puters in the core stage and the strap-on boosters. Crucial commands such as nominal or emergency shutdown of both core stage and Blok-A engines and separation of the boosters were issued by the core stage computers [6].

Each booster had a single inertial guidance platform (17L27) built by NPO Elektromekhanika in Miass (Chelyabinsk region). The core stage’s intertank area housed three inertial guidance platforms (KI21-36) developed by NPO Rotor in Moscow and based on similar systems built for the 15A35 (SS-19 “Stiletto”) and 15A18 (SS-18 “Satan’’) missiles. Pre-launch alignment of the booster platforms took place with an optical system (17Sh14) (precision 7′) and that of the core stage platforms with an automatic system (17Sh15) (precision 45”) The automatic system consisted of three instruments mounted on a black plate outside the intertank area of the core stage. The plate was detached from the core stage and retracted to the launch tower with less than a minute to go in the countdown after the final pre-launch alignment. Failure of the plate to properly disengage led to the abort of the first Buran launch attempt on 29 October 1988 [7].

With the N-1 failures fresh in their memories, Soviet designers went to great lengths to protect the rocket against the consequences of leaks and engine failures. There was a so-called Fire and Explosion Warning System, consisting of gas and fire detectors and a system to purge the tail sections of the core stage and boosters with nitrogen and extinguish fires with freon. This was activated both during the count­down and launch. Installed on the pad was a hydrogen burnoff system to eliminate hydrogen vapors exhausted into the RD-0120 engine nozzles during the start sequence. This differed from the hydrogen igniters on the Space Shuttle launch pads in that the hydrogen was burnt off well away from the engine nozzles [8].

Energiya was also equipped with a so-called Engine Emergency Protection System, comprising a wide range of sensors in the engine compartments to monitor pressures, temperatures, turbine rates, etc. In case an anomaly was detected, any of the engines could be shut down immediately before failing catastrophically. Depend­ing on the moment when the shutdown took place and the type of payload carried (an orbiter or unmanned payload canister), the flight control system could then decide on a further course of action. This could involve shutting down the diametrically opposed engine to continue controlled flight, increasing the burn time of the remain­ing engines to deploy the payload in a lower or even nominal orbit, initiating a return to launch site maneuver, guiding the rocket to a safe impact area, etc. This would not only ensure the safety of the crew, but also facilitate post-flight analysis of the failure. The system was designed to deal with over 500 types of anomalies and was said to be a major improvement over the analogous “KORD” system on the N-1 rocket.

The safety systems were not only used during launch countdowns and ascent, but also during bench tests of the RD-170 and RD-0120 engines and test firings of the core stage and strap-ons. The bench tests, especially those of the RD-170, showed that the Engine Emergency Protection System could not always respond to rapidly escalating problems such as turbopump burn-throughs or cracks in the turbopump rotors, a problem that had not been fully solved by the time Energiya made its two missions [9].

The two orbital maneuvering engines (Russian acronym DOM, also referred to as 17D12) were a further development of NPO Energiya’s 11D58 engine used in the Blok-D, an upper stage for the Proton rocket and later also employed by Sea Launch’s Zenit-3SL. Each having a vacuum thrust of 8.8 tons and a specific impulse of 362 s, they performed final orbit insertion, orbit circularization, orbit corrections, and the deorbit burn, and were also supposed to be activated in certain launch abort scenarios to burn excess propellant. A long-term objective was to use the DOM engines to provide additional thrust during a nominal launch, a technique that NASA introduced with the Shuttle’s OMS engines on STS-90 in 1998.

Usually, only one of the two was required for any given standard burn, with the other acting as a back-up. Simultaneous ignition of both engines was only required in launch emergencies. The DOM ignition process began with a 20-25 second burn of two primary thrusters to force the LOX and sintin out of their tanks. The engine used a closed-cycle scheme, re-routing the gases used to drive the turbopump to the combustion chamber. During each burn the propellant tanks were pressurized with gaseous helium. In order to save helium, gaseous oxygen was used to pressurize the LOX tank for the deorbit burn. The engine nozzles could be gimbaled up to 6 degrees in two axes (pitch and yaw) for thrust vector control. Each DOM was designed to be ignited up to 15 times during a single mission.

A nominal re-entry could be initiated whenever Buran’s ground track carried it over or near one of three runways available in the Soviet Union. The primary landing site was at Baykonur, with back-up sites available in the Soviet Union’s Far East and in the Crimea (see Chapter 4). The ship had a maximum cross-range capability of 1,700 km, but that was only required for an emergency return back to Baykonur after a single revolution when the vehicle was launched into a polar orbit. For more common inclinations below 65° a cross-range capability of 1,050 km was sufficient.

Deorbit preparations began with the crew realigning the GSPs, retracting an­tennas, closing the payload bay doors, and preparing hydraulic systems for re-entry. When descending from an altitude of 250 km, about one hour would elapse between the deorbit burn and touchdown, with the vehicle covering a total distance of about 20,000 km and reducing its speed from Mach 25 to zero. After the deorbit burn, performed with the help of the DOM engines, Buran needed some 25 minutes to reach the official boundary between space and the atmosphere at 100 km, at which point it was still at a range of 8,500 km from the runway. It was only then that the three Auxiliary Power Units were activated.

The return through the atmosphere was divided into three phases: “Descent”, “Pre-Landing Maneuvering”, and “Approach and Landing”. These correspond roughly to the three major phases of a Shuttle Orbiter return (“Entry”, “Terminal Area Energy Management”, and “Approach and Landing”).

“Descent” was the hypersonic phase of the re-entry (Mach 28-Mach 10 at 100km-20km altitude) where the vehicle was exposed to the highest temperatures and achieved maximum cross-range. The flight control system guided the orbiter through a tight corridor limited, on the one hand, by altitude and velocity require­ments (in order to make the runway) and by thermal constraints, on the other hand. Buran’s angle of attack was kept at a high value (39°) during most of this phase to keep the temperatures within acceptable limits, while roll reversals were used to bleed off air speed and thus reduce kinetic energy. When the vehicle reached Mach 12, the angle of attack was gradually lowered from 39° to 10° to increase the lift-to-drag ratio. As the atmosphere thickened, the ship gradually transitioned from 20 aft attitude control thrusters to conventional aerodynamic control surfaces. The thrusters were used up to an altitude of 10 to 20 km. Between altitudes of about 80 and 50 km Buran was enveloped in a sheath of ionized air that blocked all communications with the ground. After coming out of the blackout, the ship’s RDS system began beaming pulses to transponders on the ground to furnish the on-board computers with range data. Azimuth and range data from the more traditional RSBN beacon navigational aid system were only used as a back-up to the RDS data.

During the “Pre-Landing Maneuvering” phase (Mach 10-Mach 2 at 20 km-4km altitude) Buran gradually transitioned from hypersonic to supersonic speeds and lined itself up with the runway for the final approach and landing. At this stage it intercepted one of two so-called “Heading Alignment Cylinders’’ (TsVK), imaginary cylinders to align the vehicle with the runway. Which of the two was chosen mainly depended on the wind direction. By the end of this phase Buran reached an “entry point’’ 14.5 km from the runway to begin the final descent. Primary navigational input throughout this phase still came from the RDS rangefinder system, backed up by the RSBN for azimuth and range data and by the RVB high-altitude altimeter and

SVSP air data system for altitude data. The SVSP probes were deployed at an altitude of 20 km.

The Approach and Landing phase saw the orbiter moving from hypersonic to subsonic speeds and finally coming to a stop on the runway. It began with a steep glideslope of —17° to —23° degrees (depending on landing mass), allowing the ship to correct any small trajectory errors it still had at the entry point. At an altitude of 400-500 m a pre-flare maneuver was started to position the vehicle for a shallow glideslope of —2° in preparation for landing. A final flare at an altitude of 20 m led to touchdown some 1,000 m past the runway threshold at a speed between 300 and 330 km/h. Wind speed limits were 5m/s for tail winds, 20m/s for head winds, and 15m/s for crosswinds. After touchdown, speed was brought down to zero by the brake chutes and the main gear brakes, with the speed brakes only used in manual landings. Steering during roll-out was provided by the nose gear steering system and by differential braking. The maximum roll-out distance was 1,800 m. The navigation aids during Approach and Landing were the RMS microwave system for altitude and azimuth, the RDS rangefinder system for range and the RVM low-altitude altimeter for altitude.

The landing could be performed in automatic, flight director, or manual mode. Automatic mode was the preferred mode even for manned missions (see Chapter 7). Flight director systems, also used in aviation, provide visual indications on the pilots’ displays of what the autopilot would want to do if it were flying the vehicle under the current settings. In other words, the pilots fly the vehicle manually but are guided by the autopilot. Simulations showed that the use of this mode throughout descent would be monotonous and tiring and should be restricted to the final approach and landing, especially if visibility was poor. Moreover, this mode did not give the crew the necessary psychological comfort because it could not always anticipate unexpected events. In manual control the pilots themselves determined the flight path using information on the expected touchdown point and remaining energy and also by relying on navigational aids, outside visual clues, and data uplinked from the ground. If all that information was available to them, they could switch to manual mode at an altitude of about 20 to 30 km. In emergency situations they could land the vehicle using only navigational aids or information provided by Mission Control [30].

The bulk of the design work on the core stage was performed by a branch of NPO Energiya situated in the city of Kuybyshev (renamed Samara in 1991). Situated on the banks of the Volga river almost 1,000 km east of Moscow, this city is home to some of the most important Russian space-related enterprises. The most famous of these is a design bureau that originated as Branch nr. 3 of Sergey Korolyov’s OKB-1 in 1959. It oversaw the further development of R-7 based rockets and later also designed the lower stages of the N-1 rocket as well as the nation’s photoreconnaissance, biological, and materials-processing satellites. The bureau’s chief Dmitriy Kozlov was asked to design the core stage of NPO Energiya’s new heavy-lift rockets, but turned down the offer, electing instead to focus on ongoing projects.

As a result, Branch nr. 3 became independent as the Central Specialized Design Bureau (TsSKB) on 30 July 1974, with NPO Energiya setting up a new “Volga Branch’’ in Kuybyshev to work on the core stage. Actually, the branch was set up at a time when the Energiya rocket as such did not yet exist and NPO Energiya was still working on its early RLA concepts. Receiving basic parameters from NPO Energiya’s central design bureau in Moscow, a 1,000-man strong team under the leadership of Boris G. Penzin put out all the necessary blueprints for the construction of the core stage. According to one veteran this was so much that “not even two Energiya rockets could lift it off the ground’’. The Volga Branch was also responsible

for designing the Blok-Ya launch table adapter. Penzin retired in 1987 and was replaced by Stanislav A. Petrenko.

Assembly of core stage elements took place at the Progress factory, also situated in Kuybyshev, although that was primarily aligned with Kozlov’s design bureau. The construction of the giant core stage required the construction of several new halls as well as several other facilities, such as chambers for cryogenic tests of the propellant tanks using liquid nitrogen. The Energiya core stage was flown to Baykonur in two separate sections. A branch of the Progress factory was responsible for final core stage assembly and Energiya integration at the Energiya assembly building at Baykonur. The director of Progress for most of the Buran years was Anatoliy A. Chizhov (1980-1997) [6].

An initial group of civilian test pilots from the Flight Research Institute were selected as candidates for the Buran program on 12 July 1977 by an order of the head of the institute. They were:

• Igor Petrovich Volk;

• Rimantas Antanas-Antano Stankyavichus [6];

• Anatoliy Semyonovich Levchenko;

• Aleksandr Vladimirovich Shchukin;

• Oleg Grigorevich Kononenko;

• Nikolay Fyodorovich Sadovnikov.

A seventh pilot, Aleksandr Ivanovich Lysenko, had been pre-selected to become a member of the group, but while the necessary documents were still being prepared, Lysenko was killed when his MiG-23UB fighter crashed on 3 June 1977.

Selecting the group had been more problematic than anticipated. There was little willingness among LII’s pilots to enter the program because of the stringent medical examinations. In fact, initially only Volk and Levchenko had volunteered. Many feared that if anything was found that would disqualify them for Buran, they would also lose flight status for their test pilot work. Because this proved a serious problem in selecting candidates, Igor Volk managed to strike a deal with Oleg Gazenko, who was in charge of the medical screenings. The deal implied that as soon as it would become clear that a pilot was deemed medically unfit for the cosmonaut program, the selection process would be halted, both the pilot and Volk would be informed, and the pilot could return to test flying in LII, no questions asked [7].

Igor Volk can probably be called a logical choice as member of the group. In May 1976 he had already test-flown the 105.11 (nicknamed “Lapot”), an atmospheric test bed of the Spiral spaceplane. However, Volk himself has stressed that he made only one flight on “Lapot” at the invitation of the Mikoyan design bureau and was not involved in the program as such [8].

Late in 1977 the group lost a member when Sadovnikov decided to move from LII to the Sukhoy design bureau and become a test pilot there. Between April and June 1980 he would fly 15 combat missions in Afghanistan on Su-25 fighter jets. After returning to Sukhoy, he went on to become their lead test pilot and a Hero of the Soviet Union before passing away on 22 July 1994, only 47 years old.

Sometime in 1978 Igor Volk became the commander of the group [9]. Eventually, the group would become known as the “Wolf Pack”, a tongue-in-cheek reference to Volk, whose name is Russian for “wolf”. The cosmonauts from later LII selections would become known as the “Wolf Cubs”.

On 3 August 1978 Volk, Stankyavichus, Levchenko, Shchukin, and Kononenko passed the so-called Chief Medical Commission (GMK), which cleared them for preliminary space-related training such as centrifuge tests and parabolic flights on aircraft to simulate zero-g [10]. Almost five months later, on 30 December 1978, the five went through the next phase in the selection process, appearing before the State Interdepartmental Commission (GMVK), the top government commission for cos­monaut selection. Its main task was to select cosmonauts on the basis of their political reliability and both moral and human qualities [11]. Headed by Leonid Smirnov, the chairman of the Military Industrial Commission, it consisted of representatives of the appropriate ministries and the KGB and also included Kerim Kerimov, the chairman of the State Commission for manned spaceflight [12]. All five were given the go-ahead to begin their OKP at the Gagarin Cosmonaut Training Center the following April, thereby receiving the official status of “cosmonaut candidates”. Unlike Air Force cosmonaut candidates that were selected for flights on Soyuz, they went through their OKP in periodic sessions, continuing their regular test pilot work at LII at the same time.

In December 1980 the Wolf Pack members finished OKP training and passed their final exams. Sadly, Oleg Kononenko was not among them. He had died on 8 September 1980 while testing a naval version of the Yakovlev Yak-38 vertical take­off and landing plane in the South China Sea. Shortly after take-off from the aircraft carrier Minsk, the aircraft developed engine trouble and crashed into the ocean before Kononenko had a chance to eject. He was posthumously awarded a second Order of Lenin. One LII pilot has stated that before his death, Oleg Kononenko had been slated to become commander of the LII cosmonaut group [13]. This has not been confirmed by other sources and it should be noted that throughout their careers Volk had been senior to Kononenko.

At this point, the LII test pilots were not yet on an equal footing with the “career cosmonauts” of TsPK and NPO Energiya. The Wolf Pack was considered a special­ized group, temporarily assigned to one particular task—namely, to fly Buran’s atmospheric and orbital test flights. Their status was somewhat comparable with that of “payload specialists’’ in the US Space Shuttle program, individuals not employed by NASA who are assigned to particular missions to operate one or more payloads and then return to their usual line of work.

All that changed on 23 June 1981, when MAP issued an order to set up its own cosmonaut team, something which became official on 10 August 1981 with a corresponding order from the chief of LII. This is considered the official date of the formation of the LII Buran cosmonaut team, which now consisted of Volk, Levchenko, Stankyavichus, and Shchukin. The move may have been linked to the success of the first US Space Shuttle mission in April 1981, which in many ways was an eye-opening event for officials in charge of the Energiya-Buran program. It should be noted though that the members of the LII team continued their usual work as test

pilots throughout their Buran careers [14]. At this point they also received the official title of “cosmonaut-testers”, the same title given to the career cosmonauts of TsPK and NPO Energiya after their OKP. Before that they had been named “cosmonaut – researchers”, just like scientists of the Academy of Sciences and doctors of the Institute of Medical and Biological Problems. The official formation of the LII cosmonaut team was apparently also related to a new “Statute for Cosmonauts” approved by the Central Committee of the Communist Party and the Council of Ministers on 30 April 1981.

Meanwhile, LII was looking for more pilots to expand its ranks. In November 1979 deputy MAP minister Ivan Silayev had already called for expanding the LII group, but it was not until February 1982 that four more candidatures were presented to MAP:

• Pyotr Vasilyevich Gladkov;

• Ural Nazibovich Sultanov;

• Vladimir Yevgenyevich Turovets;

• Viktor Vasilyevich Zabolotskiy.

Reportedly, the four had already undergone initial screening in 1979. In June 1982 two more names were added to the list of candidates:

• Magomed Omarovich Tolboyev;

• Vladimir Viktorovich Biryukov.

Sadly, Vladimir Turovets had to be dropped very early on in the process, when he was killed in the crash of a Mil Mi-8 helicopter on 8 February 1982. Turovets, born on 20 February 1949 in the Ukraine, had been an LII pilot since June 1977 and a Test Pilot 3rd Class since 1980. His assignment to the Buran team would probably have been problematic anyway because of an incident in which, as a salute to his fellow LII test pilots, he had made a low-altitude pass over the site where Aleksandr Lysenko and fellow pilot Gennadiy Mamontov had crashed in June 1977 [15]. The fact that Turovets was not liked by many people could also have had a negative impact on his selection, even though colleagues have described him as a gifted man and an excellent pilot.

Pyotr Gladkov and Vladimir Biryukov were not selected and returned to test flying. Gladkov, born on 22 July 1949 in Krasnodar, mainly flew state-of-the-art fighter aircraft like the MiG-29, MiG-31, and Su-27, but also heavy transport planes such as the Ilyushin Il-76 and Tupolev Tu-154. For this work he would be awarded the title of Merited Test Pilot of the Russian Federation in December 1997. Vladimir Biryukov, born on 9 June 1950 in the Sverdlovsk region, had become a test pilot at the Flight Research Institute in 1981, upon graduation from test pilot school. In October 1996, he too was awarded the title of Merited Test Pilot of the Russian Federation.

Left over were Tolboyev, Zabolotskiy, and Sultanov. When still in the military, Tolboyev had already tried to become a cosmonaut in the TsPK Buran selection group of 1976, but he hadn’t managed to pass the medical commission at the time [16]. Both Zabolotskiy and Sultanov had already been involved in Buran-related research since 1978. This included a series of experiments called “Immersion” (1978-1980), in which they spent some time in simulated zero-g in a water tank at

Pyotr Gladkov (left), Vladimir Turovets (center), and Vladimir Biryukov (B. Vis files).

the Institute of Medical and Biological Problems and then performed landings with a Buran-type steep glideslope on Il-18 and Su-7 aircraft [17].

In September 1982 MAP decided that Zabolotskiy, Sultanov, and Tolboyev would undergo medical screening for possible inclusion in the LII cosmonaut team. While Zabolotskiy failed the initial medical, Sultanov and Tolboyev were accepted by the GMK on 25 January 1983, passed the GMVK on 9 March 1983, and were officially included in the LII team as cosmonaut candidates by a MAP order on 25 April 1983. Zabolotskiy was finally declared fit by the GMK on 4 April 1983, but it took almost another year for him to be accepted by the GMVK (15 February 1984) and be included in the team by MAP (12 April 1984).

In spite of the selection of these three new candidates, LII still felt that it needed more cosmonauts. In September 1983 two more pilots were recommended to MAP:

• Sergey Nikolayevich Tresvyatskiy;

• Yuriy Petrovich Sheffer.

Sheffer and Tresvyatskiy passed the GMK on 8 July 1984 and 17 April 1985, respectively, and were both accepted as cosmonaut candidates by the GMVK on 2 September 1985. They were officially included in the team by a MAP order on 21 November 1985. That same month they began their OKP training at Star City together with Tolboyev, Zabolotskiy, and Sultanov, finishing it in May 1987. On 5 June 1987 they were awarded their certificates of cosmonaut-testers.

In the meantime, there had been another organizational change at LII in May 1987, when MAP decided to create the so-called Departmental Training Complex for Cosmonaut-Testers (OKPKI for Otraslevoy Kompleks Podgotovki Kosmonavtov – Ispytateley). In a sense this was LII’s own cosmonaut training center. Volk was named head of OKPKI, with Levchenko being assigned as his deputy. Stankyavichus

in turn became the commander of the LII cosmonaut team, with Shchukin acting as his deputy.

OKPKI numbered around 60 people. Apart from the cosmonaut team itself, it consisted of medical, engineering, administrative, and various support departments. One of these support departments had three cameramen, whose job was to film and photograph every test flight that was conducted with the BTS-002 atmospheric test bed and the Tu-154LL and MiG-25 training aircraft.

The LII cosmonaut team spent the next years performing Buran-related test flights. Volk, Levchenko, Stankyavichus, and Shchukin performed take-off runs and approach and landing tests on the BTS-002 between December 1984 and April 1988. Stankyavichus and Zabolotskiy would conduct one additional ground run in December 1989. The others flew flight profiles on the Tupolev Tu-154LL flying laboratory, MiG-25, Su-27, and other types of aircraft.

The team suffered a major blow in August 1988, when two of its members died only two weeks apart. Levchenko passed away from a brain tumor on 6 August and Shchukin perished in the crash of a Su-26M sports plane on 18 August. This necessitated more organizational changes. Stankyavichus became deputy head of OKPKI, Zabolotskiy took Stankyavichus’ place as commander of the cosmonaut team, and Tolboyev was named his deputy, replacing Shchukin.

The deaths of Levchenko and Shchukin reduced the LII cosmonaut team to just seven men and it was decided to select a new candidate. Yuriy Yiktorovich Prikhodko passed the GMK on 21 October 1988 and got the nod from the GMYK on 25 Jan­uary 1989, officially becoming a member of the team by a MAP order on 22 March 1989. He finished his OKP training in 1990.

It almost seemed as if OKPKI was under a curse when the team suffered yet another loss on 9 September 1990. Rimantas Stankyavichus was killed during a demonstration flight at an air show in Italy. His Su-27 didn’t pull out of a loop in time and crashed. Stankyavichus was buried in Kaunas in his native Lithuania.

After the break-up of the Soviet Union in late 1991, it became increasingly clear that there simply wasn’t enough room in the space budget to keep Buran alive. When the program was officially terminated in 1993, the fate of the pilot teams looked sealed. In 1995 the GMYK recommended both LII and GKNII to either reassign their Buran pilots to other programs or disband the teams. While the GKNII team was officially disbanded in late 1996, the LII team officially continued to exist, reportedly at the insistence of Igor Volk, who held out hope that the Buran program would one day be resurrected. Although the LII team was never officially disbanded, it eventually simply dissolved itself as cosmonauts began to leave OKPKI and move on in their careers. The last one to depart LII was Vladimir Tresvyatskiy in late 2004 (for further careers of the LII pilots see Appendix B).

LII’s Buran cosmonaut team can probably be regarded as the most diverse group ever selected. No fewer than six nationalities from the former Soviet Union were represented among the eleven men that made up the group. Kononenko, Prikhodko, Sheffer, Tresvyatskiy, and Zabolotskiy were Russians, while Levchenko and Volk were Ukrainians. Shchukin was a Belorussian, Stankyavichus was Lithuanian, Sultanov was a Bashkir, and Tolboyev was an Avar (a people of about 300,000 in Daghestan).

One of the main motives for the choice of a four-chamber rather than a single­chamber LOX/kerosene engine in 1973 was the possibility to test major components of the engine (primarily the combustion chamber) individually and only later to assemble them for test firings of the complete engine. This followed from the negative experience with the single-chamber 640-ton thrust hypergolic RD-270 engine for Chelomey’s UR-700 rocket, where engineers had moved to all-up tests straightaway. All the 27 test firings carried out in 1967-1969 had ended in some kind of failure before work on the engine was discontinued.

The component tests were conducted between 1974 and 1980 using test models known as “oxygen installations” (UK). Most of these were built on the basis of blueprints and components developed in the early 1970s for the RD-268, a 100-ton thrust engine burning unsymmetrical dimethyl hydrazine (UDMH) and nitrogen tetroxide (N2O4). This was possible because UDMH/N2O4 engines use virtually the same ratio of propellants as LOX/kerosene engines. It did require the use of new materials compatible with LOX/kerosene and modifications to two test firing stands of Energomash on the banks of the Khimka river in the northwest outskirts of Moscow. These were completed in the first eight months of 1974.

The first two of these test models (1UK and 2UK) were essentially 100-ton thrust experimental model engines to test various aspects of the RD-170, such as the ignition sequence, mixing of the propellants in the combustion chamber and gas generator, cooling of the combustion chamber, and the use of reusable materials. A modified version known as 1UKS burned recycled oxidizer gas produced in a gas generator, as was the case for the RD-170. Between August 1974 and November 1977 as many as 346 test firings of these three types of engines were conducted lasting a total of 19,658 seconds.

The next series of tests involved an installation called 3UK, designed to test the RD-170’s gas generator. This consisted of a full-size gas generator, two turbopumps, and a mock-up combustion chamber, making it possible to simulate the pressure, propellant expenditure, and temperature in the gas generator at levels between 30 and 80 percent of nominal values. The tests were conducted between June 1976 and September 1978. A total of 77 3UK installations underwent 132 test firings lasting a total of 5,193 seconds. About 60 mixing heads were tested, with two being chosen for test firings of complete RD-170 engines.

Also built were experimental engines called 2UKS that closely imitated the operating conditions of the RD-170’s combustion chamber, but inherited their turbopumps from earlier designs. Therefore, the chamber developed only 80 percent of the nominal thrust at a pressure of 200 rather than 250 atmospheres. Also tested was the gimbaling system and several of the engine’s automatic systems. A total of 42 2UKS engines accumulated about 6,000 seconds of burn time in 68 tests from May 1977 until June 1978. Interestingly, the 2UKS served as the basis for the development of the 85-ton thrust RD-120, which would later power the second stage of the Zenit rocket.

Finally, Energomash engineers built the 6UK, which essentially was a real RD-170 without a combustion chamber, the main purpose being to test the turbopump assembly. The installation underwent 31 tests between June 1978 and December 1980. The tests revealed that the turbopump was susceptible to burn – throughs and vibrations. Although as many as 23 6UK installations were used, they accumulated just 280 seconds of testing time. Since the 6UK was nearly as expensive as a complete RD-170/171, the test program was limited and the problems with the turbopump assembly were not debugged by the time the full-scale RD-170 test firings got underway. Therefore, the 6UK was much less effective in paving the way to those test firings than the other UK installations, setting the stage for a major crisis in the Energiya program in the early 1980s.

The aerodynamic behavior of Buran was studied using 85 different scale models (ranging from 1: 3 to 1: 550) in 25 wind tunnels simulating Mach 0.1 to 2.0. These wind tunnels were situated at TsAGI in Zhukovskiy, and at SibNIA and the Institute of Theoretical and Applied Mechanics (ITPM), both in Novosibirsk. A total of 36,630 wind tunnel tests were conducted prior to the maiden flight of Buran.

The Russians also developed 1: 8 scale models of Buran called BOR-5 to study the vehicle’s behavior at re-entry speeds. Unlike BOR-4, they simulated the shape of Buran itself and were launched on suborbital trajectories. The purpose of these flights was:

– to determine major aerodynamic characteristics in real flight conditions at high velocities;

– to determine aerodynamic coefficients, the lift-to-drag ratio, balancing characteristics, roll and pitch stability and to compare them with calculated characteristics;

– to investigate pressure distribution along the vehicle’s surface;

– to determine heat and acoustic loads;

– to check the adequacy of the techniques used to calculate aerodynamic characteristics.

The BOR-5 models weighed 1,450 kg and were 3.856 m long. Because of their small size and the specifics of their trajectory, they were exposed to much higher tempera­tures than Buran and therefore were covered with an ablative heat shield rather than

tiles. The nosecap was made of a tungsten-molybdenum alloy. Just like the BOR-4 vehicles, they were equipped with a wide range of sensors to measure temperatures, aerodynamic characteristics, and orientation. The data obtained by these sensors were sent back in real time via telemetry.

The BOR-5 models were launched from Kapustin Yar by the Kosmos-3M-RB5 rocket and launched in the direction of Lake Balkhash, covering a distance of about 2,000 km. Having reached a maximum altitude of 210 km, the second stage of the Kosmos booster pitched down to accelerate the model to Mach 18.5 at 45 degrees before separation. After separation from the second stage, the model used small gas thrusters for orientation, switching to aerodynamic surfaces as it entered the denser layers of the atmosphere. Beginning at an altitude of 50 km, it followed the same changes in bank angle and angle of attack as Buran, albeit at much higher speeds than the full-scale orbiter. At an altitude of 7 km a parachute was deployed to reduce the vertical landing speed to 7-8 m/s.

The BOR-5 vehicles were built at NPO Molniya’s EMZ factory with the assis­tance of specialists from other divisions of NPO Molniya and also from the Flight Research Institute. Like the BOR-4 missions, the test flights were supervised by a State Commission headed by Gherman Titov.

The first BOR-5 (serial nr. 501) was launched on 6 July 1984, but was lost when it failed to separate from the second stage due to an electric fault. The first successful mission took place with vehicle nr. 502 on 17 April 1985. Post-flight analysis did

reveal significant damage to the nosecap and leading edges of the wings, which altered the vehicle’s aerodynamic characteristics. Therefore, on subsequent missions those areas were protected with a special molybdenum alloy and a special anti-oxidation coating. Three more successful missions (using models nr. 503, 504, 505) were con­ducted on 27 December 1986, 27 August 1987, and 22 June 1988. Models 501 to 504 were outfitted with small mock-up turbojet engines on either side of the vertical stabilizer, but these were no longer mounted on the final BOR-5 vehicle because by then it had been decided to fly Buran without turbojet engines.

Vehicle 505 was unsuccessfully put up for auction in the United States in 1991 and was stored in the Mojave Desert for about four years before being put on display at the Santa Barbara Museum of Flight. In 1997 it was purchased by a person in Merritt Island, Florida, who still owns the vehicle [19].