|-Antonov is no more.|
|-Buran is now a museum.|
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|-Transport of the OK-TVA shuttle to the VDNKh park.|
|-Dismantling of the OK-TVA shuttle.|
The numerous studies in laboratory and wind tunnels have made it possible to define the new design of BOR lifting bodies. They became at their turns the models for the various orbital systems of the USSR.
In order to determine the characteristics of stability and the manoeuvrability of the lifting bodies, BOR mock-up ("Беспилотный орбитальный ракетоплан", Orbital Plane without Pilot) of 1:3 and 1:2 scales were tested in the suburbs of Moscow. First model "BOR-1" had a 3 m length and a mass of 800 kg. It was sent by the launcher Cosmos-2 on June 15, 1969 according to a sub-orbital trajectory and an altitude of 100 km. At the time of the re-entry in the atmosphere its speed was of 13 000 km/h, although it was burned on all its surface, to 60-70 km of altitude it still transmitted informations on its trajectory which was correct. Apparatuses "BOR-2" and "BOR-3", manufactured on the 1:3 and 1:2 scale were entirely made of metal, without heat shield and were launched in space according to the same trajectory and with the same launcher.
For Buran it was necessary to create a reliable technology of heat shield consisted of various materials: ceramics tiles, refractory and elastic felt and finally a matter very resistant to heat containing carbon for the nose and the leading edge of the wings. "BOR-4" lifting body was built to validate the design of these materials.
The dimensions of the "BOR-4" nose corresponded almost with those of Buran. Moreover, it is being a counterpart of the "SPIRAL" lifting body at the 1:2 scale in regards of the fuselage. It has a 3.859 m length, a wingspan of 2.8 m (wings folded up), a starting mass of 1 450 kg, 1 047 kg in orbit and 795 kg at the return. The aircraft was equipped with piloting and measurement systems for the engines and the wings.
The telemetric system of "BOR-4" registered the data of flight in RAM and transmitted them to 2 relay ships and a ground station. The temperature measurements were taken by 150 probes placed under the shield and under the outside layer of the tiles to 0.3 mm. The other recorded parameters were acceleration, the angular velocities, the wings's position, etc.
The wings of "BOR-4", just as that the "SPIRAL" ones could be turned along a radial axis, moreover the fold angle defined the angle of attack for which the lifting body is stable during the re-entry. As it is known Buran and the American shuttle are unstable during the re-entry and great angles of attack are required. The fact of having directional wings was a real innovation for the sixties because that made it possible to reduce the angle of attack and the heating on the nose and the leading edge of the wings. This is why it is called lifting body because the major part of the lift is produced by the body of the plane.
The first trial flight of "BOR-4" in sub-orbital trajectory took place on December 5, 1980, from the Kapustin Yar base, in direction of the lake Balkhach, this flight made it possible to test the whole systems of the lifting body. The productive flight of this mock-up confirmed the choices made for refractory materials and the on-board equipments. The ulterior apparatuses were used directly to test the heat shield of Buran these is why they had to be often modified. The structure of the heat shield of the wings was different from the remainder of the body. Indeed, because of the aerodynamic profile of the lifting body the wings were thin and could not support the heavy tiles. The interior cavity of wing was filled by a porous matter (the same as felt which holds the tiles on the fuselage) and impregnated with a special composition based on water. Thus, the vapor was used for cooling the structure during the intense heating on the return trajectory.
The orientation of the lifting bodies in space was made by 8 gases engines controlled by the program of flight (an inertial system). At the beginning of the 2nd revolution the solid propellant engine located "on the back" of the apparatus gave the impulse of braking for the re-entry in the atmosphere. During the descent, the stability of the apparatus was ensured by the directional wings. The angle of attack for the first flight was of 57° then 52° and 54° for the following. The slope of the wings was also used to direct the lifting body and to enable him to reach the predicted impact point.
Assembling of the lifting body in the factory.
1-Nasal thermal shield; 2-Electrical battery; 3-Tank for the fuel, NO3 + UDMH; 4-Parachute; 5-Navigation system and on-board electronic; 6-Radio equipment; 7-Scientific equipment; 8-Actuator of the wings; 9-Wings; 10-Vertical stabilizer; 11-Engines; 12-Central bloc of the GRD engines, pitching; 13-Steel frame.
1-Agglomerated quartz; 2-Anti-erosion coating; 3-Protective lacquer; 4-Interior protection; 5-Adhesive; 6-Metal layer; 7-Refractory materials; 8-Metal frame.
After braking, the gliding flight in the dense layers of the atmosphere and left the plasma zone, at an altitude of 30 km, "BOR-4" started to glid into spiral to reduce its speed, at 7 500 m it spread the parachutes to prepare to the sea landing at 7-8 m/s. After the sea landing a trap door opened on the back of the apparatus to spread out the radio antenna and a conical balloon, provided with a scintillating lamp, inflated.
The flights of "BOR-4" made it possible to make enormous progress in the design of heat shield, for the creation of the Buran's one:
This apparatus developed from the studies of "BOR-4" should have a 12.5 m length, a wingspan of 9.5 m and a mass of 13-15 t. It was elaborate for being an interception vessel, armed with space-space missiles. For its putting into orbit it should use the "Zenith-2" launcher. According to the report of the American ministry of defense in 1986 it was created in response of the military uses of the American shuttle. In 1987 the "Hurricane" project is stopped, on the side we can see illustrations of the work "The Secret Story of the Soviet Space Shuttle" where we see the "Hurricane" in miniature version on a "Proton" and "Zenith-2" launcher, and a space shuttle version on the "Energia" launcher.
In spite of the information collected by the flights of "BOR-4", mainly for the heat shield, it was necessary to make new tests to validate the aerodynamic profile of Buran. That's why "BOR-5" was created. It was the exact copy of Buran on the 1:8 scale and was not by definition a lifting body. These atmospheric tests in conjunction with wind tunnel tests have made it possible to determine:
The flying mock-up were equipped with probes. There were probes (molybdenum alloy) on interior surface of the shuttle. The outside was covered with a heat shield made up of refractory tiles in which were laid out at 0.3 mm of depth the platinum probes.
The heat shield of "BOR-5" was mainly distinguished from the Buran's one by the fact that the elements was 8 times smaller (fuselage of 3.856 m long instead of 30.85 m for Buran), to keep a coherence in real tests "BOR-5" was launched less higher (15-20 km) and less quickly (until Mach 15). Moreover, the surface of the elements protected by the shield was increased and this one slightly modified because the curvatures radius (of the wings and the nose) being shorter have higher temperature there, direct consequence of "BOR-5"'s dimensions.
The rocket К65М-РБ5 (foreign designation SL-8) launched the apparatus of 1450 kg, from the Kapustin Yar base, at 210 km of altitude, after which the upper stage of the rocket gave an additional impulse to "BOR-5". To guarantee the tests the re-entry speed in the atmosphere at 100 km was to be between 7 300 m/s and 4 000 m/s, at the time of re-entry "BOR-5" separated from the accelerator and continued its flight according to the ballistic curve. At the altitude of 50 km, the plane changed its angle of attack to have the same one as Buran. As for "BOR-4" the piloting of "BOR-5" was made by gas engines out of the atmosphere, but in the atmosphere it was achieve by the control surfaces of the plane, it was the first time in the country that control surfaces were used at so high speeds.
The distance of flight for "BOR-5" from the starting point to the landing was nearly 2 000 km, at 7-8 km of altitude it was slowed down while flying in spiral and at 3 km a parachute opened to make fall speed to 7-8 m/s.
The first 2 flights (N501-502 mock-up) showed that in the zones of high heats the surface of the nose and the leading edge of the wing were damaged. Thereafter the N503-505 models received modifications on the refractory materials, molybdenum addition. After these additions no more degradations was observed and the aerodynamic characteristics was really improved.
Planes "BOR-4" and "BOR-5" were manufactured at the Experimental Machines Factory chaired by Vladimir Mikhalovitch Miasitchev (Владимир Михайлович Мясищев) with the collaboration of LII and Molniya. The tests of the 2 planes were carried out by representatives of LII and with the participation of specialists in the military test institute of Molniya and other organizations under the direction of Goskomissi (Госкомисси), chaired by the first chief assistant of the Police headquarters of the spatials methods (GUKOS) and by the General-lieutenant of aviation G.S. Titovym (Г.С.Титовым).
Closure of the Buran project does not have made it possible to develop the plane "BOR-6" which was based on the "BOR-4" and provided with special antennas to communicate in the plasma zone.
After a few years of having remained in hangars models "BOR" were found progressively in international exhibitions then foreign museums and finally in private collections. Today there does not remain any more "BOR" mock-up in Russia, thus the latter does not only export its gas, oil and wood, but also space curiosities of its history. The pictures presented below are those of a new owner (located on the left) of a "BOR-5".
This BOR 5 is now property of the Technik museum at Speyer since mid-2008.
In practice, the significant payload requirement eliminated a stubby-shaped body orbiter configuration from because the Shuttle's fuselage needed to be a rectangular box with rounded The aerodynamics of building a large vehicle without were simply too daunting. bodies also were rejected another reason: the invention lightweight tiles that provide protection. This invention meant an orbiter with delta could still be built enough to be a spacecraft. Thus after the A initial round of selections, NASA rejected lifting designs. If it weren't the payload bay requirement, lifting body configuration might worked well. Lifting bodies have been a good between ballistic capsules and or straight winged vehicles. are lighter, have simpler and encounter fewer reentry problems than winged vehicles. bodies have better lift drag ratios than ballistic enabling them to be more accurately.
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