Shuttle Buran

A. The Soviet reusable spacecraft program Buran began in 1976 at TsAGI as a response to the United States Space Shuttle program. Soviet politicians were convinced that the Space Shuttle could be used for military purposes, hence posing a potential threat to the balance of power during the Cold War. The project was the largest and the most expensive in the history of Soviet space exploration.

B. Because Buran's debut followed Space Shuttle Columbia's and there were visual similarities between the two shuttle systems, during the Cold War many speculated that espionage played a role in the development of the Soviet shuttle. However, it is now known that while externally it was an aerodynamic copy of the Space Shuttle, internally it was all engineered and developed domestically.

C. The first and only orbital launch of the unmanned shuttle Buran was on 15 November 1988. It was lifted into orbit by the specially designed Energiya booster rocket. The life support system was not installed and no software was installed on the CRT displays. The shuttle orbited the Earth twice before returning, performing an impressive automated landing on the shuttle runway at Baikonur Cosmodrome. This is a capability that the U.S. shuttle system does not have.

D. The Buran orbiter is the first reusable manned space vehicle in our country. The Buran orbiter is the space airplane which may descent from an orbit and land to an airdrome. The Buran is our first vehicle capable not only to put pay-loads into Space, but also to provide their orbit maintenance and repair as well as return to the Earth.

E. The Buran orbiter is able to put up to 30 tons into Space and to return up to 20 tons of payload to the Earth. The availability of a cargo compartment of impressive sizes on the vehicle permits to transport orbital station modules or large structures up to 17 m long and 4, 5 m in diameter and not only 2-4 crew members but up to 6 passengers can be accommodated in a crew cabin.

F. Expendable space vehicles perform a ballistic or sliding descent in the atmosphere and parachute landing. The necessity to provide a space vehicle return from the Space and to bring it to the airdrome forced the designers to decide many complex problems. The gliding descent from the orbit through dense layers of atmosphere has stipulated the necessity to use a principally new reusable thermal protection system designed to sustain 100 flights.

G. For the Buran orbiter three kinds of thermal protection have been developed:

- " carbon-carbonic" material with maximum operating temperature up to 1650 degrees C for the components with the highest thermal load -the fuselage nose and wing leading edge;

- ceramic tiles for parts heating up to 1250 degrees C;

- flexible material for surface parts with the temperature not higher than 379 degrees C.

All of them surpassed by strength the materials used in the USA Space Shuttle construction.

H. Each of almost forty thousand tiles of ceramic thermal protection had its original geometry differing from the others by plane form, side surfaces view and inside and outside surfaces curvature, availability of cuts and notches. The measurements of a real frame surface geometry under each tile in more than 100 points were made to ensure the tiles fitting closely. To execute all this manually was impossible. The special software was developed and as a result manufacturing and installation of tiles were carried out completely on paperless technology without drawings, using the data bank. The bank data is based on the interface between a design office and plants. The data bank information describes the geometry, technology parameters and materials. More than one billion manufacturing control and testing programmes are automatically generated on the plant.

I.

The Buran descending from a space orbit passes all possible for an airplane flight performances in the atmosphere starting with large hypersonic (M-25) up to landing (M=0, 2) speeds. In this connection the aerodynamic scheme without a horizontal tail with a double swept wing, with elevons, rudder-aerodynamic brake and balance flap as control surfaces has been chosen. This assembly was worked up during wind tunnel tests and evaluated in the BOR-5 suborbital flying model flights.

J.

For working up the most responsible flight phase - landing approach and landing - the Buran flying prototype was constructed. In general it distinguished from the orbital vehicle by installation of four turbojet engines and accordingly by capability of an independent takeoff from the airfield. 24 flights were executed on the prototype, in 15 of them completely automatic mode landing was made. There was no pilot onboard the orbiter but it having made two turns around the Earth completely automatically controlled touched the runway with the accuracy which experienced pilots could envy. It was the first in the world automatic landing of a spaceplane.

K. The main differences between the space aeroplane Buran and the Space Suttle-orbiter are:

- the automatic landing of Buran from orbit onto airdrome;

- the absence of the main rocket engine on the orbital space aeroplane. The main engine was placed onto a central block of a carrier-rocket Energia which is able to launch into an orbit 120 tonns of payload against 30 tonns for the Space Shuttle;

- the high lift/drag ratio of the space aeroplane Buran is 6.5 against 5.5 for the Space Shuttle;

- the space aeroplane Buran returned 20 tonns of payloads against 15 tonns for the Space Shuttle orbiter from an orbit to an aerodrome;

- the cutting lay-out pattern of thermoprotection tiles of Buran is optimal and longitudinal slits of tile belts are orthogonal to the flow line. Sharp angles of tiles are absent. The tile belts of the Buran fuselage and fin have an optimal position.

L. The Buran orbiter flight was a necessary step in the space engineering progress but it has left its trace not only in this field. Born in the course of work on the Buran project new materials, technologies, computer designing methods and equipment components find an application in far, at first sight, from space branches of economy.

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