Space Shuttle
Orbiter Structures
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
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
Orbiter Structures
Orbiter Structures
Basic Orbiter specs
 Length
37.2 m (122')
 Height
7.4 m (57')
 Wingspan
3.8 m (78')
 Launch weight (approx)
104,545 kg (230,000 lb)
 Cargo bay capacity
4.6 m x 18.3 m (15' x 60')
27,273 kg (60,000 lb) (max, 28.5o inclination)
 Primary structure
Aluminum alloys, steel alloys,
titanium, and composites
 Design life
100 flights
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
Orbiter Primary Structures
Orbiter Structures
Orbiter constructed as three fuselage sections
 Forward fuselage
 Mid fuselage
 Aft fuselage
Orbiter Structures
Orbiter Structures – Forward Fuselage
Orbiter Structures
Forward fuselage
 Double shell
pressurized
structure
 Composed of Al
2219 alloy
 Pressure vessel
serves as crew
compartment
Orbiter Structures
Orbiter Structures – Forward Fuselage (interior)
Orbiter Structures – Forward Fuselage
Orbiter Structures
Forward fuselage
 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
Orbiter Structures – Forward Flight Deck
Orbiter Structures - Wings
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-supersonicsubsonic flight stability
 Outboard section includes a leading-edge spar for
mounting the RCC panels and insulation attachments
Orbiter Structures - Wings
Orbiter Structures – Simple Aircraft Wing
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
Orbiter Structures – Control Surfaces
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
Orbiter Structures
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
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
Orbiter Structures
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
Orbiter Structures
Orbiter Structures – Aft Fuselage
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
Orbiter Structures – Aft Fuselage
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
Orbiter Structures – Aft Fuselage
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
Orbiter Structures – Aft Fuselage
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
Orbiter Structures – FRCS Module
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
Orbiter Structures – FRCS Module
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
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
Orbiter Structures – Vertical Tail
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
Orbiter Structures – OMS Pods
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
Orbiter Structures – OMS Pods
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
Orbiter Structures – Body Flap
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
Orbiter Structures – Aero Surfaces
Orbiter Structures – Aero Surfaces
Orbiter Structures
Mechanical Systems
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
Orbiter Structures – Aero Surfaces
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
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
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
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
Orbiter Structures – Airlock
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 hightemperature resistance
 Two inner panes attached to the crew
cabin are manufactured for high
differential pressure resistance
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
Orbiter Structures
– Windows
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
Orbiter Structures
– Landing Gear
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
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
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
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
Orbiter Structures - 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
Orbiter Structures - SRMS
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