NASA's John F. Kennedy Space Centerin Florida is responsible for all launch, landing and turnaround operations for STS missions requiring equatorial orbits.
The Lyndon B. Johnson Space Center n Houston, Texas, is responsible for the integration of the complete space shuttle vehicle and is the central control point for space shuttle missions.
NASA's George C. Marshall Space Flight Center in Huntsville, Ala., is responsible for the space shuttle main engines, external tanks and solid rocket boosters.
NASA's National Space Technology Laboratories at Bay St. Louis, Miss., is responsible for testing the space shuttle main engines.
NASA's Goddard Space Flight Center in Greenbelt, Md., operates a worldwide tracking station network.
The United States Air Force operates the space shuttle launch and landing facility at Vandenberg Air Force Base in California for STS missions requiring polar orbit.
The Kennedy Space Center has primary responsibility for prelaunch checkout, launch, ground turnaround operations and support operations for the space shuttle and its payloads. Space shuttle payloads are processed in a number of facilities at KSC and the nearby Cape Canaveral Air Force Station. Payloads are installed in the space shuttle orbiter horizontally in the Orbiter Processing Facility or vertically at the launch pad. Payloads to be installed horizontally in the orbiter at the Orbiter Processing Facility are verified in the Operations and Checkout Building at KSC. Payloads installed vertically in the orbiter at the launch pad consist primarily of automated spacecraft involving upper stages and their payloads (e.g., satellites).
KSC's responsibility extends to ground operations management systems and plans, processing schedules, facility design and logistics in support of the space shuttle system and payloads.
The center established the requirements for facilities and ground operations
support at Vandenberg Air Force Base and designated contingency landing sites.
KSC also supports the Department of Defense for ground operations at Vandenberg
Air Force Base and maintains ASA acilities and
ground support
equipment here.
The launch facilities-Launch Complexes 39-A and 39-B-and the technical
support base of the center's industrial area were carved out of virgin
savanna and marsh in the early 1960s for the Apollo program.
In reshaping KSC for the space shuttle, planners took maximum advantage
of existing buildings and structures from the Apollo program that could
be modified, scheduling new ones only when a unique requirement existed.
New facilities that have been built to support space shuttle operations
are the shuttle landing facility
(runway); the Orbiter Processing Facility;
and recently the Orbiter Modification and
Refurbishment Facility, Tile Processing Facility, Solid Rocket Booster Storage
and Processing Facility, Shuttle Logistics Building and Solid Rocket Booster
Assembly and Refurbishment Facility.
KSC is located at 28.5 degrees north latitude and 80.5 degrees west longitude.
It encompasses approximately 140,000 acres of land and water. This area, with
the adjoining bodies of water, is sufficient to afford adequate safety to the
surrounding communities during space shuttle launch and landing activities.
The shuttle processing contractor performs all launch processing
and turnaround activities at the Kennedy Space Center and Vandenberg Air
Force Base. Lockheed Space Operations Company, Titusville, Fla., was
awarded the contract in 1983
to perform space shuttle launch processing operations previously carried
out by more than a dozen separate contractors,
which included the major hardware manufacturers.
The SPC is responsible for processing individual vehicle elements, integrating
those elements in preparation for launch, performing cargo integration and
validation activities with the orbiter,
operating and maintaining assigned facilities and required support equipment
and performing those tasks necessary to accomplish launch and postlaunch
activities successfully.
The OPF has two
identical bays that are each 197 feet long, 150 feet wide and 95 feet high;
have an area of 29,000 square feet; and are equipped with two 30-ton bridge
cranes with a hook height of approximately 66 feet. A low bay separating
the two bays is 233 feet long, 97 feet wide and 24.6 feet high. A
10,000-square- foot annex is located on the north side of the facility.
Another new 34,000-square- foot, three-story annex will provide additional
office space.
In the high bays, a trench system under the floor contains electrical,
electronic, communication, instrumentation
and control cabling; hydraulic supply and return plumbing; gaseous
nitrogen, oxygen and helium plumbing; and compressed air distribution
plumbing. Gaseous nitrogen, helium and compressed air are supplied by
the systems in the Vehicle Assembly
Building. All of these systems are used to support processing and
maintenance of the orbiters during ground turnaround operations.
The two high bays have an emergency exhaust system in case of
hypergolic spills. The low bay houses areas for electronic
equipment, a launch processing
system interface, mechanical and electrical equipment shops and
thermal protection system
repair. The low bay also includes provisions for a
communications room,
offices and supervisory control rooms.
Some orbiter processing
activities performed in the OPF are
hazardous, and personnel who are directly involved are required
to wear protective suits, called self-contained atmosphere
protective ensembles. The use of SCAPE suits is required during
operations involving the reaction
control system, orbital
maneuvering system, and
auxiliary power units
and their hypergolic propellants.
Fire protection systems are provided in all three bays.
Two large rolling ridges span the main access bridge to provide
complete access to installed payloads, radiators, internal areas
of the payload bay and external areas of the
payload bay doors.
Each of the rolling bridges supports two independently movable trucks
with a personnel bucket at the bottom of each vertically telescoping
arm. The buckets are manually rotatable around a full circle.
The bridges, trucks and telescoping arms are electrically powered
and controlled from the buckets or the catwalk.
Flip-up work platforms parallel the payload bay area to
provide access to radiators, the inside
payload bay doors,
payload bay door hinges and trunnion points.
Other platforms prvide access to other
orbiter elements.
The hinges of the payload
bay doors are not designed to support the weight of the doors while
they are open horizontally in the Earth's 1-g environment.
A counterweight zero-gravity device supports the weight of the doors
while they are open for processing in the OPF.
The orbiter processing flow begins
when an orbiter lands at the
shuttle landing facility
after a mission in space or a ferry flight aboard the shuttle
carrier aircraft. In either case, the
orbiter is towed to the
OPF within hours of its arrival.
Access to the crew module is established soon after the
orbiter lands. Flight
crew equipment is
removed at that time, along with any middeck experiments
flown on the mission.
Processing starts when the
orbiter is jacked up off
its landing gear and leveled, workstands are moved into position
and preparations begin to gain access to various
orbiter areas.
The orbiter is connected to
ground power, facility ground coolant, purge air and the
LPS.
Initial safing operations include hooking up purge, vent and drain
lines. Any unexpended pyrotechnics (ordnance devices), such as
those used for backup landing gear deployment, are disabled and
safed. Purging and deservicing of the orbiter's
orbital maneuvering system/reaction
control system, forward
reaction control system
and auxiliary power unit
hypergolic systems are initiated.
Some of these are hazardous operations, which require that the
OPF be cleared of all non-essential
personnel. Hypergolic deservicing operations require that
personnel wear SCAPE suits.
The hypergolic lines of the OMS/RCS and forward
RCS are drained of trapped
propellants and their interface connections are purged.
Residual hypergolic fuels in onboard tanks are not usually
drained.
When required, the OMS/RCS pods
and the forward RCS
are removed and taken to the
Hypergolic Maintenance and Checkout Facility in the industrial
area for maintenance.
After the orbiter has been
rolled into the OPF, a purge of the
space shuttle main engines
is initiated to remove moisture produced as a by-product of the combustion of
liquid oxygen and liquid hydrogen.
Fuel cell cryogenic tanks are drained of residual reactants and
rendered inert using gaseous nitrogen in the oxygen system and
gaseous helium in the hydrogen system. High-pressure gases are
vented from the environmental
control and life support system.
Before postflight deservicing can continue beyond initial safing
operations, certain vehicle systems must be mechanically secured
and personnel access installed.
Space shuttle main engine gimbal locks and engine covers are
installed, and engine heat shields are removed.
Aft access
doors are removed, and workstands are installed in the
orbiter's rear compartment.
The payload bay doors
are opened, and access provisions are installed to support payload
operations. Any hazardous payloads are also rendered safe during
these early OPF operations.
Payloads and the associated airborne
support equipment from the previous flight are removed from the
orbiter payload bay, and
the bay is prepared for the installation of new payloads.
The remote manipulator system arm is removed or installed,
as required for the next mission.
During routine deservicing operations, non-storable consumables
are off-loaded from the orbiter
and waste products are removed. Potable water, water from the
water spray boilers
and lube oil from the auxiliary power
units are drained, and APU
lube oil filters are removed.
After initial safing is completed, postflight troubleshooting of
anomalies that occurred during launch, flight or re-entry begins.
Orbiter components are removed and repaired or replaced as required
based on anomaly reviews and then retested in parallel with other
processing activities.
Visual inspections are made of the orbiter's
thermal protection system,
selected structural elements, landing gear, tires and other
systems to determine if they sustained any damage during flight and landing.
Any damage to the thermal protection
system must be repaired before the next mission.
TPS operations are conducted
in parallel with most of the activities in the
Orbiter Processing Facility.
There are some 27,446 tiles and thermal blankets on the outside of each
orbiter and some 6,000
thermal control
blankets on the inside.
TPS maintenance is provided in the new
Thermal Protection System
Facility across the street from the OPF. The 33,000-square-
foot facility was located near the OPF to
minimize the time it takes to transport the tiles and
thermal control
system blankets between the two facilities. Several trips
are required before the tiles and some blankets are
installed on the orbiter.
The closeness of the facilities is also expected to minimize
damage to the delicate tiles.
During OPF processing,
any vehicle modifications required in addition to routine
postflight deservicing/servicing and checkout are performed.
Planned modifications are typically put into work as soon as
practical after the orbiter returns
and are completed in parallel with prelaunch servicing whenever possible.<
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Modifications may be performed to meet future mission requirements,
resolve an identified deficiency or enhance vehicle performance by
replacing existing hardware with new, improved designs.
Orbiter modifications, if they are extensive, may be performed
with the vehicle powered down. Many modifications, however,
can be completed in parallel with routine servicing while
the orbiter is powered up.
Where possible, modification work is completed in the
OPF and
Orbiter Modification and
Refurbishment Facility while the
orbiter is in a horizontal
position. While some modification work can be carried out in
the Vehicle Assembly Building
or on the pad if necessary, the OPF and OMRF offer
the best access and support equipment for conducting such work.
Except during hazardous operations, routine preflight servicing
can begin while deservicing activities are still under way or
modifications are in work. Routine servicing includes reconfig
uring orbiter systems for flight,
performing routine maintenance, replacing parts and installing new
mission flight kits and payloads. Consumable fluids and gases are
loaded aboard, and the
APU lube oil system is serviced.
As systems servicing is completed, functional checks are performed
to verify flight readiness prior to closeout. Any system that
fails the functional check undergoes troubleshooting to identify
the problem. If required, subsequent repairs or replacements are
performed
The orbiter's hydraulically activated flight control surfaces are
thoroughly checked out.
A new payload may be installed in the OPF
before shuttle vehicle integration or at the launch pad after
shuttle integration. Depending on the particular mission,
new payloads could be installed at both locations. If payloads
are installed in the OPF, the
orbiter-to-payload interfaces are verified before the
orbiter is moved to the
VAB.
A crew equipment
interface test is performed during the OPF
flow to identify any problems associated with flight
crew equipment.
Following all space shuttle main engine work, the orbiter's
main propulsion system,
including the three main engines, undergoes a helium signature
leak check. Successful completion of this test generally clears
the way for the closeout of the aft
engine compartment.
Electrically initiated pyrotechnic devices (ordnance) required for
orbiter systems are installed
and checked out. These include small explosive charges like those
used for the backup deployment of the
orbiter landing gear or
emergency jettison of the remote manipulator system, Ku-band
antenna, side hatch jettison and
secondary emergency egress jettison.
Upon completion of all payload installation activities or
any other work being performed in the payload bay, the clamshell-shaped
payload bay
doors are closed and latched. If no payloads are to be
installed at the pad, this represents final closeout of the
orbiter
midbody for flight.
The final tasks to be completed in the
OPF before the
orbiter is moved to the
Vehicle Assembly Building
are to weigh the orbiter and
determine its center of gravity. Vehicle performance is affected
by both weight and center of gravity, and flight programming requires
an accurate determination of both parameters.
All ground support and access equipment is then removed,
and the orbiter is
towed into the Vehicle
Assembly Building transfer aisle through the large door at
the north end of the high bay.
The OMRF high bay is 197 feet long, 150 feet wide and 95
feet high, the same as the two OPF bays.
The facility's electrical, mechanical and
communications control rooms are located in an
adjacent support bay. There is office space for personnel
and a conference room with a window that overlooks the processing bay.
Only non-hazardous work will be performed in the OMRF
until it is properly outfitted like the
OPF to handle hazardous operations.
In the meantime, work on the
orbiter includes most
thermal protection system operations,
thermal protection system
rewaterproofing,
modifications that the facility can support and general maintenance.
Future upgrades to the facility will allow safing and deservicing; limited
orbiter power-up using mobile
electrical ground power; servicing of the orbiter's
power reactant storage
and distribution system; dumping of the orbiter's flight recorders,
which requires support of the
Launch Control Center computers;
servicing of the orbiter's Freon coolant loop systems; and other
tests requiring support of the
Launch Control Center.
One of the largest buildings in the world, the
VAB covers 8 acres and has a volume of
129,428,000 cubic feet. It is 525 feet tall, 715 feet long and
518 feet wide. The building is divided into a 525-foot-tall high
bay and a 210-foot-tall low bay. A transfer aisle running north
and south connects and transects the two bays, permitting easy
movement of vehicle elements.
The high bay is divided into four separate bays. The two on
the west side of the structure-Bays 2 and 4-are used for
storing space shuttle orbiter
external tanks. The two bays facing east-Bays 1 and 3-are
used for the vertical assembly of space shuttle vehicles on the
mobile launcher platform.
Extendable platforms, modified to fit the space shuttle
configuration, move in around the vehicle to provide access
for integration and final testing. When checkout is complete,
the platforms move back, and the
VAB doors are opened to permit the
crawler-transporter
to move the mobile launcher platform
and assembled space shuttle vehicle to the launch pad.
The high bay door is 456 feet high. It is divided into lower
and upper sections. The lower door is 152 feet wide and 114
feet high with four door leaves that move horizontally. The
upper door is 342 feet high and 76 feet wide with seven door
leaves that move vertically.
The low bay was the initial site for refurbishment and
subassembly of solid rocket booster segments. These
activities now occur at a new facility north of the
VAB.
Existing pneumatic, environmental control, light and water
systems have been modified in both bays. The north doors to the
VAB transfer aisle have also
been widened 40 feet to permit the
orbiter
to enter when it is towed over from the
Orbiter Processing Facility.
The doors are slotted at the center to accommodate the orbiter's
vertical stabilizer.
The Vehicle Assembly Building
has more than 70 lifting devices, including two 250-ton bridge cranes.
The VAB is designed to withstand winds
of up to 125 miles per hour. Its foundation rests on more than
4,200 open- end steel pilings 16 inches in diameter driven down
60 feet to bedrock.
The storage cells provide only the minimum access and equipment
required to secure the
external tank in position.
After the tank is transferred to the checkout cell, permanent
and mobile platforms are positioned to provide access to inspect
the tank for possible damage during transit and to remove
hoisting equipment. The liquid oxygen and liquid hydrogen
tanks are then sampled and receive a blanket pressure of gaseous
nitrogen and gaseous helium, respectively, in preparation for a
normal checkout.
The external tank subsystem checkout
includes an inspection of the external insulation and connection of
ground support equipment
(including the launch processing system)
to the appropriate interfaces. Electrical,
instrumentation
and mechanical function checks and tank and line leak checks
are performed in parallel.
After satisfactory checkout of the
external tank subsystems,
ground support equipment and
launch processing system
equipment are removed and stored, and
external tank closeout is initiated.
Forward hoisting equipment is attached and work platforms are stored-or
opened-in preparation for transferring the tank to the
mobile launcher platform.
The external tank is
hoisted vertically from the checkout cell by the 250-ton
high bay crane and transferred to the
mobile launcher platform
in High Bay 1 or 3 for mating with the already-assembled
solid rocket boosters. After the
external tank and solid rocket
booster are mated, the integration cell
ground support equipment
is connected, and
intertank work platforms are installed.
A considerable amount of final closeout work is performed on the
boosters and the tank after they are mated.
Three engine workstands are available to support major stand-alone
engine work, if required. The facility can support main engine
disassembly and reassembly, checkout and leak testing.
Engines, mounted on engine handling devices and protected by a
cylindrical shipping cover, arrive by truck from NASA's
National Space Technology Laboratories
and are off-loaded in the VAB transfer
aisle next to the engine workshop. The engines are then pulled
into the workshop and undergo receiving inspections. Normally,
newly delivered engines are transferred to an engine installer
and transported to the
Orbiter Processing
Facility for installation.
Routine postflight deservicing of the engines is performed in the
OPF with the engines in place aboard the
orbiter.
More extensive between-flight servicing can be performed in
the main engine workshop. The shop also supports engine
removal operations and the preparation of engines for
shipment back to NSTL or Rocketdyne in Canoga Park, Calif.,
the manufacturer of the SSMEs.
The shop provides storage for test equipment and serves as a staging area for
SSME operations performed in the
OPF and
VAB and at the launch pad.
ORBITER
PROCESSING FACILITY
After they arrive at the ennedy Space Center. space shuttle orbiters are processed
between missions in a structure analogous to a sophisticated hangar-the
Orbiter Processing Facility.
The OPF
is capable of handling two orbiters in parallel. It is located near
the west side of the Vehicle Assembly Building
in order to minimize orbiter towing distance
as the processing flow continues.
ORBITER MODIFICATION AND REFURBISHMENT FACILITY
The OMRF was designed as a third bay where space shuttle orbiters
could be inspected, repair work and off-line modifications could
be performed, and orbiters could be stored. It is located north
of the Orbiter Processing Facility.
LOGISTICS FACILITY
The
Logistics Facility
is a 324,640-square-foot building located south of the
Vehicle Assembly Building.
It houses 190,000 space shuttle hardware parts, and about 500
NASA and contractor personnel work there. The most unusual feature of the
Logistics Facility
is its state-of-the-art parts retrieval system, which includes
automated handling equipment to find and retrieve specific space shuttle parts.
VEHICLE ASSEMBLY BUILDING
The Vehicle Assembly Building,
built for the vertical assembly of Saturn launch vehicles, is the heart
of Launch Complex 39 and was modified to support the assembly of the space shuttle.
EXTERNAL TANK PROCESSING
The external tank is transported to the Kennedy Space Center
by barge from Martin Marietta's Michoud assembly facility at New Orleans, La.
On arrival at the space center, the tank and the associated hardware
are off-loaded at the barge turn basin. The
external tank is transported horizontally to the
Vehicle Assembly Building
on a wheeled
transporter and is transferred to a vertical storage or
checkout cell. High Bays 2 and 4 each contain one
external tank storage and one checkout cell.
SPACE SHUTTLE MAIN ENGINE WORKSHOP
The
space shuttle main engine workshop
is located in the Vehicle Assembly Building
in a low bay checkout cell that was converted into an enclosed,
environmentally controlled engine workshop. The workshop serves as a
receiving and inspection facility for SSMEs and as a support facility for all
SSME operations at Kennedy.
SOLID ROCKET
BOOSTER PROCESSING
The solid rocket motor segments and associated hardware are shipped to the
Kennedy Space Center
by rail from the contractor's facility in Utah.
The segments are transported horizontally and have transportation covers.
End rings provide segment handling points, environmental protection,
and protection of the solid-grain
propellant and the outer edge of each segment from potential impact damage.
When they arrive at KSC, the segments are delivered to the solid rocket motor Rotation, Processing and Surge Facility, a group of steel-framed structures designed to withstand hurricane-force winds.
The RPSF, located north of the Vehicle Assembly Building, comprises a processing facility, a support building and two segment surge (storage) buildings. The facilities isolate hazardous operations associated with solid rocket motor rotation and processing (formerly performed in High Bay 4 of the VAB) and avert impacts to VAB launch-support capabilities.
The rotation building is 98.6 feet high and has an area of 18,800 square feet.
The main facility in the complex is used for solid rocket motor receiving, rotation and inspection and supports aft booster buildup. Rail tracks within the building permit railroad cars containing the segments to be positioned directly under one of the two 200-ton overhead bridge cranes. A tug vehicle capable of pulling and stopping a fully loaded segment car moves and positions railcars in the building.
Recovered booster segments are loaded onto railcars for shipment back to the manufacturer at a site on Contractor Road.
Two surge buildings located nearby contain 6,000 square feet each of floor area for storage of eight segments (one flight set). The buildings are 61 feet in height in the aft segment storage area and 43 feet in the forward and center segment storage area.
Paved roads between the processing facility, the two storage buildings and the VAB permit transporters to transfer the segments and other hardware from one facility to another.
Live solid rocket motor segments arrive at the processing facility and are positioned under one of the cranes. Handling slings are then attached to the railcar cover, and it is removed. The segment is inspected while it remains in the horizontal position.
The two overhead cranes hoist the segment, rotate it to the vertical position and place it on a fixed stand. The aft handling ring is then removed. The segment is hoisted again and lowered onto a transportation and storage pallet, and the forward handling ring is removed to allow inspections. It is then transported to one of the surge buildings and temporarily stored until it is needed for booster stacking in the VAB.
In 1986, a new Solid Rocket Booster Assembly and Refurbishment Facility was constructed at KSC after recompetition of the Marshall Space Flight Center's booster assembly contract.
Solid rocket booster operations are performed by both the shuttle processing contractor and the booster assembly contractor, who is responsible for booster disassembly and refurbishment and the assembly and checkout of forward and aft skirt subassemblies in the VAB. Booster retrieval operations, parachute refurbishment and booster stacking activities, in addition to integrated checkout, are performed by the shuttle processing contractor.
Refurbishment and subassembly operations previously performed in the VAB low bay and other outlying facilities are now conducted in the new facility located south of the VAB.
Aft skirts, fully configured and checked out in the Solid Rocket Booster Assembly and Refurbishment Facility, are delivered to the RPSF on dollies and hoisted into position on workstands. An inspected aft segment is then hoisted into position for mating with the aft skirt. When the aft segment assembly is completed and transferred to a pallet, it is transported directly to the VAB or to one of the two storage buildings.
Solid rocket booster elements, such as forward skirts, aft skirts, frustums, nose caps, recovery systems, electronics and instrumentation components, and elements of the thrust vector control system are received in this facility.
Assembly and checkout of the forward assembly (nose cap, frustum and forward skirt) and aft skirt assembly are also performed here in addition to refurbishment of recovered booster flight hardware.
The structural assemblies and components required to build up the forward assembly, aft skirt and external tank attach hardware are either shipped to KSC new or refurbished on site.
When completed, the aft skirt assemblies are transferred to the RPSF for assembly with the aft solid rocket motor segments.
An SRB hydraulic power unit ''hot fire'' facility is located in the southeast corner of the 44-acre site. The facility features a test stand that supports the hot-firing of the solid rocket booster's hydrazine-fueled thrust vector control system. Before each flight, the solid rocket booster aft skirt assemblies containing the TVC are transported to the facility and test-fired before the aft booster buildup.
The stacking of the solid rocket booster major assemblies begins after the buildup of aft booster assemblies at the Solid Rocket Motor Processing Facility (north of the VAB) and checkout of the forward nose skirt assemblies in the Solid Rocket Booster Assembly and Refurbishment Facility.
The booster stacking operation is accomplished in the following sequence:
1. The aft booster assemblies are transferred from the buildup area in the Rotation, Processing and Surge Facility to the High Bay 1 or 3 integration cells in the VAB and attached to the mobile launcher platform support posts.
2. Continuing serially, the aft, aft center, forward center and forward rocket motor segments are stacked to form complete solid rocket motor assemblies. As each segment is mated, the joint seal is inspected visually.
3. Segment seal integrity is then demonstrated by a leak check and decay test between the redundant seals. The forward skirt/nose assemblies are transferred from the SRB ARF to the High Bay 1 or 3 integration cell and stacked atop the completed solid rocket motor assemblies to form a complete set of boosters.
An alignment check of the complete flight set of solid rocket booster assemblies is performed after the stacking operations are completed. Integrated and automated systems testing of the assembled solid rocket boosters is accomplished on the mobile launcher platform, using the launch processing system to simulate the external tank and orbiter.
Before the space shuttle vehicle is transferred to the launch pad, solid rocket booster flight batteries are installed. Final connection of the solid rocket booster pyrotechnic systems is performed at the launch pad.
The solid rocket booster's hydraulic power units are serviced with hydrazine during the prelaunch propellant-servicing operations at the launch pad
Almost complete external access to the shuttle vehicle is provided in the Vehicle Assembly Building. Access to the payload bay is through the crew compartment since the payload bay doors cannot be opened in the Vehicle Assembly Building.
The mobile launcher platform is a two-story steel structure 25 feet high, 160 feet long and 135 feet wide. It is constructed of welded steel up to 6 inches thick. At their park site north of the Vehicle Assembly Building, in the Vehicle Assembly Building high bays and at the launch pad, the mobile launcher platforms rest on six 22-foot- tall pedestals.
Three openings are provided in the mobile launcher platform-two for solid rocket booster exhaust and one for space shuttle main engine exhaust. The solid rocket booster exhaust holes are 42 feet long and 20 feet wide. The space shuttle main engine exhaust opening is 34 feet long and 31 feet wide.
Inside the platform are two levels with rooms and compartments housing launch processing system hardware interface modules, system test sets, propellant-loading equipment and electrical equipment racks.
Unloaded, the mobile launcher platform weighs 8.23 million pounds. The total weight with an unfueled space shuttle aboard is 11 million pounds.
The space shuttle vehicle is supported and restrained on the mobile launcher platform during assembly, transit and pad checkout by the solid rocket booster support/hold-down system. Four conical hollow supports for each booster are located in each solid rocket booster exhaust well. The supports are 5 feet high and have a base diameter of 4 feet.
Posts on the aft skirts of the SRBs rest on spherical bearings atop the mobile launcher platform hold-down posts. A 28-inch-long, 3.5-inch-diameter stud passes vertically through the SRB post, spherical bearing and hold-down post casting to secure the booster to the platform. A frangible, or explosive, nut at the top of the stud and a nut at the bottom are tightened to preload the stud to a tension of up to 850,000 pounds.
When full main engine thrust is developed during the final moments of the launch countdown, ignition signals are sent to the two SRBs. Simultaneously, the explosive nuts at the tops of the studs are triggered. The preloaded studs are expelled downward into deceleration stands (''sandbuckets'') and the fractured halves of the explosive nuts are contained within spherical, 10-inch-diameter debris catchers on top of the solid rocket booster aft skirt posts. This sequence releases the solid rocket boosters and the entire space shuttle vehicle for flight.
Two tail service masts, one located on each side of the space shuttle main engine exhaust hole, support the fluid, gas and electrical requirements of the orbiter's liquid oxygen and liquid hydrogen aft T-0 umbilicals. The TSM assembly also protects the ground half of those umbilicals from the harsh launch environment. At launch, the solid rocket booster ignition command fires an explosive link, allowing a 20,000-pound counterweight to fall, pulling the ground half of the umbilicals away from the space shuttle vehicle and causing the mast to rotate into a blastproof structure. As it rotates backward, the mast triggers a compressed-gas thruster, causing a protective hood to move into place and completely seal the structure from the main engine exhaust.
Each TSM assembly rises 31 feet above the mobile launcher's deck, is 15 feet long with umbilical retracted, and is 9 feet wide. The umbilical carrier plates retracted at launch are 6 feet high, 4 feet wide and 8 inches thick, or about the size of a thick door.
The liquid oxygen umbilical runs through the TSM on the east side of the mobile launcher, and the liquid hydrogen umbilical runs through the TSM on the west.
Gaseous hydrogen, oxygen, helium and nitrogen; ground and flight system coolants; ground electrical power; and ground-to-vehicle data and communications also flow through the TSM umbilical links.
Work platforms used in conjunction with the mobile launcher platform provide access to the space shuttle main engine nozzles and the solid rocket boosters after they are erected in the Vehicle Assembly Building or while the space shuttle is undergoing checkout at the pad.
The main engine service platform is positioned beneath the mobile launcher platform and raised by a winch mechanism through the exhaust hole to a position directly beneath the three engines. An elevator platform with a cutout may then be extended upward around the engine bells. The orbiter engine service platform is 34 feet long and 31 feet wide. Its retracted height is 12 feet, and the extended height is 18 feet. It weighs 60,000 pounds.
Two solid rocket booster service platforms provide access to the nozzles after the vehicle has been erected on the mobile launcher platform. The platforms are raised from storage beneath the mobile launcher into the solid rocket booster exhaust holes and hung from brackets by a turnbuckle arrangement. The solid rocket booster platforms are 4 feet high, 20 feet long and 20 feet wide. Each weighs 10,000 pounds.
The orbiter and solid rocket booster service platforms are moved down the pad ramp to a position outside the exhaust area before launch.
The transporters have a leveling system designed to keep the top of the space shuttle vehicle vertical within plus or minus 10 minutes of arc-about the dimensions of a basketball. This system also provides the leveling operations required to negotiate the 5-percent ramp leading to the launch pads and to keep the load level when it is raised and lowered on pedestals at the pad and in the Vehicle Assembly Building.
The overall height of the transporter is 20 feet, from ground level to the top deck, on which the mobile launcher platform is mated for transportation. The deck is flat and about the size of a baseball diamond (90 feet square).
Each transporter is powered by two 2,750-horsepower diesel engines. The engines drive four 1,000-kilowatt generators that provide electrical power to 16 traction motors. Through gears, the traction motors turn the four double-tracked crawlers spaced 90 feet apart at each corner of the transporter.
North of the Orbiter Processing Facility is a weather-protected crawler-transporter maintenance facility in which components of the crawler-transporters can be repaired or modified. It includes a high bay with an overhead crane for lifting heavy components and a low bay for shops, parts storage and offices. A pit has been built outside on the crawlerway to accommodate track segment removal and installation.
The crawler-transporters move on a roadway 130 feet wide, almost as broad as an eight-lane turnpike. The crawlerway from the VAB to the launch pads consists of two 40-foot-wide lanes separated by a 50-foot-wide median strip. The distance from the Vehicle Assembly Building to Launch Complex 39-A is 3.4 miles and 4.2 miles to Launch Complex 39-B. The roadway is built in three layers with an average depth of 7 feet. The top surface is river gravel. The gravel is 8 inches thick on curves and 4 inches on straightaway sections.
When the space shuttle vehicle is fully assembled and checked out in the VAB, the crawler-transporter is driven into position beneath the mobile launcher platform. The transporter jacks the mobile launcher off its pedestals, and the rollout to the launch pad begins. It takes approximately five hours for the unusual transport vehicle to make the trip from the VAB to the launch pad. During the transfer, engineers and technicians aboard th crawler, assisted by ground crews, operate and monitor systems while drivers steer the vehicle towards its destination.
After the mobile launcher platform is ''hard down'' on the launch pad pedestals, the crawler is backed down the ramp and returned to its parking area.
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