Various materials applied
to the outer structure protect the orbiter from excessive heat.
- Seven different materials,
chosen for their weight efficiency and stability at high temperatures,
- RCC protects areas where
temperatures exceed 2,300 degrees F during entry.
Reusable Surface Insulation Tiles
- Black tiles are applied
on areas where temperatures do not exceed 2,300 degrees F.
Refractory Composite Insulation Tiles
- Black tiles developed
later in the program replace some HRCI tiles.
Reusable Surface Insulation Tiles
- White tiles are used in
areas where temperatures do not exceed 1,200 degrees F.
Flexible Reusable Surface Insulation Blankets
- Quilted composite fabric
replaced most of the LRSI tiles.
Reusable Surface Insulation
- Nomex felt blankets are
used on the payload bay doors and other areas where temperatures
do not exceed 700 degrees F.
- Various materials are
used to fill in gaps.
- Each tile has a unique
- Flags and letters are
- After each flight the
orbiter is rewaterproofed.
- List of contractors for
the thermal protection system.
Along with SRBs, provides
velocity increment necessary to reach orbit.
- The main propulsion system
includes three main engines, controllers and supporting equipment.
Main Propulsion System Helium Subsystem
- Helium is used to purge
tanks and actuate valves.
Propulsion System Propellant Management Subsystem
- Liquid hydrogen and liquid
oxygen are fuels used by the system.
- The external tank feeds
fuel to the main propulsion system.
Shuttle Main Engines
- The main engines are reusable,
high-performance, liquid-propellant rocket engines with variable
- A pogo suppression system
prevents engine thrust oscillation.
Shuttle Main Engine Controllers
- Each controller operates
in conjunction with other components to provide a self-contained
system for engine control, checkout and monitoring.
- There are three separate
means of detecting malfunctions within the main propulsion system.
- Three hydraulic systems
supply pressure to the main propulsion system, providing thrust
vector control and actuating engine valves on each SSME.
- Ascent thrust vector control
directs thrust of the main engines and SRBs to control attitude
and trajectory from liftoff through second-stage ascent.
Oxidizer and Fuel Flow Sequence
- The complete sequence
begins several hours before launch and ends after main engine cutoff.
Propulsion System Contractors
- List of contractors.
Tank Separation System
Includes system components
on both sides of the separation.
- When the external tank
separates from the orbiter, several components act at once for a
- Mated pairs of disconnects
contain valves that allow propellant to flow until time for ET separation.
Tank Separation System
- The external tank is separated
from the orbiter at three structural attach points.
- After external tank jettison,
doors close the umbilical cavities.
The orbital maneuvering system
provides the thrust for orbit insertion, circularization, orbit transfer,
rendezvous, and deorbit.
- The OMS is housed in two
independent pods located on each side of the orbiter's aft fuselage.
- The OMS system uses helium
to pressurize fuel tanks.
Storage and Distribution
- OMS propellant tanks enable
the orbiter to reach a 1,000-foot-per-second velocity change.
Bipropellant Valve Assembly
- Each OMS engine receives
pressure-fed propellants at its bipropellant valve assembly.
Thrust Chamber Assembly
- The thrust chamber is
where the fuel and oxydizer react in the injector.
- The OMS thrusting sequence
commands the OMS engines on or off and commands the engine purge
Thrust Vector Control System
- The engine TVC system
consists of a gimbal ring assembly, two gimbal actuator assemblies,
and two gimbal actuator controllers.
- OMS thermal control is
achieved by insulation in the OMS pods and strip heaters.
- OMS propellant can be
used to operate the Reaction Control System.
- The OMS-to-aft-RCS propellant
quantities are calculated by burn time integration.
- The abort control sequence
software manages OMS and RCS configuration and thrusting periods
during ascent aborts.
Engine Fault Detection and Identification
- The OMS engine FDI function
detects and identifies off-nominal performance of the OMS engine.
Gimbal Actuator FDI
- The OMS gimbal actuator
FDI detects and identifies off-nominal performance of the pitch
and yaw gimbal actuators of the OMS engines.
The RCS units provide the
thrust for pitch, yaw and roll maneuvers and for small velocity changes
along the orbiter axis.
- The forward and aft RCS
systems consist of helium storage tanks, pressure systems, propellant
systems, and thermal control.
- Gaseous helium supplies
pressure to the fuel and oxidizer tanks.
- A system of tanks, lines
and valves distributes propellant to the RCS thrusters.
- Onboard computers calculate
the usable percent of fuel and oxidizer in each RCS module.
- Isolation valves control
the amount of propellant being fed to each RCS module.
- Each RCS engine contains
a fuel and oxidizer valve, injector head assembly, combustion chamber,
nozzle and electrical junction box.
- Heaters maintain propellant
and pod temperatures within safe operating ranges.
- Based on crew commands,
the onboard computers direct RCS burns.
EPS subsystems work together
to provide electrical power to the vehicle during all mission phases.
- The EPS consists of three
subsystems: power reactant storage and distribution, fuel cell power
plants, and electrical power distribution and control.
Reactant Storage and Distribution
- Cryogenic hydrogen and
oxygen are stored in specially-equipped tanks.
Cell Power Plants
- The fuel cells are located
under the payload bay area and in the forward portion of the orbiter's
Power Distribution and Control
- The EPDC subsystem distributes
28-volt dc electrical power and generates and distributes 115-volt,
three-phase, 400-hertz ac electrical power to all of the space shuttle
systems' electrical equipment throughout all mission phases.
Control and Life Support System
ECLSS systems interact to
provide a habitable environment for the flight crew and cooling or heating
for various orbiter systems and components.
- The ECLSS consists of
atmosphere and water treatment and thermal systems.
Compartment Cabin Pressurization
- The cabin is pressurized
to 14.7 psia and maintained at an average 80-percent nitrogen and
20-percent oxygen mixture by the air revitalization system.
- There are five independent
air loops in the cabin.
Coolant Loop System
- The WCLS provides thermal
conditioning of the crew cabin by collecting heat at a heat exchanger
and transferring it to the water coolant loops.
Thermal Control System
- The ATCS consists of Freon
interchangers, radiators and heat exchangers to control thermal
and Waste Water
- The supply and waste water
systems provide water for the flash evaporator, crew consumption
- The waste collection system
is an integrated, multifunctional system used primarily to collect
and process biological wastes from crew members in a zero-gravity
- A single waste water tank
receives waste water from the ARS humidity separator and the waste
- The airlock and airlock
hatches permit EVA flight crew members to transfer from the middeck
crew compartment into the payload bay in EMUs without depressurizing
the orbiter crew cabin.
Activity Mobility Units
- EMU space suits provide
the necessities for life support during space walks.
Altitude Protection System
- The crew altitude protection
system is worn by the flight crew members during launch and entry.
Thermoelectric Generator Cooling and Gaseous Nitrogen Purge for
- A cooling and purge system
is installed in Discovery and Atlantis to support those payloads
with RTGs or gaseous nitrogen purging requirements.
The orbiter has three APUs,
hydrazine-fueled, turbine driven power units produce pressure for the
vehicle's hydraulic systems.
Water Spray Boilers
The water spray boiler system
consists of three identical independent water spray boilers, one per
corresponding auxiliary power unit and hydraulic system.
The hydraulic system consists
of three independent systems, each providing mechanical shaft power
to drive a hydraulic pump.
Each landing gear includes
a shock strut with two wheel and tire assemblies.
- The landing gear system
on the orbiter is a conventional aircraft tricycle configuration
consisting of a nose landing gear and a left and right main landing
Landing Gear Brakes
- Each of the orbiter's
four main landing gear wheels has electrohydraulic disc brakes and
an anti-skid system.
- The orbiter nose wheel
is steerable after nose wheel touchdown at landing.
Designed to provide the crew
with both visual and aural cues when a system exceeds predefined operating
- The orbiter lighting system
provides both interior and exterior lighting.
Detection and Fire Suppression
- Smoke detection and fire
suppression capabilities are provided in the crew cabin avionics
bays, the crew cabin and the Spacelab pressurized module.
Deployment and Retrieval System
- The payload deployment
and retrieval system includes the electromechanical arm that maneuvers
a payload from the payload bay of the space shuttle orbiter to its
deployment position and then releases it.
- Non-deployable payloads
are retained by passive retention devices, and deployable payloads
are secured by motor-driven, active retention devices.
Ground-based, orbiter and
satellite systems are employed to keep the crew in touch with Mission
Flight Tracking and Data Network
- Provides tracking, data
acquisition and associated support.
and Data Relay Satellite System
- Provides continuous global
coverage of Earth-orbiting satellites at altitudes from 750 miles
to about 3,100 miles.
- Transfers telemetry information,
commands, documentation and voice communications.
- Information is transferred
through hardline and radio frequency links.
- Operates in the S-band
portion of the RF spectrum of 1,700 to 2,300 MHz.
- Used only when the
orbiter is on orbit.
- Ku-Band system includes
a rendezvous radar that skin-tracks satellites and other rendezvous
- Used to transfer information
between orbiter and its payloads.
- Used as a backup fro
S-Band PM and Ku-Band voice communications, primarily for EVAs.
- Interfaces with caution/warning
system, UHF, S-Band, Ku-Band, and tacan systems.
- Several camera systems
are used by the flight crew to document activities during the mission.
- Used to collect, route
and process information throughout the orbiter and its payloads.
Code Modulation Master Unit
- Receives data from
MDMs and formats them for transmission to the ground.
- Responsible for processing
and routing commands, telemetry and voice between the orbiter
and the ground.
Command Interface Logic
- Also referred to as
the ground command interface logic controller.
Computer and Communication Interface
- Computers process
communication controls and provide a command path between the
ground and orbiter subsystems.
- A stable crystal-controlled
timing source for the orbiter.
- Used for serial recording
and dumping of digital voice and PCM data.
- Records and dumps
payload data through S-Band or Ku-Band transmitter.
- Interim system designed
tro transmit written data from the ground to the crew.
and Graphics System
- Fax scanner on the
ground that sends text and graphics to hard copier in orbiter.
- Used to support on-orbit
activities that require visual feedback to the crew.
- Used for serial recording
and dumping of digital voice and PCM data.
Experiments Support Systems for OV-102 (Columbia)
- Records data obtained
through OEX sensors.
Infrared Leeside Temperature Sensing
- Obtains high-resolution
infrared imagery of orbiter surfaces during atmospheric entry.
Entry Air Data System
- takes measurements
required for precise determination of air data during launch
and landing phases.
Upper Atmosphere Mass Spectrometer
- Obtains measurements
of free-stream density during atmospheric entry.
Coefficient Identification Package
- A group of sensors
palced on the orbiter to obtain experiment measurements unavailable
through the baseline system.
- Measures low-level
aerodynamic accelerations along the orbiter's principal axed
Auxiliary Data System
- Measures and records
selected pressure, temperature, strain, vibration and event
or assists in controlling, most of the shuttle systems.
Controls, or assists in
controlling, most of the shuttle systems.
The vehicle relies on
computerized control and monitoring for successful performance.
Navigation and Control
GNC software commands
effect vehicle control and provide sensor data needed to compute
- DPS software is divided
into two major groups: system software and applications software.
- Five identical computers
aboard the orbiter control vehicle systems.
- Computing functions
for all mission phases requires about 400,000 words of computer
CRT Display System
- Displays on the flight
deck allow onboard monitoring of systems, software processing
and manual control for crew data and software manipulation.
- The GPC complex requires
an accurate time source because its software uses GMT to schedule
Data Bus Network
- Network is divided
into specific groups that perform specific functions.
- DPS MDMs convert and
format serial digital GPC commands into separate commands for
various vehicle system hardware.
- Send signals to arm
and safe pyrotechnics during SRB/ET separation.
Bus Isolation Amplifiers
- Interfacing devices
for the GSE/LPS and SRB MDMs.
- The fifth GPC, loaded
with different software, provides backup in case primary GPCs
Provide the flight crew
with data required to fly the vehicle manually or to monitor automatic
Control System Hardware
- Hard-wired to one
of eight flight-critical MDMs.
- Include IMUS, tacan
units, air data probe assemblies, and more.
- Consist of an all-attitude,
four-gimbal, inertially stabilized platform.
- Two star tracker units
are part of the navigation system.
Optical Alignment Sight
- Used if IMU alignment
is in error more than 1.4 degrees.
- Determine slant range
and magnetic bearing to ground station.
- Provides information
on the movement of the orbiter in the air mass.
Scan Beam Landing System
- Used during landing
phase to determine slant range, azimuth and elevation to landing
- Measure absolute altitude
from the orbiter to nearest terrain within beamwidth of orbiter's
- Sense vehicle acceleration
along lateral and vertical axes.
Rate Gyro Assemblies
- Used by flight control
system to sense roll, pitch and yaw rates during ascent and
Rocket Booster Rate Gyro Assemblies
- Used as feedback to
find rate errors from liftoff to SRB separation.
- Used by flight crew
to gimbal engines and OMS/RCS systems.
- Used for manual control
of translation along the longitudinal, lateral, and vertical
axes to control RCS.
Stick Steering Push Button Light Indicators
- Indicate control stick
- Command orbiter rotation
about the yaw axis by positioning the rudder during atmospheric
- Used during ascent
to vary thrust level of main engines; used during entry to control
- Provide manual control
for positioning body flap during entry.
- Provide signals to
GPCs, prohibiting execution of related software commands while
RHC is active.
- Used to move the aerosurfaces
in roll, pitch and yaw.
- Receive commands during
atmospheric flight, causing aerosurface deflections.
- Composed of several
software modules that interpret maneuver commands and generate
commands for the appropriate effectors.
- OMS/RCS thrusting
periods can be used to correct or modify the orbit as required.
- Black boxes are situated
in several locations around the orbiter.
- Provide attitude data,
including attitude rates and errors.
- Displays a pictorial
view of the vehicle's position.
- Display vehicle angle
- Display vertical acceleration,
vertical velocity, barometric altitude and radar altitude.
- Displays actual and
commanded positions of elevons, body flap, rudder, aileron and
Control System Push Button Indicators
- Transmit moding requests
to digital autopilot.
- Indicate RCS jet comands
by axis and direction.
- Senses linear acceleration
along the Z axis of the vehicle.
- Optical miniprocessor
that cues the commander during final landing approach.