The content of this page is adapted from Semyonov (ed.) 1995, ch. 3.3, with additional information from Lozino-Lozinsky (ed.) 1997 and airframe blueprints published by Vadim Lukashevich on buran.ru, and follows some of the conventions from HAER TX-116. See *Bibliography* for more details.
Coordinate system
The Buran orbiter uses a longitudinal line 292 mm below the axis of the sill longeron as the X-axis of the coordinate system (the “construction horizontal line”). Measurements along the X-axis typically treat the tip of the orbiter’s nose cap as the origin, with values increasing towards the aft of the orbiter. Vertically along the plane of symmetry, the positive Y-axis designates the up direction. The Z-axis increases laterally from the plane of symmetry.
On this page, the length of a component refers to its dimensions along the X-axis, the width—along the Z-axis and height—along the Y-axis, unless specified otherwise. Dimensions of airframe components are based on the “theoretical contour” or mold line, that is, they include the thickness of the thermal protection applied to the skin panels.
center mass coordinates must be as follows: X = (19744…20361) mm from fuselage forebody nose along the longitudinal axis; Y = (620…1380) mm down from fuselage construction horizontal line; Z = ± 16 mm from surface symmetry
Airframe
The orbiter’s airframe was constructed using conventional techniques with frames, bulkheads, ribs, spars, longerons and skin panels joined by rivets, threaded fasteners and welds. The structure was primarily made of aluminum alloys, with a number of components made of titanium and steel alloys and composite materials.
The airframe was divided into five major sections:
- forward fuselage and cabin module
- mid-fuselage and aft fuselage
- two wings with elevons
- vertical stabiliser with rudder-airbrake
- body flap
the mid-fuselage and payload bay doors, the aft fuselage, the body flap, two wings and the vertical stabiliser.
An orbital ship is a manned spacecraft that is complex in design and layout, incorporating many systems, assemblies, mechanisms and equipment. The basis of the OK design is the glider, which forms aerodynamic contours, absorbs loads in all phases of the flight, serves as the hull of the ship, equipped during its assembly, and includes systems and elements that ensure descent and landing. Its mass, including its own systems, is about 40% of the launch mass of the OK. The airframe and its systems are discussed in more detail in Chap. 3. During the assembly process of the spacecraft, the systems and assemblies necessary for space flight are installed on the airframe (control systems, power supplies, etc., radio engineering complex, propulsion systems, etc.), constituting about 20% of the launch vehicle mass, as well as universal equipment for work with NG and replacement compartments, constituting up to 11% of the starting mass of OK. Being connected by electrical circuits, all systems 1.4
The fuselage is 30,850 mm long (including the nose cap), 5,500 mm wide and 6,200 mm tall and is divided into two major sections: F-1, which is the forward fuselage (NChF); and F-2, which consists of the mid-fuselage (SChF) and the aft fuselage (KhChF).
Airframe components are generally fabricated from D16 aluminum for formed sheet metal parts and 1163 aluminum for parts milled from plate; exceptions will be indicated.
Forward fuselage
The forward fuselage is 9,000 mm long, 5,500 mm wide and 6,000 mm tall and houses the Cabin Module (MK) and nose ODU block along with other systems.
The bulkhead just forward of the Cabin Module is part of the nose ODU block; during orbiter processing they are removed together, allowing better access to the forward fuselage.
Mid-fuselage
The mid-fuselage is 18,500 mm long, 5,500 mm wide and 6,000 mm tall and is the structural backbone of the orbiter. It joins to the forward fuselage and crew cabin at the forward end and the aft fuselage at the rear. Along the bottom of each side is the wing attachment interface with the main landing gear trunnion supports further aft, and centrally at the front is the nose landing gear compartment. Four-segment payload bay doors with radiators are attached to the mid-fuselage and enclose the payload bay. The mid-fuselage is also home to payload bay equipment such as the two robotic manipulator arms, the docking module, payload attachment systems, laboratory modules and one of the high gain antennas, as well as orbiter systems like the fuel cells and their fuel tanks, environmental and thermal control system tanks.
Its structure is composed of 26 frames connected by two sill longerons running along the top edge of the payload bay and skin panels with stringers on the sides of the fuselage and its bottom surface. Beneath the payload bay, the frames are further reinforced by strengthening elements made from titanium alloy tubes arranged in a truss structure. Corrugated panels are attached to the frames to create the interior surface of the payload bay.
The frames are spaced 650-750 mm on center and are indexed starting from frame 7 at the forward end; the first 22 frames are indexed in pairs as 7, 7A, 8, 8A, etc., until frame 17A; the remaining four frames are indexed frame 18 through frame 21.
Five frame types are used in the structure.
Frame 7, which is the forwardmost frame and transfers the loads from the forward Energia attachment point, the forward hoisting fittings and the nose landing gear, uses two milled aluminum webs spaced 200 mm apart and connected with tie rods. Each web consists of three sections: a pair of upper segments, which support the hoisting fittings, and a lower section. The most loaded, central part of the lower section is milled from VT23 alloy titanium plate.
Frames 7A, 8 and 8A, located near the nose landing gear compartment, are also each split in three sections. The two upper segments are standard flange-web constructions with corrugated aluminum webs. The lower section is a truss structure with VT23 titanium tube diagonals.
Frames 9, 9A and 10 are simple web and rib structures. Frame 9A uses a corrugated aluminum web, while frames 9 and 10 are milled from aluminum plate and have cradle attachment points.
The twelve frames 10A through 16 are each split in three sections, the lower, central truss section and two full-height vertical segments on the sides. The construction of the vertical segments alternates between the frames, with 10A, 11A, 12A, etc. frames using corrugated webs and 11, 12, 13, etc. frames using milled webs with cradle attachment points.
The last seven frames, 16A through 21, use a similar construction to frames 10A through 16 but their lower sections integrate the wing carry-through structure made of titanium upper and lower flanges with titanium diagonals. Frames 16A, 17, 18 and 20 use milled aluminum webs, with cradle attachment points on frames 17, 18 and 20. Frames 17A, 19 and 21 use corrugated aluminum webs.
The outside surface of the mid-fuselage extends to the aft fuselage and is divided into four sections along the length of the fuselage, connected together by bolts. In each section, the bottom and sides of the fuselage consist of chemically milled skin panels with open-section stringers. The panels are uniform in thickness across the entire airframe. In the wing carry-through and main landing gear trunnion area of the wing attachment interface, milled titanium panels are used instead of the aluminum skins.
Skin panels on the sides of the fuselage have cutouts for the hatches of the airframe pressurization and ventilation system (SNVP) and for oxygen and hydrogen fill hatches for the fuel cell (EChG). Each side has six inward-opening SNVP hatches measuring 510 x 200 mm and fitted with rubber seals. Fuel cell fill hatches are 500 x 600 mm and open outwards; they are fitted with rubber seals and thermal barriers and a locking system.
Forward of the wing attachment interface, a wing glove fairing is attached on each side of the mid-fuselage over the existing skin panels. The glove is made from stamped skin panels with open-section stringers and bent aluminum profile ribs. The glove is riveted to the fuselage side along the edge of the attachment interface. Maintenance hatches in the fuselage sides provide access to the glove volume.
The bending and torsional loads of the fuselage are carried by sill longerons, which run along the top edge of the mid-fuselage at either side; their axis is located 292 mm above the reference plane and they are L-shaped in cross-section. The longerons also support the twelve payload bay door hinge brackets on each side and the robotic manipulators.
As the payload bay opening creates a structural gap in the fuselage, the payload bay doors were designed to carry additional torsional loads of the fuselage when closed. More details on the payload bay doors page.
On each side of the orbiter, there are twelve cradle attachment points, with eleven of those machined into the mid-fuselage frames, and an extra attachment point on frame 22, which is technically part of the aft fuselage. Payload trunnion cradles span two neighboring cradle attachment points and are secured to the sill longeron with four bolts below the cradle’s top edge. The cradles can hold trunnion attachment fixtures for deployable payloads or fixed payloads like laboratory modules, extra propellant tanks or the SPK (cosmonaut maneuvering unit) pallet. There are also attachment points along the keel of the payload bay.
Electrical cables run along cable trays located on both sides of the payload bay. The starboard tray also accommodates the ODU propellant lines connecting the base block to the nose block. Thermal insulation cloth “The upper chords of the frames have pile linings that secure the fabric lining of the OPG, which ensures stabilization of the thermal conditions of the equipment located in the SChF.”
Mass report of built mid-fuselage segments:
| Airframe | Mass (kg) |
|---|---|
| 0.01 | 20,060.306 |
| 0.02 | n/a |
| 0.03 | 23,441.096 |
| 0.04 | 9,921.127 |
| 0.05 | n/a |
| 0.06 | n/a |
| 0.11 | n/a |
| 0.16 | 10,139.833 |
| 1.01 | 10,237.670 |
| 1.02 | 10,256.333 |
| 2.01 | 10,222.692 |
| 2.02 | 10,190.008 |
| Design mass | 9,161 |
Aft fuselage
The aft fuselage section is 3,600 mm long, 5,500 mm wide and 6,000 mm tall. It is joined to the mid-fuselage at the forward end, the wing consoles at the sides and it supports the vertical stabiliser and the body flap as well as the Integrated Propulsion System (ODU) Base Block along with two aft ODU thruster blocks.
Its structure consists of the aft payload bay bulkhead, designated frame 22, and five frames designated 23, 23A, 24, 25 and 26, as well as skin-stringer panels, diagonal braces and spars. Frames 22, 24 and 26 are the main load-carrying frames of the aft fuselage, while frames 23, 23A and 25 act are lightly loaded and mainly support the skin-stringer panels; the upper aft fuselage spars are aligned with the sill longerons and carry bending loads through the orbiter.
Frame 22 is milled from VT23 titanium with corrugated aluminum webs. It is the aftmost frame directly connected to the wings and the aftmost frame with cradle attachment points. It supports the ONA-I antenna. Frame 24 consists of two milled VT23 aluminum webs separated by intercostals and supports the aft Energia attachment points, as well as the aft hoisting fittings. It is braced against frame 26 by twelve titanium tie rods and against frame 22 by two tie rods. Where possible, the spars of the aft fuselage are continuations of their counterparts on the mid-fuselage, most notably the sill longeron.
Along with the ODU, the aft fuselage houses a number of orbiter systems. At the bottom and offset to the port side, the high gain ONA-II is stowed in a compartment protected by an outward-opening door. The door is held by ten electrically-driven locks and is fitted with two rubber seals. Three Auxiliary Power Units (VSU) are mounted behind the frame 22 bulkhead, two on the starboard side and one on the port side.
Two niches for the Air-Breathing Propulsion System (VRDU) turbofan engines are located on the aft fuselage shoulders. The use of VRDU engines on first series orbiters was abandoned in late-1987 or early-1988 and the niches on orbiters 1K and 2K were closed off with aluminum panels and covered in thermal blankets. The aft fuselage of second series orbiters did not include the niches at all.
A drag chute housing is mounted below the vertical stabiliser on the aft bulkhead.
nose rcs block includes fwd fuse bulkhead, removed together for service Lower antenna left hand side
Wings
connected with shear bolts along both the top and bottom surface at
Bibliography
- Semyonov (ed.) 1995, ch. 3.3
- Lozino-Lozinsky (ed.) 1997 and
- airframe blueprints published by Vadim Lukashevich on buran.ru