1. Space Shuttle Orbiter Structures

2. Orbiter Structures
Similarities of the Space Shuttle Orbiter to conventional commercial transport aircraft are numerous
High-lift main wings
Vertical stabilizer and rudder
Tubular/cylindrical fuselage
Horizontal (runway) landing on main and nose wheel landing gear
Aluminum alloy primary structure
Monocoque outer skin structure (skin and stringer) add to strength of inner members
Similar fabrication methods
Hydraulic aero surfaces used for flight control in the atmosphere

3. Orbiter Structures
Differences between the Space Shuttle Orbiter and conventional commercial transport aircraft are also numerous
No rear horizontal wing or forward canard for pitch control
Orbiter pitch control with bodyflap, split elevons, and speed brake
Top-opening cargo bay
Insulation over entire outer surface
Hypersonic flight control using gas jets
Some of the subsonic and supersonic flight is controlled with aero surfaces
Unpowered flight through the atmosphere during reentry and landing

4. Orbiter Structures

5. Basic Orbiter specs Orbiter Structures Length 37.2 m (122')
Height m (57')
Wingspan m (78')
Launch weight (approx) ,545 kg (230,000 lb)
Cargo bay capacity m x 18.3 m (15' x 60') ,273 kg (60,000 lb) (max, 28.5o inclination)
Primary structure Aluminum alloys, steel alloys, titanium, and composites
Design life flights

6. Orbiter Structures
Primary structures
The Orbiter is comprised of nine major sections that house the systems, payloads and crews, covered by thermal protection insulation.
1. Forward fuselage
2. Wings
3. Midfuselage
4. Payload bay doors
5. Aft fuselage
6. Forward Reaction Control System
7. Vertical tail
8. OMS/RCS System
9. Body flap

7. Orbiter Primary Structures

8. Orbiter constructed as three fuselage sections
Orbiter Structures
Orbiter constructed as three fuselage sections
Forward fuselage
Mid fuselage
Aft fuselage

9. Orbiter Structures

10. Orbiter Structures – Forward Fuselage

11. Orbiter Structures
Forward fuselage
Double shell pressurized structure
Composed of Al 2219 alloy
Pressure vessel serves as crew compartment

13. Orbiter Structures

14. Orbiter Structures – Forward Fuselage (interior)

15. Orbiter Structures – Forward Fuselage

16. Forward fuselage Orbiter Structures
Initially covered mostly with high-temperature reusable surface insulation (HRSI) with the exception of the nose cap and wing leading edges
Much of the HRSI was replaced with Advanced Flexible Reusable Surface Insulation (AFRSI)
Nose cap Composed of reinforced carbon-carbon (RCC)
Primary flight operations are conducted in upper flight deck and lower mid deck
Access hatches for the airlock/docking tunnel and side hatch are located on the mid deck
Contains 12 window sets that are made up of triple-pane silica glass

17. Orbiter Structures – Forward Flight Deck

18. Orbiter Structures - Wings

19. Orbiter Structures
Wings
The Orbiter wings structure consists of a single pair of main wings attached to the mid fuselage assembly
Composed of aluminum alloy using a skin-stringer design with a double-delta shape for hypersonic-supersonic-subsonic flight stability
Outboard section includes a leading-edge spar for mounting the RCC panels and insulation attachments

20. Orbiter Structures - Wings

21. Orbiter Structures – Simple Aircraft Wing

22. Orbiter Structures
Wings
Trailing-edge spar provides a structural mount for the split elevon hinges and actuators
Aluminum alloy honeycomb skin panels
Split elevon configuration allows roll and pitch control, with yaw controlled by the rudder mounted on the vertical tail
Complex thermal protection required because of gaps and moving surfaces

23. Orbiter Structures – Control Surfaces

24. Aluminum alloy structure
Orbiter Structures
Mid Fuselage
Designed to carry the payload weight while providing a rigid structure to transfer loads form the main engines and SRBs to and from the Orbiter
Designed also to eliminate torsional rotation between the aft and forward fuselage sections
Aluminum alloy structure
Dimensions are 60' in length and 17' in width
Consists of 12 main frames and braces that also incorporate trusses and stringers for rigidity

25. Orbiter Structures

26. Orbiter Structures
Mid Fuselage
Longerons on the upper section add stiffness and provide a rigid frame for the payload bay doors
Prevents any distortion that could keep the payload bay door from opening or closing
Skin panels were machined and included wing gloves ahead of the sidewall sections attached to the wings on each side
Landing gear support structures were placed on the aft sidewall section of the mid fuselage

27. Orbiter Structures
Payload bay doors
Each payload door is composed of five graphite epoxy honeycomb panels with expansion joints for thermal gradients during the extreme temperatures in space and during reentry
Two aft panels and two forward radiator panels on each door
The two radiator panels on the forward half of the door that can be extended outward to increase the cooling efficiency
Each of the 18.3 m (60') long doors are covered with surface insulation quilts

28. Orbiter Structures

29. Orbiter Structures
Payload bay doors
Two Freon cooling loops circulate independently through the radiator panels
Additional radiator panels can be added to the payload bay doors if needed for additional cooling capacity
The payload bay doors are opened and closed with a 16.8 m (55') torque shaft
Positive position latches for the doors can be operated either manually or automatically

30. Orbiter Structures

31. Orbiter Structures – Aft Fuselage

32. Orbiter Structures
Aft Fuselage
Orbiter aft fuselage houses the main propulsion system, the bulk of which are the three SSMEs and the propellant distribution manifold
Houses the APU and hydraulic systems, the flash evaporators and the ammonia boiler
Supports the OMS pods and the vertical tail on the upper section
Structure is comprised of:
SSME thrust structure
Secondary internal structure
Outer shell made of machined aluminum alloy that adds structural strength

33. Orbiter Structures – Aft Fuselage

34. Orbiter Structures
Aft Fuselage
Aft fuselage skin and structure also create a pressure seal that is vented with actuators for equalizing pressures during ascent and reentry
Constructed from aluminum alloys
Primary SSME thrust structure is constructed of titanium truss members

35. Orbiter Structures – Aft Fuselage

36. Orbiter Structures
Aft Fuselage
The upper, outboard section provides the attachment surface for the OMS pods
Constructed from aluminum alloys
Top section is the vertical stabilizer support frame
Constructed of titanium
Bottom aft section includes the body flap hinge points and actuators

37. Orbiter Structures – Aft Fuselage

38. Forward Reaction Control System
Orbiter Structures
Forward Reaction Control System
Forward and aft RCS provides attitude control for pitch, roll, and yaw on the Orbiter
Also furnishes minor translational control for docking and undocking and for ET separation
FRCS consists of a structural frame for the thrusters, propellant tanks, and associated hardware including helium tanks to pressurize the propellant tanks

39. Orbiter Structures – FRCS Module

40. Forward Reaction Control System
Orbiter Structures
Forward Reaction Control System
Forward and aft RCS provides attitude control for pitch, roll, and yaw on the Orbiter on orbit
Augments control surfaces in aerodynamic flight
Also furnishes minor translational control for docking and undocking and for ET separation
FRCS consists of:
Structural frame for the thrusters
Propellant tanks
Associated hardware including helium tanks to pressurize the propellant tanks

41. Orbiter Structures – FRCS Module

42. Orbiter Structures
Vertical tail
Vertical tail and rudder assembly provide yaw control and longitudinal stability
Tail assembly is effective only in the low supersonic and subsonic regime
Yaw control in hypersonic and high supersonic flight is provided by the RCS system
Constructed of aluminum alloy skin, stringers, ribs, and spars
Aluminum honeycomb skin on the lower trailing edge
Vertical tail supports the rudder and speed brake assembly

43. Orbiter Structures
Vertical tail
Surface including the rudder and speed brake is covered with thermal tiles and blankets,
Thermal barrier and seals placed at the hinge and interface regions of the tail
Split rudder configuration allows left and right deflection for yaw control
Separates vertically for added drag to reduce speed - the speed brake
Also used for additional pitch control during the energy management phase and approach for landing

44. Orbiter Structures – Vertical Tail

45. Aluminum alloy frames, braces and ribs
Orbiter Structures
OMS/RCS system pods
Two aerodynamic pods are placed on the Orbiters outboard aft fuselage to house the two OMS and smaller RCS engines
Pods are constructed primarily of graphite epoxy composite honeycomb skin sections
Aluminum alloy frames, braces and ribs
Titanium and corrosion-resistant steel fittings used near the engines as stiffeners

46. Orbiter Structures – OMS Pods

47. Each OMS pod is independent and removable for maintenance operations
Orbiter Structures
OMS/RCS system pods
Each OMS pod is independent and removable for maintenance operations
Low-Temperature Reusable Surface Insulation tiles cover most of the exposed surface of the OMS/RCS pods
Thermal barriers surround the OMS and RCS engines to protect the aft fuselage equipment

48. Orbiter Structures – OMS Pods

49. Orbiter Structures
Body flap
Body flap is an aerosurface that furnishes additional pitch control for the Orbiter's flight through the atmosphere
Also used for load reduction during the Orbiter's ascent to orbit
Also deflects hot airflow from entering the Space Shuttle Main Engines during reentry

50. Orbiter Structures – Body Flap

51. Orbiter Structures
Body flap
Constructed of aluminum alloy skin and stringer panels, ribs, and spars
Powered by four hydraulic rotary actuators within the lower aft fuselage
Entire surface covered with reusable insulation tiles, with heat seals and barriers used for protection of the joints and moving surfaces

52. Orbiter Structures – Aero Surfaces

53. Orbiter Structures – Aero Surfaces

54. Orbiter Structures Mechanical Systems

55. Purge, Vent & Drain System (PVDS)
Orbiter Structures
Purge, Vent & Drain System (PVDS)
PVDS is designed to accommodate the pressure changes, and the buildup of hazardous gases and fluids during normal flight operations
An array of purge, dilution, vent (passive and active) and drain mechanisms are built into many of the Orbiter's pressurized sections to moderate pressure changes, and evacuate, or dilute, accumulated gases and fluids
In addition, a number of components (SSME e.g.) require an inert gas purge to remove propellants or hazardous gases/liquids
Pressurized nitrogen and helium gas purge subsystems supply the gas flow for fluid and gas removal to space
Air is also used for post-landing pressure equilibration in several sections of the Orbiter

56. Orbiter Structures – Aero Surfaces

57. Airlock Airlock module allows crew access to:
Orbiter Structures
Airlock
Airlock module allows crew access to:
Payload bay for extravehicular activity
Pressurized transfer tunnel to onboard facilities such as the Space Lab module (no longer used)
ISS access docking port

58. Airlock Airlock interior is 170 cubic feet (4.81 m3) in volume
Orbiter Structures
Airlock
Airlock interior is 170 cubic feet (4.81 m3) in volume
Includes accommodations for two fully-suited astronauts
Oxygen supply
Air revitalization
Water
Electrical power
Communications
Lighting

59. Orbiter Structures
Airlock
Structure includes two hatches – one on the Orbiter interior and the second in the payload bay
Hatches have pressure locks and seals for airlock access through each hatch in both directions
Airlock pressurization for EVA is controlled by an automated system to allow a low-pressure pure oxygen environment to prepare astronauts for EVA

60. Orbiter Structures
Airlock
The Orbiter's Airlock Module can also be used as a hypobaric chamber in case of a depressurization accident and/or decompression sickness
The Orbiter's airlock is located either in the mid deck within the crew compartment, or in the payload bay if sufficient room is available

61. Orbiter Structures – Airlock

62. Windows Orbiter contains as many as 13 window sets
Orbiter Structures
Windows
Orbiter contains as many as 13 window sets
Located in the forward and aft flight decks (10)
One in the crew side access hatch
Two in the airlock
Each window set except the payload bay observation windows is comprised of three panes
Provide pressure containment, light transmission properties, and physical strength
Outer pane is manufactured for high-temperature resistance
Two inner panes attached to the crew cabin are manufactured for high differential pressure resistance

63. Orbiter Structures
Windows
Observation windows are polished surface, optical quality glass
Composed of aluminosilicate (inner and outer panes), and fused silica (middle)
Coatings are used on the surfaces to reduce reflectivity and IR heat inflow (inner pane) and to maximize visible light transmission (inner and outer panes)
Window shades and filters are provided to reduce unnecessary heat and light exposure
Shades are provided for all windows
Filters are supplied for the aft and overhead viewing windows

64. Orbiter Structures – Windows

65. Orbiter Structures
Landing Gear
Orbiter's landing gear system closely resembles a conventional aircraft tricycle gear configuration
Employs a nose gear and two main gear
Each landing gear mechanisms includes an extension assembly with a shock strut

66. Orbiter Structures – Landing Gear

67. Orbiter Structures
Landing Gear
Each gear includes a dual-wheel and tire assembly that is attached to high-performance brakes with anti-skid control
Braking on the rear landing gear and steering on the nose gear is operated with triple-redundant hydraulic system controls
The nose landing gear is located in the lower forward fuselage which is retracted forward and up into the lower forward fuselage

68. Orbiter Structures
Landing Gear
Gear mechanism is enclosed by two insulated, heat seal doors that are covered on the outside with HRSI insulation tiles
Deployment of the Orbiter's landing gear in flight is controlled by the hydraulic system under pilot command
Emergency release of the gear is provided by pyrotechnic actuators that release a mechanical lock for each gear that can be activated one second after the pilot command is initiated

69. Orbiter Structures
Landing Gear
The nose and main landing gear can be retracted only during ground operations
Modifications and improvements include
Stiffening the gear structure
Increasing the axle thickness to reduce tire damage
Larger carbon disk brakes and improved 34-ply rating (16 cord) tires

70. Shuttle Remote Manipulator System (SRMS)
Orbiter Structures
Shuttle Remote Manipulator System (SRMS)
Space Shuttle payload deployment and retrieval system (aka Canadarm-1) has the capability to transfer payloads from the Orbiter's cargo bay to free-flight, or to grasp and transfer payloads from free-flight and return them to the cargo bay for repairs or return to the Earth, or to maneuver astronauts for ISS assembly
More recently, the SRMS has been outfitted with a 50’ boom extension as an imaging platform
Mounted on the port-side payload bay longeron opposite the Ku-band radar unit

71. Orbiter Structures - SRMS

72. Shuttle Remote Manipulator System (SRMS)
Orbiter Structures
Shuttle Remote Manipulator System (SRMS)
Can be deployed only while the payload bay doors are extended
Can be jettisoned with pyro charges in case of malfunction or jamming
Controls for the unit are located in the aft flight deck, giving the operator command over the arm and its functions

73. Orbiter Structures - SRMS

74. Resources
NSTS  National Space Transportation System Press Kit, NASA, 1988
Space Shuttle Operations and Technology, Lance Erickson, Linus Publications, 2007
SP-407  NASA SP-407, Space Shuttle, Lyndon B. Johnson Space Center, 1976