Category Energiya-Buran

While Gorbachov’s policy of openness or glasnost had enabled unprecedented media coverage of Buran’s maiden flight, it also exposed the program to severe and often sound criticism, especially as the launch date for the next mission kept slipping and few realistic missions for the Soviet shuttle were announced. All this was against the backdrop of increasing public skepticism about the cost and purpose of the space program in general.

As in the US, much of the criticism came from space scientists, who saw little scientific value in Buran. In a rarely seen op-ed on the space program published in the official Communist Party newspaper Pravda in March 1989, the Institute of Space Research’s K. Gringauz called Energiya-Buran a remarkable engineering feat, but pointed out that just like the Space Shuttle in the US it had caused significant cuts in scientific space research, the difference being that the USSR had a smaller economic potential and—unlike the US—already had a permanently manned space station and adequate space transportation systems available. Gringauz continued:

“Rockets of the Energiya type can apparently be used not only to launch Buran, but also for manned flights to Mars. However, the beginning of such flights is planned for 2015, and in a quarter century’s time the control systems and all its special components will have become obsolete. In my opinion, it cannot be ruled out that the main reason for developing the Energiya-Buran system was the industry’s striving for self-confirmation and not the real needs of the country and science’’ [8].

The following month Pravda’s science editor lamented the lack of progress in the program and its high cost:

“Much has been said and written about Buran and all kinds of hopes were pinned on it. But after its unmanned test flight it has got stuck in the hangars of Baykonur. Can’t it be incorporated into the well-established system of space stations and expendable spacecraft? Have technical difficulties been discovered? As usual, one can only guess, because no news is leaking out from those hangars. But even without such news, it is clear that billions of rubles so badly needed for the national economy have been withdrawn from circulation for a long time to come’’ [9].

In late 1991 Yaroslav Golovanov, one of the country’s most respected space journalists, published a damning analysis of Buran’s intended missions in the pres­tigious Izvestiya newspaper. For one, he said, Buran was not an effective satellite launcher:

“The cost of a single [Space Shuttle] flight is some 10-20 times higher than people initially thought it would be. Of course, our Buran… is infected with the same disease… The Buran launch cost roughly 170 million rubles. Calcula­tions show that that puts the cost of lifting one kilogram of payload on Buran at 6,000 rubles. If that payload were launched on a Soyuz rocket, it would cost only one-sixth of that.”

As for returning satellites from space, Golovanov wrote that “not a single of our puny satellites is so valuable that its return via Buran wouldn’t be wasteful,” adding that no such satellites were going to appear in the foreseeable future either. He also questioned the need to use Buran for servicing space stations, quoting Soviet space officials themselves as saying that their expendable transport ships were more effec­tive. Turning to the military uses of Buran, Golovanov noted its ineffectiveness as a quick-response weapon because of the lengthy launch preparations and the limited number of launch azimuths. Concluding his analysis, Golovanov wrote:

“Who can explain to me and to the millions of my countrymen—whose money has been used to build that star plane—why we need it if none of the space systems that has been created or is actually under development has been adapted to be put into orbit by Buran or Energiya or brought back down from orbit [by Buran]?’’ [10]

Faced with ever more penetrating questions from journalists relishing their newly found freedom, Soviet space officials had little choice but to disclose the true motives behind the creation of Energiya-Buran. In a television interview on 12 April 1991 Yuriy Semyonov said:

“I have to say frankly that Buran was developed to counter the Shuttle. It’s only now that everyone, including [Defense Minister] Marshal Yazov, is repudiating it: they say Buran is unnecessary… The project was originated by the Defense Ministry, although they are now disowning it. All this took place before my very eyes. It was designed to counter or parry, as it were, the work that was being done in the United States’’ [11].

Responding to criticism about the lack of payloads, officials were quick to point out that Buran should not be primarily seen as a system to launch and retrieve ordinary satellites. In an interview in late 1989 Aleksandr Dunayev, the head of Glavkosmos, said:

“The irony is that we have always said that the Energiya-Buran system should not be regarded as a transportation system (what will it carry?); it will be considerably more costly than conventional launch vehicles, and now these very arguments are being used against us: We have made a mistake, they say. We have made no mistake. The Energiya-Buran system was conceived primarily for defense purposes and it was deemed quite essential, and all other issues … were to be secondary. Does this mean that the system has no peaceful applica­tions? It is impossible to imagine that’’ [12].

When elaborating on those “peaceful applications”, Buran’s designers were hardly able to make a convincing case. Speaking in an interview shortly after Buran’s flight, Semyonov said Buran’s primary task would be:

“to launch costly facilities outfitted with unique scientific instruments, for example, large optical telescopes, with sophisticated electronic equipment. Other uses could include the creation in orbit of big radio telescopes, aerial systems, solar power stations, and interplanetary complexes. These are ex­tremely expensive constructions, each of which is the only one of its kind and needs to be serviced by manipulators, robots, and qualified personnel.’’ [13].

However, as Semyonov was probably all too well aware himself, such plans existed only on paper and would take many years if not decades to come to fruition. The harsh truth was that Buran was slowly turning into a relic of the Cold War and its developers were having a difficult time concealing it.

Although Energiya never came anywhere close to flying in the Buran-T configura­tion, there was no lack of ideas for payloads. As mentioned earlier, in September 1989

The Globis communications satellite (source: RKK Energiya).

NPO Energiya’s new chief Yuriy Semyonov canceled plans to launch two Proton payloads on the Energiya 2L vehicle and ordered the use of that rocket instead to orbit a heavy geostationary communications platform called Globis. The idea to build these heavy communications satellites had originated in 1988 as a result of efforts to find useful payloads for Energiya, the existence of which could no longer be justified on the basis of Buran alone. Studies showed that a small network of such platforms could vastly improve communication links over the vast territory of the Soviet Union and eliminate the need to regularly launch smaller communications satellites, thereby preventing overcrowding of the geostationary belt. It was estimated that three such satellites could replace 32 conventional communications satellites. The Globis satellites, sometimes referred to in the Soviet press as the “czar satellites”,
were to use a heavy bus called a Universal Space Platform (UKP) that could also be adapted for other missions.

Semyonov showed himself a staunch supporter of the idea even before being assigned to the top post at NPO Energiya, defending the need to build such satellites at the May 1989 meeting of the Defense Council and several days later at the Council of Ministers. This resulted in a decision to hold a competition on developing future communications satellite systems, which also involved NPO PM in Krasnoyarsk, which had had a monopoly in the field until then and naturally was vigorously opposed to the Globis concept, which it saw as a case of inventing a payload to fit a rocket.

The original plan was to launch a prototype satellite weighing 13-15 tons on the Energiya 2L rocket in late 1992-1993. It would be delivered to geostationary orbit by a duo of modified Blok-DM stages (10R and 20R) known together as 204GK. The first generation of operational satellites, weighing 16-18 tons, would be launched using the same 204GK upper-stage combination in 1994-1995 and the second gen­eration, weighing 21-23 tons, would be launched beginning in 1996 using a cryogenic upper stage. Several profiles were studied to place the satellites into geostationary orbit, including one using a circumnavigation of the Moon.

After much lobbying the project was sanctioned by a decree of Gorbachov signed on 5 February 1991. In May of that year Semyonov approved a new deployment plan, with the first-generation satellites (mainly serving the Soviet Union) to fly in 1996-1998 and the second generation (to be used for global communications) to follow in 1999-2000. The satellites would use at least some tried-and-tested technol­ogy, such as the retractable solar panels developed for Mir’s Kristall module.

After the failed August 1991 coup and the resulting collapse of the Soviet Union, work on the project slowed down as the money ran out. On 1 July 1992 the govern­ment of the Russian Federation approved a plan to continue work on Globis on a commercial basis, but the necessary financial support was not found and the project was closed down along with Energiya in mid-1993 [58].

The Assembly and Fueling Facility (MZK) and Dynamic Test Stand (SDI) on Site 112A, both turned over to RKK Energiya, are no longer being used and have not been refurbished for years. The MZK now serves a storage facility for two full-scale orbiters (the 2K flight vehicle and the OK-MT engineering test model). The SDI still houses a mock-up of the Energiya-M launch vehicle. The Russian Space Agency is considering dismantling these facilities [81].

Energiya-Buran launch pads

The two Energiya-Buran launch pads 37 and 38 on Site 110 of the cosmodrome (the former N-1 pads), now owned by the Nllkhimmash organization, are in poor shape. Maintenance work was discontinued in 1993 and many parts were stolen by mar­auders. The underground levels of the pads are flooded with an estimated 50,000 m3 of water. All that Nllkhimmash does is to guard the pads and ensure that any useful remaining parts can be used in other programs. Six boxcars’ worth of equipment was dismantled for use in the Sea Launch program. If this site is ever reactivated, the cheapest option will probably be to tear down the existing infrastructure and build new launch pads from scratch [82].

Most of the SSTO designs studied thus far require the use of air-breathing hypersonic scramjets, thereby limiting the amount of fuel that needs to be carried on board. The Russians did extensive research on such scramjets, which have applications not only in aerospace planes but also in aviation and long-range missiles. They were the first to test hypersonic scramjets in flight under a research program called Kholod (“Cold”). Initiated by the Military Industrial Commission in March 1979, Kholod was actually a wide-ranging research program to study the use of cryogenic fuels such as hydrogen and methane in aviation. This included studies of efficient ways of producing such

propellants, but also the study of hydrogen-fueled scramjets. The latter component of the Kholod program was entrusted to the Baranov Central Institute of Aviation Engine Building (TsIAM), while actual construction of the scramjet took place at the Soyuz design bureau (the former OKB-300), already involved earlier in developing propulsion systems for Spiral’s hypersonic aircraft.

The 1 m long scramjet was configured with an asymmetrical three-shock fixed intake and a coaxial combustion chamber. It was launched by the S200 surface-to-air missile from the Saryshagan test site near Lake Balkhash in Kazakhstan and remained attached to the rocket throughout the flight, although at least some of the vehicles were recovered. Five missions were flown with mixed success between November 1991 and February 1998. The French space agency CNES took part in missions 2 and 3 and NASA was involved in the final two missions. The last mission, using a modified version of the scramjet developed at KBKhA in Voronezh, reached a record velocity of Mach 6.47 [29].

NASA used the acquired experience for its own hypersonic scramjet test program called Hyper-X, in which small X-43A experimental research aircraft with an airframe-integrated scramjet were launched from a B-52 bomber using modified single-stage Pegasus rockets. After an initial launch failure in 2001, the X-43A reached record speeds of Mach 6.83 and Mach 9.6 during two test flights in 2004. In Russia, the Soyuz design bureau also had plans for an air-launched, hydrogen – powered scramjet test bed (GLL-31) capable of reaching Mach 10. This would be launched from the belly of a MiG-31 jet with the help of a modified S-300 surface-to – air missile and be separated from the missile for later parachute recovery (unlike the

non-recoverable X-43A). Soyuz also worked on a ground-launched, kerosene-fueled scramjet capable of reaching Mach 4.5, but the status of the latter two projects is unclear [30].

In 1993 TsIAM together with the Flight Research Institute (LII) and NPO Mashinostroyeniya (the former Chelomey bureau) started work on a new hypersonic scramjet test effort under the Oryol program, more specifically under the propulsion component of the program designated Oryol-2-1. This resulted in a new scramjet test bed called Igla (“Needle”), intended to conduct free-flight tests with the scramjet configured to operate in a usable flight vehicle. Measuring 8 m long, the vehicle has a three-module scramjet engine powered by liquid hydrogen and is launched by a UR-100N (SS-19 “Stiletto”) intercontinental ballistic missile (also used as the basis for the Rokot launch vehicle). Capable of operating up to Mach 14.0, it parachutes down back to Earth after separation from the launch vehicle [31].

There is some speculation that Igla may have made its first test flight as part of a major military exercise staged by Russia’s armed forces on 18 February 2004. This saw the launch of several rockets from Plesetsk and Baykonur, with President Vladimir Putin on hand at Plesetsk to witness the launches there. After the Baykonur launch, which involved a UR-100N, Putin said:

“An experiment has been conducted and successfully concluded. Very soon we will have in service the most up-to-date technical systems, which are able to hit intercontinental targets at hypersonic speed and with great precision and have the ability to carry out a deep maneuver both in altitude and direction.’’

Putin was apparently referring to maneuverable hypersonic warheads that are extremely difficult to counter with missile defense systems. NPO Mashinostroyeniya started work on such a system under the name Albatros in 1987, which was then abandoned at the end of the Cold War but may have been resurrected after the United States’ withdrawal from the Anti Ballistic Missile treaty in 2002 [32].

All indications are that scramjet research in Russia is now mainly being per­formed in the interests of the military, but the experience will still come in handy if Russia ever decides to build an SSTO aerospace plane in the distant future.

Another application of liquid-fuel rocket engines in aviation was to augment the performance of existing aircraft. In 1932 GDL had worked on a project to install two ORM-52 engines on the I-4 (ANT-5) fighter to improve its combat performance, but those plans were never realized due to the institute’s high workload. In 1939-1940 Glushko proposed to use the ORM-65 engines on experimental bombers called S-100 and Stal-7, but he was eventually ordered to develop the four-chamber RD-1. By the time Korolyov arrived in Kazan in late 1942, a 300 kg thrust single-chamber version of the engine was already undergoing tests.

Korolyov proposed to fly this version of the engine on a Pe-2 dive-bomber of aircraft designer Vladimir Petlyakov, not only to augment its performance, but also to speed up the development of the four-chamber version that Korolyov intended to employ on his short-range interceptor. With the engine installed in the rear fuselage of the plane, the RD-1’s turbopump would be driven by one of the two M-105 propeller engines mounted under the wings. The combination of the RD-1, the fuel tanks, the turbopump assembly, propellant feed systems, and other components was known as RU-1.

The first rocket-powered flight of the modified Pe-2 bomber (Pe-2RD) took place on 1 October 1943. The first two series of test flights, with the engine either ignited during take-off or at altitudes less than 5 km, revealed problems with the RD-1’s electric ignition system, which was therefore replaced by a chemical ignition system. The modified engine (RD-1KhZ) was subsequently flown in a third series of test flights and was ignited at altitudes up to 7 km. In 1943-1945 the Pe-2RD made more than 100 flights. Korolyov was on board for some of the test flights. Plans for further modifications of the rocket-powered Pe-2 were never realized.

The RD-1 and RD-1KhZ were also flown on three Lavochkin planes (La-7R1, La-7R2, and La-120R) in 1944-1946, on the Sukhoy Su-7 in 1945, and on the Yakovlev YaK-3 in 1945. However, partly because of the low reliability of the

RD-1 engine and also because of the emergence of the jet engine, none of these planes ever went into production [8].

With turbojet development in the Soviet Union slow to take off, there was continued interest in rocket-propelled aircraft in the first post-war years, not only to counter the new threat of US strategic bombers, but also to explore the behavior of aircraft at supersonic speeds.

One project was initiated before the end of the war at NII-1, the new name given to the former NII-3 after it had merged in May 1944 with Bolkhovitinov’s OKB-293 (which also included a rocket engine department headed by Isayev). Headed by Ilya Frolov, the new effort was mainly intended to compare the performance of a pressure-fed and a turbopump-fed engine in future rocket fighters. For this purpose NII-1 developed two aerodynamically identical airplanes with straight wings: 4302 nr. 2 with a pressure-fed Isayev RD-1M engine and 4302 nr. 3 with a turbopump-fed Dushkin RD-2M-3. The RD-2M-3 was a two-chamber design with a 1,100 kg thrust main chamber and a 300 kg thrust supplementary chamber. Both chambers would be used for take-off, after which the pilot would shut down the main chamber and use the thrust of the smaller one to search for and engage the target. This technique was more fuel-efficient and allowed the plane to stay in the air longer. A glider version (4302 nr. 1) towed by a Tupolev Tu-2 made 46 flights beginning in 1946. Of the two rocket-powered versions only 4302 nr. 2 was eventually flown, making one single flight in August 1947 before funds were transferred to another rocket plane project initiated by Mikoyan.

In February 1946 the Soviet government ordered both the OKB-301 Lavochkin bureau and the OKB-155 Mikoyan bureau to develop rocket interceptors capable of reaching speeds up to Mach 0.95 and altitudes of up to 18 km. Both planes were to be equipped with modified Dushkin RD-2M-3V dual-chamber engines. Lavochkin’s team studied a plane with a radar sight called La-162, but abandoned work on it in late 1946, preferring to fully concentrate their efforts on jet aircraft. The Mikoyan version was called I-270 and was heavily influenced by the German Me-263-V1 rocket fighter, which had been captured by the Red Army and carted off to the Soviet Union. The Me-263-V1 was one in a long line of Messerschmitt rocket fighters, one of which (the “Komet”) had been the only rocket fighter ever to be used in combat. Although the I-270 featured a similar cockpit and landing gear arrangement, it was substantially longer than the Me-263 and also had mid-mounted straight wings and a tee tail rather than the swept wings and tailless design of the German interceptor.

Two experimental I-270 planes were built, one designated Zh-1 and the other Zh-2. Towed by a Tu-2 bomber, Zh-1 made 11 unpowered test flights between February and June 1947. Zh-2 performed the first rocket-propelled flight in Septem­ber 1947, but was irreparably damaged when it landed far off the runway. Zh-1 also suffered damage on its first powered flight in October 1947 when the landing gear

failed to deploy, but was repaired for one final flight in May 1948. The test flights were rather conservative, with the planes developing speeds of only about 600 km/h.

In the second half of 1945 the design bureau of Pavel V. Tsybin was tasked with studying various wing configurations for use at near supersonic speeds. For this purpose the bureau developed “Flying Laboratories” (LL) powered by a Kartukhov PRD-1500 solid rocket motor. Two configurations were tested: LL-1 (or Ts-1) with straight wings and LL-3 (or Ts-3) with 30° forward-swept wings. The LL-1 and LL-3 made about 130 flights in 1947-1948, with the latter reaching speeds of up to Mach 0.97. A planned LL-2 with 30° swept-back wings was not flown because that wing configuration had already been tested on the MiG-15 and La-15 fighters.

Meanwhile, the Soviets were also out to break the sound barrier with rocket – propelled airplanes, relying both on a captured German and a derived domestic design. The German rocket plane was the 346, originally developed by the German Institute for Sailplane Flight (DFS) in 1944. After shutting down its engine, the plane was supposed to glide over enemy territory to take reconnaissance photos and then re-ignite the engine to gain enough speed and altitude to glide back to a friendly base in France or Germany. It had a long, slender fuselage reminiscent of a rocket, with 45° swept-back wings. Thrust was to be provided by a dual-chamber HWK 109-509C. The pilot was supposed to lie in a prone position. In case of an emergency the cabin could be separated from the airplane, with the pilot subsequently ejecting for a parachute landing.

Having fallen into Soviet hands at the end of the war, the German team that had been working on the 346 was sent to Podberyozye (some 100 km north of Moscow) in October 1946 to continue development of the rocket plane under the leadership of Hans Rossing in a newly created Soviet-German design bureau called OKB-2. In the second half of 1948 Rossing’s team completed work on a glider version of the plane called 346-P, which was flown several times by German test pilot Wolfgang Ziese in 1948-1949. The carrier aircraft for these and subsequent test flights was an American B-29 bomber confiscated by the Russians after having made an emergency landing in Vladivostok in 1944. In 1949 Ziese and Soviet pilot Pyotr Kazmin were behind the controls for three drop tests of a version of the 346 carrying a mock-up rocket engine (346-1). Despite landing problems on all three flights, the team pressed ahead with the development of the first rocket-propelled model called 346-3.

Ziese performed three powered flights in August-September 1951. During the third flight he lost control of the plane after engine shutdown, forcing him to separate the cabin and eject. With only one of the two combustion chambers activated during these test flights, the maximum speed reached was just over 900 km/h. The 346 could have broken the sound barrier with both chambers working, but OKB-2 was reportedly wary of making such an attempt because of aerodynamic in­sufficiencies in the airplane. Plans for a delta-wing supersonic rocket plane called 486 were scrapped and the German team was eventually repatriated to the GDR in 1953.

Concurrently with the Germans at Podberyozye, a team under Matus Bisnovat worked on an indigenous supersonic rocket plane called Samolyot-5 (“Airplane-5”). Bisnovat had been placed in charge of the OKB-293 design bureau in June 1946,

when it separated from NII-1 to once again become an independent entity. With its 45° swept-back wings, Samolyot 5 was outwardly very similar to the 346, also featuring a jettisonable cabin. It would use a twin-chamber Dushkin RD-2M-3F with a total thrust of 1,600 kg to reach speeds of up to Mach 1.1.

Bisnovat’s team initially developed a scale model called “Model 6” that was dropped on four occasions from a Tu-2 bomber between September and November 1947. Claims that speeds of Mach 1.28 and Mach 1.11 were attained on the two final flights are hard to verify because the speedometers were not retrieved intact. With the Dushkin engine not yet ready, a glider version designated 5-1 performed three drop tests from a Pe-8 bomber between July and September 1948, but it was damaged beyond repair in a landing accident on the final mission. Eight or nine more drop tests were conducted with airplane 5-2 between January and June 1949, but that same year financing for Samolyot-5 was discontinued even though the Dushkin engine had been test-fired and installed on the 5-2 [9].

By the end of the 1940s the era of the rocket planes was drawing to a close. Because of their limited flight times, they had little military value, among other things because the pilot had a hard time gliding back to a safe landing. Another safety issue was the use of toxic nitric acid in all the rocket engines developed for the Soviet rocket planes. A much cheaper, safer, and more efficient way of shooting down enemy bombers was the use of surface-to-air missiles, something that the Russians realized shortly after the end of the war when they stumbled on advanced German SAM missiles such as the Wasserfall.

After the war, rocket engines were a handy way of testing aircraft performance at supersonic speeds, but their development was gradually being overtaken by that of the jet engine, even though the Russians mainly relied on copies of German and British engines. While Chuck Yeager had become the first man to break the sound barrier on the X-1 rocket plane on 14 October 1947, the Russians achieved the same feat a year later, but not on one of their rocket-propelled aircraft. On 26 December 1948 Oleg Sokolovskiy became the first Soviet pilot to exceed Mach 1, flying a

Lavochkin La-176 jet plane. Despite the simultaneous development of the 346 and Samolyot-5, no Russian pilot ever flew faster than the speed of sound on a rocket – propelled aircraft. In the first half of 1950 a special commission set up under the Ministry of the Aviation Industry concluded that rocket engines had little future in aviation and a government decree in June 1950 closed down all further work on rocket engines for aircraft at NII-1.

Ever since the reorganization of NII-1 under the Ministry of the Aviation Industry in 1944, one of its main goals had been to incorporate rocket and ramjet technology into aviation. On 29 November 1946 the new head of NII-1 became Mstislav Keldysh. One of his first assignments was to study a German hypersonic winged trans­continental bombardment aircraft known as the Silbervogel (“Silver Bird”) or the “antipodal bomber”. This was the brainchild of Dr. Eugene Sanger and mathematician-cum-wife Irene Brendt, who proposed it in a document in August 1944, one copy of which was found by the Russians in Germany after the war. Launched horizontally by a rocket-powered sled, it would use its own rocket engines to boost itself to orbital altitude and subsequently ricochet off the Earth’s atmo­sphere, dropping a bomb over the desired target during one of the dips. Stalin was impressed enough by the Silbervogel to dispatch an Air Force officer named Grigoriy Tokaty-Tokayev to kidnap Sanger in France in 1948, but Tokaty-Tokayev took the opportunity to defect to the West instead [10].

Actually, by this time Keldysh had already come to the conclusion that the Silbervogel was an unrealistic design, among other things because of the high specific impulse required for the engines and the high propellant load. In 1947 he had come up with an alternative intercontinental bomber that would use a combination of supersonic ramjets (scramjets) and rocket engines to perform a mission very similar

to the Silbervogel. In what amounted to the first serious Soviet spaceplane proposal, Keldysh’s single-seater bomber would be horizontally rail-launched as the Sanger/ Bredt bomber, but then switch to two wing-mounted scramjets to reach an altitude of 20 km. Subsequently, the scramjets would be jettisoned, after which a 100-ton thrust rocket engine would kick in to send the vehicle to the upper reaches of the atmosphere, where it would fly several “dip-and-skip” trajectories to reach its final target. The scramjet and rocket engines would share several systems such as a common kerosene tank and also a common hydrogen peroxide tank to drive the turbopumps [11].

As the Cold War shifted into higher gear in the late 1940s, the Russians began looking at more realistic ways of delivering nuclear warheads over intercontinental distances. Unlike the US, the USSR did not have the luxury of having bases along the enemy borderline, making rockets a more convenient way of transporting nuclear bombs than strategic bombers. The leading rocket research institute was NII-88, set up in 1946. Sergey Korolyov, released from the sharaga in 1945 to study V-2 missiles in Germany, headed one of its departments. By the end of the decade NII-88 was investigating both ballistic and cruise missiles as a means of delivering nuclear bombs over long distances. In the winged arena, the emphasis now shifted from a hori­zontally launched piloted bomber with rocket and scramjet engines to a vertically launched unmanned two-stage cruise missile carrying rocket engines in the first stage and supersonic ramjets in a winged second stage. Unlike the ballistic missiles, the cruise missiles would remain within the boundaries of the Earth’s atmosphere, developing top speeds of around Mach 3.

A Soviet government decree issued on 4 December 1950 approved a new rocket research program, one part of which (“theme N-3’’) focused on intercontinental missiles. The conclusion of the N-3 studies was that the development of a cruise missile with a range of 8,000 km was feasible, but needed to be preceded by further

research into scramjets and navigation systems. A government decree on 13 February 1953 gave the go-ahead for the simultaneous development of both intercontinental ballistic and cruise missiles, assigning both tasks to OKB-1, which was the name given to Korolyov’s reorganized department within N11-88 in 1950. Since the cruise missile required a significant leap in technology, OKB-1 would first design an intermediate Experimental Cruise Missile (EKR). With a targeted range of 730 km, it would consist of an R-11 missile as the first stage and a winged second stage with a Bondaryuk RD-40 scramjet.

By the end of 1953 preliminary ground-based testing of EKR components had given the Russians enough confidence to skip this intermediate step and move directly to an intercontinental cruise missile with a range of 8,000 km. Since Korolyov’s OKB-1 was too heavily preoccupied with its R-7 ICBM, responsibility for the cruise missiles was entrusted to the aviation industry by a government decree released on 20 May 1954. Three aviation design bureaus were tapped to build cruise missiles with different missions:

• OKB-49 (Georgiy Beriyev): a missile called Burevestnik (“Petrel”) or “P-100” to be used for long-range reconnaissance (fulfilling the same role as the American U-2 reconnaissance aircraft) and also to deliver small 1.2-ton nuclear warheads.

• OKB-301 (Semyon Lavochkin): a missile called Burya (“Storm”) or La-350 to transport 2.18-ton atomic bombs.

• OKB-23 (Vladimir Myasishchev): a missile called Buran (“Blizzard”) or M-40 to transport 3.4-ton hydrogen bombs.

Keldysh’s NII-1, which had once again become independent in 1952 after having been a branch of the Central Institute for Aviation Materials (TsIAM) since 1948, had overall scientific supervision of the cruise missile effort, relying on its earlier experience in high-speed and high-altitude aeronautics obtained during the antipodal bomber projects.

All cruise missiles consisted of a “core stage’’ with air-breathing scramjet engines, flanked by rocket-powered “strap-on boosters’’ (two for Burevestnik and Burya and four for Buran), giving them an appearance somewhat reminiscent of the Space Shuttle. Burevestnik seems to have been a very short-lived program that never came close to flying. Buran featured four first-stage boosters with Glushko RD-212 kerosene/nitric acid engines and a core stage with a Bondaryuk RD-018 scramjet. In August 1956 OKB-301 started work on an improved version (Buran-A or M-40A) with upgraded RD-213 engines, increasing payload capacity to 5 tons. Interestingly, Myasishchev at one point considered equipping Buran with a small crew cabin, from which the pilot was to eject prior to impact. One of the objectives of this plan was to see if a man could endure the psychological and physical rigors of hypersonic flight. Buran was scrapped in November 1957 before making its first flight.

Burya’s two strap-ons had Isayev S2.1100 rocket engines (later replaced by the S2.1150) and the core stage was powered by a Bondaryuk RD-012 scramjet. The missile underwent a series of 17 test flights from the Vladimirovka test range in the Volgograd region between September 1957 and December 1960. The maximum range achieved was 6,425 km, less than the prescribed 8,000 km, because the scramjet had a tendency of igniting too early. However, even as Burya was overcoming its teething problems, its fate had already been sealed by the successful test flights of OKB-1’s R-7 ICBM, the first of which took place in August 1957. Cruise missiles were very vulnerable to defensive measures due to their low flight altitudes (around 17-25 km) and took more than two hours to reach their targets, whereas ICBMs could deliver their deadly cargo in a matter of minutes. The US Air Force had come to the same conclusion, closing down its Navaho intercontinental cruise missile project in July 1957. The Soviet government followed suit by releasing a decree on 5 February 1960 that canceled all further work on Burya, although it allowed some of the remaining missiles to be tested in flight [12].

For many years official histories of the Soviet space program created the impression that Vostok had been the only Soviet piloted space project in the late 1950s/early 1960s. Not until the days of glasnost in the late 1980s/early 1990s did it emerge that just like the United States the Soviet Union had considered winged spacecraft as an alternative to ballistic capsules in the early years of the space program. Surprisingly, it turned out that this option was studied in no fewer than five design bureaus.

In the US winged spacecraft were long seen as the logical culmination of research into high-speed aeronautics conducted since the mid-1940s with air-launched rocket – propelled X-planes. The first phase had seen aircraft such as the X-1, X-2, and

Skyrocket gradually push the envelope from Mach 1 to Mach 3 between 1947 and 1956. Phase 2 had been initiated in late 1954 with the decision to press ahead with the development of the X-15 high-altitude hypersonic research aircraft, which eventually performed a largely successful test program between 1958 and 1969. Ultimately, suborbital and orbital capability would be achieved using the “boost-glide” principle, where a spaceplane would be launched vertically with the help of a con­ventional rocket and eventually glide back down to the runway like an ordinary aircraft. In late 1957, responding to Sputnik, the Air Force consolidated three “boost-glide” feasibility studies (Hywards, Brass Bell, and Rocket Bomber) into a single program called “Dyna-Soar” or X-20. Unlike the X-15, however, Dyna-Soar was not seen as an experimental system, but an operational weapon system capable of orbital nuclear bombardment, reconnaissance, and satellite identification and neutralization [13].

During 1958 the exigencies of the Cold War and the fledgling space race with the Soviet Union gradually pushed the ballistic capsule approach to the foreground, especially after the formation of NASA in October of that year. Having lost face after the early Sputnik successes, the United States was intent on restoring its reputation by putting the first man into orbit and capsules were a more efficient and quicker way of achieving that goal than winged spacecraft. The Air Force continued work on Dyna-Soar against the backdrop of NASA’s Project Mercury, but in December 1963, with the first flight an estimated three years away, Secretary of Defense Robert McNamara canceled the program. X-20 funds were reappropriated to a military space station called the Manned Orbiting Laboratory (MOL). After that the United States did not have another officially sanctioned spaceplane project until the approval of the Space Shuttle by President Nixon in early 1972.

The winged approach to piloted spaceflight was probably less central in Soviet thinking than it was in the US, at least when it came to building the first manned spacecraft. For one, the Soviet aviation industry and the Air Force were far removed from missiles and space-related matters after the Ministry of the Aviation Industry had declined offers in 1945-1946 to bear responsibility for long-range missile pro­grams. Instead, the assignment went to the Ministry of Armaments, which had developed artillery during the Second World War. This had far-reaching implications for the Soviet space program (essentially an offshoot of the missile program), which until the break-up of the USSR remained tightly in the grip of the “artillery” camp. Moreover, missiles were soon favored over strategic bombers to deliver nuclear warheads to US territory and there was little incentive for research into high-speed, high-altitude aircraft, reflected in the absence of high-altitude “X-type” airplane research programs in the Soviet Union. On top of that, Soviet leader Nikita Khrushchov had become particularly enamored with missiles in the mid-1950s, curtailing contracts for the aviation industry and even dissolving several aviation design bureaus towards the end of the decade.

The earliest plans for piloted missions beyond the atmosphere revolved around the use of converted R-2 missiles to send people on vertical trajectories to altitudes of up to 200 km. Although one common cabin design was planned, different methods were studied for returning the capsule to Earth. One option presented by Korolyov

during a speech in September 1955 was to equip such a capsule with wings, allowing it to make a long ballistic suborbital flight rather than a short vertical hop [14].

Research on piloted spaceflight began in earnest in the spring of 1957 with the establishment within OKB-1 of Department 9, which was to focus exclusively on the development of lunar probes and piloted spaceships, signaling the beginning of the bureau’s reorientation from missiles to spaceflight. Between September 1957 and January 1958 OKB-1 and the NII-1 research institute carried out a comparative analysis of various basic shapes for piloted spaceships, paying particular attention to thermal protection requirements and the ^-forces exerted on the crew. The con­clusion was that the heat-resistant alloys available at the time were not up to the task of protecting winged vehicles with high lift-to-drag ratios against the severe thermal stresses of re-entry. Instead, the recommendation was that the first piloted spaceship should have a lift-to-drag ratio between just 0.5 and 0, depending on the ^-forces that were deemed acceptable for the crew. The ship would preferably be shaped as a blunt cone with a rounded nose and a spherical base, with the pilot being ejected from the descent capsule before touchdown.

In April 1958 one of the main obstacles to manned ballistic flight was eliminated when a key meeting of leading experts in the field of aviation medicine came to the conclusion that people could withstand forces of up to 10g as long as the body was properly positioned inside the capsule. All this would lead later that year to preliminary designs for the manned vehicle that eventually became Vostok, redesigned in early 1959 to serve the dual function of carrying people into space and performing unmanned photoreconnaissance missions [15].

Nevertheless, Korolyov, a veteran of several rocket plane projects in the 1930s and 1940s, did not abandon the idea of winged piloted spaceflight. Outlining their ideas on the future of spaceflight in a joint letter to the government on 5 July 1958, Korolyov and his associate Mikhail Tikhonravov called for developing a manned space capsule in the 1958-1960 timeframe and then to design a manned vehicle “with a gliding return profile” in 1959-1965 [16].

Preoccupied with work on the R-7 rocket and the first satellites, Korolyov turned to a befriended aircraft designer to start preliminary research on a manned space – plane. This was Pavel V. Tsybin, who had got acquainted with Korolyov back in the early 1930s while building gliders. After leading research on the LL “flying labora­tories” in the late 1940s, Tsybin worked on missiles at N11-88 from 1949 to 1951 and subsequently became involved in the design of the air-launched Kometa anti-ship cruise missile at the Mikoyan design bureau. Finally, in May 1955 Tsybin was placed in charge of a newly founded design bureau called OKB-256, situated in Podberyozye, which in 1956 became part of the newly founded city of Dubna. Its primary assignment was to create the RS, a long-range bomber powered by super­sonic ramjet engines, although by mid-1956 the focus had shifted to a supersonic reconnaissance aircraft named RSR.

Sometime later, presumably in 1958, Korolyov proposed Tsybin to design a small winged spaceship that could be orbited by an R-7 based rocket. Tsybin’s team readily set to work, assisted by specialists from OKB-1. What they came up with was a vehicle called PKA (for “Gliding Space Apparatus’’), which because of its shape was also nicknamed Lapotok (“little bast shoe’’).

Having a launch mass of 3.5 tons, the one-man spaceplane was to be placed into a circular 300 km orbit by a Vostok rocket for missions lasting up to 24-27 hours. Built into the fuselage was a small pressurized cabin with a control panel, life support systems, and three windows, one of them for an astronavigation system. In case of a launch abort, the pilot could eject from the cabin up to an altitude of 10 km and in an emergency at higher altitudes the entire spaceplane would be separated from the rocket. Located behind the cabin was a pressurized instrument compartment with on-

orbit and re-entry support systems. The spaceplane also had a detachable engine compartment with two 2,350 kg thrust nitric acid/kerosene engines, one for on-orbit maneuvers and the other for the deorbit burn. Also on this compartment were an infrared vertical sensor and a thermal control system using radiators. The dry mass of the engine unit was 350 kg and the propellant mass at launch was 430 kg. For orientation in orbit and during the early stages of re-entry the ship used small hydrogen peroxide thrusters.

The deorbit, re-entry, and landing phase was to last up to 90 minutes. After the deorbit burn the engine compartment was to be separated at an altitude of 90 km. During re-entry the spaceplane’s steel fuselage was protected from the high tempera­tures by a heat shield consisting of a 100 mm thick organic silicon layer and a 70 mm thick fibre layer as well as by special air ducts to cool the outside structure. Places with maximum heat exposure such as the nose of the heat shield and the leading edges of the two elevons and the tail were to be cooled with the help of liquid lithium. During maximum heating the angle of attack was 55 to 60°. At an altitude of 20 km, having reduced its speed to 500-600 m/s, the PKA would deploy two wings with a span of 7.5 m and an area of 8.7 m2, which until then had remained folded back to protect them against the highest temperatures during re-entry. The spaceplane was to land on a dirt runway using a skid landing gear. Landing speed was 180-200 km/h and landing mass was 2.6 tons.

The preliminary design (“draft plan’’ in Russian terminology) for the PKA was officially approved by Tsybin on 17 May 1959 and the following day Korolyov sent a letter to the State Committee of Defense Technology (GKOT, the former Ministry of Armaments) with the request to include the spaceplane in its long-range plans and assign OKB-256 to the project as the lead organization [17]. However, wind tunnel tests conducted at the Central Aerohydrodynamics Institute (TsAGI) showed that the PKA would be exposed to much higher temperatures than expected (up to 1,500°C), requiring significant changes to the heat shield. Moreover, it turned out

that the use of liquid lithium to cool the hottest parts of the fuselage would make the design much heavier and more complex than anticipated [18].

Tsybin invited specialists of the All-Union Institute of Aviation Materials (VIAM) to deal with these issues, but by the end of 1959 clouds were gathering not only over the PKA, but over Tsybin’s design bureau as well. The RS supersonic strategic bomber had been canceled in the wake of the Soviet Union’s early ICBM successes and in October 1959 OKB-256 was absorbed by Myasishchev’s OKB-23. When OKB-23 in turn became a branch of Vladimir Chelomey’s OKB-52 in late I960, Tsybin returned to Korolyov’s OKB-1, where he would eventually go on to play an important role in the Energiya-Buran program and later in the design of single-stage-to-orbit spaceplanes [19].