Kennedy Space Center Story

Text Size

Chapter 5
1991 Edition

Constructing the Spaceport

Launch Complex 39, originally designed to accommodate Apollo-Saturn V space vehicles, taxed the ingenuity of its construction team. Architectural Forum magazine described the four-year, $800 million-project as "one of the most awesome construction jobs ever attempted by Earth-bound men."

Its principal features included:

* A hangar big enough to enclose four Apollo-Saturn V space vehicles, each standing 363 feet (111 meters) tall and measuring up to 33 feet (10 meters) in diameter.

* Movable platforms on which the rockets were assembled and transported to the launch pad, and from which they were launched.

* A system of carrying rockets and launchers, weighing 12 million pounds (5.44 million kilograms) to and from the firing site.

* A movable service structure 45 stories tall that permitted technicians to complete preparations at the launch pad.

* A control center from which preparations were monitored and controlled through launch.

KSC planners drew up the requirements while the Army Corps of Engineers created a new management office, the Canaveral District, to supervise brick and mortar construction contracts for NASA. The Florida East Coast Railroad built a causeway across the Indian River, connecting the spaceport and the mainland in order to haul freight directly to the building site. Structural steel, rolled in northern mills, came by truck from Tampa, on Florida's west coast, where it had received special treatment against corrosion.

Late in 1962, sufficient planning data had been collected from rocket and spacecraft designers to begin detailed drawings for the huge hangar, to be designated the Vehicle Assembly Building (VAB). The Apollo-Saturn V was by far the largest space vehicle in the world, and the structure originally built to accommodate it is one of the world's largest in volume. The building encloses 130 million cubic feet (3.68 million cubic meters) and covers eight acres (3.2 hectares).

Debus conceived a cruciform shape in his early sketches of the hangar. Another plan proposed lining up checkout bays in a single row that would have resulted in a narrow, slablike shape. NASA chose a back-to-back layout, with a transfer aisle between rows of checkout and assembly bays. The boxlike, rectangular shape that resulted was both more economical and stronger, capable of withstanding hurricane-force winds.

More than 98,000 tons (89,000 metric tons) of steel were used to construct the VAB. In all, 45,000 separate pieces of steel weighing from 150 to 72,000 pounds (68 to 32,659 kilograms) were required. More than 1 million bolts secured the steel members. The paperwork for the VAB project alone was monumental. Approximately 2,500 separate drawings were submitted. It took an entire railroad freight car to move the final specifications printed for the bidders.

Clearing and filling operations for the VAB began in November 1962. Since the average height of the terrain was barely above sea level, dredges were brought nearby Banana River to pump fill onto the land. This dredging raised the land level to almost seven feet (2.1 meters) by July 1963 and, at the same time, opened up the channel and turning basin for the barges that would transport the rocket stages. In all, 1,500,000 cubic yards (1,140,000 cubic meters) of soil were pumped from the river bottom to the site.

The foundation presented unusual problems. Tests showed a three-foot (one-meter) limestone shelf 118 feet (36 meters) below the surface. The layers below that were silt overlaying bedrock at a depth of 160 feet (49 meters). Core borings revealed petrified wood, carbon-dated to be 25,000 years old. It was decided that the massive VAB would rest upon steel pipe pilings, 16 inches (41 centimeters) in diameter and 3/8 inch (10 millimeters) thick, driven into the limestone bedrock. The foundation contractor spent six months driving 4,225 pilings through the upper limestone layer. When the job was complete, 128 miles (206 kilometers) of steel pipe had been buried. Each pile was filled with sand to within one foot (30.5 centimeters) of the top, and concrete caps were poured around clusters of from six to 20 pilings. Since the piling penetrated a salty chemical solution below the surface, there was a tendency for electrolysis to occur. Cathodic protection had to be applied to neutralize the current; otherwise, the foundation would have corroded and the VAB could claim to be the world's largest wet cell battery.

To anchor the building securely, 30,000 cubic yards (23,000 cubic meters) of concrete formed the floor slab.

The building was structurally completed in June 1965 when a large steel beam painted white for the purpose was autographed by construction workers, NASA, and Corps of Engineers employees, and hoisted into place at the traditional topping-out ceremony.

Looming above the flat terrain, the VAB does not forcibly impress visitors because there is no other nearby tall structure to provide a comparison. Not until one enters the transfer aisle and looks up to the supporting beams under the roof can the dimensions of the building be grasped. It measures 716 feet (218 meters) in length, twice the size of a football field, and 518 feet (1 58 meters) in width. It is 525 feet (160 meters) high. Under strong wind pressure the structure can sway 12 inches (30.5 centimeters).

The VAB is divided into two main sections. The high bay portion contains four bays, each large enough to accommodate a mobile launcher carrying a fully assembled space vehicle.

For Apollo, the low bay portion contained eight cells used for preparation and checkout of the second and third stages of the Saturn V. Each cell was a structural steel assembly equipped with work platforms that opened to receive the stage and then enclosed it. Mechanical and electrical systems in each cell permitted simulation of stage interfaces and operations with other stages, as well as with the instrument unit.

Three high bays were fully equipped for the Apollo-Saturn V vehicles. The fourth was reserved for other vehicles that might later be required. Any vehicle that can fit within the high bay doors can be prepared for launch in the building. Five pairs of extensible work platforms were installed in each operational bay. Some were one story tall, others two stories, and some as high as a three-story building. The platforms were installed on the sides of the bay and could be adjusted upward or downward, in and out, encircling the Saturn V stages during checkout and preparation. They were retracted against the walls when the vehicle was moved to the firing site.

There are 141 lifting devices in the building ranging from one-ton (0.9-metric ton) hoists to two 250-ton (227-metric ton) bridge cranes with hook heights of 462 feet (141 meters). The largest cranes were used to lift and mate rocket stages, and were required to hold the load up to 50 minutes without moving more than 1/32 inch (eight millimeters). Electronic controls enabled operators to move the cranes in all directions at speeds as low as 1/10 foot (2.5 millimeters) per minute--the remarkably slow speed was required in mating Saturn V stages.

Gigantic doors in the shape of an inverted "T" form the outer wall of the high bays. Four leaves slide horizontally to close the lower portion, Seven leaves above them operate vertically. The doors are taller than St. Peter's Basilica, the Statue of Liberty, or Chicago's Wrigley Tower. It takes 45 minutes to open a door.

To prevent condensation and fogging within the structure, a gravity ventilation system forces a complete change of air every hour through 125 ventilators placed on the root. Selected work areas within the building are air-conditioned.

Much of the office space in the upper levels housed the checkout instrumentation of the stages. Sixteen high-speed elevators served the 3,000 employees working in the VAB during the Apollo program. Each contractor occupied floors convenient to his stage -- Boeing next to the first stage, North American the next levels, Douglas Aircraft above them, and IBM near the instrumentation unit.

Operations during the Apollo program generally followed this sequence:

* A mobile launcher was carried into a high bay and parked on support pedestals by the crawler-transporter.

* The first stage of the Saturn V rocket was off-loaded from a barge at the turning basin and hauled, horizontally, into the low bay on a transporter.

* Moved into the transfer aisle, the stage was positioned in front of a high bay, picked up by the 250-ton (227-metric ton) crane, tilted into a vertical position, raised 195 feet (59 meters) and then passed through an opening in the bay trusswork and gently lowered to the deck of the launcher.

* Second and third stages were brought into the low bay and placed in checkout cells, those on the east side holding the larger second stage, while the smaller stages were placed in the west cells.

* Inspection, checkout, and interface checks of all three stages proceeded concurrently. Then the second stage was removed by crane, carried into the transfer aisle, raised vertically through the bay opening, and placed atop the first stage. The same procedure was followed to stack the third stage, and finally the instrument unit topped off the launch vehicle.

* Each stage was electronically connected with a computer in the base of the mobile launcher, which communicated with a computer in the Launch Control Center firing room. Checkout instrumentation located in adjoining laboratories near the bay was hooked up, and the preparation work continued.

* Meanwhile, the spacecraft modules had been put through similar testing in the Industrial Area. When these tests had been satisfactorily completed, the spacecraft was assembled, carried to the VAB on a low-bed transporter, and moved into the transfer aisle. The Powerful crane lifted the spacecraft through the opening in the bay and placed it atop the Saturn V.

* When the preparations in the VAB had been completed, the crawler-transporter returned, the bay doors opened, and the machine picked up the mobile launcher and rocket for the transfer to the launch pad.

Connected with the VAB on the southeast by a cableway and personnel access corridor three floors above the ground is the Launch Control Center. The Launch Control Center, which differs completely in shape and construction from the squat, conical blockhouses that dot Cape Canaveral, contains four levels. Offices, service areas, originally a cafeteria and a control center for launch support functions occupy the first level. The second level houses telemetry and recording equipment, instrumentation and data reduction facilities. The third level divides into four firing rooms or control rooms. During Apollo, three of the four firing rooms contained a computer room, mission control room, test conductors platform, visitors gallery and adjacent offices. (The fourth firing room was never equipped with checkout consoles.) The fourth level contains offices and mechanical equipment.

From the firing rooms in the Launch Control Center, the launch crews monitored and controlled the multiple technical operations performed in the course of the checkout, mating, testing, fueling and launching of the powerful Apollo systems.

Two separate computer systems were employed. The Acceptance Checkout Equipment, designed and operated by General Electric Co., was used for Apollo spacecraft. Housed in the KSC Industrial Area five miles (eight kilometers) away, the equipment allowed engineers to monitor 24,000 samples of spacecraft test data per second. The Launch Control Center housed the Saturn ground computer system, which had two RCA 11OA computers--one in the active firing room, the other in the base of the mobile launcher. The measuring program for the Saturn V rocket checked 2,728 discrete functions, providing verification that critical components were operating properly during prelaunch tests and launch.

The same contractor that built a stage also provided the engineers who manned the consoles controlling its preparation for flight. All functioned under the direction of KSC's government employees.

Launch crews in old Cape Canaveral blockhouses viewed launches on closed-circuit television monitors or through periscopes. The Apollo-Saturn V firing room crews watched rockets lift off through huge windows in the east wall. The three firing rooms equipped for Apollo were connected with the three bays of the VAB also equipped for these missions. Using the same instrumentation for prelaunch checkout in the VAB and for fueling and launching at the pad assured uniform standards of measurement, regardless of where the space vehicle happened to be at the time. The fourth Launch Control Center firing room functioned as a planning center for daily work schedule discussions, where progress of the checkout was plotted and the government/contractor engineers exchanged schedule information.

South of the Launch Control Center is the barge terminal, consisting of a turning basin, dock, barge slips and material handling area. Here the barges arrived with the first and second stages of the Saturn V, each too long to be shipped by air or land. The barges crossed the Gulf of Mexico, circled the southern tip of the Florida Keys and proceeded up the Atlantic coastline to Port Canaveral, through the Banana River lock and channel to the receiving dock. The Saturn V third stage, instrument unit, and Apollo spacecraft arrived by air in special cargo planes called "Guppies."

The mobile launchers were the key to the mobility characterizing Launch Complex 39 operations. The mobile launchers were transportable steel structures which moved erected Saturn V vehicles to the launch pad. Three identical launchers were built for the three equipped high bays of the VAB. Erection of structural steel for the first launcher began in July 1963, and the third was topped out in March 1965.

Capped by a 25-ton (23-metric ton) hammerhead crane, a mobile launcher stood 445 feet (136 meters) tall, and weighed a total of 6,300 tons (5,700 metric tons) when carrying an unfueled Apollo-Saturn V.

A mobile launcher had two functional areas, a launcher base and an umbilical tower. The launcher base was a two-story steel platform about one-half acre (0.2 hectare) in size on which a Saturn V was assembled, transported to the launch site, and launched. Within the base was a computer linked with the computer in the firing room of the Launch Control Center.

A red umbilical structure towered over the base. It carried nine swing arms, or bridges, for direct access to the space vehicle; 17 work platforms; and distribution lines for propellant, pneumatic, electrical, and instrumentation systems. Swing arms were mechanical bridges operated by hydraulic systems. They provided access to the Apollo-Saturn V during assembly, checkout and servicing. Arm number 9, 320 feet (98 meters) above the base, connected with the Apollo spacecraft, and was used by the astronauts to enter the command module.

Swing arm technology had been successfully used at Complexes 34 and 37 on Cape Canaveral for the smaller Saturn I vehicles. Those required at Complex 39 were much heavier and proposed difficult engineering problems. They supported propellant lines through which fuel entered tanks of all three Saturn V powered stages, as well as supporting electrical and pneumatic feeds from the ground. Four arms could be disconnected prior to launch, but five others carried lines that could not disengage until the rocket began to move. In the jargon of the Space Center, they had to swing clear at "first motion." They retracted in two to five seconds to provide room for the wider, lower stages of the giant Saturn V to pass as it rose. As a further precaution, the rocket steered on an angle away from the umbilicals.

Giant hold-down arms, whose name accurately describes their function, were mounted on the surface of the base to support and restrain the vehicle. They held the rocket during the first 8.9 seconds after ignition of the first stage main engines until the computer in the base, in constant communication with the firing room computer, verified that each engine had built up to full power. When the computer was satisfied, it released the holddown arms and the rocket lifted from the launcher.

The launchers rest on 22-foot (seven-meter) tall pedestals in the VAB high bays or at the launch sites. A square opening in the launcher's base, directly under the Saturn V first stage, vented engine exhaust into a flame trench at the firing site.

The base of the mobile launcher was as much like a building as it was a platform for launching Saturn Vs. Within the launcher base were compartments, including a mechanical equipment room, operations support room, and television and communications equipment. Floors were suspended on springs, or shock insulators, and walls were lined with thermal and acoustical fiberglass insulation. Computers were housed in cocoonlike compartments enclosed by thick steel plates lined with fiberglass. Remotely operated, digitally controlled equipment in the base controlled propellant loading from the firing room.

During Apollo, two high-speed elevators, centrally placed in the umbilical tower, carried engineers and technicians to and from the swing arms and 17 work platforms. In an emergency the elevator used by the astronauts could be remotely controlled from the firing room, and the crew could reach the base of the mobile launcher in 30 seconds from the 320-foot (98-meter) level. There they could slide down a stainless steel chute, close to the elevator, which carried them four stories down inside the launch pad itself to a cavelike room lined with foam rubber to cushion their impact. Next to where the astronauts would land was a blast-resistant room containing 20 contour chairs and safety harnesses. The room had thick steel and concrete walls designed to withstand blast pressures of 500 pounds (227 kilograms) per square inch (6.45 centimeters) and an acceleration of 75 Gs. A floating concrete floor supported the contour chairs. It was built on a spring suspension system which reduced the 75 Gs possible on the room's dome to 4 Gs. Food and water were kept in the room for use in an emergency.

A second means of escape was also available to the Apollo astronauts. At the crew access arm level of the umbilical tower, a cage was suspended on a heavy cable. It was large enough to accommodate the three crewmen, plus the six technicians who assisted their entry into the spacecraft. The cage slid down the cable at 50 miles (80 kilometers) per hour, braking to a stop at an earth bunker 1,200 feet (366 meters) from the firing site. A 14-man rescue crew remained at the bunker during final countdown and launch. This team could use armored personnel carriers to reach the pad quickly, or to haul the astronauts from the danger area.

Means of transporting the mobile launchers and assembled Apollo-Saturn V vehicles from the VAB to the launch pads were thoroughly investigated by KSC engineers. One mode involved a barge system, floating them from the VAB to the pads in a canal. Models were tested but found infeasible. A rail system was explored but proved too costly. Ideas for pneumatic-tired transporters, air-cushion vehicles, and others were explored and discarded.

The choice was a crawler rolling on eight tracks, its propulsion system resembling those used for large power shovels employed in strip mining. In 1963 NASA awarded a contract for the construction of two crawlers. Both machines were in service by early 1967. Each weighs approximately six million pounds (2.7 million kilograms) and could transport a mobile launcher with the assembled Apollo-Saturn vehicle at a speed of one mile (1.6 kilometers) per hour. A trip to the Moon began very slowly. The crawler could also return the rocket to the VAB, if needed, with all connections intact.

In operation, the crawler moved underneath the mobile launcher and engaged its jacking system, which fitted under the platform. The launcher was raised off the support pedestals and carried into a VAB high bay, where it was carefully positioned on other pedestals. After the space vehicle had been assembled on the launcher and tested, the crawler returned to the high bay, again picked up the launcher, and carried it to the firing site.

The combined mass of crawler, mobile launcher, and Saturn V added up to 18 million pounds (8,165,000 kilograms).

The roadway which supported this weight was different from a normal highway. Known as the crawlerway, it is about the width of the New Jersey Turnpike. Each of its two lanes is 40 feet (12 meters) wide with a 50-foot (15-meter) median. To prepare the base, fill was dredged from the adjacent Barge Canal, beginning in November 1963. The roadway was built in four layers, with an average depth of seven feet (two meters). The top surface on which the transporters operate is Alabama river gravel, a loose rock that relieves friction on the crawler treads. This roadway, completed in August 1965, has 10 times the resistance of a jet airport runway.

Lining the crawlerway along the north side are utility pipelines connecting the VAB and pads, while communications and instrumentation lines are buried in ducts below the surface. Midway between the Launch Control Center and Pad A, an extension of the crawlerway veers northeast and connects with the second launch site, Pad B.

Another major element of the mobile concept was the 10.5 million-pound (4.8 million-kilogram) mobile service structure. This 410-foot (125-meter) tall steel-trussed tower supported passenger and freight elevators, a power plant, air-conditioning equipment, a computer, and television and communications systems. Its function was to provide 360-degree access to the upper portion of the space vehicle for final launch preparations.

Assembled at its parking site along the crawlerway, the mobile service structure measured 135 feet (41 meters) by 132 feet (40 meters) at its base, or roughly half the size of a football gridiron, and was 113 feet (34 meters) square at its top. it supported five enclosed work platforms, two of which were self-propelled, designed to embrace the Apollo-Saturn V upper stages. The platforms enabled technicians to conduct final inspections, load propellants in the spacecraft, install ordnance items, and prepare the lunar, command, and service modules, and the launch escape system, for flight. (The escape system was a fingerlike rocket mounted atop Apollo which could develop sufficient thrust, in an emergency, to carry the spacecraft away from the launch vehicle. Then the Apollo command module would deploy its parachute and land in the ocean, where the crew could be rescued by amphibious vehicles or helicopters waiting in the launch area for this purpose.)

The structure was completed in late 1966. Since it could be moved, the same structure served vehicles at either pad. It was carried to the pad surface by the crawler after the mobile launcher and space vehicle were positioned over the flame trench. About seven hours before launch, at the time when liquid hydrogen propellant was to be loaded in the upper rocket stages, the crawler removed the mobile service structure from the pad and returned it to its parking position.

Pad A, the first of two launch pads to be constructed, was built between November 1963 and October 1965. The second firing site, Pad B, was identical. Both were ready for use by late 1968.

A critical item influencing pad design was the size and type of flame deflector required for the Saturn V vehicle. A flame deflector is a heavy steel device built in an inverted V-pattern which converts the vertical flames from booster engines into two horizontal flows along the trench. It was desirable to keep the colossal Saturn as close to the ground as possible, in order to avoid adverse wind effects at higher levels. Unless deflected, the steams of fire would bounce off the trench floor and back up along the vehicle.

Since the water table is close to the surface, the flame deflector had to be mounted at ground level. The flame trench in which it sits is lined with fire-resistant brick. It is 58 feet (18 meters) wide and 42 feet (13 meters) high. The launch pad's overall shape is roughly octagonal, and covers about one-half square mile (130 hectares). The flame trench and concrete hardstand is in the center of the fenced area. During launch preparations, the mobile launcher supporting the Saturn V vehicle rested on six 22-foot (6.7-meter) pedestals located on the pad surface. The other fixed facilities on the hardstand included a hydrogen service tower, a fuel system service tower, and six electrical power pedestals.

Beneath the surface were four floors. A terminal connection room housed electronic equipment which was integral to the communications system connecting the mobile launcher with the firing room. Other compartments accommodated environmental control systems, high-pressure gas storage systems, and the emergency egress room for the astronauts and spacecraft close-out crew. An independent water system was installed to cool the flame deflector following rocket ignition.

Around the pad perimeter were pressure storage tanks for RP-1, the kerosene fuel for the Saturn V first stage engines; liquid oxygen, at minus 297 degrees Fahrenheit (minus 183 degrees Celsius), the oxidizer for all three vehicle stages; and liquid hydrogen, at minus 423 degrees Fahrenheit (minus 253 degrees Celsius), which fueled the second and third stages. Holding ponds within the pad area retained spilled fuel and waste water. There was a burn pond for disposal of hydrogen gas boil-off. Stainless steel, vacuum-jacketed pipes carried liquid oxygen and hydrogen from storage tanks to the pad, then to the mobile launcher and ultimately to tanks inside the vehicle stages.

Fueling an Apollo-Saturn V space vehicle required several days of carefully coordinated operations. The spacecraft was first loaded with hypergolic propellants; that is, propellants that ignite upon contact with each other. Nitrogen tetroxide, the oxidizer, was loaded into the Apollo service module tanks, the lunar module ascent and descent tanks, and the reaction control system. Aerozine-50 fuel was then loaded into the service module and lunar module tanks. Monomethyl hydrazine and nitrogen tetroxide were loaded into the auxiliary propulsion system of the Saturn V third stage at the same time the spacecraft was fueled. This system of small thrusters operated during coast periods to provide enough velocity to keep the propellants settled in the bottom of their tanks.

When this loading was completed, the launch crews started piping propellants aboard the Saturn V. This operation was remotely controlled from the firing room. The computer measured the amount of propellant within the tanks by means of probes, while the computer within the mobile launcher base controlled flow rates by modulating loading valves within each stage interface.

The RP-1 fuel (kerosene) was taken aboard the Saturn first. Then, as the terminal count began on the third day, cryogenic (kept at extremely low temperatures) propellants (liquid oxygen and hydrogen) were pumped into the vehicle.

The new launch complex and the mobile concept showed up well during a stiff testing period in 1966. For this purpose, the Marshall Space Flight Center fabricated a mockup vehicle, designated Apollo-Saturn-50OF (AS-500F), to check out launch facilities and train the rocket handling crews. It was precisely the shape and weight of the Saturn V and contained all the tankage, lines, electrical systems, and other components required to verify the launch facilities and equipment-except it had no engines.

On May 25, 1966, government and contractor employees gathered outside the VAB with astronauts to await the appearance of the gigantic AS-50OF assembly. Dr. Robert C. Seamans, then deputy NASA administrator, spoke briefly and remarked crisply, "We are now going to see if the idea works." At his signal the crawler began to emerge from the bay. High overhead loomed the launcher tower; beside it was the gleaming white rocket-the largest ever seen in the United States-visible to the public for the first time just five years after President Kennedy announced the Apollo program.

The transfer to the pad went off smoothly. Weeks of arduous testing followed. NASA was pleased with the results -- the facilities were ready on time.

From 1967 through 1973, there were 13 Saturn V launches from Complex 39. The first two were unmanned rocket and space flight development flights, and the next 10 carried three-man Apollo crews into space. The last Saturn V rocket boosted the unmanned Skylab space station into Earth orbit.

Complex 39 also served as the site for three manned Skylab launches by Saturn IBs in 1973, and for the manned Apollo-Soyuz Test Project flight in 1975 -- also boosted into Earth orbit by a Saturn IB.

During Apollo, 12 men explored the Moon. Skylab saw nine men spend extended periods of time living and working in an orbiting space station. During Apollo-Soyuz, American and Soviet crew members exchanged visits between their docked spacecraft in history's first international space mission.

Though Apollo-Saturn is history, Complex 39 -- its facilities modified and expanded to support Space Shuttle operations -- continues as the nation's primary launch base for manned space flight testament to the past and a steppingstone to a new era of exploration and utilization of the solar system for the benefit of all humanity.


Chapter 6 | Table of Contents