Space Shuttle
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Source of Acquisition NASA Washington, D. C.
National Aeronautics and Space Administration
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Space Shut
Space Shuttle
The Space Shuttle, heart of NASA's new Space Transportation System, markedly expands man's ability to do things in space at lower cost, more often, and more effectively than ever before.
The Shutt
Man, in less than one average lifetime, progressed from his first powered flight of 37 meters (120 feet) to a landing on the Moon. Orville and Wilbur Wright achieved sustained flight with a powered aircraft for 12 seconds on December 17, 1903. A telegram to their father was the initial notification to the world of this event. Just 66 years later Neil Armstrong stepped onto the surface of the Moon - - after a journey of more than 370,140 kilometers (230,000 miles) in less than four days - - while about 500 million people around the world watched the event on television or listened to it on radio. Then, on April 12, 1981, a new era in manned space flight began a America's first reusable Space s Shuttle embarked on i t s maiden voyage. Manned by Astronauts John Young, as commander, and Robert Crippen, a pilot, the s Shuttle was launched from Kennedy Space Center's Launch Complex 39-A at 7 a.m. EST. Astronauts Young and Crippen circled the Earth 36 times performing engineering tests to validate all of Columbia's systems. Fifty-four and one-half hours after lifting off, and over 933,000 miles later, Columbia and i t s crew made a spectacular landing on a runway a t Dryden Flight Research Center in California. This landing culminated a 2%-day mission described by Commander Young as "a phenomenal mission in a fantastic flying machine." The Space Shuttle Era had begun. No longer will astronauts "throw away" most of the transportation system that carries them on their missions. The Apollo-Saturn V stood 111 m. (363 ft.) t a l l on the launch pad. Only the Apollo Command Module - - 3 m. (10 ft.) high - returned to Earth, and even it was never reused. The Space Shuttle heralds an era in which space crews will use the same craft again and again. Like the conventional Earthbound carriers of today, (trucks, ships and planes) which move
The crew of the first Shuttle Left: Robert Crippen Right: John Young
freight and passengers routinely between cities and nations, Shuttle will offei- these same workhorse capabilities t o space - lifting satellites, payloads and . men and women t o do work not possible on Earth. With Shuttle, spaceflight will no longer be restricted t o relatively young men in peak physical condition who have thick log books of pilot time in jet aircraft. Now men and women in average physical condition can anticipate being selected as crew members.
Saturn V Launch Vehicle
Space Shutt
The Space Shuttle is composed of the Orbiter, an External Tank that contains all the propellant used by the Orbiter's three main engines, and two Solid Rocket Boosters. The Orbiter and boosters are reusable; an External Tank is expended on each launch. A Space Shuttle mission begins with installation of the mission payload into the Orbiter cargo bay. The Orbiter is then mated to an assembled set of boosters and tank, and rolled out to the launch pad. A t liftoff the Solid Rocket Boosters and the Orbiter main engines fire together. The two Solid Rocket Boosters are jettisoned after burnout - - about 2 minutes and 12 seconds into the flight and 44 km. (27.5 mi.) high - - and recovered by means of a parachute system. (The
Mission
boosters can then be refurbished, refilled with propellants and made ready for another Shuttle flight.) The Orbiter main engines continue to burn until the vehicle is just short of orbital velocity, a t which time the engines are shut down and the External Tank jettisoned. During i t s plunge through the atmosphere, the tank breaks up and falls into a predetermined ocean area - - the l ndian Ocean for launches from Kennedy Space Center in Florida and the Pacific Ocean for launches from Vandenberg Air Force Base in California. The Shuttle's small orbital maneuvering system engines are then used to attain the desired orbit and to make any subsequent maneuvers that may be needed during the mission. The crew begins their payload opera-
tions on orbit by performing a multitude of assigned tasks, depending upon the purpose of the mission. On some missions they miaht be settinu out satellites in " orbit, or retrieving satellites for return t o Earth. Or they might be servicing orbiting satellites, conducting experiments in space that cannot be duplicated on Earth, or studying the Earth and deep space from their unique tvantaue .~ o i nhiuh above the atmosphere. After orbital operations are completed, normally about seven days, deorbiting maneuvers are initiated. The Orbiter begins t o reenter the Earth's atmosphere at a nose-high angle of attack. During reentry, portions of the Orbiter exterior reach temperatures up t o 1,260 degrees Celsius (2,300 degrees Fahrenheit). The
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Orbiter levels into horizontal flight a t low altitude for an unpowered aircraft-type approach and landing a t a speed of about 335 km. (208 mi.) ~ e hour. r The primary shuttle landing facilities are at Kennedy and are planned at Vandenberg, with several alternate landing sites available for contingencies, including Edwards AFB, Calif., used for Orbital Flight Test Series landings. After landing, the Orbiter is to
Orbiter Enterprise arrives at the Marshall Center for ground vibration testing
Orbiter
The Orbiter is the plane-like element that carries the crew and the payloads for the Space Shuttle. About the size of a commercial DC-9 jet airliner, the Orbiter can deliver to orbit single or multiunit payloads up to 29,484 kilograms (65,000 pounds) in i t s huge 4.5 by 18 m. (15 by 60 ft.) cargo bay. I t can bring back payloads weighing up to 14,515 kg. (32,000 Ibs). The Orbiter's main structural elements are constructed primarily of aluminum. They are the forward fuselage, which contains the crew module; the mid fuselage, which includes the payload bay doors; the aft fuselage, including the engine thrust structure; the wing; and the vertical tail. The Orbiter's exterior is covered with thermal protective materials to protect the spacecraft from solar radiation and the extreme heat of atmospheric reentry. Two types of reusable surface insulation, coated silica tiles and coated flexible sheets, cover the top and sides of the Orbiter. The tiles protect the Orbiter surfaces up to 649 degrees C (1,200 degrees F), and the flexible insulation protects the Orbiter up to 371 degrees C (700 degrees F). The coating on both types of insulation gives the Orbiter a nearly white color and has optical properties that reflect the solar radiation. On the bottom of the Orbiter and on the leading edge of the tail, a high temperature reusable surface insulation, made of coated silica tiles, is used to protect the aluminum structure up to 1,260 degrees C (2,300 degrees F). The high temperature coating gives a glossy black appearance. A reinforced carbon-carbon material is used for the nose cap and the wing leading edges where the temperatures will exceed 1,260 degrees C (2,300 degrees F) during reentry. An important feature of the Orbiter is the crew and passenger accommodations. The Orbiter carries a crew of two pilots, one or more mission specialist astronauts and a many a four addis s tional payload and technical personnel occupying a two-level cabin within the crew module a t the forward end of the vehicle. The maximum crew is seven. The cabin, a combination living, working, and storage area, is pressurized with a nitrogenloxygen mixture to an atmospheric pressure of 10.1 Newtons per square centimeter (14.7 pounds per square inch) to simulate sea level conditions. (Prior U.S. manned space flight used an atmosphere at a pressure of 3.45 Nlsq. cm. (5.00 p.s.i.).
RDE1 UDR
SPEED BRAKE FORWARD REACTION CONTROL SYSTEM MODULE
AFT REACTION CONTROL SYSTEM
MAIN ENGBNES
BODY FLAP
ELEVONS
NOSE LANDING GEAR --1 SIDE HATCH
MAIN LANDING GEAR
The upper section, or the flight deck, contains the controls and displays used to pilot, monitor and control orbital maneuvering, atmospheric reentry and landing phases of the mission and to control the mission payloads. The commander and pilot are seated on this deck in the usual pilot/ copilot arrangement with duplicate controls that permit the Orbiter to be piloted from either seat and returned to Earth by one crew member in an emergency. Two others may be seated behind them on this deck. Seating for three passengers or scientists, and the habitability provisions are on the lower level or deck. The habitability provisions include a galley for food preparation (an oven and hot and cold water dispensers for the preparation of rehydratable freeze-dried foods), an eating area, personal hygiene facilities for either male or female crew members/passengers, and sleeping accommodations. For a rescue mission, the lower deck can be configured to provide still three more seats by replacing the sleeping provisions with seating. Also to support a rescue mission, all Shuttle flights will carry extravehicular activity (EVA) provisions for two EVA-trained crewmen. EVAs are planned on missions where access to the cargo bay and
the pay loads is necessary. The astronauts or payload specialists will exit the Orbiter through an airlock and hatch in the lower deck. It is also through this hatch that the scientists for the Spacelab missions will enter the pressurized Spacelab module carried in the Shuttle payload bay. Beneath the lower deck is environmental control equipment which is readily accessible through removable floor panels. The environmental control system supplies the flight crew and passengers with a comfortable and safe environment, maintaining the proper atmospheric pressure, humidity, carbon dioxide level and temperatures, and removing odors from the cabin area. Electrical power for the Space Shuttle and i t s payloads is generated by three fuel cells that use cryogenically-stored hydrogen and oxygen. The fuel cells are in the forward end of the Orbiter midfuselage. During peak and average power conditions, all three fuel cells are used; during minimum power conditions, only two fuel cells are used. The quantities of fuel (hydrogen and oxygen) normally carried by the Orbiter will be enough to generate about 1,530 kilowatt hours of energy. The amount includes 50 k.w.h. of energy required by a typical payload for a seven-day mission. I f
additional power is needed, separate fuel kits may be carried aboard, each kit supplying enough fuel for an additional 840 k.w.h. of energy. A byproduct of the chemical conversion of hydrogen and oxygen to obtain electrical energy is the production of water. All the water for human consumption aboard the Shuttle is supplied from the byproducts of the fuel cells. The broad spectrum of Shuttle missions requires the Orbiter to accommodate many different payloads. Numerous points along the sides and bottom of the cargo bay provide the places for payload attachment. Nearly all of the Orbiter systems are also involved to some degree in accommodating the variety of satellites and payloads that will be carried. Also available for use on selected missions are devices to manipulate payloads in and out of the Orbiter bay, kits to supply additional power needed by a particular payload, and kits to provide additional crew-related equipment and consumables. This flexibility gives the Orbiter the capability to carry virtually all of the U.S. planned payloads of the 1980s. The Orbiter's communication antennas, about 20 of them, are flush mounted on the forward fuselage. Throughout the mis-
sion the Orbiter will provide direct voice, command, telemetry, and television communications with the ground crew, crewmen on EVA, and with detached payloads through its communications system and a network of ground stations and communications satellites. Three main propulsion rocket engines used during launch are in the aft fuselage. Two orbital maneuvering rockets in external pods on the aft fuselage provide thrust for orbit insertion, orbit changes, rendezvous, and return to Earth. Reaction control thrusters in the two orbital maneuvering system pods and in a module in the nose section of the forward fuselage provide attitude control in space and precision velocity changes for the final phases of rendezvous and docking, or orbit modification. The reaction control thrusters, in conjunction with the Orbiter's aerodynamic control surfaces, also provide attitude control of the Orbiter during reentry. The reaction control system controls the Orbiter a t high altitude and velocity, and the aerodynamic control surfaces provide control of the Orbiter a t speeds less than Mach 2. The Orbiter is equipped with an automatic landing system. It will land a t speeds of about 335
kph (208 mph), faster than most aircraft. The development of the Orbiter is the responsibility of the Johnson Space Center. Rockwell International Space Division is performing the design, development, and test of the Orbiter and its integration with other elements of the Shuttle. Subcontractors to Rockwell are manufacturingsome of the major Orbiter subassemblies with final assembly being performed a t Rockwell's Palmdale, Calif. facilities. Each completed Orbiter is transported, in its operational configuration, from its final assembly site to either the Kennedy Space Center or Vandenberg Air Force Base launch sites, atop a modified Boeing 747 airplane. This same mode of transportation can be used to transfer Orbiters between launch sites and to retrieve an Orbiter that has landed a t an auxiliary landing field.
Main Propulsion System testing at NSTL
Space Shutt e Main Engine
The Space Shuttle Main Engine, which powers the Space Shuttle, along with two Solid Rocket Boosters, is the most advanced liquid-fueled rocket engine ever built. It features variable thrust permitting the engine thrust to be tailored to mission needs, and can operate effectively a t both high and low altitudes. It has the highest thrust for i t s weight of any engine yet developed and can operate up to 7.5 hours of accumulated firing time before major maintenance or overhaul. The Main Engine is reusable for up to 55 separate Shuttle missions. Three main engines are mounted on the Orbiter aft fuselage in a triangular pattern. The engines are so designed and mounted that they can be gimballed or pointed directionally during flight. Thus, in conjunction with the two Solid Rocket Boosters, they are used to steer the Shuttle as well as boost it into orbit. Propellants for the engines, liquid hydrogen and liquid oxygen, are carried in the large External Tank, the largest element of the Space Shuttle. Propellants can be supplied to the engines a t a rate of about 17 1,396 liters (45,283 gallons) per minute of hydrogen and about 63,588 liters (16,800 gal.) per minute of oxygen. Many unique and innovative features have been designed into the engine to satisfy the performance, life, reliability, and maintainability requirements of the Shuttle. One of these features includes the use of a staged combustion power cycle coupled with high combustion chamber pressures. In the staged combustion cycle, liquid hydrogen is partially burned at high pressure and relatively low temperature in preburners and then completely combusted at high temperature and pressure in a main combustion chamber before expanding through the high-arearatio nozzle. The rapid mixing of the propellants under these conditions is so complete that a combustion efficiency of about 99 percent is attained. The engine also uses i t s super-cold hydrogen fuel to cool all combustion devices in direct contact with high-temperature combustion products, such as the belllike engine nozzles, thereby contributing to the long engine life. During engine operation or testing, engineers frequently talk in terms of three primary levels of thrust or power - - minimum, rated and full power. Engine thrust, however, can be varied throughout the range from minimum to full power level depending upon mission needs.
Single engine testing
Most Shuttle flights will be launched a t rated power level, or 100 percent of rated thrust, with each engine developing 2,090,560 N. (470,000 Ibs,) of thrust a t altitude or 1,668,000 N. (375,000 Ibs.) a t sea level. On Shuttle flights where heavy payloads dictate an extra measure of power, up to 109 percent of rated thrust can be commanded. This level is called "full power." During the latter part of ascent, engine thrust is reduced to ensure that an acceleration force of no more than three times that of Earth's gravity is reached. This acceleration level, permitted by the throtrleable Shuttle engines, is about one-third the acceleration experienced on previous manned space flight and is well under the physical stress limits of non-astronaut scientists who will fly aboard the Shuttle. The lowest thrust throttle setting, the minumum power level, equals 65 percent of rated power. Among the key components of the engine are i t s four turbopumps (two iow pressure and two high pressure), two preburners, the main injector, the main combustion chamber, the nozzle, and the hot-gas manifold. The low pressure fuel turbopump and the low pressure oxidizer turbopump, set 180 degrees apart on the engine, are joined to the Shuttle propellant lines com-
ing from the External Tank and are secured in a fixed position by Shuttle Orbiter structural members. The discharge (output) of each low pressure pump is connected to the inlet of the corresponding high pressure pump by lines (ducts) that have flexible joints to allow the deflection required during engine movement for steering. The high pressure pumps are also 180 degrees apart and are mounted on the engine between the low pressure pumps. The preburners comprise the first stage in the engine's stagedcombustion cycle. Here, all the
liquid hydrogen and part of the liquid oxygen is burned at a low mixture ratio to produce hydrogen-rich steam that drives the two high pressure turbopumps. The main injector mixes and distributes the propellants into the main combustion chamber where the high pressure combustion takes place. The combustion gases are then exhausted through the 77.5: 1 area ratio nozzle. The structural backbone of the engine is the hot-gas manifold which supports the two preburners, the high pressure
r GIMBAL BEARING
LOW-PRESSURE FUEL DUCT --r
LOW.PRESSURE FUEL TURBOPU HIGH-PRESSURE. FUEL TURBOPUMP
pumps, the main injector, the pneumatic control assembly, and the main combustion chamber with the nozzle. Attached to the dome-injector, the gimbal bearing functions a s the thrust point between the engine and the Orbiter and permits the engine to be swivelled for Shuttle steering. The Shuttle main engine is the first rocket engine to use a builtin electronic digital controller. The controller accepts commands from the Orbiter for engine start, shutdown, and change in throttle setting and also monitors engine operation. In the event of a failure the controller will take action automatically to correct the problem or shut down the engine safely. The development responsibility for the engines is assigned to the Marshall Space Flight Center at Huntsville, Ala., with the Rocketdyne Division of Rockwell International in Canoga Park, Calif., performing the design, production and test functions. The electronic controller is developed by Honeywell, Inc., of Minneapolis, Minn., a a subs contractor to Rocketdyne. Testing of the engine and components is conducted a t several locations: component testing a t the contractors' facilities; combustion chamber life cycle and augmented spark igniter testing
and control system simulation a t Marshall Center facilities; and engine test firings for development and flight acceptance a t the National Space Technology Laboratories INSTL) near Bay St. Louis, Miss., and at Rocketdyne's Santa Susana facility in California. Each engine, prior to flight, is test fired on a NASA static test stand a t NSTL.
Recovery of boosters at
Solid Rocket Booster
Two Solid Rocket Boosters are used for each Space Shuttle flight to help provide the initial ascent thrust to lift the Shuttle with its payload from the launch pad to an altitude of about 44 km. (27.5 mi.). Prior to launch, the entire Shuttle weight is supported by the two boosters. The Solid Rocket Booster is made up of six subsystems: the solid rocket motor, structures, thrust vector control, separation, recovery and electrical and instrumentation subsystems. The overall length of the Solid Rocket Booster is 45.5 m. (149.1 ft.), and the diameter i s 3.7 m. (12.2 ft.). The heart of each booster is the motor, the largest solid rocket motor ever flown and the first designed for reuse. It is made up of 11 segments joined together to make four loading segments which are filled with propellant at the manufacturer's site. The segmented design permits ease of fabrication, handling and transportation. The segments are shipped from the manufacturer's plant to the launch sites by rail in specially built canisters carried on flat rail cars. There they are assembled to make up a complete motor. Propellant loading of the motor segments is completed in pairs from batches of propellant ingredients to minimize any thrust imbalances between boosters used for a single Shuttle flight. Propellant loading is also done in such a manner using different internal propellant shapes, called cores, so as to cause a regressive thrust approximately 55 seconds into the Shuttle flight to prevent overstressing the Shuttle vehicle during the critical phase of flight called the period of maximum dynamic pressure. This is referred to as "Max 0." Each motor, when assembled, contains about 503,600 kg. (1.1 million Ibs.) of propellant and, a t launch, will develop a thrust of 12.9 million N. (2.9 million Ibs). The exhaust nozzle in the aft segment of each motor helps steer the Shuttle during flight. It can be moved up to 6.65 degrees by the booster's hyd~aulically operated thrust vector control subsystem which is controlled by the Orbiter's guidance and control computer. Throughout flight, measurements are taken to verify proper booster performance, and the signals are routed to the Orbiter for data recording and transmission to the ground. Electrical power for Solid Rocket Booster subsystems is supplied from the Orbiter fuel cells through interconnect cabling from the External Tank. At burnout, the two Solid Rocket Boosters are separated from the External Tank by pyrotechnic (explosive) devices and moved away from the Shuttle vehicle by eight separation rocket motors, four housed in the forward nose frustum and four on the aft skirt. Each of the eight separation motors develops a thrust of 97,856 N. (22,000 Ibs.) for a duration of a little more than one-half second, just enough to move the boosters away from the still-accelerating Orbiter and External Tank. Also a part of the system is a device for separating electrical interconnection with the External Tank. The Solid Rocket Booster recovery subsystem provides the method to control the boosters' final descent velocity and attitude after separation. The recovery subsystem, located in the forward section of each booster and within the nose cap, consists of parachutes and location aids to help in the search and retrieval operations for each expended booster and its parachutes after they reach the ocean. Following separation and entry into the lower atmosphere a t about 4,700 m. (15,400 ft.), each booster is,slowed by a pilot and a drogue parachute and finally by three main parachutes, each 31.7 m. (115 ft.) in diameter. They impact the water, a f t end first, about 257.5 km. (160 mi.)
NOZZLE EXTENSION
7
FRUSTUM
FORWARD MOTOR SEGMENT
SYSTEMS TUNNEL
TWO CASE STIFFENER RINGS
AFT SKIRT
Boosters are assembled in a vertical position
downrange a t a speed of about 95.5 kmlhr (60 mph). By entering the water this way, the air in the hollow boosters is trapped and compressed, causing the boosters to float with the forward end sticking up out of the water. At booster impact, the main parachutes are disconnected and direction-finding beacons and lights are actuated t o guide recovery craft to the booster and the parachutes. The parachutes are picked up by a recovery craft and the boosters towed t~ shoi-e, where they are disassembled for refurbishment. The motor segments are shipped to the manufacturer by rail for refurbishment and reloading for another Shuttle flight. The other systems are refurbished a t either the launch site or a t their respective manufacturer's location. The thrust vector control subsystem, structural subsystem, and the electrical subsystems are planned for 20 flights and the recovery subsystem for 10 flights. The separation system is not planned for reuse. The Marshall Space Flight Center performed the detailed design and integration work on the Solid Rocksubsystems "in-house." et ~ooster The motor was developed by the Wasatch Division of the Thiokol Chemical Corp. of Brigham City, Utah, which provides new and refurbished motors for flight.
The structural elements of the booster are manufactured to Marshall design by the McDonnell Douglas Astronautics Co. of Huntington Beach, Calif. United Space Boosters, Inc., Huntsville, Ala., is responsible for preassembly and checkout of the forward and aft skirt booster assemblies as well as final assembly of the complete boosters. A t the launch site, the two boosters are assembled vertically on the launch platform. Following assembly sf the boosters, the External Tank is attached to the boosters and finally the Orbiter and payload to the External Tank, making the Shuttle ready for checkout and flight.
Solid rocket propellant being mixed
Inside of a liquid hydrogen tank during assembly a t Michoud
Externa
The External Tank has two major roles in the Space Shuttle program. First, to contain and deliver quality propellants, liquid hydrogen and liquid oxygen, to the engines. Second, to serve as the structural backbone of the Space Shuttle during launch operations. It is the only major element of the Shuttle not designed to be reused. The External Tank is composed of two tanks, a large hydrogen tank and a'smaller oxygen tank, joined together by a collar-like intertank to form one large propellant storage container 46.89 m. (153.84 ft.) long and 8.4 m. (27.58 ft.) in diameter. The oxygen tank is the forward portion of the External Tank and when loaded, contains 632,772 (1,395,000 Ibs.) of liquid oxygen. (As a comparison, the oxygen tank has 552 cubic meters or 19,563 cubic feet - - more volume than that of a 186 sq.m. or 2,000 sq. ft. house.) The forward end of the oxygen tank curves to a point to reduce aerodynamic drag and i t s tip serves as a lightning rod for the Shuttle vehicle once the Shuttle has cleared the launch pad. Prior to launch, lightning protection is provided by the launch tower. The liquid hydrogen tank, aft of the oxygen tank, is about two ' and one-half times larger than the oxygen tank. In this tank is stored 106,142 kg. (234,000 Ibs.) of cold liquid hydrogen (about minus 251 degrees C or minus 420 degrees F). The intertank joins the two tanks and provides a protective compartment to house some of the instrumentation components in the space between the two propellant tanks. For launch, the External Tank supports the Orbiter and Solid Rockets Boosters a t attach points on the tank. Since thrust is generated by the Orbiter main engines and the Solid Rocket Boosters, the External Tank must absorb the thrust loads for the Shuttle during launch. The intertank takes the major thrust loads from the Solid Rocket Booster, and the Orbiter main engine thrust loads are transferred through other attach fittings on the tank. Most of the outer surfaces of the tank are protected thermally. Spray-on foam insulation is applied over the forward portion of the oxygen tank, the intertank, and the sides of the hydrogen tank. The foam insulation is needed to reduce ice or frost formation on the tank during launch preparation, thus protecting the Orbiter insulation from freefalling ice during flight. It also serves to minimize heat leaks into the tank which would cause excessive boiling of the liquid
INTEGRAL STRINGERS
FORWARD ATTACH
BAFFLES
PLATE
propellants, and to prevent liquification and solidification of the air next to the tank. An ablating material that chars away, taking heat with it, is applied under the foam to the front and back ends of the External Tank and to other areas where aerodynamic heating is most severe during flight. This protection is also needed in areas where exhausts of launch engines provide high radiant energy to the tank and where separation motors' exhaust plumes may strike the tank. The External Tank, having no electrical power sources of i t s own, obtains all needed electrical energy from the Orbiter fuel cells. It does, however, provide the cabling needed to carry power and signals to the External Tank electronics and instrumentation components and to the two Solid Rocket Boosters. Fluid controls and valves, except the vent valves, for operation of the engines are located in the Orbiter. This is done to minimize throw-away costs since the External Tank is not reused. During flight the two tanks are pressurized by gases supplied from the three engines. Pressurization is needed for structural support of the tank and also for operating-pressure requirements of the engine pumps. Near the end of the launch
phase of a Shuttle mission when the Orbiter is just short of orbital velocity the main engines are cut off. About 10 seconds later, the External Tank is severed from its attachment to the Orbiter, playing a totally passive role in the separation sequence. Just prior to separation the External Tank tumbling system is activated opening a valve and venting the oxygen tank through the nose cap. This causes the External Tank to tumble a t a rate that will assure the tank will break up as predicted upon reentry and fall within the designated ocean impact area. The External Tank i s manufactured, assembled and given final acceptance testing a t the Michoud Assembly Facility (MAF) in New Orleans, a Marshall Space Flight Center plant once used to build the first stages of the Saturn I B and Saturn V launch vehicles for the Apollo and Skylab Programs. The tanks are built a t Michoud by the Denver Division of Martin Marietta Aerospace. when production reaches maximum, the tanks will be produced at a rate of about 55 tanks per year. The barge transportation system that was developed to deliver NASA's Saturn stages to Kennedy is used for the delivery of the External Tank to the launch
sites. For shipment to Vandenberg a barge capable of hauling more than one External Tank will be used. During transportation, the External Tank rests on a wheeled transporter, modified from the Saturn Program, and remains on the transporter until it arrives a t the Vehicle Assembly Building at the Kennedy Center or a t the launch pad a t Vandenberg. A barge takes about five days to move an External Tank from Michoud to the Kennedy dock. Shipment to California by barge is by way of the Panama Canal and will take about 25 days. After arrival a t the launch site, the tanks are stored until needed for flight - vertically in the VAB a t Kennedy and horizontally on the transporter at Vandenberg.
The Space Shuttle has the capability to conduct a wide variety of space missions in response to national and worldwide needs. The primary mission for the Space Shuttle is the low-cost delivery of payloads to and from Earth orbit. The Shuttle system can place payloads of up to 29,484 kg. (65,000 Ibs.) into low Earth orbit and return payloads up to 14,515 kg. (32,000 Ibs). Payloads with propulsion stages can place satellites into high Earth orbit or into lunar or planetary trajectories. Already planned for Shuttle are payloads that will help to further improve weather forecasting and communications and Earth-observation satellites that will permit a continuous inventory of the world's natural resources and permit them to be applied more effectively to meeting human needs. Other Shuttle payloads will continue to obtain information on the chemistry and physics of the Sun, stars, planets, and the space through which Earth is traveling. Still others will extend into space man's earthbound research in such areas as medicine, biology, chemistry, physics, and material manufacturing processes. Foremost among the planning is Spacelab, a fully-equipped space laboratory being developed
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by I European nations under I the guidance of the European Space Agency and supported by NASA with the Marshall Space Flight Center performing as the lead center. Spacelab, carried into space in the Orbiter cargo bay, will be adaptable to many types of space operations, accommodating up t~ four nonastronaut scientists t o conduct a myriad of experiments in a true space environment - - Earth observations, space technology, biological studies and others. In addition to i t s Spacelab development role, the Marshall Center will manage the first three missions, now set to begin in 1983. Another significant payload for the mid-1980s i s the Space Telescope, being developed by the Marshall Center and associates as an optical telescope that will be placed in orbit enabling scientists to see deep into space - - seven times farther than ever before. The Shuttle will place the unmanned telescope in orbit and later serve as a base from which astronauts may make repairs and possibly replace instrument packages for new experiments. Major payload activity is also forecast for geosynchronous orbits, deep-space missions, elliptical orbits and higher circular orbits. Payloads with such destinations will require a pro-
pulsion stage in addition to the Shuttle. The Space Shuttle will deliver the payload, with a propulsion stage attached, t o low Earth orbit and will stand by until the stage boosts the payload to the desired orbit. Initially, Inertial Upper Stages are being developed for such non-planetary missions. An advanced reusable orbiter transfer vehicle is also being studied by Marshall. Yet another payload of major significance is the Marshall Center's proposed Space Platform, an experiment-supporting system that would be carried into orbit by the Shuttle in the late 1980s. The platform is designed to fill the growing needs of the scientific and industrial communities who require longer orbiting times, greater power and other services for their research and observations in space. One of the pri-
Spacelab 2 Configuration
Far left: Space Telescope Center left: Spacelab Left: Building Space Structures
mary advantages of the platform i s that it can provide power for ' long periods of time, either to experiments on board the Shuttle or to those left attached to the platform after the Shuttle returns to Earth. The initial platform would provide 12 kw. of power and would have growth capability to a t least twice that amount, but future designs may provide as much as 100 kw. or more. By the early 1990s the platform may even evolve to a manned version, in which rotating crews would permanently live and work in space. The Space Shuttle will not be limited to uses that can be forecast today. The reduction in the cost of Earth-orbital operations and the new operational techniques will enable new and unforeseen solutions of problems. Some of these could be the key to understanding the physi-
Spacelab 1 Payload Specialists in the Marshall Center Mockup
cal processes that will allow man to develop unlimited pollutionfree power, and t o attain knowledge that will lead to new products and industries.
Spacelab 1 Configuration
Spacelab Habitable Module
Inertial Upper Stage
Launch Operations
Space Shuttle flights will be launched from two locations: Kennedy Space Center in Florida and Vandenberg Air Force Base in California. These sites were selected based upon both NASA and Department of Defense (DOD) needs for projected payloads and requirements for no land mass overflight dliring the launch of the Shuttle. Kennedy is used t o launch both NASA and DOD payloads into orbits of 39 to 57 degrees inclination with respect to the equator, and Vandenberg will be used for launches with orbital inclinations from 56 to 104 degrees. (A due east launch from Kennedy would yield an orbit of about 28.5 degrees inclination while a due south launch from Vandenberg would yield an orbit of 90 degrees, or a polar orbit.) Range safety criteria restrict the launch directions (azimuths) from each launch site to preclude a released tank or booster from impacting a land area. From Kennedy the northernmost azimuth is limited by the southeast portion of Newfoundland; and the southernmost azimuth is limited by the Bahama Islands. From Vandenberg, the land constraints include portions of Mexico t o the southeast and the Hawaiian Islands to the southwest. The direction of Earth rotation also has a significant bearing on
the payload launch capabilities of the Shuttle. A due east launch from Kennedy, using the Earth's easterly rotation as a launch assist, will permit a payload weighing up t o 29,484 kg. (65,000 Ibs.) to be launched. A polar orbit launch from Vandenberg, where the Earth's rotation neither assists nor hinders the Shuttle's capabilities, will permit a payload of up to 18,144 kg. (40,000 Ibs.) to be carried into orbit. The most westerly launch from Vandenberg will allow a payload up to only 14,5 15 kg. (32,000 Ibs.) to be transported to orbit since the Earth's rotation is counter to the westerly launch azimuth.
Ground Turnaround
The ground turnaround cycle for Shuttle starts on the runway after the Orbiter has landed. Preliminary safing and servicing tasks are completed on the runway before the Orbiter is towed to the safing and deservicing area where DO0 payloads are removed, pressurized containers and fuel cell reactants (oxygen and hydrogen) are vented, and the hazardous fuel modules are removed. At the Kennedy Center, the Orbiter is then transferred to a maintenance and checkout facility where it undergoes inspection, maintenance, limited servicing, and checkout, e.g., inspection of the insulation. New payloads are then installed in the Orbiter in preparation for premate checkout of the Orbiter prior to vehicle assembly. (Cer. tain time-critical payloads or hazardous payloads, and all DOD payloads, will be installed on the launch pad using the Payload Changeout Room a t the pad.) The hypergolic modules (hazardous fuels for reaction control, power units, maneuvering systems, etc.) which have undergone separate inspection, maintenance and checkout a t the hypergolic servicing facility are installed before the Orbiter is transferred to the Vehicle Assembly Building (VAB). Assembly and checkout of the Space Shuttle vehicle begins with mating of the two Solid Rocket Booster motor segments on the mobile launch platform. The External Tank, having previously undergone i t s premate processing in the VAB, is then moved to the assembly area and mated to the two Solid Rocket Boosters. The Orbiter is then towed into the VAB transfer aisle, i t s landing gear is retracted, and it is lifted into positionaand mated with the External Tank to complete the Shuttle assembly. The connections are verified in the Shuttle interface test, and ordnance is added to the Shuttle for separation and range safety functions. Launch pad operations include rollout of the vehicle, connection of the pad interfaces, launch readiness checkout, countdown preparations, loading of cryogenics, flight crew ingress, and the final automatic countdown sequencing. Operations a t Vandenberg will be generally similar, although different facilities will be used. When Shuttle becomes fully operational it will be capable of a 14-day turnaround at Kennedy, from landing to lift-off. The turnaround figure is based upon 160 working hours, amounting to two shifts a day, five days a week, for two weeks. Vandenberg operation will take slightly longer, or about 205 hours.
Orbiter Processing Facility
Checkout on the Pad
The Shutt e Deve opment Team
Management of the Space Shuttle Program is shared by NASA Headquarters, the three NASA centers involved in manned space flight and many aerospace contractors. Overall direction of the Shuttle Program is the responsibility of NASA Headquarters in Washington, D.C. Johnson Space Center is responsible for program management and systems integration and is also the development center for the Orbiter. The Marshall Center is responsible for development of the External Tank, Solid Rocket Booster and the Shuttle main engines, as well as certain systems test and integration functions. The Kennedy Space Center serves as the launch and landing site for missions requiring easterly launches. The Defense Department will operate the Vandenberg AFB launch and landing site. Hundreds of private firms, educational institutions, research organizations and federal agencies were involved in creating the Space Shuttle. Some firms supplied small items such as nuts and bolts; others provided complete systems. The Shuttle prime contractors and some key subcontractors are included in the following list.
ORBITER
PRIME CONTRACTOR
- Rockwell International, Space Division,
SUBCONTRACTS
Bethpage, N. Y.
Downey, Calif.
Wing
- Grumman Aerospace,
Vertical f a i l - Fairchild Republic, Farmingdale, N. Y. M i d Fuselage - General Dynamics, San Diego, Calif. Reusable Surface Insulation - Lockheed Missiles and Space Co., Sunnyvale, Calif. Orbital Maneuvering System - McDonnell Douglas Astronautics Co., St. Louis. Mo. Orbital Maneuvering Engines - Aerojet Liquid Rocket Co., Sacramento, Calif.
EXTERNAL TANK
PRIME CONTRACTOR
- Martin Marietta Aerospace,
SUBCONTRACTS
-
Denver, Colo.
lntertank Dome Caps
-
Avco Corp., Nashville, Tenn.
General Dynamics, San Diego, Calif.
Ogive and Dome Gores - Aircraft Hydroforming, Gardena, Calif. Tank Weld Tools - L T V Aerospace, Dallas, Tex. GorelDome Weld Tools
-
The Boeing Company, Seattle, Wash.
SOLID ROCKET BOOSTER
PRIMARY MANAGEMENT - Marshall Space Flight Center, Huntsville, Ala.
SUBCONTRACTS
Assembly and Checkout - United States Boosters Inc., Huntsville, Ala. Solid Rocket Motor - Thiokol Corp., Brigham City, Utah Structures - McDonnell Douglas Astronautics Co., Huntington Beach, Calif. Decelerator Subsystem - Martin Marietta Aerospace, Denver, Colo. Integrated Electronics Assembly - Bendix Corp., Teterboro, N. J. Booster Separation Motor - United Technology Corp., Sunnyvale, Calif. Parachutes - Pioneer Parachute Co., Manchester, Conn.
SPACE SHUTTLE M A I N ENGINE
PRIME CONTRACTOR
- Rockweli International, Rocketdyne Div.,
SUBCONTRACTS
Canoga Park, Calif.
Controller
- Honeywell Inc.,
Minneapolis, Minn.
Hydraulic Actuator System - Hydraulic Research, Valencia, Calif.
a U. S. GOVERNMENT PRINTING OFFICE : 1982
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Source of Acquisition NASA Washington, D. C.
National Aeronautics and Space Administration
I
Space Shut
Space Shuttle
The Space Shuttle, heart of NASA's new Space Transportation System, markedly expands man's ability to do things in space at lower cost, more often, and more effectively than ever before.
The Shutt
Man, in less than one average lifetime, progressed from his first powered flight of 37 meters (120 feet) to a landing on the Moon. Orville and Wilbur Wright achieved sustained flight with a powered aircraft for 12 seconds on December 17, 1903. A telegram to their father was the initial notification to the world of this event. Just 66 years later Neil Armstrong stepped onto the surface of the Moon - - after a journey of more than 370,140 kilometers (230,000 miles) in less than four days - - while about 500 million people around the world watched the event on television or listened to it on radio. Then, on April 12, 1981, a new era in manned space flight began a America's first reusable Space s Shuttle embarked on i t s maiden voyage. Manned by Astronauts John Young, as commander, and Robert Crippen, a pilot, the s Shuttle was launched from Kennedy Space Center's Launch Complex 39-A at 7 a.m. EST. Astronauts Young and Crippen circled the Earth 36 times performing engineering tests to validate all of Columbia's systems. Fifty-four and one-half hours after lifting off, and over 933,000 miles later, Columbia and i t s crew made a spectacular landing on a runway a t Dryden Flight Research Center in California. This landing culminated a 2%-day mission described by Commander Young as "a phenomenal mission in a fantastic flying machine." The Space Shuttle Era had begun. No longer will astronauts "throw away" most of the transportation system that carries them on their missions. The Apollo-Saturn V stood 111 m. (363 ft.) t a l l on the launch pad. Only the Apollo Command Module - - 3 m. (10 ft.) high - returned to Earth, and even it was never reused. The Space Shuttle heralds an era in which space crews will use the same craft again and again. Like the conventional Earthbound carriers of today, (trucks, ships and planes) which move
The crew of the first Shuttle Left: Robert Crippen Right: John Young
freight and passengers routinely between cities and nations, Shuttle will offei- these same workhorse capabilities t o space - lifting satellites, payloads and . men and women t o do work not possible on Earth. With Shuttle, spaceflight will no longer be restricted t o relatively young men in peak physical condition who have thick log books of pilot time in jet aircraft. Now men and women in average physical condition can anticipate being selected as crew members.
Saturn V Launch Vehicle
Space Shutt
The Space Shuttle is composed of the Orbiter, an External Tank that contains all the propellant used by the Orbiter's three main engines, and two Solid Rocket Boosters. The Orbiter and boosters are reusable; an External Tank is expended on each launch. A Space Shuttle mission begins with installation of the mission payload into the Orbiter cargo bay. The Orbiter is then mated to an assembled set of boosters and tank, and rolled out to the launch pad. A t liftoff the Solid Rocket Boosters and the Orbiter main engines fire together. The two Solid Rocket Boosters are jettisoned after burnout - - about 2 minutes and 12 seconds into the flight and 44 km. (27.5 mi.) high - - and recovered by means of a parachute system. (The
Mission
boosters can then be refurbished, refilled with propellants and made ready for another Shuttle flight.) The Orbiter main engines continue to burn until the vehicle is just short of orbital velocity, a t which time the engines are shut down and the External Tank jettisoned. During i t s plunge through the atmosphere, the tank breaks up and falls into a predetermined ocean area - - the l ndian Ocean for launches from Kennedy Space Center in Florida and the Pacific Ocean for launches from Vandenberg Air Force Base in California. The Shuttle's small orbital maneuvering system engines are then used to attain the desired orbit and to make any subsequent maneuvers that may be needed during the mission. The crew begins their payload opera-
tions on orbit by performing a multitude of assigned tasks, depending upon the purpose of the mission. On some missions they miaht be settinu out satellites in " orbit, or retrieving satellites for return t o Earth. Or they might be servicing orbiting satellites, conducting experiments in space that cannot be duplicated on Earth, or studying the Earth and deep space from their unique tvantaue .~ o i nhiuh above the atmosphere. After orbital operations are completed, normally about seven days, deorbiting maneuvers are initiated. The Orbiter begins t o reenter the Earth's atmosphere at a nose-high angle of attack. During reentry, portions of the Orbiter exterior reach temperatures up t o 1,260 degrees Celsius (2,300 degrees Fahrenheit). The
-
Orbiter levels into horizontal flight a t low altitude for an unpowered aircraft-type approach and landing a t a speed of about 335 km. (208 mi.) ~ e hour. r The primary shuttle landing facilities are at Kennedy and are planned at Vandenberg, with several alternate landing sites available for contingencies, including Edwards AFB, Calif., used for Orbital Flight Test Series landings. After landing, the Orbiter is to
Orbiter Enterprise arrives at the Marshall Center for ground vibration testing
Orbiter
The Orbiter is the plane-like element that carries the crew and the payloads for the Space Shuttle. About the size of a commercial DC-9 jet airliner, the Orbiter can deliver to orbit single or multiunit payloads up to 29,484 kilograms (65,000 pounds) in i t s huge 4.5 by 18 m. (15 by 60 ft.) cargo bay. I t can bring back payloads weighing up to 14,515 kg. (32,000 Ibs). The Orbiter's main structural elements are constructed primarily of aluminum. They are the forward fuselage, which contains the crew module; the mid fuselage, which includes the payload bay doors; the aft fuselage, including the engine thrust structure; the wing; and the vertical tail. The Orbiter's exterior is covered with thermal protective materials to protect the spacecraft from solar radiation and the extreme heat of atmospheric reentry. Two types of reusable surface insulation, coated silica tiles and coated flexible sheets, cover the top and sides of the Orbiter. The tiles protect the Orbiter surfaces up to 649 degrees C (1,200 degrees F), and the flexible insulation protects the Orbiter up to 371 degrees C (700 degrees F). The coating on both types of insulation gives the Orbiter a nearly white color and has optical properties that reflect the solar radiation. On the bottom of the Orbiter and on the leading edge of the tail, a high temperature reusable surface insulation, made of coated silica tiles, is used to protect the aluminum structure up to 1,260 degrees C (2,300 degrees F). The high temperature coating gives a glossy black appearance. A reinforced carbon-carbon material is used for the nose cap and the wing leading edges where the temperatures will exceed 1,260 degrees C (2,300 degrees F) during reentry. An important feature of the Orbiter is the crew and passenger accommodations. The Orbiter carries a crew of two pilots, one or more mission specialist astronauts and a many a four addis s tional payload and technical personnel occupying a two-level cabin within the crew module a t the forward end of the vehicle. The maximum crew is seven. The cabin, a combination living, working, and storage area, is pressurized with a nitrogenloxygen mixture to an atmospheric pressure of 10.1 Newtons per square centimeter (14.7 pounds per square inch) to simulate sea level conditions. (Prior U.S. manned space flight used an atmosphere at a pressure of 3.45 Nlsq. cm. (5.00 p.s.i.).
RDE1 UDR
SPEED BRAKE FORWARD REACTION CONTROL SYSTEM MODULE
AFT REACTION CONTROL SYSTEM
MAIN ENGBNES
BODY FLAP
ELEVONS
NOSE LANDING GEAR --1 SIDE HATCH
MAIN LANDING GEAR
The upper section, or the flight deck, contains the controls and displays used to pilot, monitor and control orbital maneuvering, atmospheric reentry and landing phases of the mission and to control the mission payloads. The commander and pilot are seated on this deck in the usual pilot/ copilot arrangement with duplicate controls that permit the Orbiter to be piloted from either seat and returned to Earth by one crew member in an emergency. Two others may be seated behind them on this deck. Seating for three passengers or scientists, and the habitability provisions are on the lower level or deck. The habitability provisions include a galley for food preparation (an oven and hot and cold water dispensers for the preparation of rehydratable freeze-dried foods), an eating area, personal hygiene facilities for either male or female crew members/passengers, and sleeping accommodations. For a rescue mission, the lower deck can be configured to provide still three more seats by replacing the sleeping provisions with seating. Also to support a rescue mission, all Shuttle flights will carry extravehicular activity (EVA) provisions for two EVA-trained crewmen. EVAs are planned on missions where access to the cargo bay and
the pay loads is necessary. The astronauts or payload specialists will exit the Orbiter through an airlock and hatch in the lower deck. It is also through this hatch that the scientists for the Spacelab missions will enter the pressurized Spacelab module carried in the Shuttle payload bay. Beneath the lower deck is environmental control equipment which is readily accessible through removable floor panels. The environmental control system supplies the flight crew and passengers with a comfortable and safe environment, maintaining the proper atmospheric pressure, humidity, carbon dioxide level and temperatures, and removing odors from the cabin area. Electrical power for the Space Shuttle and i t s payloads is generated by three fuel cells that use cryogenically-stored hydrogen and oxygen. The fuel cells are in the forward end of the Orbiter midfuselage. During peak and average power conditions, all three fuel cells are used; during minimum power conditions, only two fuel cells are used. The quantities of fuel (hydrogen and oxygen) normally carried by the Orbiter will be enough to generate about 1,530 kilowatt hours of energy. The amount includes 50 k.w.h. of energy required by a typical payload for a seven-day mission. I f
additional power is needed, separate fuel kits may be carried aboard, each kit supplying enough fuel for an additional 840 k.w.h. of energy. A byproduct of the chemical conversion of hydrogen and oxygen to obtain electrical energy is the production of water. All the water for human consumption aboard the Shuttle is supplied from the byproducts of the fuel cells. The broad spectrum of Shuttle missions requires the Orbiter to accommodate many different payloads. Numerous points along the sides and bottom of the cargo bay provide the places for payload attachment. Nearly all of the Orbiter systems are also involved to some degree in accommodating the variety of satellites and payloads that will be carried. Also available for use on selected missions are devices to manipulate payloads in and out of the Orbiter bay, kits to supply additional power needed by a particular payload, and kits to provide additional crew-related equipment and consumables. This flexibility gives the Orbiter the capability to carry virtually all of the U.S. planned payloads of the 1980s. The Orbiter's communication antennas, about 20 of them, are flush mounted on the forward fuselage. Throughout the mis-
sion the Orbiter will provide direct voice, command, telemetry, and television communications with the ground crew, crewmen on EVA, and with detached payloads through its communications system and a network of ground stations and communications satellites. Three main propulsion rocket engines used during launch are in the aft fuselage. Two orbital maneuvering rockets in external pods on the aft fuselage provide thrust for orbit insertion, orbit changes, rendezvous, and return to Earth. Reaction control thrusters in the two orbital maneuvering system pods and in a module in the nose section of the forward fuselage provide attitude control in space and precision velocity changes for the final phases of rendezvous and docking, or orbit modification. The reaction control thrusters, in conjunction with the Orbiter's aerodynamic control surfaces, also provide attitude control of the Orbiter during reentry. The reaction control system controls the Orbiter a t high altitude and velocity, and the aerodynamic control surfaces provide control of the Orbiter a t speeds less than Mach 2. The Orbiter is equipped with an automatic landing system. It will land a t speeds of about 335
kph (208 mph), faster than most aircraft. The development of the Orbiter is the responsibility of the Johnson Space Center. Rockwell International Space Division is performing the design, development, and test of the Orbiter and its integration with other elements of the Shuttle. Subcontractors to Rockwell are manufacturingsome of the major Orbiter subassemblies with final assembly being performed a t Rockwell's Palmdale, Calif. facilities. Each completed Orbiter is transported, in its operational configuration, from its final assembly site to either the Kennedy Space Center or Vandenberg Air Force Base launch sites, atop a modified Boeing 747 airplane. This same mode of transportation can be used to transfer Orbiters between launch sites and to retrieve an Orbiter that has landed a t an auxiliary landing field.
Main Propulsion System testing at NSTL
Space Shutt e Main Engine
The Space Shuttle Main Engine, which powers the Space Shuttle, along with two Solid Rocket Boosters, is the most advanced liquid-fueled rocket engine ever built. It features variable thrust permitting the engine thrust to be tailored to mission needs, and can operate effectively a t both high and low altitudes. It has the highest thrust for i t s weight of any engine yet developed and can operate up to 7.5 hours of accumulated firing time before major maintenance or overhaul. The Main Engine is reusable for up to 55 separate Shuttle missions. Three main engines are mounted on the Orbiter aft fuselage in a triangular pattern. The engines are so designed and mounted that they can be gimballed or pointed directionally during flight. Thus, in conjunction with the two Solid Rocket Boosters, they are used to steer the Shuttle as well as boost it into orbit. Propellants for the engines, liquid hydrogen and liquid oxygen, are carried in the large External Tank, the largest element of the Space Shuttle. Propellants can be supplied to the engines a t a rate of about 17 1,396 liters (45,283 gallons) per minute of hydrogen and about 63,588 liters (16,800 gal.) per minute of oxygen. Many unique and innovative features have been designed into the engine to satisfy the performance, life, reliability, and maintainability requirements of the Shuttle. One of these features includes the use of a staged combustion power cycle coupled with high combustion chamber pressures. In the staged combustion cycle, liquid hydrogen is partially burned at high pressure and relatively low temperature in preburners and then completely combusted at high temperature and pressure in a main combustion chamber before expanding through the high-arearatio nozzle. The rapid mixing of the propellants under these conditions is so complete that a combustion efficiency of about 99 percent is attained. The engine also uses i t s super-cold hydrogen fuel to cool all combustion devices in direct contact with high-temperature combustion products, such as the belllike engine nozzles, thereby contributing to the long engine life. During engine operation or testing, engineers frequently talk in terms of three primary levels of thrust or power - - minimum, rated and full power. Engine thrust, however, can be varied throughout the range from minimum to full power level depending upon mission needs.
Single engine testing
Most Shuttle flights will be launched a t rated power level, or 100 percent of rated thrust, with each engine developing 2,090,560 N. (470,000 Ibs,) of thrust a t altitude or 1,668,000 N. (375,000 Ibs.) a t sea level. On Shuttle flights where heavy payloads dictate an extra measure of power, up to 109 percent of rated thrust can be commanded. This level is called "full power." During the latter part of ascent, engine thrust is reduced to ensure that an acceleration force of no more than three times that of Earth's gravity is reached. This acceleration level, permitted by the throtrleable Shuttle engines, is about one-third the acceleration experienced on previous manned space flight and is well under the physical stress limits of non-astronaut scientists who will fly aboard the Shuttle. The lowest thrust throttle setting, the minumum power level, equals 65 percent of rated power. Among the key components of the engine are i t s four turbopumps (two iow pressure and two high pressure), two preburners, the main injector, the main combustion chamber, the nozzle, and the hot-gas manifold. The low pressure fuel turbopump and the low pressure oxidizer turbopump, set 180 degrees apart on the engine, are joined to the Shuttle propellant lines com-
ing from the External Tank and are secured in a fixed position by Shuttle Orbiter structural members. The discharge (output) of each low pressure pump is connected to the inlet of the corresponding high pressure pump by lines (ducts) that have flexible joints to allow the deflection required during engine movement for steering. The high pressure pumps are also 180 degrees apart and are mounted on the engine between the low pressure pumps. The preburners comprise the first stage in the engine's stagedcombustion cycle. Here, all the
liquid hydrogen and part of the liquid oxygen is burned at a low mixture ratio to produce hydrogen-rich steam that drives the two high pressure turbopumps. The main injector mixes and distributes the propellants into the main combustion chamber where the high pressure combustion takes place. The combustion gases are then exhausted through the 77.5: 1 area ratio nozzle. The structural backbone of the engine is the hot-gas manifold which supports the two preburners, the high pressure
r GIMBAL BEARING
LOW-PRESSURE FUEL DUCT --r
LOW.PRESSURE FUEL TURBOPU HIGH-PRESSURE. FUEL TURBOPUMP
pumps, the main injector, the pneumatic control assembly, and the main combustion chamber with the nozzle. Attached to the dome-injector, the gimbal bearing functions a s the thrust point between the engine and the Orbiter and permits the engine to be swivelled for Shuttle steering. The Shuttle main engine is the first rocket engine to use a builtin electronic digital controller. The controller accepts commands from the Orbiter for engine start, shutdown, and change in throttle setting and also monitors engine operation. In the event of a failure the controller will take action automatically to correct the problem or shut down the engine safely. The development responsibility for the engines is assigned to the Marshall Space Flight Center at Huntsville, Ala., with the Rocketdyne Division of Rockwell International in Canoga Park, Calif., performing the design, production and test functions. The electronic controller is developed by Honeywell, Inc., of Minneapolis, Minn., a a subs contractor to Rocketdyne. Testing of the engine and components is conducted a t several locations: component testing a t the contractors' facilities; combustion chamber life cycle and augmented spark igniter testing
and control system simulation a t Marshall Center facilities; and engine test firings for development and flight acceptance a t the National Space Technology Laboratories INSTL) near Bay St. Louis, Miss., and at Rocketdyne's Santa Susana facility in California. Each engine, prior to flight, is test fired on a NASA static test stand a t NSTL.
Recovery of boosters at
Solid Rocket Booster
Two Solid Rocket Boosters are used for each Space Shuttle flight to help provide the initial ascent thrust to lift the Shuttle with its payload from the launch pad to an altitude of about 44 km. (27.5 mi.). Prior to launch, the entire Shuttle weight is supported by the two boosters. The Solid Rocket Booster is made up of six subsystems: the solid rocket motor, structures, thrust vector control, separation, recovery and electrical and instrumentation subsystems. The overall length of the Solid Rocket Booster is 45.5 m. (149.1 ft.), and the diameter i s 3.7 m. (12.2 ft.). The heart of each booster is the motor, the largest solid rocket motor ever flown and the first designed for reuse. It is made up of 11 segments joined together to make four loading segments which are filled with propellant at the manufacturer's site. The segmented design permits ease of fabrication, handling and transportation. The segments are shipped from the manufacturer's plant to the launch sites by rail in specially built canisters carried on flat rail cars. There they are assembled to make up a complete motor. Propellant loading of the motor segments is completed in pairs from batches of propellant ingredients to minimize any thrust imbalances between boosters used for a single Shuttle flight. Propellant loading is also done in such a manner using different internal propellant shapes, called cores, so as to cause a regressive thrust approximately 55 seconds into the Shuttle flight to prevent overstressing the Shuttle vehicle during the critical phase of flight called the period of maximum dynamic pressure. This is referred to as "Max 0." Each motor, when assembled, contains about 503,600 kg. (1.1 million Ibs.) of propellant and, a t launch, will develop a thrust of 12.9 million N. (2.9 million Ibs). The exhaust nozzle in the aft segment of each motor helps steer the Shuttle during flight. It can be moved up to 6.65 degrees by the booster's hyd~aulically operated thrust vector control subsystem which is controlled by the Orbiter's guidance and control computer. Throughout flight, measurements are taken to verify proper booster performance, and the signals are routed to the Orbiter for data recording and transmission to the ground. Electrical power for Solid Rocket Booster subsystems is supplied from the Orbiter fuel cells through interconnect cabling from the External Tank. At burnout, the two Solid Rocket Boosters are separated from the External Tank by pyrotechnic (explosive) devices and moved away from the Shuttle vehicle by eight separation rocket motors, four housed in the forward nose frustum and four on the aft skirt. Each of the eight separation motors develops a thrust of 97,856 N. (22,000 Ibs.) for a duration of a little more than one-half second, just enough to move the boosters away from the still-accelerating Orbiter and External Tank. Also a part of the system is a device for separating electrical interconnection with the External Tank. The Solid Rocket Booster recovery subsystem provides the method to control the boosters' final descent velocity and attitude after separation. The recovery subsystem, located in the forward section of each booster and within the nose cap, consists of parachutes and location aids to help in the search and retrieval operations for each expended booster and its parachutes after they reach the ocean. Following separation and entry into the lower atmosphere a t about 4,700 m. (15,400 ft.), each booster is,slowed by a pilot and a drogue parachute and finally by three main parachutes, each 31.7 m. (115 ft.) in diameter. They impact the water, a f t end first, about 257.5 km. (160 mi.)
NOZZLE EXTENSION
7
FRUSTUM
FORWARD MOTOR SEGMENT
SYSTEMS TUNNEL
TWO CASE STIFFENER RINGS
AFT SKIRT
Boosters are assembled in a vertical position
downrange a t a speed of about 95.5 kmlhr (60 mph). By entering the water this way, the air in the hollow boosters is trapped and compressed, causing the boosters to float with the forward end sticking up out of the water. At booster impact, the main parachutes are disconnected and direction-finding beacons and lights are actuated t o guide recovery craft to the booster and the parachutes. The parachutes are picked up by a recovery craft and the boosters towed t~ shoi-e, where they are disassembled for refurbishment. The motor segments are shipped to the manufacturer by rail for refurbishment and reloading for another Shuttle flight. The other systems are refurbished a t either the launch site or a t their respective manufacturer's location. The thrust vector control subsystem, structural subsystem, and the electrical subsystems are planned for 20 flights and the recovery subsystem for 10 flights. The separation system is not planned for reuse. The Marshall Space Flight Center performed the detailed design and integration work on the Solid Rocksubsystems "in-house." et ~ooster The motor was developed by the Wasatch Division of the Thiokol Chemical Corp. of Brigham City, Utah, which provides new and refurbished motors for flight.
The structural elements of the booster are manufactured to Marshall design by the McDonnell Douglas Astronautics Co. of Huntington Beach, Calif. United Space Boosters, Inc., Huntsville, Ala., is responsible for preassembly and checkout of the forward and aft skirt booster assemblies as well as final assembly of the complete boosters. A t the launch site, the two boosters are assembled vertically on the launch platform. Following assembly sf the boosters, the External Tank is attached to the boosters and finally the Orbiter and payload to the External Tank, making the Shuttle ready for checkout and flight.
Solid rocket propellant being mixed
Inside of a liquid hydrogen tank during assembly a t Michoud
Externa
The External Tank has two major roles in the Space Shuttle program. First, to contain and deliver quality propellants, liquid hydrogen and liquid oxygen, to the engines. Second, to serve as the structural backbone of the Space Shuttle during launch operations. It is the only major element of the Shuttle not designed to be reused. The External Tank is composed of two tanks, a large hydrogen tank and a'smaller oxygen tank, joined together by a collar-like intertank to form one large propellant storage container 46.89 m. (153.84 ft.) long and 8.4 m. (27.58 ft.) in diameter. The oxygen tank is the forward portion of the External Tank and when loaded, contains 632,772 (1,395,000 Ibs.) of liquid oxygen. (As a comparison, the oxygen tank has 552 cubic meters or 19,563 cubic feet - - more volume than that of a 186 sq.m. or 2,000 sq. ft. house.) The forward end of the oxygen tank curves to a point to reduce aerodynamic drag and i t s tip serves as a lightning rod for the Shuttle vehicle once the Shuttle has cleared the launch pad. Prior to launch, lightning protection is provided by the launch tower. The liquid hydrogen tank, aft of the oxygen tank, is about two ' and one-half times larger than the oxygen tank. In this tank is stored 106,142 kg. (234,000 Ibs.) of cold liquid hydrogen (about minus 251 degrees C or minus 420 degrees F). The intertank joins the two tanks and provides a protective compartment to house some of the instrumentation components in the space between the two propellant tanks. For launch, the External Tank supports the Orbiter and Solid Rockets Boosters a t attach points on the tank. Since thrust is generated by the Orbiter main engines and the Solid Rocket Boosters, the External Tank must absorb the thrust loads for the Shuttle during launch. The intertank takes the major thrust loads from the Solid Rocket Booster, and the Orbiter main engine thrust loads are transferred through other attach fittings on the tank. Most of the outer surfaces of the tank are protected thermally. Spray-on foam insulation is applied over the forward portion of the oxygen tank, the intertank, and the sides of the hydrogen tank. The foam insulation is needed to reduce ice or frost formation on the tank during launch preparation, thus protecting the Orbiter insulation from freefalling ice during flight. It also serves to minimize heat leaks into the tank which would cause excessive boiling of the liquid
INTEGRAL STRINGERS
FORWARD ATTACH
BAFFLES
PLATE
propellants, and to prevent liquification and solidification of the air next to the tank. An ablating material that chars away, taking heat with it, is applied under the foam to the front and back ends of the External Tank and to other areas where aerodynamic heating is most severe during flight. This protection is also needed in areas where exhausts of launch engines provide high radiant energy to the tank and where separation motors' exhaust plumes may strike the tank. The External Tank, having no electrical power sources of i t s own, obtains all needed electrical energy from the Orbiter fuel cells. It does, however, provide the cabling needed to carry power and signals to the External Tank electronics and instrumentation components and to the two Solid Rocket Boosters. Fluid controls and valves, except the vent valves, for operation of the engines are located in the Orbiter. This is done to minimize throw-away costs since the External Tank is not reused. During flight the two tanks are pressurized by gases supplied from the three engines. Pressurization is needed for structural support of the tank and also for operating-pressure requirements of the engine pumps. Near the end of the launch
phase of a Shuttle mission when the Orbiter is just short of orbital velocity the main engines are cut off. About 10 seconds later, the External Tank is severed from its attachment to the Orbiter, playing a totally passive role in the separation sequence. Just prior to separation the External Tank tumbling system is activated opening a valve and venting the oxygen tank through the nose cap. This causes the External Tank to tumble a t a rate that will assure the tank will break up as predicted upon reentry and fall within the designated ocean impact area. The External Tank i s manufactured, assembled and given final acceptance testing a t the Michoud Assembly Facility (MAF) in New Orleans, a Marshall Space Flight Center plant once used to build the first stages of the Saturn I B and Saturn V launch vehicles for the Apollo and Skylab Programs. The tanks are built a t Michoud by the Denver Division of Martin Marietta Aerospace. when production reaches maximum, the tanks will be produced at a rate of about 55 tanks per year. The barge transportation system that was developed to deliver NASA's Saturn stages to Kennedy is used for the delivery of the External Tank to the launch
sites. For shipment to Vandenberg a barge capable of hauling more than one External Tank will be used. During transportation, the External Tank rests on a wheeled transporter, modified from the Saturn Program, and remains on the transporter until it arrives a t the Vehicle Assembly Building at the Kennedy Center or a t the launch pad a t Vandenberg. A barge takes about five days to move an External Tank from Michoud to the Kennedy dock. Shipment to California by barge is by way of the Panama Canal and will take about 25 days. After arrival a t the launch site, the tanks are stored until needed for flight - vertically in the VAB a t Kennedy and horizontally on the transporter at Vandenberg.
The Space Shuttle has the capability to conduct a wide variety of space missions in response to national and worldwide needs. The primary mission for the Space Shuttle is the low-cost delivery of payloads to and from Earth orbit. The Shuttle system can place payloads of up to 29,484 kg. (65,000 Ibs.) into low Earth orbit and return payloads up to 14,515 kg. (32,000 Ibs). Payloads with propulsion stages can place satellites into high Earth orbit or into lunar or planetary trajectories. Already planned for Shuttle are payloads that will help to further improve weather forecasting and communications and Earth-observation satellites that will permit a continuous inventory of the world's natural resources and permit them to be applied more effectively to meeting human needs. Other Shuttle payloads will continue to obtain information on the chemistry and physics of the Sun, stars, planets, and the space through which Earth is traveling. Still others will extend into space man's earthbound research in such areas as medicine, biology, chemistry, physics, and material manufacturing processes. Foremost among the planning is Spacelab, a fully-equipped space laboratory being developed
'
by I European nations under I the guidance of the European Space Agency and supported by NASA with the Marshall Space Flight Center performing as the lead center. Spacelab, carried into space in the Orbiter cargo bay, will be adaptable to many types of space operations, accommodating up t~ four nonastronaut scientists t o conduct a myriad of experiments in a true space environment - - Earth observations, space technology, biological studies and others. In addition to i t s Spacelab development role, the Marshall Center will manage the first three missions, now set to begin in 1983. Another significant payload for the mid-1980s i s the Space Telescope, being developed by the Marshall Center and associates as an optical telescope that will be placed in orbit enabling scientists to see deep into space - - seven times farther than ever before. The Shuttle will place the unmanned telescope in orbit and later serve as a base from which astronauts may make repairs and possibly replace instrument packages for new experiments. Major payload activity is also forecast for geosynchronous orbits, deep-space missions, elliptical orbits and higher circular orbits. Payloads with such destinations will require a pro-
pulsion stage in addition to the Shuttle. The Space Shuttle will deliver the payload, with a propulsion stage attached, t o low Earth orbit and will stand by until the stage boosts the payload to the desired orbit. Initially, Inertial Upper Stages are being developed for such non-planetary missions. An advanced reusable orbiter transfer vehicle is also being studied by Marshall. Yet another payload of major significance is the Marshall Center's proposed Space Platform, an experiment-supporting system that would be carried into orbit by the Shuttle in the late 1980s. The platform is designed to fill the growing needs of the scientific and industrial communities who require longer orbiting times, greater power and other services for their research and observations in space. One of the pri-
Spacelab 2 Configuration
Far left: Space Telescope Center left: Spacelab Left: Building Space Structures
mary advantages of the platform i s that it can provide power for ' long periods of time, either to experiments on board the Shuttle or to those left attached to the platform after the Shuttle returns to Earth. The initial platform would provide 12 kw. of power and would have growth capability to a t least twice that amount, but future designs may provide as much as 100 kw. or more. By the early 1990s the platform may even evolve to a manned version, in which rotating crews would permanently live and work in space. The Space Shuttle will not be limited to uses that can be forecast today. The reduction in the cost of Earth-orbital operations and the new operational techniques will enable new and unforeseen solutions of problems. Some of these could be the key to understanding the physi-
Spacelab 1 Payload Specialists in the Marshall Center Mockup
cal processes that will allow man to develop unlimited pollutionfree power, and t o attain knowledge that will lead to new products and industries.
Spacelab 1 Configuration
Spacelab Habitable Module
Inertial Upper Stage
Launch Operations
Space Shuttle flights will be launched from two locations: Kennedy Space Center in Florida and Vandenberg Air Force Base in California. These sites were selected based upon both NASA and Department of Defense (DOD) needs for projected payloads and requirements for no land mass overflight dliring the launch of the Shuttle. Kennedy is used t o launch both NASA and DOD payloads into orbits of 39 to 57 degrees inclination with respect to the equator, and Vandenberg will be used for launches with orbital inclinations from 56 to 104 degrees. (A due east launch from Kennedy would yield an orbit of about 28.5 degrees inclination while a due south launch from Vandenberg would yield an orbit of 90 degrees, or a polar orbit.) Range safety criteria restrict the launch directions (azimuths) from each launch site to preclude a released tank or booster from impacting a land area. From Kennedy the northernmost azimuth is limited by the southeast portion of Newfoundland; and the southernmost azimuth is limited by the Bahama Islands. From Vandenberg, the land constraints include portions of Mexico t o the southeast and the Hawaiian Islands to the southwest. The direction of Earth rotation also has a significant bearing on
the payload launch capabilities of the Shuttle. A due east launch from Kennedy, using the Earth's easterly rotation as a launch assist, will permit a payload weighing up t o 29,484 kg. (65,000 Ibs.) to be launched. A polar orbit launch from Vandenberg, where the Earth's rotation neither assists nor hinders the Shuttle's capabilities, will permit a payload of up to 18,144 kg. (40,000 Ibs.) to be carried into orbit. The most westerly launch from Vandenberg will allow a payload up to only 14,5 15 kg. (32,000 Ibs.) to be transported to orbit since the Earth's rotation is counter to the westerly launch azimuth.
Ground Turnaround
The ground turnaround cycle for Shuttle starts on the runway after the Orbiter has landed. Preliminary safing and servicing tasks are completed on the runway before the Orbiter is towed to the safing and deservicing area where DO0 payloads are removed, pressurized containers and fuel cell reactants (oxygen and hydrogen) are vented, and the hazardous fuel modules are removed. At the Kennedy Center, the Orbiter is then transferred to a maintenance and checkout facility where it undergoes inspection, maintenance, limited servicing, and checkout, e.g., inspection of the insulation. New payloads are then installed in the Orbiter in preparation for premate checkout of the Orbiter prior to vehicle assembly. (Cer. tain time-critical payloads or hazardous payloads, and all DOD payloads, will be installed on the launch pad using the Payload Changeout Room a t the pad.) The hypergolic modules (hazardous fuels for reaction control, power units, maneuvering systems, etc.) which have undergone separate inspection, maintenance and checkout a t the hypergolic servicing facility are installed before the Orbiter is transferred to the Vehicle Assembly Building (VAB). Assembly and checkout of the Space Shuttle vehicle begins with mating of the two Solid Rocket Booster motor segments on the mobile launch platform. The External Tank, having previously undergone i t s premate processing in the VAB, is then moved to the assembly area and mated to the two Solid Rocket Boosters. The Orbiter is then towed into the VAB transfer aisle, i t s landing gear is retracted, and it is lifted into positionaand mated with the External Tank to complete the Shuttle assembly. The connections are verified in the Shuttle interface test, and ordnance is added to the Shuttle for separation and range safety functions. Launch pad operations include rollout of the vehicle, connection of the pad interfaces, launch readiness checkout, countdown preparations, loading of cryogenics, flight crew ingress, and the final automatic countdown sequencing. Operations a t Vandenberg will be generally similar, although different facilities will be used. When Shuttle becomes fully operational it will be capable of a 14-day turnaround at Kennedy, from landing to lift-off. The turnaround figure is based upon 160 working hours, amounting to two shifts a day, five days a week, for two weeks. Vandenberg operation will take slightly longer, or about 205 hours.
Orbiter Processing Facility
Checkout on the Pad
The Shutt e Deve opment Team
Management of the Space Shuttle Program is shared by NASA Headquarters, the three NASA centers involved in manned space flight and many aerospace contractors. Overall direction of the Shuttle Program is the responsibility of NASA Headquarters in Washington, D.C. Johnson Space Center is responsible for program management and systems integration and is also the development center for the Orbiter. The Marshall Center is responsible for development of the External Tank, Solid Rocket Booster and the Shuttle main engines, as well as certain systems test and integration functions. The Kennedy Space Center serves as the launch and landing site for missions requiring easterly launches. The Defense Department will operate the Vandenberg AFB launch and landing site. Hundreds of private firms, educational institutions, research organizations and federal agencies were involved in creating the Space Shuttle. Some firms supplied small items such as nuts and bolts; others provided complete systems. The Shuttle prime contractors and some key subcontractors are included in the following list.
ORBITER
PRIME CONTRACTOR
- Rockwell International, Space Division,
SUBCONTRACTS
Bethpage, N. Y.
Downey, Calif.
Wing
- Grumman Aerospace,
Vertical f a i l - Fairchild Republic, Farmingdale, N. Y. M i d Fuselage - General Dynamics, San Diego, Calif. Reusable Surface Insulation - Lockheed Missiles and Space Co., Sunnyvale, Calif. Orbital Maneuvering System - McDonnell Douglas Astronautics Co., St. Louis. Mo. Orbital Maneuvering Engines - Aerojet Liquid Rocket Co., Sacramento, Calif.
EXTERNAL TANK
PRIME CONTRACTOR
- Martin Marietta Aerospace,
SUBCONTRACTS
-
Denver, Colo.
lntertank Dome Caps
-
Avco Corp., Nashville, Tenn.
General Dynamics, San Diego, Calif.
Ogive and Dome Gores - Aircraft Hydroforming, Gardena, Calif. Tank Weld Tools - L T V Aerospace, Dallas, Tex. GorelDome Weld Tools
-
The Boeing Company, Seattle, Wash.
SOLID ROCKET BOOSTER
PRIMARY MANAGEMENT - Marshall Space Flight Center, Huntsville, Ala.
SUBCONTRACTS
Assembly and Checkout - United States Boosters Inc., Huntsville, Ala. Solid Rocket Motor - Thiokol Corp., Brigham City, Utah Structures - McDonnell Douglas Astronautics Co., Huntington Beach, Calif. Decelerator Subsystem - Martin Marietta Aerospace, Denver, Colo. Integrated Electronics Assembly - Bendix Corp., Teterboro, N. J. Booster Separation Motor - United Technology Corp., Sunnyvale, Calif. Parachutes - Pioneer Parachute Co., Manchester, Conn.
SPACE SHUTTLE M A I N ENGINE
PRIME CONTRACTOR
- Rockweli International, Rocketdyne Div.,
SUBCONTRACTS
Canoga Park, Calif.
Controller
- Honeywell Inc.,
Minneapolis, Minn.
Hydraulic Actuator System - Hydraulic Research, Valencia, Calif.
a U. S. GOVERNMENT PRINTING OFFICE : 1982
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