Buran (spacecraft)

''Buran'' (russian: Буран, , meaning "Snowstorm" or "Blizzard"; GRAU index serial number: 11F35 1K, construction number: 1.01) was the first spaceplane to be produced as part of the Soviet/Russian Buran program. Besides describing the first operational Soviet/Russian shuttle orbiter, "Buran" was also the designation for the entire Soviet/Russian spaceplane project and its orbiters, which were known as "Buran-class orbiters".

Buran completed one uncrewed spaceflight in 1988, and was destroyed in the 2002 collapse of its storage hangar. The Buran-class orbiters used the expendable Energia rocket, a class of super heavy-lift launch vehicle.

It is named after the Asian wind.

Construction

The construction of the Buran spacecraft began in 1980, and by 1984 the first full-scale orbiter was rolled out. Over 1000 companies all over the Soviet Union were involved in construction and development. The Buran spacecraft was made to be launched on the Soviet Union's super-heavy lift vehicle, Energia. The Buran program ended in 1993.

Technical description

The Buran orbiter is built around a "glider", which is its main structural component, since all other components such as wings and the crew cabin are attached to it. The components necessary for flight make up approx. 20% of the weight of the orbiter, while another 11% of weight is added by payload systems and removable parts. The wings of the Buran orbiter contain elevators whose position can be changed from +35° to −20°.

Exterior

Similarly to US space shuttle orbiters, Buran orbiters have their exterior covered in 38,600 heat shielding tiles designed to withstand 100 reentries, which themselves were very similar to the ones in the space shuttle, however, the carbon-carbon Buran heat tiles have an antioxidant molybdenum disilicide coating. The black coating in the carbon-carbon heat tiles helps dissipate heat, and, similarly to the heat tiles used in the space shuttle, Buran heat tiles are glued to the orbiter, and the bottom of the heat tiles are left uncoated to equalize the pressure in the tile with that of its surroundings, preventing additional mechanical loads. The gaps between tiles are deliberate to allow for thermal expansion. The gaps were filled with quartz fiber, rope, alkaline elements, inserts and brush seals, and the carbon-carbon heat tiles were also waterproofed.

The Buran and space shuttle orbiters are exposed to similar temperatures, and both have similar levels of insulation.
Buran has a different carbon-carbon heat tile layout in its underside, in which all gaps between heat tiles are parallel or perpendicular to the direction of airflow through the orbiter's underside, reducing heat in between heat tiles and in the boundary layer between the heat tiles and surrounding air, while helping maintain a laminar airflow through the orbiter.

Crew cabin

The cabin is an all-metal, welded, pressurised compartment housing the crew's workplaces, control and life support systems. It has three decks. The Command Module on the upper deck is the workspace for the crew and serves to accommodate the commander, pilot, engineer and mission specialist's seats, as well as the RMS operator's workplace. The middeck houses life support and auxiliary equipment, and up to six crewmembers could be seated there during launch and reentry. The lower deck houses the power systems. The cockpit is similar in layout to that of the space shuttle, with three cathode-ray tube displays.

Automatic landing system

The automatic landing system is capable of performing a fully automatic descent, approach and landing from any point located in the "admissible starting conditions area" at altitude, controlling the orbiter's flight during the descent. Covering during the approach and eventually slowing down from to zero.

The first Buran flight was notable for the automatic landing system electing to perform an unlikely (estimated 3% probability) manoeuvre at the key point, which was needed to extend the glide distance and bleed excessive energy. The standard approach was from the south and consisted of two left turns onto the final approach course. Instead, it performed additional turns in both directions and overflew the field to its northern side, before making a right turn back onto the final course. The landing system elected to perform the manoeuvre as the orbiter's energy didn't decrease enough due to strong-gusty winds in the area, measured at and gusting up to at ground level.

Docking system

The docking module (russian: label=none, Стыковочный модуль) is mounted into the forward part of the payload bay. It is a spherical compartment with a diameter of , with a cylindrical tunnel leading to the androgynous peripheral docking unit (APAS-89). Unlike the U.S. Space Shuttle, the docking compartment for Buran features an extendable tunnel to increase clearance between orbiter and station. Another hatch, facing into the payload bay, was to support extravehicular activity from the orbiter.

Remote manipulator

The Onboard Manipulator System (russian: label=none, Система Бортовых Манипуляторов), similar to the Space Shuttle's RMS, was developed at the Central Research and Development Institute for Robotics and Technical Cybernetics to support operations with payload. It could be operated both in manual and automatic modes. Buran-class orbiter could carry, depending on the mission, one or two manipulator arms.

Laboratory modules

To expand Buran capabilities, pressurised modules similar to ESA's Spacelab were designed based on the 37K design. These modules had to be both compartments to conduct experiments and logistics volume, could be mounted either in the payload bay and connected to the crew cabin via tunnel or be temporarily docked to Mir's Kristall side docking port. On Buran maiden flight, the Accessory Unit (russian: label=none, Блок Дополнительных Приборов) 37KB No.37070 was installed into the orbiter's payload bay. It carried recording equipment and accumulators providing power to onboard systems as the regular fuel cells based power system were not ready at the time. The second unit, 37KB No.37071 was built in 1987. It was planned to build a third unit, 37KB No.37072, but this never happened because of programme cancellation.

Propulsion

Orbital maneuvering is provided by the Joint Propulsion System (russian: label=none, Объединенная двигательная установка).

Operational history

Orbital flight

The only orbital launch of a Buran-class orbiter, 1K1 (first orbiter, first flight) occurred at 03:00:02  UTC on 15 November 1988 from Baikonur Cosmodrome launch pad 110/37. Buran was lifted into space, on an uncrewed mission, by the specially designed Energia rocket. The automated launch sequence performed as specified, and the Energia rocket lifted the vehicle into a temporary orbit before the orbiter separated as programmed. After boosting itself to a higher orbit and completing two orbits around the Earth, the ODU (russian: объединённая двигательная установка, сombined propulsion system) engines fired automatically to begin the descent into the atmosphere, return to the launch site, and horizontal landing on a runway.

After making an automated approach to Site 251, Buran touched down under its own control at 06:24:42 UTC and came to a stop at 06:25:24, 206 minutes after launch. Despite a lateral wind speed of , Buran landed only laterally and longitudinally from the target mark. It was the first spaceplane to perform an uncrewed flight, including landing in fully automatic mode. It was later found that Buran had lost only eight of its 38,000 thermal tiles over the course of its flight.

Projected flights

In 1989, it was projected that Buran would have an uncrewed second flight by 1993, with a duration of 15–20 days. Although the Buran programme was never officially cancelled, the dissolution of the Soviet Union led to funding drying up and this flight never took place.

Specifications

The mass of Buran is quoted as 62 tons, with a maximum payload of 30 tons, for a total lift-off weight of 105 tons.

Mass breakdown
* Total mass of structure and landing systems:
* Mass of functional systems and propulsion:
* Maximum payload:
* Maximum liftoff weight:

Dimensions
* Length:
* Wingspan:
* Height on gear:
* Payload bay length:
* Payload bay diameter:
* Wing chine sweep: 78 degrees
* Wing sweep: 45 degrees

Propulsion
* Total orbital manoeuvring engine thrust:
* Orbital manoeuvring engine specific impulse:
* Total manoeuvring impulse: unknown
* Total RCS thrust:
* Average RCS specific impulse:
* Normal maximum propellant load:

Unlike the US Space Shuttle, which was propelled by a combination of solid boosters and the orbiter's own liquid-propellant engines fuelled from a large tank, the Soviet/Russian launch system used thrust from each booster's RD-170 liquid oxygen/kerosene engine (each with 4 nozzles), developed by Valentin Glushko, and another four RD-0120 liquid oxygen/liquid hydrogen engines attached to the central block.

List of vehicles

Five orbiters were planned to be built (designated 1K-5K, K stands for russian: label=none, Корабль, lit=craft, flying article), and hull numbering starts with 1 or 2 (e.g. 1.01), two originally ordered in 1970s and three ("second series") additionally ordered in 1983. For research and testing purposes, several test articles produced, designated 1M-8M (M stands for russian: label=none, Макет, lit=mock-up), hull numbering starts with 0 (e.g. 0.02). The programme prefix OK stands for russian: label=none, Орбитальный Корабль, lit=Orbital Vehicle and carries the GRAU index number 11F35.

By 1991 two operational vehicles were delivered to Baikonur, three others were under construction at Tushino.

Most of the geo-locations below show the orbiter bodies on the ground; in some cases Google Earth's History facility is required to see the orbiter within the dates specified.

Related test vehicles and models

See also

* MAKS (spacecraft) – Soviet air-launched spaceplane concept
* Mikoyan-Gurevich MiG-105 – Soviet spaceplane test program
* OK-GLI – Buran Analog BST-02 test vehicle
* Space Shuttle program – American spaceplane program
* Tupolev OOS – Soviet air-launched spaceplane concept

References

Further reading

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External links

{{DEFAULTSORT:Buran (Spacecraft)
Buran-class orbiters
Aircraft first flown in 1988
Crewed spacecraft
Man-made disasters in Kazakhstan
Partially reusable space launch vehicles
Rocket-powered aircraft
Soviet inventions
Spacecraft launched by Zenit and Energia rockets
Spacecraft launched in 1988
Tailless delta-wing aircraft
1988 in the Soviet Union
2002 disasters in Kazakhstan
2002 in Kazakhstan