Unmanned Orbital Rocket Planes type "BOR"

Russia

Type / Application:

Space plane recovery test

The Gromov Flight Research Institute (LIl) built several scale models of the spaceplane known as Unmanned Orbital Rocket Planes (Bespilotnye orbitalnye raketoplany or BOR) to test its performance during suborbital and orbital missions.These were BOR-l (a wooden mock-up), BOR-2 (a 1:3 scalemodel) and BOR-3 (a 1:2 scale model), both with ablative heatshields, several of which were launched on suborbital trajectories by R-12 missiles from the Kapustin Yar cosmodrome near Volgograd between 1969 and 1974.
A full-scale prototype for subsonic flights (105.11) was ready by the mid-1970s and made several manned autonomous flights as well as piloted drop tests from the belly of a Tu-95K between June 1976 and September 1978. A model for supersonic tests (105.12) was built, but never flown and a model for hypersonic tests (105.13) was partially built. In 1975 plans were drawn up for a 1:2 unmanned scale model called BOR-4 that would be launched on orbital test missions. Unlike the real Spiral, this would be equipped with a non reusable ablative heatshield, but would provide critical data on the spaceplane's aerodynamic characteristics throughout the flight regime.
The Russians had worked out their own test programme for Buran's thermal protection system weIl before the Space Shuttle began flying. Besides tests in thermal vacuum chambers, Ilyushin-18D and MiG-25 aircraft were used to test tiles and felt reusable surface insulation at subsonic and super-sonic speeds. The thermal insulation was installed on areas of the aircraft that were subjected to the highest dynamic pressure and acoustic loads from the engines. In addition to that, the Russians had the unique opportunity to test the materials inactual re-entry conditions. All they needed to do was to dust off the old plans for the BOR-4 vehicle and cover it with Buran's heatshield materiais. Even though BOR-4's shape was not representative of Buran, the heatshield tests did not require a vehicle that exactly mimicked Buran's shape. The most important thing was to ensure that the heat-resistant materials would be exposed to the same type of temperatures for about the same period of time. Moreover, the nose section of the BOR-4 test vehicle did more or less match the contours of Buran's nose section. In 1977 it was decided to develop two types of scale models in support of the Buran programme and fly each ofthem five times:
- BOR-4: a 1:2 scale model of the Spiral spaceplane totest Buran's heats hield materials on orbital missions.
- BOR-5: a 1:8 scale model of Buran to test Buran's aerodynamic characteristics on suborbital missions.

BOR-4 DESIGN AND MISSION PROFILE:

Just like the Spiral spaceplane, BOR-4 was a flat-bottomed lifting body with a vertical fin and foldable wings. It was 3.859 m long with a launch mass of about 1,450 kg and a landing mass of 795 kg. The BOR-4 vehicles made it possible to test the three main types of thermal insulation used on Buran,namely tiles, felt reusable surface insulation and reinforced carbon-carbon. Black tiles (using both the TZMK-IO and TZMK-25 substrate) covered the belly, white tiles (with TZMK-10 substrate) were installed on the sides and ATM-19 feltinsulation protected the upper part of the vehicle. Carbon-carbon GRA VIMOL material was used only on the nosecap,with the wing leading edges being too thin for installation of such material.

Distrubution of heatshield material over BOR-4's surface.
Key: l.nosecap with reinforeed carbon-carbon material("GRAVIMOL"); 2. TZMK-IO and TZMK-25 tiles with blackcoating; 3. TZMK-IO tiles with white coating; 4. ATM-19 feit re-usabie surface insulation; 5. calorimetrie sensors; 6. thermal paioton upper and lower surface; 7. thermocouples on the nosecap,tiles and airframe; 8. thermal sensors in between tile. (source: Publishing House of Moscow Aviation Institute)

The tiles were not attached to BOR's airframe, but to a thin layer of aluminium of the same composition as that used in Buran's airframe. In between this aluminium layer and the actual airframe was an ablative heatshield material (PKT-FL)that had been planned for the original BOR-4 vehicle to be flown in support of the Spiral programme. This provided then ecessary redundancy in case any of the Buran heatshield material bumt through during re-entry. The area between the nosecap and the airframe was filled with insulating material made of heat-resistant fibres. Since the wings were much thinner than the rest of the airframe, they were filled with aporous feIt material impregnated with a water-based substance. Evaporation of that substance provided enough cooling for the wingduring re-entry in case the Buran heatshield material proved ineffective.
BOR-4 was equipped with 150 thermocouples, installed mainly on the airframe and just under the coating of some of the tiles. In addition to that it had accelerometers, angular velocity sensors, pressure sensors and sensors that indicated the position of the wings. Information obtained from the sensors was recorded on board and sent back to Earth in "packages". Baikonur no longer supported that rocket at the time and although Plesetsk did, it was situated too far north to place the spaceplane models into the proper inclination. The rockets used for the BOR-4 missions had originally been earmarked for other missions, but had already surpassed their guaranteed "shelf life" and would have been used for test launches anyway.
The vehicle would be launched with its two wings completely folded so that it fitted under the rocket's fairing. After release from the launch vehicle, the wings were moved to a position that would keep the vehicle stable during re-entry at an angle of attack of between 52° and 57° between altitudes of 70 and 60 km. Orientation in orbit was carried out with the help of eight microthrusters burning hypergolic propellants. After a single revolution of the Earth BOR-4 initiated its descent back to Earth, firing what is believed to have been a jettisonable solid-fuel motor mounted on top of the vehicle. At an altitude of30 km the on-board control system sent BOR-4 on a steep spiralling trajectory to decrease speed and at 7.5 km the spacecraft deployed a parachute that reduced the vertical landingspeed to 7-8 mis.
Since the vehicle was not equipped with a landing gear, it needed to land on water to ensure that its heatshield remained intact for post-flight analysis. The only major bodies of water on Soviet territory that would be in the BOR's flight path were the Black Sea and Lake Balkhash. However, the Russians had never returned a winged vehicle or lifting body from orbit and were not confident they could aim the spacecraft for precision splashdowns in the Soviet Union. Therefore they opted to land the first vehicles in the Indian Ocean, where they would still come down in water even if they fell short of or overshot the planned landing area. That did, however, significantly increase the cost of the recovery operations, which, moreover, would be hard to conceal from the prying eyes of Western reconnaissance aircraft.
After splashdown a conieally shaped float was inflated on top of the spacecraft to improve its buoyancy. The float also had flashing lights and antennae to make it easier for there covery forces to locate the BOR. Before being hoisted onboard a recovery ship, a crew was sent out to the vehic1e to disarm an on-board self-destruct system.
BOR-4 MISSIONS:
BOR-4 was designed at the Gromov Flight Research Institute(Lll) in Zhukovskiy under the leadership of Viktor Utkin and the vehic1es were manufactured and covered with heat-resistant materials at the Tushino Machine Building Factory, the production facility aligned with NPO Molniya which manufactured the Buran airframes. The man in charge of the BOR-4 programme at NPO Molniya was Stepan Mikoyan,a deputy of chief designer Gleb Lozino-Lozinskiy. The BOR-4 test flights were co-ordinated by a government commission headed by former cosmonaut Gherman Titov.
The orbital flights were preceded by an experimental suborbital launch on 5 December 1980 in the direction of Lake Balkhash. This mission was intended to test the launch vehicle,the aerodynamie characteristies of the vehic1e and the performance of the aerodynamie surfaces and rocket thrusters Designated BOR-4S (tail number 401), the vehicle only had the ablative heatshield. Maximum altitude was 198 km and maxi-mum speed Mach 26.5. The final part of the flight was monitored by two IIyushin 18RT aircraft flying in the vicinity of Lake Balkhash. These were modified IIyushin 18D aircraft specially adapted to perform tracking of 1aunches in areas that were not covered by Soviet ground-based or sea-based tracking means. The vehicle was successfully recovered and was on display at the MAKS air show near Moscow in August 2005.
Analysis of the suborbital mission took longer than expected and necessitated some changes to the vehicle's design. In the spring of 1982 seven Soviet ships set sail for the Indian Ocean to support the first orbital mission of a BOR-4 vehicle. (see next Cosmos flights)
BOR 4 #2: Cosmos 1374
BOR 4 #3: Cosmos 1445
BOR 4 #4: Cosmos 1517
BOR 4 #5: Cosmos 1614

Launch list:

Satellite	Date	LS	Launcher	Remarks:
- (#1 s/n°401)	05.12.80	KY?	Cosmos?	Suborbital test. Landed near Lake Balkhash
Cosmos 1374 (#2 s/n° 404)	03.06.82	KY	Cosmos-3M-RB5	Landed in Indian Ocean
Cosmos 1445 (#3 s/n° 403)	15.03.83	KY	Cosmos-3M-RB5	Landed in Indian Ocean
Cosmos 1517 (#4 s/n° 405)	27.12.83	KY	Cosmos-3M-RB5	Landed in Black Sea
Cosmos 1614 (#5 s/n° 406)	19.12.84	KY	Cosmos-3M-RB5	Intended Black Sea landing, not recovered

Ref.: #5(03/07) - update: 03.03.07

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