Find a Security Clearance Job!





The launch pads are roughly octagonal in shape; each contains about 0.25 of a square mile of land. The pads are elevated above the surrounding terrain: 39-A is 48 feet above sea level and 39-B 55 feet. The hardstand area at the top of each pad measures 390 by 325 feet.


    The fixed service structure, located on the west side of the pad, is a square cross section steel structure that provides access to the space shuttle orbiter and to the rotating service structure. It is a part of the structure removed from the Apollo mobile launchers when they were converted for space shuttle use. The fixed service structure is essentially an open-framework structure 40 feet square that is permanently fixed to the pad surface. The fixed service structure tower supports the hinge about which the rotary bridge supporting the rotating service structure pivots as it moves between the orbiter checkout position and the retracted position. A hammerhead crane atop the fixed service structure provides hoisting services required in pad operations. Fixed service structure levels are at 20-foot intervals beginning at 27 feet above the surface of the pad. The height of the fixed service structure to the top of the tower is 247 feet. It is 265 feet to the top of the hammerhead crane, and the top of the lightning mast is 347 feet above the pad surface.

    The fixed service structure has three space shuttle service arms: an access arm and two vent arms.

    The orbiter access arm swings out to the orbiter crew compartment hatch to allow personnel to enter the crew compartment. The outer end of the access arm ends in an environmental chamber (white room) that mates with the orbiter and holds six persons. The arm remains in the extended position until seven minutes 24 seconds before launch to provide emergency egress for the flight crew. The orbiter access arm is extended and retracted by four hydraulic cylinders that rotate it through an arc of 70 degrees in approximately 30 seconds. In its retracted position, the arm is latched to the fixed service structure. The orbiter access arm is located 147 feet above the pad. It is 65 feet long, 5 feet wide and 8 feet high and weighs approximately 52,000 pounds.

    The external tank hydrogen vent umbilical and intertank access arm consists of a retractable arm, a fixed structural platform and a vent line (assembly and mechanism). This arm provides access for the mating of the umbilical to the vehicle and access to the intertank area. It is 48 feet long and weighs 15,800 pounds. It rotates through 210 degrees to its extended position. It is retracted after umbilical/vent line mating at approximately T minus five days, leaving the umbilical vent line connected to the external tank to support tanking and launch.

    The structural platform provides mounting interfaces, supports equipment and protects the umbilical from the launch environment. It is mounted on the northeast corner of the fixed service structure 169 feet above the pad surface and weighs approximately 100,000 pounds.

    The vent line provides continuous venting of the external tank during and after hydrogen loading (tanking). It also supports vehicle service lines (small helium and nitrogen lines and electrical cables).

    The external tank's gaseous oxygen vent arm system is a retractable arm and vent hood assembly designed to vent gaseous oxygen vapors away from the space shuttle vehicle. These vapors are created as the liquid oxygen in the external tank boil off (change from liquid to gas). The arm truss section is 65 feet long from tower hinge to vent hood hinge. The diameter of the vent hood is 13 feet.

    Before cryogenic loading, the arm is swung into position over the external tank and the hood is lowered into position over the external tank vent louvers. Two inflatable dock seals envelop the vent louvers, providing an exhaust path between the louvers and the exhaust ducts.

    Approximately 2.5 minutes before launch, the vent hood is raised to clear the external tank (it takes approximately 25 seconds to raise the hood). The arm is then retracted to the latchback position against the fixed service structure one minute 45 seconds before launch. It is not latched at this time because of the possibility of a launch countdown hold. In the event of a launch countdown hold after the arm is retracted, the arm can be re-extended and the vent hood lowered onto the external tank. When the countdown resumes, the arm recycles through the sequence. The arm is latched when the SRB ignition signal is given at T minus zero minutes.

    The fixed service structure also includes the emergency exit system, or slidewire. The slidewire provides an escape route for personnel aboard the space shuttle and on the orbiter access arm of the fixed service structure until the final 30 seconds of the countdown. Seven slidewires extend from the level to the orbiter access arm to the ground on the west side of the pad. One three-man basket with a flat bottom and netting all around is suspended from each wire and positioned on the fixed service structure for quick entry in an emergency. Each basket holds a maximum of four persons. When boarded and released, each basket slides down a 1,200-foot wire to the bunker west of the launch pad. The baskets are slowed and brought to a stop at the landing zone by a deceleration system made up of a braking system catch net and drag chain.

    The lightning mast extends above the fixed service structure and surrounding pad equipment and provides protection from lightning strikes. The 80-foot-tall fiberglass mast is grounded by a cable that starts from a ground anchor 1,100 feet south of the fixed service structure, angles up and over the lightning mast, then extends back down to a second ground anchor 1,100 feet north of the fixed service structure. The mast functions as an electrical insulator holding the cable away from the fixed service structure and as a mechanical support in rolling contact with the cable. The mast and its support structure extend 100 feet above the fixed service structure.


    The rotating service structure provides protected access to the orbiter for changeout and servicing of payloads at the pad. The structure is supported by a rotating bridge that pivots about a vertical axis on the west side of the pad's flame trench. The rotating service structure rotates through 120 degrees (one-third of a circle) on a radius of 160 feet. The hinge column rests on the pad surface and is braced to the fixed service structure. Support for the outer end of the bridge is provided by two eight-wheel, motor-driven trucks that move along circular twin rails installed flush with the pad surface. The track crosses the flame trench on a permanent bridge.

    The rotating service structure is 102 feet long, 50 feet wide and 130 feet high. The elevation of the main structure above the surface of the pad ranges from 59 to 189 feet. The structure has orbiter access platforms at five levels to provide access to the payload bay while the orbiter is being serviced in the rotating service structure. Each platform has independent extendable planks that can be arranged to conform to a payload's configuration. With the exception of Spacelab and other horizontally handled payloads, satellites and experiments may be loaded into the orbiter from the rotating service structure under environmentally clean, or ''white room,'' conditions.

    The payload changeout room is the enclosed, environmentally controlled portion of the rotating service structure that supports payload delivery at the launch pad and subsequent vertical installation in the orbiter payload bay.

    The orbiter midbody umbilical unit provides access and services to the midfuselage portion of the orbiter on the pad. A sliding extension platform and a horizontally moving line-handling mechanism provide access to the midbody umbilical door on the left side of the orbiter and fluids to the orbiter's power reactant storage and distribution system and payloads. Liquid oxygen and liquid hydrogen for the fuel cells and gases, such as nitrogen and helium, are provided through the umbilical unit. The unit is 22 feet long, 13 feet wide and 20 feet high. The orbiter midbody umbilical unit extends from the rotating service structure at levels ranging from 158 to 176 feet above the surface of the pad.

    The hypergolic umbilical system carries hypergolic fuel and oxidizer, helium, and nitrogen service lines from the fixed service structure to the vehicle. The system also provides for rapidly mating the lines to and demating them from the vehicle. Six umbilical handling units-manually operated and locally controlled-are structurally attached to the rotating service structure.

    The umbilical handling units consist of three pairs located on the left and right sides of the-

    1. Aft end of the orbiter, serving the orbital maneuvering system and reaction control system.

    2. Nose section, serving the forward RCS.

    The orbiter midbody umbilical unit and hypergolic umbilical system connections with the orbiter are severed when the rotating service structure is prepared for retraction to its park site.

    The OMS/RCS pods are made of an epoxy material that tends to absorb moisture with time, affecting its structural qualities. The only way to drive the moisture out is to heat the pods. Two large clamshell-like enclosures have been built at the base of the rotating service structure so they completely envelop the OMS/RCS pods when the rotating service structure is in position around the orbiter. These enclosures are purged with heated air as long as necessary to drive out the absorbed moisture.


    A sound suppression water system is installed on the launch pads to protect the orbiter and its payloads from damage by acoustical energy reflected from the mobile launcher platform during launch. The system includes an elevated water tank with a capacity of 300,000 gallons. The tank is 290 feet high and stands on the northeast side of the pad. The water is released just before the ignition of the orbiter's three main engines and twin solid rocket boosters and flows through parallel 7-foot-diameter pipes to the pad area.

    Water pours from 16 nozzles atop the flame deflectors and from outlets in the space shuttle main engine exhaust hole in the mobile launcher platform at main engine ignition (T minus 6.6 seconds). When solid rocket booster ignition and lift-off follow at T minus zero, a torrent of water flows onto the mobile launcher from six large quench nozzles, or ''rainbirds,'' mounted on its surface.

    Water is also sprayed into the primary solid rocket booster exhaust holes to provide overpressure protection to the orbiter at solid rocket booster ignition. The peak flow rate from the prelift-off and postlift-off systems is 900,000 gallons per minute nine seconds after lift-off.

    The rainbirds are 12 feet high. Two of them, those in the center, are 42 inches in diameter. The other four are 30 inches in diameter. Acoustical levels reach their peak when the space shuttle is about 300 feet above the mobile launcher platform.

    Below 300 feet, the rocket exhaust is channeled over the flame deflectors and into the flame trench. Above 300 feet, sound is reflected off the metal plates of the mobile launcher platform's surface. In terms of time, the maximum sound reflection comes about five seconds after lift-off. The problem ends after the shuttle has been airborne for about 10 seconds and has reached an altitude of 1,000 feet.

    Design specifications for space shuttle payloads require an ability to withstand acoustical loads of up to 145 decibels. The system reduces the acoustical levels within the orbiter's payload bay to about 142 decibels, 3 decibels below the design requirement.

    The solid rocket booster ignition overpressure suppression system was installed to alleviate the effect of the initial reflected pressure pulse when the solid rocket boosters ignite. This pressure pulse, without the overpressure suppression system, exerts a pressure on the wings and ailerons that approaches the design limit. The overpressure system is designed to reduce this pressure by a factor of 3. The system was designed and installed following STS-1 as a direct result of overpressures measured during the launch.

    The system has two primary components. A water spray system fed from large headers provides a cushion of water directed down into and around the primary flame hole (directly beneath the stationary solid rocket booster). This barrier is supplemented by a series of water bags in the primary and secondary flame hole, which provides a water mass to dampen the blow-back pressure pulse. The water spray and the water barrier largely block the path of a reflected pressure wave and greatly decrease its intensity.

    An engine deluge system consisting of 22 water nozzles spaced around the space shuttle main engine exhaust hole in the mobile launcher platform is designed to cool the aft end of the orbiter following flight readiness firing of the main engines and is also available in the event of an on-pad abort. After the engines are shut down, there can still be some residual hydrogen remaining in the vicinity of the main engines' nozzles that can burn for an appreciable period of time. The system is fed by a 6-inch-diameter supply line and can provide a flow of up to 2,500 gallons per minute directed at the orbiter's engine nozzle/boattail area to control hydrogen afterburning and provide cooling water.


    During the orbiter main engine start sequence, hydrogen vapors are exhausted into the engine nozzles before ignition. At ignition the hydrogen-rich atmosphere in the engine bell is ignited, causing a small ''explosion'' that could damage the engine bells. To preclude this, six hydrogen burnoff preignitors have been installed on the tail service mast, positioned toward main engines 1, 2 and 3.

    Just before main engine ignition, the hydrogen burnoff ignitors are initiated and throw thousands of hot, luminescent balls into the area below the engine bells to ignite any free hydrogen. Rough combustion at main engine start is thus avoided.


    Pad structures are insulated from the intense heat of launch by the flame deflector system, which protects the flame trench floor and the pad surface along the top of the flame trench. The flame trench transecting the pad's mound at ground level is 490 feet long, 58 feet wide and 40 feet high. It is made of concrete and refractory brick.

    The orbiter flame deflector is fixed and is 38 feet high, 72 feet long and 57.6 feet wide. The deflector weighs 1.3 million pounds.

    The top of the solid rocket booster flame deflector abuts with that of the orbiter flame deflector to form a flattened, inverted V-shaped structure beneath the mobile launcher platform's three exhaust holes. The solid rocket booster deflector is 42.5 feet high, 42 feet long and 57 feet wide. The structure weighs 1.1 million pounds.

    The deflectors are built of steel and covered with a high-temperature concrete surface with an average thickness of 5 inches. There are two movable solid rocket booster side flame deflectors, one located on each side of the flame trench. They are 19.5 feet high, 44 feet long and 17.5 feet wide.


    Propellant servicing of the orbiter's reaction control systems, the solid rocket boosters' hydraulic power units and the external tank is performed at the pad. Cross-country lines lead from various propellant storage facilities to the pad structures and umbilical connections.

    The liquid oxygen used as an oxidizer by the orbiter's main engines is stored in a 900,000-gallon storage tank located at the northwest corner of the pad with the control and distribution system. This ball-shaped storage vessel is a huge vacuum bottle designed to store cryogenic (supercold) liquid oxygen at a temperature lower than minus 297 F. One gallon of liquid oxygen weighs approximately 10 pounds. It is transferred to the pad by one of two main pumps capable of pumping 1,300 gallons per minute.

    The liquid hydrogen used as a fuel by the orbiter's main engines is stored in an 850,000-gallon storage tank located at the northeast corner of the pad with the control and distribution system. This large ball-shaped storage vessel is also a huge vacuum bottle designed to contain and store liquid hydrogen, a cryogenic fluid much colder than liquid oxygen. Liquid hydrogen vaporizes at temperatures above minus 423 F at sea level. Because of its lightness (one gallon of liquid hydrogen weighs approximately 0.5 of a pound), pumps are not needed to transfer it to the pad. Vaporizers convert a small portion of the liquid hydrogen stored in the tank into a gas, and the gas pressure exerted from the top of the tank moves the liquid hydrogen into the transfer lines and to the pad.

    Vacuum-jacketed transfer lines carry these supercold fluids to the mobile launcher platform, where they are fed through the tail service masts and T-0 umbilicals to the orbiter and then to the external tank.

    The hypergolic storage area and distribution system provide the propellant for the orbiter's OMS/RCS engines, which use monomethyl hydrazine as a fuel and nitrogen tetroxide as an oxidizer. These fluids are stored at ambient temperatures and are hypergolic; that is, they ignite on contact. They are stored separately in well-separated areas at the southwest and southeast corners of the pads. These propellants are fed by transfer lines to the pad and through the fixed service structure to the rotating service structure hypergolic umbilical system.

    Other fluids and gases supplied on the pad include helium, nitrogen, shop air, Freon 21 and ammonia.


    A wide range of payloads-some to be deployed from the space shuttle, others only to be carried into space in the payload bay and returned at the end of the mission-are delivered to KSC to undergo final processing, checkout and installation aboard the orbiter. Space shuttle payload processing is performed in parallel with vehicle processing so that fully integrated and tested payloads are ready for installation in the orbiter at the appropriate time to support the launch schedule.

    In order to obtain the shortest possible space shuttle turnaround flow, KSC performs a simulated orbiter-to-cargo interface verification of the entire payload before its is installed in the orbiter.

    Payloads follow one of two functional flows: they are installed horizontally in the orbiter in the OPF or vertically at the pad.

    Multiuse Mission Support Equipment. Essential to the processing of payloads at various Kennedy Space Center shuttle facilities is the multiuse mission support equipment. This consists of the payload canister, payload canister transporter, payload strongback and payload handling fixture.

    Payload Canister. The payload canister is a payload-bay-sized container that is used to transport fully integrated shuttle payloads from the Vertical Processing Facility to the launch pad's payload changeout room or from the Operations and Checkout Building to the OPF in a controlled environment.

    Two identical canisters are available for use. Each is 65 feet long, 18 feet wide and 18 feet 7 inches high. They have the capability to carry vertically or horizontally processed payloads up to 15 feet in diameter and 60 feet long, matching the capacity of the orbiter payload bay. They can carry payloads weighing up to 65,000 pounds.

    Payload trunnion and keel support structures support a payload loaded into the canister in the same way it is supported in the orbiter payload bay. Clamshell-shaped doors at the top of the canister operate like the orbiter payload bay doors, with the same allowable clearances.

    Payload Canister Transporter. The payload canister transporter is a 48-wheel, self-propelled truck designed to operate between and within space shuttle payload processing facilities. Two are used to transport the payload canisters and their associated hardware throughout KSC. Each is 65 feet long and 23 feet wide. Their flatbeds can be lowered to 5 feet 3 inches or raised to 7 feet plus or minus 3 inches.

    The transporter's wheels are independently steerable, permitting it to move forward, backward, sideways or diagonally or turn on its own axis like a carousel. It has self-contained braking and stabilization jacking systems.

    A bare transporter weighs 230,000 pounds. With a full load of diesel fuel and with the environmental control system, fluids and gas service, electrical power system, and instrumentation and communication system modules mounted, the transporter has a gross weight of 258,320 pounds.

    The transporter is steerable from diagonally opposed operator cabs on each end. Its top speed unloaded is 10 mph. The maximum speed of the fully loaded transporter is 5 mph. Because payload handling will require precise movements, the transporter has a creep mode that permits it to move as slowly as 0.25 of an inch per second or 0.014 mph. Interfacility drive power is provided by a 400-horsepower diesel engine. Intrafacility drive power comes from an 82-kilowatt electric motor. The transporter can carry the payload canister in either the horizontal or vertical position.

    Payload Strongback. The payload strongback provides support for all payload sections during horizontal handling. A major use of the strongback is the handling of Spacelab, but it will also be used to unload a wide variety of payloads during postflight handling in the Orbiter Processing Facility. Movable attachment points permit the strongback to be used for different payloads.

    The strongback consists of a rigid steel frame with adjustable beams, brackets and clamps. It will not induce any bending or twisting loads on payload elements. The strongback is 60 feet long, 16 feet wide and 9 feet high and weighs 40,000 pounds.

    Payload Handling Fixture. The payload handling fixture is designed for use in handling space shuttle payloads at any of the contingency landing sites. It can be transported via C-5A and can be erected in the field to support the full size and weight capacity of the space shuttle payload bay.

    For horizontally processed payloads, a truck crane procured locally will lift the payload out of the space shuttle's payload bay and lower it into the PHF. For vertically installed payloads, the PHF can be rotated to a vertical position for deservicing.


    Automated deployable payloads-such as telecommunications spacecraft-and their associated upper stages are received and initially processed at facilities at the Cape Canaveral Air Force Station. Other shuttle payloads, including free-flying deployable/retrievable pallets and small, self-contained payloads (getaway specials), are also processed at CCAFS facilities.

    Building AE, Building AO, and Building AM contain high bay clean rooms used in the processing of deployable spacecraft. Hangar S supports processing of free-flyer pallets. Getaway specials are processed at the refurbished Delta Third Stage Facility.

    Department of Defense payloads also are processed at CCAFS facilities.

    Deployable spacecraft that are to be placed in geosynchronous orbit require an upper stage to boost them from the space shuttle's low Earth orbit to a geosynchronous transfer orbit with an apogee of approximately 22,300 miles. These upper stages are received and processed at facilities at the CCAFS.

    Explosive Safe Area 60A serves as a receiving and integration facility for the payload assist module upper stage and its associated airborne support equipment. The PAM is mated with the spacecraft at the facility, and they are transported to the Vertical Processing Facility at the Kennedy Space Center for integrated testing.

    The Delta Spin Test Facility is used for balancing and testing Delta-class space transportation system upper stages for spacecraft that use spin-stabilized guidance.

    The inertial upper stage is received at the Solid Motor Assembly Building in the Titan III complex at the Cape Canaveral Air Force Station. Operations in this building are under the management of the U.S. Air Force. For non-DOD missions, the IUS is moved to the Vertical Processing Facility at KSC for mating with its spacecraft. DOD spacecraft are mated at the Air Force station at the Shuttle Payload Integration Facility.


    Radioisotope thermoelectric generators, which will be used to generate power on payloads, are stored in a building located in a remote part of the KSC industrial area.


    The Vertical Processing Facility in KSC's industrial area is designed to accommodate all vertically processed payloads through cargo integration. The VPF consists of an environmentally controlled high bay and airlock and single-story support facilities along the sides of the high bay.

    The high bay area has a ceiling height of 105 feet and a usable floor area of 10,153 square feet. Equipment enters the airlock through a 71-foot-high, 24-foot-wide door. Access to the high bay from the airlock is through a 71-foot-high by 38-foot-wide door.

    Two payload workstands with six fixed platforms provide access to payloads in the high bay. Two bridge cranes, 25 tons and 12 tons, can be linked to provide 35-ton lift capability. A 10-ton monorail crane is located in the airlock. The six fixed platform levels are serviced by a 2-ton hoist.


    Located west of the Vertical Processing Facility and the Hypergolic Maintenance and Checkout Facility in KSC's industrial area is the new Payload Hazardous Servicing Facility. This unique facility can double as a payload processing facility and a hazardous processing facility.

    As a payload processing facility, the PHSF supports the assembly and testing of payload components and systems. As a hazardous processing facility, it supports the integration of solid rocket motors with the payloads and ordnance and hazardous fuel servicing.

    The facility is environmentally controlled by a class 5,000 air at filter discharge. The temperature remains at 70 F, plus or minus 5 F.

    A 70-foot-wide, 110-foot-long service bay features a 50-ton electrically operated running bridge crane with an 85-foot hook height. The payload airlock is 58 feet wide and 80 feet long and has a 15-ton electrically operated running bridge crane with a 75-foot hook height. The access doors to the PHSF are 35 feet wide and 75 feet high.

    The west end of the service bay has a 20-foot by 40-foot sloped floor for fuel servicing. An emergency exhaust system is provided for diluting and removing hazardous fuel and oxidizer vapors. The service bay's fire protection system consists of a deluge system, sprinklers and fire hoses. Fuel waste and oxidizer are disposed of through trench drains in the service bay that lead to 7,500-gallon and 1,500-gallon stainless steel tanks, respectively. The drains and vents are equipped with aspirators and scrubbers.

    East of the PHSF is the Facility Control Building, which features two 1,200-square-foot payload control rooms. This facility provides two-way communication links to the PHSF service bay, Payload Processing Facility, VPF, Operations and Checkout Building and launch pad. Its location permits simultaneous operations to be conducted at the PHSF and VPF and pad even during hazardous operations at the PHSF without having to vacate the building. This building also contains offices, a ground station, electrical and mechanical shops and an area for donning SCAPE suits and equipment.


    The payload changeout room is built into the launch pad's rotating service structure and functions as an environmentally controlled facility supporting cargo delivery to the pad and subsequent vertical installation in the orbiter cargo bay. Seals around the mating surface of the payload changeout room fit against the orbiter or payload canister and permit the payload bay or canister doors to be opened and the cargo to be removed without exposing it to outside air and contaminants. A clean-air purge in the PCR maintains environmental control during cargo operations. Payloads are removed from the payload canister and installed vertically in the orbiter using the extendable payload ground handling mechanism. Fixed and extendable work platforms provide work access in the PCR.


    Vertically integrated payloads normally are received in payload processing facilities in Buildings AE, AO and AM and Hangar S at the Cape Canaveral Air Force Station or in the Spacecraft Assembly and Encapsulation Facility 2 in the KSC industrial area. These payloads consist primarily of automated satellites or spacecraft using upper stages, and their processing normally involves hazardous operations that are conducted in explosive safe areas located at the CCAFS. Vertical integration into a complete shuttle payload is performed in the Vertical Processing Facility.

    Spacecraft undergo buildup in the clean room environments of one of the payload processing facilities to which they are initially assigned and where they receive preintegration testing.

    After functional tests are completed, spacecraft are moved to a safe area for hazardous operations. These areas are the Delta Spin Test Facility and the explosive safe area at the CCAFS. Activities performed in these areas include the installation of solid propellant apogee motors or ordnance separation devices, hydrazine loading, and any other work involving items that are potentially explosive or hazardous.

    Upon completion of these hazardous operations, a spacecraft is ready to be transported to the Vertical Processing Facility.

    After it has been fully checked out at the appropriate facility, the spacecraft's upper stage is transported to the VPF for mating with its spacecraft.

    The final integration and testing of vertically integrated payloads is accomplished in the VPF. Operations in the VPF are conducted under environmentally controlled conditions.

    The entire facility is a clean room. Its temperature is controlled at 75 F and relative humidity is maintained at 45 percent, plus or minus 5 percent.

    Spacecraft processing in the VPF depends on the type of upper stage involved. A spacecraft already mated with a PAM-D is removed from the transporter container and installed directly in one of two workstands. A spacecraft using an IUS is installed in one of two workstands, where it is mated with an IUS that was previously installed in the stand.

    Regardless of where the upper stages are mated to their spacecraft, the entire space shuttle payload is eventually assembled in a single VPF workstand. Individual payloads (spacecraft mated with an upper stage) are tested before any combined payload testing or simulated orbiter-to-payload testing. These stand-alone tests are performed using portable test equipment or the remote ground checkout equipment.

    The last major test in the Vertical Processing Facility is the cargo integration test. Cargo integration test equipment verifies payload/cargo mechanical and functional interfaces with the orbiter before the payload is shipped from the VPF to the launch pad. CITE processing of the entire payload begins with power-on health and status checks, functional tests, computer and communications interface checks (performed on the IUS), and spacecraft command and monitor tests. These are followed by a mission simulation test that simulates all normal mission functions through payload deployment.

    If required, an end-to-end test is performed with the participation of other NASA field centers involved in the payload portion of the mission.

    After the completion of testing, the entire space shuttle payload is placed in the payload canister by the vertical payload handling device and transported to the launch pad. Environmental conditioning and system monitoring are provided during transport operations to the payload changeout room on the rotating service structure.

    At the pad, the canister is hoisted to the proper elevation in the retracted RSS and locked into position. The environmental seals of the payload changeout room are then inflated to seal against the sides of the canister. The space between the closed doors of the PCR and the canister are purged with clean air to ensure the required cleanliness before the doors of the PCR and canister are opened.

    The payload is then transferred from the canister into the PCR by the payload ground handling mechanism. The PGHM is retracted into the PCR, and the canister and PCR doors are closed. The environmental seal is deflated, and the canister is lowered onto its transporter and taken to a storage facility. The RSS is then moved into position to enclose the orbiter's payload bay and establish environmental seals. The space between the closed doors of the PCR and the payload bay are then purged with clean air.

    After the PCR doors and payload bay doors are opened, the PGHM extends the payload into the orbiter. The payload is secured to the orbiter, and the PGHM is retracted and secured. During this operation, the PCR's environmental control is maintained, and the payload bay is purged with clean temperature- and humidity-controlled air.


    Horizontally integrated payloads are received, assembled and integrated in the Operations and Checkout Building before they are mated with the orbiter at the Orbiter Processing Facility. The Spacelab and its payloads constitute a large majority of the horizontal payloads.

    The Operations and Checkout Building is a five-story structure containing 600,000 square feet of offices, laboratories, astronaut crew quarters and spacecraft assembly areas. It is located in the industrial area immediately east of the KSC headquarters building.


    The Spacelab assembly and test area is located in the Operations and Checkout Building. It is 650 feet long and 85 feet wide. It is divided into a high bay area 157 feet long and 104 feet high and a low bay area 475 feet long and 70 feet high. The assembly and test area is environmentally controlled to 75 F (plus or minus 2 F). Relative humidity is maintained below 60 percent.

    The major Spacelab facilities in the O&C Building are the two integrated assembly and checkout workstands, engineering model workstand, pallet staging workstands, a rack/floor workstand, a tunnel maintenance area, an airlock maintenance area and two end cone stands.

    The two integrated workstands are controlled from two automatic test equipment control rooms located on the third floor. Control of the assembly and checkout workstands can be switched to either control room.

    Mechanical and electrical ground support equipment required to support Spacelab assembly and testing are located in and around the workstands. These arrangements make it possible to support two independent Spacelab processing flows.

    To assist in Spacelab-orbiter interface verification, an orbiter interface adapter and two racks simulating the orbiter's aft flight deck are provided at the end of the workstand.

    Orbiter electrical, gas and fluid interfaces are provided through ground support equipment cables or lines.


    The Spacelab ground operations concept permits a user to design and develop an experiment that can be integrated with other individual experiments into a complete Spacelab payload.

    The processing of Spacelab payloads begins with the integration and checkout of experiment packages and equipment with the appropriate structural mounting elements-racks for the Spacelab pressurized module and pallet segments for the experiments to be exposed to the space environment.

    Experiments sponsored by the European Space Agency undergo preliminary integration in Europe before they are shipped to the United States.

    All payload elements are delivered to the launch site in as near flight-ready condition as practical.

    After delivery of individual experiments and payloads to the Operations and Checkout Building, the Spacelab ''train'' of pallets and racks is assembled using the pallet and rack stands. Following mechanical buildup of the payload train, the Spacelab elements are transferred to the Spacelab integration workstand for integration with the Spacelab module or support systems igloo.

    Spacelab operational hardware undergoes refurbishment and buildup in parallel with payload buildup. After buildup of the total Spacelab and payload configuration in the workstand, the module's aft and forward end cones are installed, pallets are positioned, and utilities are connected between pallets and the module.

    The CITE stand simulates the orbiter and supports highly realistic space shuttle/Spacelab electrical and mechanical interface testing.

    Upon completion of checkout and test activities, the Spacelab is hoisted by bridge cranes and strongback, installed in the payload canister, and moved to the Orbiter Processing Facility by the payload canister transporter. Environmental conditioning, via air purge and system monitoring, are provided during the trip to the OPF.

    The payload is removed from the canister and installed in the orbiter in the OPF. The payload is hoisted in a horizontal attitude from its canister, positioned over the orbiter, lowered, and secured in the payload bay. The strongback and facility crane support this operation.

    After payload installation, the space shuttle/payload interfaces are connected and verified. A cargo integrated test is conducted to complete the verification of interfaces between the payload and the orbiter, including validation of payload data via the orbiter data system, where applicable.

    Upon completion of testing and final closeouts, the payload bay doors are closed and latched. The payload bay environment with the doors closed is maintained by providing a purge of clean air at 70 F and a relative humidity of 30 to 50 percent. At this point, the orbiter is powered down for movement to the Vehicle Assembly Building. No power or purge is provided from this point until the completion of space shuttle vehicle assembly in the VAB. The orbiter's payload is quiescent during VAB operations, and no access is planned.

    The payload purge is resumed after the shuttle elements have been mated on the mobile launcher platform. Space shuttle power is available after the mobile launcher platform and external tank interfaces have been connected and verified. The clean air purge to the payload bay is maintained while the space shuttle is being rolled out on the crawler-transporter to the pad.

    The orbiter is powered down during the movement to the pad, and power is not available to a payload during this time unless it is provided by a self-contained source.

    After the mobile launcher platform has been mated hard down on its mounts at the pad and umbilicals have been connected, the shuttle vehicle is powered up.

    Access at the pad to payloads installed during horizontal processing at the pad is not planned, although the capability exists to open the payload bay doors and reach the payloads from the payload ground handling mechanism's extendable platforms.


    Since getaway special payloads have limited interfaces with the orbiter and are not installed in the orbiter on trunnions, they cannot be processed as standard payloads. They are received and built up in the Getaway Special Facility, formerly the Delta Third Stage Facility, at the CCAFS. They are installed in the orbiter at the Orbiter Processing Facility.

    Most small, self-contained payloads do not require processing through the horizontal cargo integration test equipment facility in the Operations and Checkout Building and will be built up, attached to a special bridge beam, and installed in the orbiter much like any other bridge beam.


    The flight hardware associated with life science payloads normally follows the flow for horizontally integrated payloads. However, live specimens for these payloads are received at Hangar L at the Cape Canaveral Air Force Station. Technical activities in Hangar L are managed by NASA's Ames Research Center. KSC has operations and maintenance responsibility.

    Hangar L houses the Life Sciences Support Facility, which processes space shuttle life science payloads. The facility includes laboratory and holding areas for specimens and support areas for principal investigators.

    Life science specimens, or live specimens already in their flight containers, are installed in the payload bay at the launch pad from a special access platform mounted on the payload ground handling mechanism or in the orbiter middeck area of the crew cabin through the crew entry hatch.


    The processing of Department of Defense payloads at the eastern launch site is similar to KSC payload processing, except that payload buildup and integration are accomplished in DOD facilities at the Cape Canaveral Air Force Station in a secure environment. DOD spacecraft arrive at the Skid Strip at the CCAFS and are off-loaded from the air transporter (C-5A or 747 aircraft). If assembly and checkout are required, spacecraft are transported to an assembly area-normally the Satellite Assembly Building at the CCAFS.

    After spacecraft are assembled and checked out, they are transported to the Shuttle Payload Integration Facility. The SPIF is a DOD facility, similar to KSC's Vertical Processing Facility, and is located in the Solid Motor Assembly Building at the CCAFS.

    Spacecraft requiring minimal assembly are transported directly to the SPIF from the Skid Strip.

    Activities in the SPIF vary depending on the DOD spacecraft. Spacecraft requiring the inertial upper stage are mated with an IUS that has already been assembled and checked out in the SMAB east bay and installed in the SPIF integration cell. A spacecraft requiring a payload assist module upper stage is integrated with the PAM enroute to the SPIF and arrives fully integrated for installation in the SPIF integration cell. Spacecraft not requiring an upper stage are installed directly in the integration cell.

    After all space shuttle payload elements (spacecraft or spacecraft and upper stage) that comprise a space shuttle payload have been installed in the SPIF integration cell, subsequent processing activities are fundamentally the same.

    Space shuttle cargo integration testing is conducted using the DOD's orbiter functional simulator, a system similar to the cargo integration test equipment used at KSC. Following any testing unique to a payload, such as communications checks with the Payload Operations Center, the assembled and fully tested cargo is removed from the integration cell using the DOD handling fixture and inserted in the KSC-provided canister for transport from the SPIF to the shuttle launch pad.

    The DOD payload is transferred to the payload changeout room in the rotating service structure and placed in the orbiter payload bay for final checkout and interface verification testing. Final ordnance connections are performed, and the DOD payload is ready for launch.


Table of Contents

Information content from the NSTS Shuttle Reference Manual (1988)
Last Hypertexed Wednesday October 11 17:48:56 EDT 1995
Jim Dumoulin (

Join the mailing list