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. See Bibliography for more details.
Coordinate system
The Buran orbiter uses a longitudinal line 292 mm below the axis of the sill longeron (or 2600 mm below the top of the payload bay doors) as the X-axis of the coordinate system (the “construction horizontal line”); a horizontal plane coincident with the X-axis will be referred to here as the “reference plane”. 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 (averaged) thickness of the thermal protection applied to the skin panels.
Airframe
The orbiter’s airframe is constructed using conventional techniques with frames, bulkheads, ribs, spars, longerons and skin panels, joined by rivets, threaded fasteners and occasionally welds. Airframe components are generally fabricated from D16 aluminum alloy for formed sheet metal parts and 1163 aluminum alloy for parts milled from plate. Skin panels are 3 mm thick across the entire airframe. [AKS thermal designing] Stringers are generally open contours 40 mm tall and spaced 140 mm on center, measured along the principal axes, with narrower spacing (e.g. 125 or 130 mm) on some sections of the wing to achieve even spacing in between wing spars.
The airframe is 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 airframe and hardware required for atmospheric flight account for approximately 40% of the launch mass of the orbiter. Systems required for in-space operation (propulsion, power, communications, avionics) make up the next 20% of the launch mass. Payload systems and non-deployable payloads account for up to 11% of the launch mass.
The fuselage is 30,850 mm long (including the nose cap), 5,500 mm wide (across mold line; excluding payload bay door hinges and wing carry-through eyelets) 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).
Forward fuselage
The forward fuselage is 8,700 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 approximately 6,200 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 wing carry-through located in the aft section of the mid-fuselage. Forward of the wing carry-through, the fuselage side panels contain the inboard supports for the main landing gear. The nose landing gear compartment is located centrally in the forward section of the mid-fuselage.
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 and one of the high gain antennas, as well as orbiter systems like the fuel cells and their fuel tanks and environmental and thermal control system tanks.
The mid-fuselage structure is composed of 26 open-contour frames, spaced 650-750 mm on center, 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 liner panels are attached to the frames to separate the payload bay volume from the lower mid-fuselage.
Continuing the numbering of the forward fuselage, the forwardmost frame of the mid-fuselage is designated Frame 7, with indices increasing towards the rear of the orbiter. The first 22 frames are indexed in pairs (7, 7A, 8, 8A, 9, 9A, etc.), until Frame 17A, with the remaining four frames conventionally numbered Frame 18 through Frame 21.
Five frame types are used in the structure:
Frame 7, which is the forwardmost frame, is a power frame made up of two milled aluminum webs spaced 200 mm apart and connected with tie rods. The frame joins the mid and aft fuselage and is the attachment point for some of the cabin module tie rods; it also transfers the loads from the forward attachment point with the Energia, the forward hoisting fittings and the nose landing gear. Each of the two webs 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; it serves as the forward bulkhead of the nose landing gear compartment.
Frames 7A, 8 and 8A, located near the nose landing gear compartment, are each split in three sections. The two full-height vertical segments either side are standard flange-web constructions with corrugated aluminum webs. The lower central section is built around the landing gear compartment, with a truss structure with VT23 titanium tube diagonals either side. Frame 8A serves as the landing gear compartment’s aft bulkhead.
Frames 9A, 10A and 11A are partial frames; they feature narrowed full-height vertical segments at either side, but omit the central flanges and diagonals, using a single rib along the bottom surface of the fuselage instead. These frames create three double-width bays, where the fuel cells with their tankage and instrumentation are installed.
Twelve frames (9, 10, 11, 12 through 13A and 14A through 16A) are also each split in three sections: the lower, central truss section with aluminum flanges and titanium diagonals, and two full-height vertical segments on the sides. The construction of the vertical segments alternates between the frames, with A-suffixed frames using corrugated webs and non-A frames using milled webs. Non-A frames are outfitted with bridge fitting attachment points.
Frame 14 and the last six frames, 17 through 21, use a similar construction to the twelve frames described above, but their lower sections integrate the wing carry-through structure composed of titanium upper and lower flanges with titanium diagonals. Frames 14, 16A, 17, 18 and 20 use milled aluminum webs, with bridge fitting attachment points on frames 14, 17, 18 and 20. Frames 17A, 19 and 21 use corrugated aluminum webs.
The outside surface of the mid-fuselage is divided into four sections along the length of the fuselage, connected by bolts. In each section, the bottom and sides of the fuselage consist of chemically milled skin panels with open-section stringers spaced 140 mm apart on center. 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 with vertical stiffeners are used instead of the aluminum skins. The panels forward of the wing carry-through support the main landing gear on the inboard side.
Skin panels on the sides of the fuselage have cutouts for 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 actuated, 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, thermal barriers and a locking system; they are opened by hand by pad personnel.
Forward of the wing attachment interface, a wing glove fairing is attached on each side of the mid-fuselage over the skin panels. The glove is made from stamped skin panels with open-section stringers and bent aluminum profile ribs; it spans from the forward end of the mid-fuselage until Frame 11. 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, the robotic manipulator brackets and mount points, as well as the payload bridge fittings.
As the payload bay opening creates a structural gap in the fuselage, the payload bay doors are 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 bridge fitting attachment points, with eleven of those machined into the mid-fuselage frames, and an extra attachment point on frame 22, which is part of the aft fuselage. A bridge fitting spans two neighboring cradle attachment points and is secured to the sill longeron with four bolts below the fitting’s top edge. The bridge fittings can hold trunnion attachment fixtures for deployable payloads or fixed hardware like laboratory modules, extra propellant tanks or hardware pallets. Keel payload attachment fittings can be installed between the upper flanges of neighboring mid-fuselage frames along the centerline of the fuselage.
Electrical cables run along cable trays located on both sides of the payload bay. The starboard tray also accommodates the ODU propellant lines, which allow crossfeed between the ODU base block at the rear of the orbiter and the nose ODU cluster. 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 |
| 0.16 | 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 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.
The aft payload bay bulkhead (frame 22) is milled from VT23 titanium plate with corrugated aluminum webs. It is the aftmost frame directly connected to the wing torque box 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.
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 does not feature 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
Mass report of built aft fuselage segments:
| Airframe | Mass (kg) |
|---|---|
| 0.01 | n/a |
| 0.02 | n/a |
| 0.03 | n/a |
| 0.04 | 4,907.850 |
| 0.05 | 5,888.720 |
| 0.06 | 3,950.652 |
| 0.16 | n/a |
| 1.01 | 5,597.464-5,934.399 |
| 1.02 | 5,636.842 - 5,770.045 |
| 2.01 | n/a |
| 2.02 | n/a |
Wings
The orbiter’s two wings provide lift and control during the atmospheric phase of flight. Each wing is approximately X long with a maximum width of 9.21 meters and a maximum thickness of X TK. Each wing consists of a wing glove, an intermediate section with the main landing gear well, the landing gear door, a torque box, the leading edge thermal protection segments, elevons and elevon seal panels.
trailing edge dihedral The wing console is constructed from spars planar to the fuselage frames, ribs and skin-stringer panels, with a leading edge spar at the forward edge.
The wing glove is made up of seven spars; the forward and aftmost spars (No. 1 and 4) are standard flange-and-web construction, while the five inner spars use T-shaped flanges with VT23 titanium posts and diagonals. At the forward end, Spar 1 is covered by the
main section is composed of the torque box and intermediate section with the main landing gear well and stub spars extending to the edge of the wing.
The wings form a blended double-delta planform, with the main section of the wing swept by 45 degrees along the leading edge and a 78 degree sweep along the leading edge of the wing glove. The bottom surface of the fuselage is a continuation of the lower wing surface, forming a single smooth profile 23.92 meters in span, with a wing area of around 250 m2 TK.
On each wing, the leading edge is formed by 22 reinforced carbon-carbon segments which protect the wing structure from the heat of reentry. They are mounted to the leading edge spar through TK alloy brackets to thermally isolate them from the wing structure. The segments overlap one another with the gaps sealed with quartz fiber rope.
Along the trailing edge of the wing console, two elevons are mounted, with their trailing edge swept forward by 11 TK degrees.
The consoles are joined to the mid-fuselage by shear bolts through eyelets in the wing carry-through along the top and bottom surfaces of the wing with one pair of eyelets at Spar 4 of the glove and Frame 14 of the fuselage and seven pairs of eyelets on spars No. 5 through No. 8, which correspond to fuselage frames No. 17 through No. 22.
The spars are aligned with the mid-fuselage frames, with the strake’s forwardmost Spar 1 at Frame 11 and its aftmost Spar 4 at Frame 14, shared with the main wing section. The main wing section’s aftmost Spar 8 is aligned with Frame 22, or the rear payload bay bulkhead.
corrugated leading edge spars
Bibliography
- Semyonov (ed.) 1995, ch. 3.3
- Lozino-Lozinsky (ed.) 1997 and
- Airframe blueprints published by Vadim Lukashevich on buran.ru
