Buran - Reusable soviet space shuttle.

The shuttle is intended for tasks of defense, maintenance of various space objects and for their return on earth, the delivery of modules and cosmonauts for the assembly of great orbital structures, the repatriation of defective material, of missions of long duration, the development of equipments and techniques of production related on space and their delivery on ground, to the carriage of various equipment and passengers according to the route ground-space-ground.

External configuration

The Buran shuttle is built according to the scheme of a plane: this plane has a delta wing with variable leading edge angle and ends with elevons (device placed on the trailing edge of a delta wing combining the action of elevators and ailerons), the rudder splits into 2 parts and do also the function of air-brake, the landing is ensured at the manner of a plane by 3 gears with one under the cockpit.

Interior configuration

In the front part of the shuttle is the hermetically insulated cabin which occupies a volume of 73 cubic meters. This cabin is reserved to the crew (2-4 people) and to the travellers (up to 6 people), for the on-board equipments and the engines.

The medium part is occupied by the payload bay which opens thanks to folding doors, in which is installed the arm manipulator for the various operations of handling space objects. Under the payload bay is located the power generating unit and air-conditioning. In the tail of the shuttle take place the engines and the machines of the hydraulic system. For the structure of Buran, various materials were used such as aluminium alloys and steel. To resist heat during the re-entry in the dense layers of the atmosphere, the external surface of the shuttle was covered by a special heat shield.

The tiles which cover the upper part are less exposed to the heat, but the others are built with quartz fibres and can tolerate a temperature up to 1300°C. For some parts (nose and the leading edge of the wings, where the temperature reaches 1500°C-1600°C) the tiles are made up of carbon. The most intense stage of the heating is accompanied by the formation of a characteristic plasma, however the temperature of the structure of the shuttle does not exceed 160°C at the end of the flight. Each 38 600 tile has a specific place which made the external shape of the body of the shuttle. For the reduction of the thermal stress, large curvating radius where used for the nose, the fuselage and the wings. Lastly, the structure was made to support 100 flights.

Motorization and the on-board equipment

The engine system is used for the propulsion in space, the run or the correction between various orbits, the operations of precise movements close to the spacecrafts, the orientation and the stabilization of the Buran shuttle and its slowdown for the return on earth. The engine system includes 2 engines for the orbital operations functioning with liquid oxygen and kerosene, and 46 engines (orbital maneuvering system) with gas for the control of trajectory, gathered in 3 blocks (1 in the nose and 2 in the tail). The on-board equipment is composed of more than 50 different machines, the radio, TV and telemetric sets, the systems for maintaining life, air-conditioning, navigation, the supply energy, etc... They are controlled by the computers in the cockpit and make it possible to ensure the Buran shuttle a stay of 30 days in orbit. The heat released by the on-board equipment is brought towards the radiators located on the inside part of the leaves of the payload bay, and radiate in space (during an orbital flight when the payload bay is open).

Geometry and mass

The length of Buran is 35.4 m, the height is 16.5 m, the span of the wings is 24 m, wing surface is 250 m2, the width of the fuselage of 5.6 m, the height is 6.2 m, the payload bay has a diameter of 4.6 m and a length of 18 m. The starting mass reaches 105 t, the mass of payload that can be put into orbit is 30 t and return value is 15 t. Propellant total mass is 14 t. Great dimensions of the shuttle are not easy for the installations on the ground this is why it (as well as the elements of Energia) is delivered to the cosmodrome by a modified plane, the VM-T of the factory of experimental construction V.M. Miasichtchev (В.М.Мясищев) (the shuttle whose vertical stabilizer is removed weighs almost 50 t) or by the An-225 especially conceived for this task.

Putting into orbit

The launching of Buran is carried out by the universal 2 stages launcher Energia, on which it is fixed on the central block. The engines of the 1 st and 2nd stages of Energia are ignited practically simultaneously and develop a thrust of 34840 kN for a starting mass, Energia and Buran, of almost 2400 t (90% of the mass is due to propellant). For the first test of Buran, having taken place on the cosmodrome of Baikonur on November 15, 1988, the flight of Energia lasted 476 s for an altitude of almost 150 km (the blocks of the 1 st stages, the booster rockets, separated at 146 second and 52 km height). Then it is the engine of the principal block which taken the relay until the rocket reach the transitional orbit. The maximum altitude of putting into orbit for Buran is 250 km for a payload of 30 t and 8 t of propellant.

For its first flight, the Buran shuttle had an orbit altitude of 250.7/260.2 km (slope of 51.6°) and a period of revolution of 89.5 min. With a loading of propellant of 14 t and a payload of 27 t, the altitude of 450 km can be reached.

If a technical incident occurs during the separation of stage 1 or stage 2 of Energia, the on-board computer "decide", according to the altitude traveled, of the ejection of the shuttle for the low orbit or a trajectory of flight for the Buran-Energia couple, then of the separation of the shuttle for a landing on the main aerodrome. During a normal operation of the Energia launcher, which speed does not stop increasing until orbiting, it flies according to the calculated trajectory and splashdown in the Pacific Ocean.

The return on earth

To leave the orbit, the shuttle turns over 180° thanks to the gas orbital maneuvering systems (the tail ahead), then the principal engine begin an urgent braking to give it the necessary impulse to slow down. The shuttle enter the descent trajectory, it turns over 180° again (nose ahead) and get on its trajectory with a great angle of attack. Until the altitude of 20 km the trajectory is controlled by the orbital maneuvering system and the aerodynamics systems (drift, elevons), then on the end of the flight, in fact only the aerodynamic systems are used. The profile of the shuttle ensures a good aerodynamic quality to it, enabling it to carry out a controlled descent on 2000 km, and finally after some operations facing the landing strip. At the same time, the trajectory chosen for the descent makes it possible to compensate the approach speed of the shuttle which is 300 to 360 km/h at the landing time. The length necessary for the landing is 1100 to 1900 m. For the improvement of the exploitation possibilities of Buran, it was planned to use 3 aerodromes, one at the cosmodrome (5 km length, 84 m broad at 12 km of the launching pad), another one in Asia (Horol, in the north of Vladivostok) and another at the West (Simferopol, in Ukraine). The whole radio systems of the aerodrome (500 km of ray), ensure the detection of the shuttle, its return towards the aerodrome (including in automatic mode) and its landing.

The first trial flight of Buran was completed after the execution of 2 revolutions around the Earth, then by the successful landing in automatic mode on the aerodrome in the area of Baikonur. The breaking impulse was started at an altitude of 250 km, at a distance of almost 20 000 km from the aerodrome.

The development of Buran went on 10 years. Ten years during which important research tasks and experiments were carried out in various technical fields: acoustics, thermodynamics, systems design, dynamics of flight on simulator, design of the control panel, making of new materials, developing of methods and equipment for the landing in automatic mode (flying laboratories), atmospheric flight tests of the similar shuttle (another model of Buran with turbines, BTS-002), outsides tests of the heat shield and aerodynamic tests on BOR-4 and BOR-5 models, etc.

In May 1974, a large shake-up of Soviet space program took place which to the Buran half of the Vasiliy Mishin, who was the chief at the influential TsKBEM design bureau, unceremoniously fired while he was in hospital. TsKBEM merged with Valentin Glushko's EnergoMash bureau to form the powerful Energia Scientific Production Organization (NPO Energia). then took over this huge new supervising virtually all Soviet human spacecraft, vehicles, and reconnaissance satellites. Famed Soviet pioneer Sergei Korolev had founded the of NPO Energia, but now Glushko even more power. As one of first official acts, the vindictive Glushko an order suspending all work on N1 and associated lunar projects. In single stroke, Glushko had cancelled Mishin's plans for space exploration. Glushko was interested in a new super-heavy launch Despite many possible scenarios, it was what the prime goal or mission such a vehicle would be. Nevertheless, began some initial work on what the Energia launch vehicle in 1974. however, the military found a purpose such a vehicle.