aerospace industry

aerospace industry


      assemblage of manufacturing concerns that deal with vehicular flight within and beyond the Earth's atmosphere. (The term aerospace is derived from the words aeronautics and spaceflight.) The aerospace industry is engaged in the research, development, and manufacture of flight vehicles, including unpowered gliders (glider) and sailplanes (see gliding), lighter-than-air craft (see balloon and airship), heavier-than-air craft (both fixed-wing and rotary-wing; see airplane and military aircraft), missiles (see rocket and missile system), space launch vehicles (launch vehicle), and spacecraft (manned and unmanned). Also included among its concerns are major flight-vehicle subsystems such as propulsion and avionics (aviation electronics) and key support systems necessary for the testing, operation, and maintenance of flight vehicles. In addition, the industry is engaged in the fabrication of nonaerospace products and systems that make use of aerospace technology.

Character of the industry
      Technological progress is the basis for competitiveness and advancement in the aerospace industry. The industry is, as a result, a world leader in advancing science and technology. Aerospace systems have a very high value per unit weight and are among the most complex, as measured by the number of components in finished products. Consequently, it is economically and politically prestigious for a country to possess an aerospace industry. Among the world's largest manufacturing industries in terms of monetary value of product output and employment, the aerospace industry is characterized by a relatively small number of large firms and numerous international partnerships at every level.

      For the major aerospace countries, their own military establishments and, in some cases, foreign militaries constitute the largest customers. The next most important buyers are the world's commercial airlines, primarily American, European, and Asian–Pacific Rim carriers. Most general aviation (primarily private, business, and nonairline commercial) aircraft are sold in the United States, with Europe becoming a growing marketplace and special-use markets developing in the Middle East and Latin America.

      Of the nearly 50 countries that have one or more aerospace companies, the United States possesses the world's largest aerospace industrial complex. (While some companies are dedicated solely to aerospace, others are more diversified.) Although their own government is the major procurer of military systems, American firms are also the dominant supplier of both military and civil aerospace hardware to the rest of the world. Today, non-American companies seek a larger portion of the global market and challenge American dominance.

       Russia retains the second largest aerospace industry in the world. After the breakup of the Soviet Union in 1991, Russia acquired most of the highly competent Soviet design bureaus. Partnerships with American and European firms were initiated, and Russia entered Western markets for the first time.

      Western Europe's aerospace industry has become a strong global player, with France, the United Kingdom, and Germany particularly active. Through the success of cooperative programs such as the Airbus (Airbus Industrie) line of commercial transports and the Ariane family of space launch vehicles, the European industry has gained considerable experience in the development and manufacture of almost the entire range of aerospace systems. Sweden's industry is smaller than that of the other major European aerospace countries, but through its national policy of selective specialization it, too, has developed a high degree of competence.

      In the Asia–Pacific Rim region, Japan has the leading aerospace industry, but—compared with the United States, western Europe, and Russia—its capabilities are still limited. Japanese companies also perform as key subcontractors to firms in the United States and Europe. China has built aircraft of Soviet design since the early 1950s, with indigenous design efforts generally confined to adapting Soviet technology. It is in the process of forging partnerships with a number of foreign ventures in both aircraft and spacecraft systems. The country also has developed space launchers, small satellites, and craft intended for manned spaceflight. Other countries with small but advanced aerospace industries are Argentina, Australia, Brazil, Canada, the Czech Republic, Greece, India, Indonesia, Israel, Italy, The Netherlands, Poland, Spain, Switzerland, Taiwan, and Ukraine. Emerging industries exist in Austria, Belgium, Chile, Colombia, Egypt, Finland, Hungary, Iraq, Lithuania, Malaysia, New Zealand, Nigeria, Norway, Pakistan, the Philippines, Portugal, Romania, Singapore, South Africa, South Korea, Turkey, Uzbekistan, and Yugoslavia.

      The interests of the U.S. aerospace industry are represented through the Aerospace Industries Association of America (AIA), an aerospace-industry-funded organization whose membership consists of the major companies in the field. The AIA provides a forum for technical and policy issues concerning the industry and serves as a lobbying agent for the common interests of its members. Its parallel in Europe is the European Association of Aerospace Industries (AECMA). Based in Brussels, AECMA interfaces with member countries as well as the European Union. In addition, Europe has several organizations at the national level. Other notable associations are the Society of Japanese Aerospace Companies (SJAC) and the Aerospace Industries Association of Canada (AIAC).

      The worldwide reduction in acquisitions of aerospace defense systems after the end of the Cold War in the early 1990s has prompted many manufacturers in the United States, Europe, and Russia to shift toward a more balanced mix of military and civil products. Some firms have adapted military aerospace hardware for civilian use or have sought nonaerospace markets for their expertise. To remain profitable, many companies have engaged in an almost continuous process of consolidations, mergers, divestitures, and international joint ventures and partnerships. Nevertheless, they all have been affected to some degree by the following developments: the ever-increasing costs of producing complex new aircraft and spacecraft, the globalization of the economy, the volatile level of government spending on defense-related projects, the state of commercial air travel and its needs, and the commercialization of space and the prospect of its low-cost access. These are the factors determining the size and scope of the aerospace industry today.


The first decade
      The origin of the aerospace industry dates to 1903 when Wilbur and Orville Wright (Wright, Wilbur and Orville) demonstrated an airplane capable of powered, sustained flight (see Wright flyer of 1903). The Wright brothers' success was due to detailed research and an excellent engineering-and-development approach. Their breakthrough innovation was a pilot-operated warping (twisting) of the wings to provide attitude control and to make turns. Patents with broad claims for their wing-warping technology were granted in Europe in 1904 and in the United States in 1906. The French government was the first to negotiate with the Wright brothers for the sale of their patents for 1,000,000 francs, with a deposit of 25,000 francs for the option, which was later forfeited. The first recorded business transaction of the aerospace industry occurred in May 1906 when J.P. Morgan and Company in New York City paid the Wright brothers the forfeited deposit. The first sale of a military aircraft was made on February 8, 1908, when the Wright brothers contracted to provide one Model A flyer (see Wright military flyer of 1909) to the Signal Corps of the U.S. Army for $25,000, with a $5,000 bonus should it exceed the speed requirement of 40 miles (65 km) per hour. The following year the aircraft successfully completed qualifying trials for completion of the sale, which included the bonus.

      In March 1909 the British entrepreneurs Eustace, Horace, and Oswald Short purchased a license to produce six Wright flyers and set up the company Short Brothers Limited on the Isle of Sheppey, establishing the world's first assembly line for aircraft. In the same year the American aviation pioneer Glenn Curtiss (Curtiss, Glenn Hammond) joined the list of airplane producers and made the first commercial sale of an aircraft in the United States. In France, Henri Farman (Farman, Henri), Louis Blériot (Blériot, Louis), Gabriel and Charles Voisin, and Léon Levavasseur entered the industry, and experimental groups started airplane production in Germany and Russia. When Blériot crossed the English Channel in July 1909 in his Blériot XI monoplane, the ensuing fame resulted in worldwide orders for more than 100 aircraft.

      In 1909, when the Wright Company was incorporated with a capitalization of $1,000,000, the Wright brothers received $100,000, 40 percent of the stock, and a 10 percent royalty on every plane sold. The company developed extensive financial interests in aviation during those early years but, counter to the recommendations of its financiers, did not establish a tight monopoly.

      By 1911, pilots were flying in competitive races over long distances between European cities, and this provided enormous incentives for companies to produce faster and more reliable aircraft. In 1911–12 the Wright Company earned more than $1,000,000, mostly in exhibition fees and prizes rather than in sales. French aircraft emerged as the most advanced and for a time were superior to those of competing countries. All planes built in this early period were similar in construction—wings and fuselage frames were made of wood (usually spruce or fir) and covered with a coated fabric.

       France and Germany, both aware of the military potential of aircraft, began relatively large-scale manufacturing around 1909. By the outbreak of World War I in 1914, France had built a total of 2,000 airplanes, of which 1,500 were military; Germany ranked second with about 1,000 military aircraft; and Britain a distant third with 176. The United States lost its lead in aeronautics as the combined civil and military market for American airplanes was insufficient to permit the industry to grow significantly; only 49 aircraft were produced in 1914. In addition, patent rights remained a major difficulty for the industry. Recognizing a national need to advance aircraft technology independently, the U.S. Congress created the National Advisory Committee for Aeronautics (NACA) in March 1915.

      French industry, assisted by rapidly expanding facilities in Great Britain, carried the production load of the Allies during the war. When the United States entered the war in 1917, however, the French government requested that it furnish more than 4,000 planes for active service by early 1918. To meet the demand, including that of the U.S. Army, the U.S. government and American aircraft manufacturers entered into a patent-licensing agreement on July 24, 1917, and formed the Manufacturers Aircraft Association, which allowed its members the use of patents for a fixed royalty fee.

      Because American aircraft manufacturers and suppliers had no experience in large-scale production, the government enlisted automobile manufacturers to mass-produce engines and airplanes. For its own use the U.S. Army ordered the production of the two-seat British De Havilland DH-4 bomber and the American-designed Curtiss JN-4 Jennie trainer. By the end of the war 4,500 DH-4s had been built in the United States, 1,213 of which were shipped to Europe. Although American production was too late to matter militarily, by the 1918 Armistice American factories were capable of producing 21,000 planes per year. Worldwide 210,000 aircraft were produced from 1914 to 1918. In the United States the greatest success of wartime production was the very advanced 12-cylinder, water-cooled, 400-horsepower Liberty engine, developed for the DH-4.

Between the wars
      The world's aircraft industry fell into sharp decline following the Armistice. Within days most contracts were canceled. The wartime-oriented industry was overcapitalized, overstocked with raw materials, overorganized, and overmanned for peacetime needs. In Europe, national governments realized that maintaining a strong air force in case of war required an aircraft industry and, therefore, subsidized commercial air transportation. Military aircraft were adapted for passengers, and trainers and fighters were used for mail service. With the exception of providing subsidies for air mail, the U.S. government did little initially to help its struggling industry, intervening only when the few remaining manufacturers were about to close, with an agreement in which the companies would use profits from government orders toward designing and building superior aircraft for the U.S. Army and Navy.

 In the 1920s Europeans and Americans competed in racing, which led to many refinements in design and performance. Notable was the general conversion from biplanes (biplane) to the more streamlined monoplanes (monoplane) and the move to all-metal airframes (airframe), which took advantage of the new lightweight aluminum alloy duralumin. The airframe revolution had actually begun during the war, in 1915, with the all-metal Junkers J-1 monoplane. The most successful postwar transport-aircraft designs were those of the Germans Hugo Junkers (Junkers, Hugo) and Claudius Dornier (Dornier, Claudius) and the Dutch Anthony Fokker (Fokker, Anthony Herman Gerard); these aircraft featured cantilevered wings, which eliminated external struts or braces.

      In 1927, following Charles A. Lindbergh (Lindbergh, Charles A.)'s solo flight from New York to Paris in the Spirit of Saint Louis, public enthusiasm for flying and aircraft expanded dramatically (a phenomenon dubbed the “Lindbergh boom”). Industry sales had more than tripled by the time the stock market crashed in 1929, when scores of aircraft companies, especially smaller new entrants, were forced out of business.

      Among an explosion of new ideas, one of the most fruitful was stressed-skin construction, in which the plane's skin carried loads in conjunction with the support framework. This approach eliminated many internal trusses and braces within the wing and fuselage, contributed to a lighter and more efficient airframe design, and changed construction techniques. European manufacturers were responsible for many technical innovations, but, owing to the fierce competition among airlines in the United States, American aircraft producers incorporated them faster and more successfully in their products.

      At its outset the aircraft-manufacturing industry was virtually self-contained in the producer's plant, with the exception of a few key products such as engines and tires. The majority of labour was associated with woodworking and sewing of fabric for the fuselage, wings, and empennage—skilled labour using limited tooling. The few machined parts and even components such as seats—devised by the airplane designers—were fabricated by specialized groups within factories.

      In the 1930s, as aircraft became more sophisticated, the demand increased for machined parts, castings, forgings, and extrusions, which all required different machinery and different skills. The result was a major vertical expansion of aircraft businesses—i.e., the move to incorporate or control all levels of component manufacture and assembly within one organization. This took the form of either expanded internal plant capabilities or the development of a group of suppliers from whom specialized components such as instruments, radios, and passenger equipment were procured. The latter group became an intrinsic part of the industry, much as engine manufacturers had earlier.

      In 1929 United Aircraft and Transport Corporation (see United Technologies Corporation) was formed in the United States, merging a number of aircraft manufacturers and airlines under William E. Boeing (Boeing Company)'s chairmanship. United's subsidiary, Boeing Airplane Company (see Boeing Company), produced its Model 247, an all-metal, twin-engine, low-wing monoplane first flown in 1933 and regarded as the first “modern” airliner. Although the aircraft was sought by most American carriers, Boeing restricted sales of 247s until the order for its sister company, United Airlines, had been filled. This prompted competing carrier Transcontinental & Western Air, Inc. ( Twa), to persuade Douglas Aircraft Company to launch its DC (Douglas Commercial) series of aircraft in 1933. Passenger service became consistently profitable for airlines for the first time in 1935 with the introduction of the DC-3, which was sold to almost all airlines in the United States and became the standard in the world (including the Soviet Union and Japan).

      In 1934, under new U.S. antitrust guidelines, aircraft manufacture was divorced from air transport, and three distinct companies—Boeing Airplane Company, United Aircraft Corporation (later United Technologies Corporation), and United Airlines—emerged from the dissolved United Aircraft and Transport Corporation. The legal separation of aircraft manufacturing and airline firms in the United States had its derivative effect on the aircraft industry elsewhere. For example, to compete with American manufacturers, particularly in the American market, European plane makers had to convince their customers that they had no reason to favour indigenous airlines with better schedules or contract terms. In addition, as European airlines became competitive in international travel, they began to be subsidized by governments, which would have found the additional obligation of financing affiliated aircraft producers too burdensome. Consequently, since the 1930s the world's aircraft makers have remained disassociated from their airline customers.

      During World War I Russian production had concentrated on large multiengine biplane bombers, few of which reached service. After 1923 the Soviet Union (Union of Soviet Socialist Republics) recognized the need for a broadly based air force. Initially planes were imported from Europe and the United States, but the need for aircraft that could operate under extreme weather conditions and from primitive airfields led to development of the indigenous Stormovik fighters about 1930. Although rugged, they did not match the German and Italian airplanes that they met during the Spanish Civil War. As a result of their designs' failing expectations and their questionable political views, many key aircraft-design leaders such as Andrey Nikolayevich Tupolev (Tupolev, Andrey Nikolayevich) and Sergey Pavlovich Korolyov (Korolyov, Sergey Pavlovich) spent years in exile or confinement during the 1930s and '40s.

 The 1930s and '40s were also the era of the “flying boat,” or Clipper (see seaplane). Planes developed by Boeing, Martin, the Sikorsky division of United Aircraft Corporation, and Short Brothers carried up to 74 passengers across transoceanic routes. In the late l940s, however, the development of a new generation of long-range, pressurized-cabin, four-engine, land-based airliners negated the need for seaworthy planes.

      The aircraft industry expanded to include autogiros (autogiro) and eventually helicopters (helicopter) in the 1930s. The first practical helicopter, the German Focke-Wulf Fw 61, flew for the first time in June 1936. In the United States in 1939, Russian émigré Igor Sikorsky (Sikorsky, Igor) designed, built, and flew the experimental helicopter Vought Sikorsky VS-300, which used a single three-bladed main rotor for lift and a small vertical rotor mounted on the tail to counteract torque. With an order from the U.S. Army in 1944, Sikorsky's R-4 became the world's first production helicopter.

      Progress also was made in the development of training systems for night and all-weather flying. In 1929 an electromechanical flight simulator was built by Edwin A. Link. The U.S. Navy placed the first large order in 1931 for the Link Trainer, which, with aircraft-specific changes, became the standard for highly sophisticated simulators.

      Germany's aircraft industry after World War I was heavily restricted by the Treaty of Versailles (Versailles, Treaty of). In 1921–22 the constraints were eased, and a productive light-aircraft industry began to develop. When restrictions were basically abolished in 1926, a number of new ventures were formed; those which survived included such companies as Arado, Dornier, Focke-Wulf, Junkers, and Heinkel. When Adolf Hitler came to power in 1933, funds were channeled into the development of the German aircraft industry through these companies. Compared with the period 1927–31, when a total of 84 million Reichsmarks were spent, funding soared to 980 million marks in 1936 alone. By the start of World War II the German aircraft industry was the most advanced in the world.

      The biggest importer of German aircraft was Japan, whose aircraft industry was technologically far behind its European and American counterparts until the early 1930s. After that time a new elevation of Japanese industry was punctuated by the performance of Mitsubishi (Mitsubishi Group)'s A6M Reisen (or Zero) fighter, which in the Pacific war was superior to its first American counterparts.

      In 1938, alarmed by Germany's conquests, the British and French started to order military aircraft from their own sources and from the United States, resulting in a new stimulus to American industry. After the United States entered the war in 1941, President Franklin D. Roosevelt ordered the domestic production of 20,000 military planes in 1942 and a doubling of production every year thereafter, this from a base of fewer than 6,000 planes a year. A total of 22,000 planes were built in 1942; by 1944 the annual rate had grown to 96,000, including several thousand delivered to the Soviet Union.

      From January 1, 1940, to August 14, 1945, the United States produced 300,317 military aircraft. Beginning in early 1942, factories ran 24 hours a day, six to seven days a week. By the end of 1943 the industry labour force had swelled to a high of 2.1 million workers, including tens of thousands of women. The Ford Motor Company plant in Michigan alone turned out 5,476 B-24 bombers in 1944–45. At its peak Douglas Aircraft Company's production line built one C-47 military transport (the military version of the DC-3) every five hours. By the summer of 1944, 15 airframe builders were producing 23 types of combat aircraft.

      To achieve this production level, facilities of existing plants were expanded, new facilities erected, nonaircraft producers (mainly automobile manufacturers) brought into the industry, qualified personnel recruited and trained, and new production processes developed. Nonaircraft producers obtained licenses to build entire products developed by the aircraft industry or acted as subcontractors for aircraft manufacturers. As a result, a revolutionary change in the technology of airframe production occurred, shifting from “job shops” with craft labour to assembly lines with workers of lesser skills. This necessitated greater standardization of parts and job processes because of the complexity of the product. For example, the 5.5-metre (18-foot) nose section of the Boeing B-29 bomber had more than 50,000 rivets and 8,000 different parts procured from over 1,500 suppliers. On the other hand, automobile-engine manufacturers were able to use existing skills to build aircraft engines along mass-production lines in already established factories.

 World War II began a differentiation among the aircraft producers. American companies such as Boeing, Martin, and Douglas, which had emphasized larger civil aircraft in the prewar years, became developers of bombers (bomber), as did Great Britain's Vickers, Avro, Bristol, and De Havilland and Germany's Dornier and Junkers. Focusing on fighters (fighter aircraft) were Curtiss, Grumman, Lockheed, and North American Aviation in the United States; Hawker and Supermarine in Britain; Messerschmitt and Focke-Wulf in Germany; and Mitsubishi and Nakajima in Japan.

      As a result of the earlier political suppression of its top designers, when the Soviet Union entered into combat with Germany in 1940, it needed to procure American fighters. Production of American designs from American-furnished tooling was carried out in factories evacuated to the east of the Ural Mountains. By 1944, however, fighters from the Yakovlev and Mikoyan-Gurevich ( MiG) design bureaus had proved to be competent native-design aircraft; they were mass-produced and served in the defeat of Germany.

      By the end of the war, airplane production in the United States and Britain (United Kingdom) had assumed the character largely maintained to the present day. Design, major assembly, and integration of systems in the makers' factories rather than the complete manufacture of an entire vehicle became the emphasis. Development departments performed most of the engineering, and supplier specialists and vendors complemented and supplemented the aircraft producers' manufacturing departments and equipment requirements. Only the United States and Britain retained advanced aircraft industries. What remained of the German industry after surrender was transported to the United States, Britain, France, and Russia. French industry had to restart completely, and the Soviet industry, although it survived the war, was not technically advanced. Japan was banned from resurrecting its industry until 1952.

      After the war, the Soviet factories and newly established design bureaus were relocated west of the Ural Mountains. Research activities at the Central Aerohydrodynamics Institute (TsAGI), the Aeroengine Institute (TsIAM), and schools such as the Moscow Aviation Institute were placed under the purview of the government's Ministry of Aircraft Production (MAP). In 1957 MAP relinquished control of the schools. The design bureaus, given status during World War II, were headed by notables such as Aleksandr Sergeyevich Yakovlev (Yakovlev, Aleksandr Sergeyevich), Artem Ivanovich Mikoyan, and Mikhail Iosifovich Gurevich. Prototypes were also built in these bureau plants, which specialized in particular classes of aircraft. In contrast to Western practice, responsibilities for aircraft types, military and civil, were specified explicitly by the government. (For additional information on the history of specific Soviet design bureaus, see Energia, MiG, Sukhoy, and Tupolev.)

The advent of jets and missiles
      The development of the jet engine about 1936–37 was the result of independent undertakings in Great Britain (United Kingdom) by Frank Whittle (Whittle, Sir Frank) and in Germany by Hans von Ohain (Ohain, Hans Joachim Pabst von). The first successful test of a turbojet engine was conducted in 1937 in Britain, while two years later the German Heinkel He 178 became the first operational aircraft powered by a jet engine.

 Jet power rendered piston-engine military aircraft virtually obsolete following the end of World War II, meaning that the surplus situation of the post-World War I era was not repeated. Nevertheless, a major contraction of the industry occurred in both the United States and Britain; by 1949, in fact, the producers were essentially the same as those of the prewar period. The Korean War saw use of the residuals from World War II, with the exception of two early jet fighters, the Lockheed P-80 and the North American Aviation F-86. Their power plants were furnished by Westinghouse, General Electric, and the Pratt & Whitney division of United Aircraft Corporation. The postwar “Century” series of fighters (i.e., fighters from various companies having an “F-” designation of 100 or higher) stressed supersonic performance, and the first production aircraft capable of flying supersonically for a sustained time was the North American Aviation F-100. Its several innovative characteristics included the use of titanium in the airframe because of the metal's lightness, strength, and heat resistance (see titanium processing: Aerospace applications (titanium processing)).

      The Soviet Union entered the jet aircraft field using conventional airframes and either German Junkers Jumo axial-flow jet engines or British Rolls-Royce Nene centrifugal-flow engines. The first all-new Soviet jet aircraft, using pirated copies of the Nene that had been upgraded by the Klimov plant, was the MiG-15 (MiG), which began deliveries to front-line fighter units in 1949. More than 15,000 aircraft of this type were built, including those produced in Soviet bloc countries. The MiG design bureau became the sole producer of Soviet fighters for many years, while the Yakovlev bureau developed several radar-equipped all-weather interceptors (such as the Yak-25, of which some 10,000 were produced). The Tupolev bureau was responsible for all bombers and civil jet transport planes.

      By 1958, combat aircraft worldwide had largely achieved supersonic breakthroughs, and a new breed of fighters emerged. Although, with time, the Soviet Union developed larger and faster fighters, initial versions were lacking in performance and weapons capacity. In Britain in the 1960s, Hawker Siddeley Aviation worked on a new type of jet fighter, the Harrier. Adjustment of the angle of the engines' nozzles allowed the aircraft to take off and land without a runway—the vertical/short-takeoff-and-landing (V/STOL) concept. For the American market, the Harrier was licensed by McDonnell Douglas and produced for the U.S. Marines.

      Immediately following World War II, because many veterans wanted to continue or learn flying, American light-plane production soared—33,254 aircraft were sold in 1946, a 455 percent increase over the last prewar sales figures. Although prospects seemed promising, rising retail prices for aircraft, high operating costs for the owner, and other factors caused the market to narrow, and by the mid 1950s only the three light-aircraft industry leaders—Beech, Cessna, and Piper—remained major forces.

 With the advent of the Cold War and as the military's transition to jet aircraft moved into high gear, a new opportunity arose—the development and production of guided missiles (guided missile). During World War II German researchers had pioneered antiaircraft missiles (missile), submarine-launched solid-fuel missiles, and surface-to-surface missiles, of which the V-2 (V-2 missile), with a top speed of 5,000 km (3,100 miles) per hour and a range of 320 km (200 miles), was the greatest achievement. The German developments and the researchers themselves provided the foundation for research and development by the victorious countries after the war. Initial postwar missile production began in the early 1950s. The first generation included artillery-like battlefield weapons, antiaircraft missiles, pilotless tactical bombers, and air-launched weapons, with increasing competition between the United States and the Soviet Union. Between 1955 and 1958 the United States worked on no fewer than nine missile programs, including ground-to-air defensive systems and pilotless bombers, both of which were also emphasized in Europe. While cooperative efforts existed between Britain and the United States, both Britain and France developed strong independent programs.

      Despite the claim of American aircraft manufacturers that they were best qualified to produce missiles, they were faced with significant competition. Nonairframe producers, particularly companies in the electronics field, were considered by the federal government to be as technically well qualified to produce missiles as companies with years of experience as aircraft manufacturers. Thus, the new dependency on electronics technology swept away an important barrier to entry into the production of military aerial vehicles. Completely new facilities were required, and the labour force, already changing as the result of the transition to jets, became increasingly composed of highly skilled scientists, engineers, and technicians. Nonetheless, the traditional aircraft companies were successful in responding to the new technological challenges and the competition. This was attributable to their already having a significant assemblage of top research-and-development personnel and an established position in handling government business. By 1959, of the 16 companies that dominated the U.S. missile business, eight—including the six largest—were traditional aircraft firms. Of the remaining eight, six were electrical and electronics manufacturers, one an automobile manufacturer, and one a subsidiary of a rubber company.

The space age (space exploration)
      Both the Soviet and the American space industries had much the same origins and impetus. The development of intermediate-range and intercontinental missiles provided not only the critical electronic technologies but also the rockets necessary to boost small payloads into orbit. Thus, the launch of Sputnik in 1957 signaled not only Soviet technical leadership in a new field but also the capability and extent of Soviet large-missile development and production. This leadership persisted into the era of manned spaceflight, and, exploiting a minimalistic but sophisticated approach to technology, it continued in the pioneering era of space vehicles and space stations.

  In the military use of space, the United States and the Soviet Union quickly turned to photographic reconnaissance from satellites (satellite communication), from which the film was recovered by means of reentry vehicles parachuted to the Earth. Their highly successful programs, including the U.S. Air Force's Corona program, which flew more than 200 camera-carrying satellites, were the forerunner of higher-resolution imaging systems as well as infrared systems for the sensing of missile launches and other phenomena, with the gathered data relayed electronically to the ground. The techniques developed for the programs were later translated into new government and commercial remote sensing applications, primarily for atmospheric, weather, and Earth-resource investigations. In 1958, in a program called Project SCORE, the U.S. Air Force launched the first low-orbiting communications satellite, premiering the transmission of the human voice from space. Others followed, initiating a rapidly growing national and international telecommunications satellite industry (see satellite communication).

 In 1958 in the United States, the National Advisory Committee for Aeronautics was succeeded by the National Aeronautics and Space Administration (NASA), and the Mercury manned spaceflight program was initiated. In 1959, to reflect the changing nature of the industry, the U.S. Aircraft Industries Association (formed in 1919 as the Aeronautical Chamber of Commerce of America to promote American civil aviation) changed its name to the Aerospace Industries Association (AIA). The Soviet Union, nevertheless, held manned space leadership, and on April 12, 1961, cosmonaut Yury A. Gagarin (Gagarin, Yury Alekseyevich), aboard Vostok 1, completed one full orbit of the Earth to become the first human being in space. Within two months, U.S. President John F. Kennedy announced the goal of the United States to land people on the Moon and to return them safely to the Earth before the end of the 1960s. In preparation for the lunar landing, NASA undertook the two-person Gemini spacecraft and recovery project with McDonnell Aircraft, which had been the prime contractor for Mercury, thus extending its role in the space program.

  NASA conducted many in-house research-and-development projects at its numerous space centres. The final development and production of flight hardware for the subsequent Apollo program, however, was carried out by a few prime contractors and elaborate networks of subcontractors and suppliers in virtually every part of the United States. For example, Grumman Aircraft produced the Lunar Modules, the actual vehicles to land on the Moon, and North American Aviation built the Command and Service modules, which remained in lunar orbit during the landings. Boeing, North American, and McDonnell Douglas each served as a contractor for one of the three stages of the Saturn V launcher, while the main engines for all stages were supplied by Rocketdyne, then a division of North American Rockwell. The number of personnel involved in the U.S. space program reflected intense activity in the industry, increasing from 36,000 in 1960 to 377,000 by 1965.

      In the early 1970s, following on the success of Apollo, NASA strove to sustain its manned space program with the development of a reusable space transportation system, or space shuttle. In initiating the project, it again distributed industrial participation throughout the United States, under the control of its own centres. Because the shuttle would have the characteristics of both an airplane and a spacecraft, NASA gave its Langley Research Center (with a long history as an aeronautical laboratory) the responsibility for the vehicle's aerodynamic design, in support of the agency's lead facility, the Johnson Space Center. The latter chose North American Rockwell (later Rockwell International) as prime contractor for the shuttle orbiter, while the craft's orbital maneuvering engine system and heat-resistant ceramic tiles were furnished by McDonnell Douglas and Lockheed, respectively. Hamilton Standard was responsible for the life-support systems, and the Marshall Space Flight Center and the Stennis Space Center had cognizance over the strap-on solid rocket boosters and external propellant tank, the former furnished by Thiokol and Hercules and the latter by Martin Marietta. Rockwell's Rocketdyne division developed the shuttle's cryogenic liquid-fuel main engines. Many other companies also played roles in development and manufacture, including suppliers of controls, components, and experiments.

Growth of the aircraft industry
      American aircraft manufacturers dominated the early post-World War II years. In 1951, 80 percent of the world's piston-engine commercial aircraft were made in the United States, and 56 percent of that American production was from Douglas. The United States, however, lagged behind Great Britain in understanding the potential of the jet airliner. In 1943 Britain had established the Brabazon Committee to assess the country's postwar needs in civil aviation. The committee suggested nine types of aircraft, of which two were produced: the turboprop Vickers-Armstrongs Viscount, which made its first airline flight in 1950, and the De Havilland DH-106 Comet, which in 1952, with the inauguration of passenger service, became the world's first jet airliner. The Comet was able to carry 36 passengers over a range of 3,200 km (2,000 miles) at a speed of 790 km (490 miles) per hour. A combination of technical flaws, however, caused explosions in flight and resulted in cancellation of the program.

      American companies learned from the design errors of the Comet. Drawing on its experience with the B-47 and B-52 jet bombers, Boeing in 1954 brought out the Boeing 367-80, the prototype of a new class of jet aircraft. Featuring an impressive combination of speed and range, the aircraft evolved into the KC-135 aerial military tanker and later into the company's first jet airliner, the 707. Pan American Airways (Pan American World Airways, Inc.)'s order for 20 Boeing 707s—and 25 similar Douglas DC-8s—initiated a worldwide jet-buying frenzy. In the 1960s jets also began to replace short-haul piston-engine aircraft. This time Europe—in particular British Aircraft Corporation, Hawker Siddeley, and France's (France) Sud Aviation—competed successfully against American manufacturers with the BAC One-Eleven, HS 121 Trident, and SE 210 Caravelle models, respectively. The French Caravelle, the prototype of which first flew in 1955, pioneered the “clean wing” design by mounting two engines, one on each side, on the rear section of the fuselage.

 The general aviation sector experienced an almost steady growth after 1955. The product lines of Beech, Cessna, and Piper expanded to include a wide variety of new aircraft types. In terms of production volume, Cessna emerged as the leader. By the mid 1960s general aviation aircraft also began to make use of turboprop engines, jet engines, and pressurized cabins. While American companies continued to dominate this market, increasing global demand stimulated non-American manufacturers. Japan, for example, successfully offered the medium-range Mitsubishi MU-2 turboprop, and Britain and France marketed competitive capability from Short Brothers and Sud Aviation, respectively. In the United States, William P. Lear (Lear, William P) paved the way for volume sales of business jets. His Learjet 23, the first aircraft of this type, began deliveries in 1964.

      The first major cooperative venture of European countries to design and build an aircraft began on November 29, 1962, when Britain and France signed a treaty to share costs and risks in producing a supersonic transport (SST), the Concorde. The two countries were not alone in the race for a supersonic airliner. The Soviet Union built the delta-wing Tupolev Tu-144 (Tupolev Tu-144), which made its maiden flight in December 1968 and which in June 1969 was the first passenger jet to fly faster than Mach 1 (the speed of sound). The Tu-144 was in service only briefly in the late 1970s before being withdrawn for reasons that proved ultimately to be fundamental design problems. The delta-wing Concorde made its first flight in March 1969 and entered revenue service in January 1976 (see supersonic flight). British Aircraft Corporation and Aerospatiale were responsible for the airframe, while Britain's Rolls-Royce and France's SNECMA (Société Nationale d'Étude et de Construction de Moteurs d'Aviation) developed the engines. The Concorde's cruise speed of about Mach 2 (twice the speed of sound) reduced the flight time between London and New York to about three hours. Although financially not profitable, the Concorde, which was taken out of service in 2003, proved that European governments and manufacturers could cooperate in complex ventures and that they remained at the technical forefront of aircraft development. In the United States the federal government was willing to pay 75 percent of the research-and-development cost of an SST. But after four years and more than $1 billion expended, with little progress and growing environmental concerns, the Boeing 2707 SST project was canceled in 1971 following withdrawal of government funding.

 In the 1960s Boeing and Lockheed submitted proposals to build a large transporter for the U.S. Air Force. Lockheed and engine manufacturer General Electric won the contract and developed the world's largest aircraft at that time, the C-5 Galaxy. Boeing and its engine partner Pratt & Whitney, however, embarked on an ambitious undertaking to develop an aircraft capable of carrying as many as 500 passengers. The end product was the first wide-body passenger jet, the four-engine Boeing 747 Jumbo Jet, which entered service in 1970. Douglas and Lockheed followed suit with somewhat smaller triple-engine wide-body aircraft, the DC-10 (1971) and L-1011 TriStar (1972), with worldwide acceptance, though not profits, for all three.

      As another outgrowth of wartime aircraft development, helicopters (helicopter) entered civilian service, first with the medical-emergency and police units of civil governments for rescue and transport operations and then with commercial companies for short-range passenger transportation in environments such as cities and forested areas requiring vertical ascent and descent. As helicopters achieved increased lift capabilities, they were used in construction for the economical transport of girders and other large structures. In the 1950s helicopter-manufacturing licenses were granted by Sikorsky (see United Technologies Corporation) to Westland in Great Britain and later by Bell Helicopter (see Textron Inc.) to Agusta in Italy and Mitsubishi in Japan. The introduction of turbines as power plants for the rotor was led by Sud-Est Aviation and later Sud Aviation (predecessors of Aerospatiale) in France. The Sud-Est Alouette II, which first flew in 1955, was the world's first turbine-powered helicopter to go into production.

      The debut of turbine-powered helicopters and their application as military attack aircraft by NATO and Soviet bloc countries and their clients marked the development of a new generation of rotary-wing aircraft. In the United States during the Vietnam War, the Bell Helicopter division of Textron developed the Bell 209 (AH-1G HueyCobra), the first helicopter designed specifically for attack. At the end of the 1960s the Soviet Union's Mil Mi-12 became the world's largest helicopter, with a maximum takeoff weight of 105 tons, and in 1978 the smaller Mil Mi-24 set a helicopter speed record of 368.4 km (228.9 miles) per hour.

Cooperation and consolidation in a global economy
      In the 1960s the high development cost of wide-body jets started a trend toward international risk sharing and cost sharing in aircraft development. American firms sought foreign partners because international cooperation was not subject to antitrust regulations and provided an excellent entry into overseas markets. This kind of partnership proved particularly important for nationalized airlines that preferred to purchase aircraft whose construction involved, at least in some way, their own domestic aerospace industry. Collaboration on an international scale also was attractive in that it lessened the possibility of a participant's canceling a project before completion, as many agreements had penalty clauses to discourage premature pullout and political pressure could be exerted from other team members. In 1969 there were worldwide about 10 cooperative ventures among manufacturers (both airframe and engine); by 1992 the number had risen close to 50.

      In 1965 the French and German governments initiated discussions about forming a consortium to build a European (Europe) high-capacity short-haul airliner. The outcome was Airbus Industrie, formed in 1970 as a Groupement d'Intérêt Economique (GIE; “Grouping of Mutual Economic Interest”), a unique and flexible form of partnership instituted by French law, in which the partners have a dual role as both shareholders and industrial participants. Later other European countries joined Airbus, resulting in the following distribution of ownership: Aerospatiale Matra (France) and DaimlerChrysler Aerospace (Dasa; Germany) with 37.9 percent each, BAE Systems (Great Britain) with 20 percent, and Construcciones Aeronáuticas S.A. (CASA; Spain) with 4.2 percent. In 2000 all the partners except BAE Systems merged into the European Aeronautic Defence and Space Company (EADS), which thus came to own 80 percent of Airbus. Belairbus (Belgium) and Alenia (Italy) participated in some projects.

 Airbus Industrie's premier aircraft, which entered service in 1974, was the A300—the world's first twin-engine wide-body jetliner. The consortium's next airliner, the A310 (entered service in 1983), introduced many new concepts, among them a two-pilot cockpit (in which the duties of a third crew member, the flight engineer, were performed by computers) and extensive use of composite materials (composite material) for the airframe. Its third product, the A320 (1988), was the first subsonic commercial aircraft to be designed with fly-by-wire (electric rather than mechanical) primary controls and the first commercial aircraft to feature the so-called glass cockpit, which used electronic rather than mechanical displays. Through its innovations and the growing range of aircraft offered, the European consortium became the second largest maker of commercial aircraft worldwide, deferring only to Boeing while relegating McDonnell Douglas to a distant third place by the mid 1990s (prior to its merger with Boeing in 1997). Although Airbus aircraft used many American-manufactured components, the program gave a tremendous boost to European aircraft suppliers.

      Europe's growing involvement in space activities provided another opportunity for international cooperation. In 1962 six western European countries and Australia signed a convention leading to the formation of the European Launcher Development Organisation (ELDO) to develop the experimental heavy-lift satellite launcher Europa, based on the British Blue Streak and French Coralie rockets. A parallel effort set the stage for the establishment of the European Space Research Organisation (ESRO), devoted to scientific space programs and the construction of satellites. In the summer of 1972 the French government proposed to other European countries a new and technologically simpler launcher. The 5th European Space Conference in December 1972 proved to be a landmark for the development of a European space industry. It approved the L-3S launcher, later named Ariane, with France as a project leader, and sanctioned Spacelab, a manned research laboratory to be carried in the cargo bay of a U.S. space shuttle, this project to be led by Germany. On an organizational level it merged the parallel activities of ELDO and ESRO under the umbrella of a single organization, the European Space Agency (ESA), which came into existence in 1975.

      The Ariane program involved nearly 50 companies from 11 European countries, with France's Aerospatiale providing strong leadership. The initial version of Ariane was first launched successfully on December 24, 1979, beginning a new era in Europe. To finance and operate the Ariane rocket and to commercialize space launch services with it, ESA set up Arianespace in March 1980 and gave it responsibility for operating the launch centre in Kourou, French Guiana. Its shareholders were 36 of the principal European aerospace firms, primarily those involved in actually building the rocket, as well as 13 major European bank groups and the French space agency CNES (Centre National d'Études Spatiales). Subsequently the Ariane series became the world's most successful commercial expendable launch vehicles.

  Spacelab, the second major European program, was developed by German companies in cooperation with manufacturers from Italy, France, Britain, and six other European countries. Taken into Earth orbit in the payload bay of a space shuttle, the laboratory consisted of two separate segments: a pressurized 16-ton module in which astronauts could work and supervise experiments in a shirtsleeve environment and a pallet for external payloads. Spacelab made its maiden voyage in November 1983 and more than a dozen flights thereafter.

      Following the lead of the flagships of international cooperation—Airbus and Ariane—many other civil and military programs were established that involved two or more companies from different countries. In 1969 European manufacturers Messerschmitt-Bölkow-Blohm, British Aircraft Corporation, and Aeritalia (predecessor of Alenia) founded Panavia Aircraft, while European engine makers Motoren- und Turbinen-Union (MTU), Rolls-Royce (Rolls-Royce PLC), and Fiat (Fiat SpA) incorporated Turbo-Union. The result of this joint effort was the successful Panavia Tornado, a multirole combat aircraft that entered service in 1980. Other European cooperations produced the French-British Jaguar fighter and the French-German Alpha Jet trainer, which entered service in 1972 and 1979, respectively. A later example, first flown in 1995, is the military transport helicopter NH-90, developed by Aerospatiale (France), DaimlerChrysler Aerospace (Dasa; Germany), and Agusta (Italy). When Boeing developed the 777 in the late 1980s and early '90s, the company for the first time offered full partnership to some subcontractors; Japanese firms held a 20 percent share in the airframe structure and also shared market and program risks.

      In the commercial engine sector, General Electric Aircraft Engines in the United States and France's SNECMA established a joint venture, called CFM International, in 1974 for production of the widely sold CFM56 turbofan (turbojet) engine. International Aero Engines (IAE), formed in 1983 as a collaboration of the American firm Pratt & Whitney, Germany's MTU, Britain's Rolls-Royce, Italy's FiatAvio, and a Japanese consortium, Japanese Aero Engines Corporation, produced the V2500 turbofan.

Mergers (merger) and divestitures
      With a decline in defense funding and a narrowing of commercial markets in the decades following World War II, the number of business opportunities shrank, and competition for each project became more intense. In response, aerospace companies sought mergers as a way to integrate strengths, to combine talent and other resources, and to reduce costs by eliminating redundancies in administrative functions, personnel, and physical facilities. Previous competitors having complementary capabilities joined forces to expand product lines and, in some cases, to offer a more comprehensive system of services and products to potential customers.

      In the 1960s, American manufacturers went through a first wave of mergers. Martin joined forces in 1961 with the nonaerospace materials firm American Marietta to form Martin Marietta Corp. Similarly, North American Aviation sought a nonaerospace partner and merged with automobile-parts supplier Rockwell Standard to form North American Rockwell Corporation (later Rockwell International Corporation) in 1967. In the same year, military manufacturer McDonnell Aircraft merged with the largely civil manufacturer Douglas Aircraft to form the balanced enterprise McDonnell Douglas Corporation. Another move involved Bell Aircraft's becoming a part of Textron Inc. in 1960.

      A second series of American divestitures and mergers began in the early 1990s. General Dynamics sold its general aviation aircraft maker, Cessna, to Textron Inc., its missile business to the Hughes Electronics (Hughes Electronics Corporation) subsidiary of General Motors, its tactical fighter business to Lockheed, and its space systems division to Martin Marietta. Ford and IBM also left the aerospace-defense sector by selling their divisions to Loral in 1992 and 1994, respectively. General Electric maintained its GE Aircraft Engines subsidiary, but its aerospace division became the property of Martin Marietta in 1993. In 1994 and 1995, four well-known airframe manufacturers merged into two. Lockheed combined with Martin Marietta to form Lockheed Martin Corporation, and Northrop acquired the ailing Grumman Corporation and later the Vought Aircraft division of LTV Corporation to create Northrop Grumman Corporation. In late 1996 Boeing (Boeing Company) acquired Rockwell International's space and defense units, and in 1997 it merged with McDonnell Douglas to establish the world's largest aerospace company. In the same year, Lockheed Martin announced its intention to acquire Northrop Grumman, but, in the face of objections from the U.S. Department of Defense that such a merger would result in an overconcentration of defense electronics in a single company and the threat of a federal antitrust suit, the acquisition plan was abandoned. This consolidation reduced the number of prime American aerospace companies to only two—Boeing and Lockheed Martin. In October 2000 Boeing acquired three units from Hughes Electronics—Hughes Space and Communications Company, Hughes Electron Dynamics, and Spectrolab—and Hughes's interest in HRL Laboratories, the company's primary research facility. These elements were combined into new subsidiary, Boeing Satellite Systems.

      In the general aviation sector, most small American manufacturers lost their independence in the 1980s and '90s and became parts of large industrial conglomerates. Beech became a subsidiary of Raytheon Company, and Cessna, as noted earlier, was acquired by Textron. Canada's Bombardier (Bombardier Inc.) acquired business jet makers Learjet and Canadair, as well as De Havilland Canada and Britain's Short Brothers.

      In Europe the changes were perhaps even more dramatic. In Britain, 12 companies, including well-known firms such as De Havilland, Bristol, and Supermarine were combined in a series of mergers in the 1950s and early '60s. The resulting two manufacturers were British Aircraft Corporation and Hawker Siddeley Aviation. In 1977 these two companies and two others were taken into public ownership and reorganized as British Aerospace (BAe). In 1999 BAe signed an agreement with General Electric Company PLC (GEC) in which GEC would divest itself of its defense electronics business, Marconi Electronic Systems, which would then merge with BAe. The resulting company became BAE Systems.

      In France, Sud Aviation, Nord Aviation, and SEREB merged in 1970 as Aerospatiale to form the country's strongest aerospace firm, while Dassault (Dassault Industries) absorbed Breguet Aviation in 1971. In 1999 Aerospatiale merged with Matra Hautes Technologies, a subsidiary of the Lagardère Group, to form Aerospatiale Matra. Germany followed Britain and France in creating a national “aerospace champion.” Beginning in 1985, luxury-car maker Daimler-Benz (later DaimlerChrysler) acquired the aerospace group Messerschmitt-Bölkow-Blohm (MBB), Dornier, and other companies to form Deutsche Aerospace, which subsequently was renamed DaimlerChrysler Aerospace (Dasa).

      The national consolidation of German aerospace companies was followed in 1990 by the merger of the space activities of France's Matra Espace and Britain's Marconi Space Systems to create Matra Marconi Space. The latter increased in size in 1994 with the acquisition of British Aerospace Space Systems. In May 2000 Matra Marconi Space and the space divisions of Dasa were combined in a joint venture under the name Astrium, 50 percent of which was owned by Aerospatiale Matra and BAE Systems and 50 percent by Dasa. Astrium was the first trinational space company, with facilities in France, Germany, and Great Britain. Its activities covered the whole spectrum of the space business, from ground systems and launch vehicles to satellites and orbital infrastructure. Two months later, in July, Aerospatiale Matra, Dasa, and Spain's Construcciones Aeronáuticas S.A. (CASA) merged to create the European Aeronautic Defence and Space Company (EADS). With central offices in France and Germany, EADS at its formation became the third largest aerospace company in the world (after Boeing and Lockheed Martin).

      In the United States and Europe, national governments played quite different roles in the mergers involving their countries. The U.S. government scrutinized each proposed merger for antitrust and anti-competition infringements and, in some cases, denied the merger, most notably that proposed by Lockheed Martin and Northrop Grumman. It approved the merger of Boeing and McDonnell Douglas with the recognition that survival of McDonnell Douglas's commercial business on its own was questionable and that one strong supplier could compete more successfully with the European Airbus consortium and maintain a favourable balance of trade. By contrast, national governments in Europe, once they overcame concerns about national pride and prestige, generally encouraged mergers in order to enhance Europe's combined ability to supply its economic union with products and compete with the United States for commercial and defense contracts. In addition, the critical mass afforded by these mergers provided a basis for negotiating with the United States for European roles in major aerospace projects such as the International Space Station.

      The aerospace industry of the former Soviet Union, particularly the defense and space sectors, absorbed a significant portion of the country's overall budget. Following the dissolution of the U.S.S.R. in 1991, its design bureaus, which were confined to Russia and Ukraine, represented the resources for the development of all aircraft and space systems. They stayed largely intact, continuing to develop advanced products while making individual partnering and marketing arrangements for aerospace vehicles and technology with the industries of Western countries, China, and India. At the same time, they supplied a dwindling market in Middle Eastern client states such as Syria and Iraq. At the start of the 21st century, negotiations were under way with the aim of merging the aircraft-oriented and space-oriented bureaus into single corporations.

      Recognizing the competitive status of its military aircraft and space launchers in the world market, Russia, in conjunction with those former Soviet republics having aircraft and space-related facilities, sustained these activities despite countervailing economic pressures. It successfully marketed MiG and Sukhoy fighters to Third World countries and formed partnerships with American and European firms in new aircraft and satellite-launcher ventures and with NASA in its manned space program—in particular, the joint effort on the International Space Station. It should also be noted that as the Soviet Union developed advanced military aircraft in the 1970s and '80s, earlier designs such as the MiG-25 (MiG) series were licensed for production to Eastern bloc partners such as Poland and the German Democratic Republic. Even older designs of the 1950s, the MiG-17 (MiG) and MiG-19 (MiG), were made available to China, which developed its own industry around versions of these aircraft. (For additional information on Russian design bureaus, see Energia and Tupolev.)

Aerospace products, manufacturers, and markets
      The product line of the aerospace industry is, by necessity, broad because its primary products—flight vehicles—require up to millions of individual parts. In addition, many support systems are needed to operate and maintain the vehicles. In terms of sales, military aircraft have the largest market share, followed by space systems and civil aircraft, with missiles still a modest grouping. The industry's customers range from private individuals to large corporations and commercial airlines, telecommunications companies, and military and other government agencies.

      Because of enormous financial and technological demands, the number of manufacturers in the industry has become increasingly limited, while the average size of aerospace firms has grown through acquisition or merger. In 2000 the world's largest aerospace companies (ranked in terms of total revenues) were Boeing (Boeing Company), Lockheed Martin (Lockheed Martin Corporation), EADS (European Aeronautic Defence and Space Company), United Technologies (United Technologies Corporation), Honeywell (Honeywell International Inc.), Raytheon (Raytheon Company), Textron (Textron Inc.), and BAE Systems. Russia's major producers included Ilyushin and Tupolev for civil aircraft, MiG and Sukhoy for military aircraft, and Energia for space launch vehicles.

Civil aircraft
      Builders of civil aircraft comprise two categories: producers of general aviation aircraft and producers of heavy aircraft. General aviation is defined as all aircraft activities not related to military, major airline, or air-cargo flying. It includes light planes and helicopters used for private pleasure flying, personal transportation, corporate travel, and short-haul commercial transportation, such as air taxis and commuter airliners, with low takeoff weights. Also encompassed are specialized aircraft such as agricultural sprayers, acrobatic craft, sailplanes, motor gliders, air ambulances, fire-control aircraft, pipeline-patrol aircraft, and others with a broad variety of civil applications. The category of heavy aircraft comprises commercial transports and cargo planes.

General aviation aircraft
      By far the world's largest market for general aviation aircraft (airplane) is the United States, with about 190,000 such aircraft (more than 70 percent single-piston-engine types) in active use in the late 1990s. Annually, these aircraft accounted for more than 27 million flight hours (nearly two times the flight hours of U.S. airlines) and 145 million passengers. Private airplanes used typically for personal transportation, sport, or training represent a market highly driven by the economy. In the United States the cost of a new aircraft—for example, a kit for an ultralight powered plane or sailplane—can be as low as that of a low-priced automobile.

      In 1978 more than 100 American companies produced some 17,800 piston-engine and turboprop general aviation aircraft. Due to judicial interpretation of U.S. product liability laws in a landmark case that year, manufacturers were put in legal jeopardy even for pilot-caused and weather-induced problems and regardless of maintenance or modifications to the aircraft. As a result, the industry experienced a major downturn. In its worst year, 1993, only 960 aircraft were sold, and only a few active producers remained in the United States.

      One response to this situation was the establishment of companies furnishing kits for aircraft, which required only experimental certificates and for which the liability could be limited to the individual building the airplane or glider. In 1994 the U.S. General Aviation Revitalization Act limited the liability of general aircraft manufacturers to 18 years after a product is placed into service. As a result, Cessna (a subsidiary of Textron (Textron Inc.) since 1992), which had stopped production of piston-engine aircraft in 1986, restarted its four-seat monoplane lines that were popular in the 1950s, '60s, and '70s. Meanwhile, the substantial general aviation aircraft industry outside the United States capitalized on the limited American supply. Active firms include Pilatus in Switzerland, Robin in France, Let and Zlin in the Czech Republic, Grob in Germany, Hagfors in Sweden, PZL Mielec in Poland, and Diamond in Canada.

 Among leading companies in the corporate aircraft market are the Canadian manufacturer Bombardier (Bombardier Inc.); the American firms Gulfstream (part of General Dynamics (General Dynamics Corp.)), Raytheon (Raytheon Company), and Cessna (see Textron Inc.); and France's Dassault (Dassault Industries). In the late 1990s the business jet market experienced an unprecedented growth due to a combination of factors. New models coupled with new technologies, a booming economy, and fractional ownership (time sharing) created a big market demand. In 1996 Boeing (Boeing Company) entered the high-end corporate aircraft business by forming the Boeing Business Jets (BBJ) joint venture with General Electric and offering a long-range business version of its 737-700 airliner. The following year, Airbus (Airbus Industrie) announced plans to offer the Airbus Corporate Jet (ACJ) based on its A319 airliner.

Commercial heavy aircraft
      The need for large-scale air transportation has been central to commercial aircraft manufacturing. As one of the world's most vital industries, airlines are key to many aspects of the world economy, from international business and tourism to routine movement of people and goods ranging from massive machinery to agricultural products and personal items. The United States has the largest number of airlines and purchases the most aircraft. In other countries there is one large flag carrier and, in some cases, intraregion private airlines. New independent low-cost carriers in the United States and Europe, particularly those flying shorter intercity routes, are also increasingly important customers.

      The smaller civil airliners, those with 15–100 seats, are generally used as regional or commuter transports and may be either turboprops or jets. Although the United States has led in most aircraft-manufacturing categories, it has lacked a foothold in the regional service aircraft market. The consortium ATR (Avions de Transport Régional), formed as a partnership between France's Aerospatiale and Italy's Aeritalia, has established itself as the market leader with its turboprops. Other firms include Bombardier (Bombardier Inc.), Fairchild Dornier, Saab, and, until bankruptcy in 1996, the Dutch group Fokker, which had an extensive line of regional turboprops and jets. Manufacturers outside the Western group include Brazil's Embraer, Indonesia's IPTN (Industri Pesawat Terbang Nusantara), and Russia's Ilyushin, Yakovlev, and Tupolev.

 In the larger commercial aircraft sector, where seat capacity ranges from about 100 to 550, competition and massive investment risks have narrowed the number of suppliers competing for the world's market to two—Boeing (Boeing Company) and Airbus (Airbus Industrie). Together, these companies offer some 11 distinct aircraft families with numerous variations to accommodate the needs of individual users. Their customers are airlines, freight carriers, and, increasingly, leasing companies. At the beginning of the 21st century, the substantial industry of the former Soviet Union was in an uncertain state, but Russia's design bureaus Tupolev and Ilyushin and Ukraine's Antonov looked to Western cooperation and investments to sustain their output and to win customers outside the former Soviet bloc.

      The large majority of military aircraft are fighters, followed by bombers, transporter-tankers, early-warning and patrol aircraft, and a variety of propeller- and jet-driven trainers. As is the case with commercial aircraft, the complexity of the technology and the immense capital requirements have narrowed the number of suppliers. In addition, the end of the Cold War initially resulted in a steep decrease in the demand for military aircraft worldwide, although conflicts in the Persian Gulf and the Balkans in the 1990s identified the need to maintain significant air forces. Some developing countries purchase or build fighter and trainer aircraft for their own needs in order to maintain an indigenous aerospace/defense industry. (In some cases, purchase agreements with foreign suppliers include provisions for a measure of indigenous development and assembly and thus the transfer of technical knowledge and skills.)

 In the United States two companies build fighters (fighter aircraft)—Boeing (Boeing Company) and Lockheed Martin (Lockheed Martin Corporation). In Europe, more so than in the United States, companies share in fighter production, an example being the Eurofighter Typhoon, developed in the mid 1980s and '90s by Germany's Dasa, British Aerospace, Italy's Alenia, and Spain's CASA and first flown in prototype in 1994. Companies operating independently with smaller fighter programs include France's Dassault (Dassault Industries) and Sweden's Saab. With the exception of providing stealth features, European manufacturers market fighters comparable in capability to those of the United States throughout the world. In Russia only Sukhoy and MiG actively make fighters. Some companies have engaged in indigenous productions for national needs, among them Mitsubishi, Kawasaki, and Fuji in Japan, Taiwan's Aero Industry Development Center, and India's Hindustan Aeronautics Ltd.

      Military transport aircraft are used to move troops and matériel such as tanks, automotive vehicles, and helicopters. With modifications they (as well as commercial airliners) serve as tankers for in-flight refueling. In comparison with freight versions of commercial aircraft, military transporters have special features such as short-takeoff-and-landing capability, loading ramps, airdrop capability, and paratroop doors. In the United States, Boeing builds the four-turbofan C-17 Globemaster III airlifter. Airbus Military, a subsidiary of Airbus Industrie, manages a multinational group of leading manufacturers in the development of the four-turboprop A400M transport for European air forces. Ukrainian manufacturer Antonov produces several transports, among them the An-225 Mriya, a six-turbofan design originally conceived to carry oversized external loads piggyback-style for the Soviet space program.

      With the advent of missiles after World War II and later with the end of the Cold War, the need for new strategic bombers (bomber) has become limited. Only one model, the Northrop Grumman B-2 flying wing, has had recent production in the U.S. Developed in the 1980s, the B-2, a stealth bomber with a weapons capacity of 23 tons, is the most expensive aircraft in the world, with a price of nearly $1 billion per plane.

Helicopters (helicopter)
 Helicopters (helicopter) occupy important niches in both military and civil aviation. Military models are of two kinds—combat and transport. Combat helicopters are designed by manufacturers specifically for that military purpose, whereas helicopters for transportation frequently exist in both civil and military variants. Short-distance personnel transportation, construction, police work, and traffic and event monitoring by the media dominate civilian uses.

      Seven Western and two Russian manufacturers produce most of the world's large military and civil helicopters. Sikorsky (part of United Technologies (United Technologies Corporation)), Bell Helicopter Textron (Textron Inc.), and Boeing have their facilities in the United States. France's Aerospatiale and Germany's Daimler-Benz Aerospace (later DaimlerChrysler Aerospace) combined their helicopter activities as Eurocopter. Other major helicopter makers are Agusta of Italy (subsidiary of Finmeccanica) and Westland of Great Britain as well as Kamov and Mil of Russia. A large number of helicopters are sold by the American producer Robinson, which builds low-cost, relatively unsophisticated training and light-use vehicles.

      In a special category is the tilt-rotor aircraft, which can operate as a helicopter or rotate its engines and fly like a fixed-wing airplane. A modern example is the V-22 Osprey, jointly produced by Bell Helicopter Textron and Boeing as a military assault transport for the U.S. Marines. First flown in prototype in 1989, the Osprey can achieve speeds in excess of 500 km (310 miles) per hour.

Unmanned aerial vehicles
      Unmanned aerial vehicles (UAVs), a class of aircraft akin to radio-controlled models and cruise missiles, have become significant factors in military reconnaissance. Carrying sensors for surveillance, they are designed to fly either for long duration at very high altitudes or for shorter periods at low altitudes and to transmit their acquired data to orbiting satellites. A subclass of UAVs, often remotely piloted and sometimes called drones, are used as aerial targets for fighters and antiaircraft weapons. Although most aircraft companies engage in UAV manufacture, Northrop Grumman and Raytheon in the United States and Israel Aircraft Industries have specialized in this area and are major suppliers to many national defense agencies.

Missiles (missile)
      Missiles (see rocket and missile system), which are unpiloted, rocket- or jet-powered delivery systems for munitions, have assumed an important role in military strategy and tactics. Originally conceived as powered artillery shells and therefore the purview of munitions manufacturers, they rapidly became products of the aerospace industry by virtue of the ranges achievable with small jet and rocket engines and of the common use of airborne launch platforms. Missiles are regarded as substitutes for very-high-cost aircraft, and the industry is a major source of new weapons to upgrade the capability of existing fighters. Long-range jet-powered cruise missiles, typified by General Dynamics and Boeing's Tomahawk, are, in fact, unpiloted aircraft equipped with conventional or nuclear warheads. Shorter-range missiles such as the Russian SCVO, Chinese Silkworm, and French Exocet have become factors in the arsenals of developing countries, with the competition for these markets being similar to that for military aircraft.

      Rocket-powered intermediate-range and intercontinental ballistic missiles designed to carry nuclear warheads have been built or integrated by major aircraft firms—submarine-based fleet ballistic missiles (FBMs) by Lockheed Martin (Lockheed Martin Corporation) and EADS (European Aeronautic Defence and Space Company) and land-based systems such as Peacekeeper and Minuteman by Lockheed Martin and Boeing, respectively.

      The structure and weight of ballistic missiles lie primarily in their rocket motors and associated liquid-fuel tanks or solid-propellant canisters. Suppliers having the largest share are Rocketdyne (see Boeing Company) and Aerojet in liquid-fuel motors and Thiokol and Alliant Techsystems for solid fuels and nozzles. Missile guidance and navigation systems provide key roles for subcontracting companies such as Litton Industries, Honeywell (Honeywell International Inc.), Rockwell Collins, and Raytheon (Raytheon Company), although the prime contractors retain responsibility for integration and testing.

      Other kinds of airborne missiles are, in essence, projectiles with aerodynamic stabilization systems, sensors, and controls that are used to seek and home in on targets. Because structure is a minimal aspect of the product, integration and testing is often the responsibility of the electronics firms supplying the guidance systems and related elements. Almost all developed countries have the capacity and industry to design and build these weapons, but American, British, French, Chinese, and Israeli products are widely purchased by developing countries.

Space launchers
      The space launch vehicle is the rocket system that lifts a payload—a satellite or other spacecraft—into orbit. With the exception of the U.S. manned space shuttle, all space missions make use of expendable launch vehicles (ELVs).

      Various companies build small ELVs capable of taking light payloads into space. In this market segment the American supplier Orbital Sciences Corporation is unique in its production of an aircraft-launched booster, Pegasus, that can carry payloads as heavy as 500 kg (1,100 pounds) into a low Earth orbit. Examples of medium-size ground-launched ELVs include Orbital Sciences's Taurus and Lockheed Martin (Lockheed Martin Corporation)'s Athena I and II, with payload capabilities in the 800–2,000 kg (1,750–4,400 pound) range for low Earth orbit. Multiton satellite payloads require large launchers, which are built by firms in the United States, Europe, Russia, Ukraine, China, and Japan. In the United States, Lockheed Martin (Lockheed Martin Corporation) makes the Atlas-Centaur and Titan families of launchers, and Boeing (Boeing Company) the Delta family. Russia's Proton launcher is the product of Khrunichev, while Ukraine's Zenit is fabricated by Yuzhnoye. In China, Great Wall Aerospace builds the Long March vehicle, and, in the mid 1990s, Japan entered the field with its first indigenous launch vehicle, the H-II. The largest share of the commercial space launch market, more than half, is held by Europe's Ariane rockets. The United States enjoyed all of the commercial launch market in the early 1980s, but by the mid 1990s its share had fallen to about 30 percent.

 The space shuttle is unique in that it is both a launch vehicle and a space platform. As a launcher, it is able to transport as much as 30 tons into a low Earth orbit. Although Rockwell delivered the last shuttle orbiter in 1991 (for an active fleet of four orbiters), each launch requires many components that must be supplied new or refurbished. For example, the external tank, which is discarded once the propellants are exhausted and disintegrates on reentry, is supplied by Lockheed Martin. The reusable solid rocket boosters are jettisoned and recovered by parachute after launch; new and rebuilt units are provided by Thiokol. To extend the reach of the shuttle's payloads to higher altitudes (and to serve as an upper stage for the Titan IV launcher), Boeing produces the solid-fueled Inertial Upper Stage rocket.

      Unmanned spacecraft are called satellites (Earth satellite) when they operate in Earth orbit and space probes when launched on a trajectory away from the Earth toward other bodies or into deep space. Whereas probes are designed for scientific missions, satellites have a wide variety of civil and military applications such as weather observation, remote sensing, surveillance, navigation, communications, and television and radio broadcasting.

      In the civil market, satellites have become the backbone of long-distance telephone and multinational television broadcasting, as well as the basis for new communications options such as global mobile telephones (see satellite communication). All major telecommunications entities use satellites as key network nodes in constellations ranging from three or four large spacecraft in geosynchronous orbit to more than 100 smaller vehicles in low Earth orbit. Many companies compete in the commercial satellite manufacturing business. In the United States they include Boeing (Boeing Company), whose acquisition of the space business of Hughes Electronics (Hughes Electronics Corporation) in 2000 made it the world's largest supplier of TV and communications satellites; Lockheed Martin (Lockheed Martin Corporation); TRW (TRW Inc.); and Loral Space & Communications. In Europe, Astrium predominates. Canada, Brazil, Australia, Japan, China, India, and Israel possess nascent industries and have built and orbited satellites. Several other countries have built subsystems and experiments for American and European unmanned and manned spacecraft, as has Russia, which has also developed and launched navigation-satellite constellations for worldwide use.

 Manned spacecraft impose far greater technical challenges and costs than unmanned systems because of the equipment necessary to sustain human crews in space and bring them back to the Earth. Current manned spacecraft are the most complex aerospace vehicles. In use at the turn of the 21st century were the U.S. space shuttle, the Russian spacecraft Soyuz, the Russian space station Mir (deliberately taken out of orbit in March 2001), and the International Space Station (ISS). The technologies of the first three craft date back to the 1960s and '70s. In the late 1990s, in concert with Russia, the European Space Agency, Japan, and Canada, the United States undertook construction of the ISS, a modular complex of habitats, laboratories, trusses, and solar arrays intended to be a permanently inhabited outpost in Earth orbit. Boeing, the prime contractor, led an industry team comprising most major American aerospace companies and hundreds of smaller suppliers and integrated the work of participants from more than a dozen other countries. Manufacturers of major ISS components outside the United States includes EADS (France-Germany-Spain), Alenia (Italy), and Mitsubishi (Japan). In 1998 the first two ISS modules were launched and joined in space, and other components were subsequently added. In November 2000 the first three-person crew, an American and two Russians, occupied the still-expanding station.

      Most unmanned scientific spacecraft and all manned space hardware are procured by government agencies. Specific examples are NASA and the National Oceanic and Atmospheric Administration (NOAA) in the United States, the European Space Agency (ESA), the Russian Space Agency (RKA), the National Space Development Agency (NASDA) in Japan, the Chinese Space Agency in China, and the Indian Space Research Organisation (ISRO) and Indian Space Agency in India.

Airships (airship)
      All airships (airship) have four principal elements in common: a cigar-shaped bag, or balloon, filled with a lighter-than-air gas (usually hydrogen or helium); a passenger car, or gondola, attached beneath the bag; engines and propellers; and rudders to steer the craft. Three basic types of airships have been built. The nonrigid airship, or blimp, is basically a balloon from which the car is suspended by cables. It is usually small and depends on the internal gas pressure to keep the balloon from collapsing. The semirigid airship, which likewise depends on the inflating gas for its shape, can be bigger because the car is supported by a structural keel that extends longitudinally along the balloon's base. The rigid airship, also called a dirigible or zeppelin, has a covered framework of girders that houses a number of separate gas-filled cells. It maintains its shape whether the gas cells are filled or empty.

      Although airships made notable advances as military and passenger vehicles in the first half of the 20th century, gains in the capabilities of conventional aircraft coupled with a series of airship disasters (the best-known being the explosion of the hydrogen-filled dirigible Hindenburg in 1937) caused enthusiasm for them to fade. In the 1970s and '80s, interest in blimps was reawakened in Britain when Airship Developments, later Airship Industries, created a successful fleet of multirole airships. The prototype, the AD500, first flew in 1979, and the production model, the Skyship 500, made its maiden flight two years later. Commercial service, consisting of sightseeing tours over London, began in 1986. Using vectored thrust and ducted engines, the Skyship design was sufficiently maneuverable to obviate the need for a large ground crew. Following bankruptcy of Airship Industries and a series of ownership changes and amalgamations in the 1990s, the company's blimp operations passed to Global Skyship Industries. With its sister company, Airship Operations, Inc., Global Skyship Industries builds and operates blimps for commercial advertising, military, and government applications worldwide.

      In the United States, American Blimp Corporation was founded in 1987 to produce simple, comparatively low-priced airships and has since become a leading maker of small blimps for advertising and airborne surveillance applications. In the same year, Goodyear Tire & Rubber Company (Goodyear Tire & Rubber Company), after having built more than 300 airships since it entered the business in the 1920s, sold its lighter-than-air operations to electronics manufacturer Loral, which liquidated the assets shortly thereafter. By the 1990s, the German company founded by Ferdinand, Graf (count) von Zeppelin (Zeppelin, Ferdinand, Graf (count) von), in 1908 was still in operation, but it had not built an airship in more than half a century. In 1993 it returned to its roots by forming Zeppelin Luftschifftechnik GmbH with the objective of developing and operating a line of semirigid new-technology (NT) airships for tourism, advertising, and surveillance applications. The first flight of a Zeppelin NT took place in 1997. Another German company, CargoLifter AG, formed in 1996, was developing a semirigid airship with a 160-metric-ton payload for heavy-lift cargo applications.

Secondary and tertiary aerospace systems
      The secondary product line of the aerospace industry comprises the numerous onboard subsystems required by the designs of the various flight vehicles. Propulsion and avionics are the two most important secondary systems. The industry's tertiary product line includes those ground-based items necessary for the support of flight vehicles.

      There are three basic types of flight vehicle-propulsion systems: piston engines (or reciprocating engines), turbine engines (true-jet, turboprop, and turboshaft engines), and rocket engines (see airplane: Propulsion systems (airplane) and rocket). At the low end of the performance spectrum are reciprocating engines. Although during World War II and the early postwar period the industry developed units having as many as 18 cylinders and capable of generating 2,000 kilowatts (about 2,700 horsepower), modern units have typically two to six cylinders and provide between 30 and 400 kilowatts (40 and 540 horsepower). More powerful turboprop engines were also produced in the past, but current needs require performance only in the range of 300–400 kilowatts (400–540 horsepower). The largest range in performance exists among turbofan jet power plants—a factor close to 50 between the least and most powerful. At the top are engines with thrusts in the range of 160–400 kilonewtons (36,000–90,000 pounds), used on long-haul jet aircraft such as the Boeing 747 and 777 and Airbus A330. Such engines make up roughly 20 percent of the total aircraft cost.

      Three large aerospace engine manufacturers have product lines that range from small turboprop power plants to the highest-thrust turbofans: General Electric (General Electric Co.) Aircraft Engines and Pratt & Whitney (a subsidiary of United Technologies (United Technologies Corporation)) in the United States and Rolls-Royce (Rolls-Royce PLC) in Britain. A number of smaller firms produce small-to-medium-size turbofans, as well as turboprop and turboshaft engines. Examples are SNECMA and Turboméca in France; the DaimlerChrysler subsidiary MTU Aero Engines in Germany; Volvo Flygmotor in Sweden; FiatAvio in Italy; Aero Engine Corporation in Japan; Williams International, Rolls-Royce Allison, Textron Lycoming, and Honeywell (Honeywell International Inc.) in the United States; and Pratt & Whitney Canada. Notable manufacturers from the former Soviet Union are Klimov, Kuznetsov, Aviadvigatel, and Saturn.

      Rocket engines are used as power plants for guided missiles and space launch vehicles and for maneuvering and maintaining the position of spacecraft. Because of the requirement for long storage, the great majority of missiles are powered by solid-fuel systems. Such systems are disadvantageous in that their thrust per quantity of fuel consumed is relatively low and that, once ignited, they cannot be turned off. Consequently, most space launch vehicles requiring control and multiple starts employ liquid-propellant systems as main engines for the primary stages but use large solid-fuel rockets as boost-stage auxiliaries for additional thrust in the initial phase of launch. Among American companies engaged in the production of rocket motors are Boeing (Boeing Company)'s subsidiary Rocketdyne, Thiokol, Kaiser Marquardt, and Aerojet General. In Europe, SEP, a division of SNECMA, predominates. Russian systems are produced by Energomash and Kuznetsov.

      Initially only low-thrust liquid-fuel systems were used for spacecraft onboard propulsion. Beginning in the 1990s, small, simple electric propulsion systems, or ion engines, have been used as well. Ion engines give a positive electric charge to atoms or molecules and then accelerate the resulting ions to high speed to produce thrust. Boeing Satellite Systems (formerly part of Hughes Electronics) makes the Xenon Ion Propulsion System (XIPS) for its own satellites and NASA spacecraft. In Europe suppliers include EADS (European Aeronautic Defence and Space Company) and the Dutch company Fokker Space.

       avionics includes all instruments, sensors, and electronic equipment and the electrical systems that link them to each other and to aerospace vehicle-control systems. It encompasses the functional equipment for guidance, navigation, and communications. A modern airline transport can contain more than 1,000 sensors and “black boxes.” The latter are metal or plastic housings in which electronic and electrical components are grouped to perform specific functions. (They differ from flight recorders (flight recorder), also dubbed black boxes, which record the performance and condition of an aircraft in flight.) For advanced military aircraft, avionics represents as much as 35 percent of the total cost; when radar and other electronic and electro-optic system adjuncts are included, the value can exceed 50 percent. For some spacecraft, the equivalent equipment can reach 70 percent of the cost. Leading manufacturers of avionics systems include Rockwell Collins, Honeywell (Honeywell International Inc.), and Litton in the United States and Thales Avionics in France.

Other secondary systems
      Modern aerospace vehicles may have dozens of separate subsystems other than propulsion and avionics. The number of individual product items is too lengthy for even a catalog listing, but a sampling of important products illustrates the breadth of the secondary product line.

      Aircraft secondary systems are reflected in an extensive industrial infrastructure, with products falling largely into four categories: (1) structural and mechanical, (2) propulsion and power-related, (3) environmental control, and (4) communications and navigation. The first category encompasses aerodynamic controls and actuators (mechanical or fly-by-wire systems), doors, engine nacelles and pylon fairings, control surfaces, and takeoff-and-landing-gear systems (including nosewheel steering, brakes, shock absorbers, and tires). The second category covers propellers, thrust reversers, fuel tanks and fuel-management systems, engine starters, auxiliary power units, air-driven generators, and electrical systems. The third category includes pressurization and air-conditioning equipment, ice-detection and anti-icing systems, electronic flight-instrumentation systems, engine-indication and crew-alerting systems, conventional cockpit instruments, and autopilots and flight directors. The fourth category encompasses communication systems, navigation equipment (including radio, optical, electronic, and inertial-reference systems; instrument-landing systems; receivers for satellite-based global positioning systems; traffic-alert and collision-avoidance systems; and heads-up displays), and cockpit voice and flight data recorders. Commercial aircraft add galleys and toilets, onboard entertainment and announcement systems, emergency slides and rafts, and other equipment for passenger comfort and safety. Special subsystems in military aircraft include ejection seats and separable cabins, multimode radar, armament, stores stations for external weapons, electronic countermeasure systems for confusing enemy defenses, arrester hooks for aircraft carrier landings, braking parachutes, identification friend or foe (IFF) systems, and photographic, infrared imaging, and other sensory devices for intelligence gathering together with onboard intelligence-processing equipment.

      Secondary products for missiles and space launch vehicles include the many sensors and control mechanisms associated with their guidance and target-acquisition functions, small rocket motors, and weapons elements (in the case of missiles). For both missiles and launch vehicles, however, avionics related to navigation and control represent the highest-value elements.

      Examples of spacecraft secondary products are power sources—such as solar panels, batteries, and fuel cells—and photographic, radar, infrared, and other types of sensory devices for military intelligence gathering and for civil use including meteorology and remote sensing of the Earth. Additionally, for manned spacecraft there are special-purpose radars for docking in space or landings; environmental-control systems; cabin instrumentation and displays; space suits; and galleys, water dispensers, and waste-management systems designed for operation under microgravity conditions.

      Many of the companies involved make lines of aerospace products that are variants of their products for other industries. An example is Goodyear Tire & Rubber (Goodyear Tire & Rubber Company), which supplies tires for aircraft as well as land vehicles. Other secondary-product companies were at one time producers of primary systems such as engines. Examples are the French firm Messier-Dowty (a subsidiary of SNECMA) and the American firm Goodrich (Goodrich Company), both of which were small-engine manufacturers before becoming major suppliers of landing gear.

Tertiary systems
      One major group of ground-based support products comprises simulation devices—systems used for training aircraft and spacecraft crews and for research-and-development processes. The simulators built in the largest quantities are chiefly for civil transport aircraft and military fighters and are used to train pilots for operating specific aircraft and handling emergency situations (see flight simulator). Two basic classes exist: full flight simulators (FFSs) and flight training devices (FTDs). FFSs are complex machines that consist of a cockpit, motion system, and visual system controlled by high-speed computers. Some models provide such realism that pilots can make the transition to a new model of aircraft solely by simulator training, a process called zero-flight-time conversion. The much simpler FTDs, also known as part-task simulators, are used for training crew members on specific aspects of flight operations—for example, the use of communications equipment. The market for airliner flight simulators is essentially served by the Canadian firm CAE Inc.; Thales Training & Simulation Ltd., a subsidiary of the French company Thales Group; and the American firm FlightSafety International. The same companies produce military simulators.

      Another major group of tertiary aerospace products are ground radars and antennas with their associated data-processing systems. This equipment is employed for air traffic control (traffic control), detection and tracking of potentially hostile flight vehicles, remote command of missile guidance, interception guidance of air-defense aircraft, and tracking of spacecraft. Air traffic control systems are produced by firms such as IBM, Boeing, and Lockheed Martin in the United States and GE Ferranti and Thales ATM in Europe. Harris Corporation and Raytheon, among others, contribute ground-based radar and data-processing equipment. A third important group of tertiary products comprises automatic checkout equipment for complex aircraft, space vehicles, and missiles.

Industry processes
      Aerospace products and the processes by which they are made are complex in nature, and knowledge of the latter is important to an understanding of the industry. A substantial investment in research, involving specialized personnel and facilities, is critical to the aerospace industry, as it is to most industries in which development and productivity play highly important roles. Subsequent product development and the transition of new technologies through design and testing to production also involve numerous processes and practices, many dependent on sophisticated equipment and facilities. The absolute size of the products themselves demands massive structures to house their assembly and, in the case of space launchers, can require the construction of immense support equipment.

      Investment sources for these processes derive from government financing on a pay-as-needed basis for military and other national projects or from capital raised by equity financing—either by public or risk-sharing private investors or by loans from normal venture sources such as banks and insurance companies. As the cost of large air transports has increased to the hundreds of millions of dollars, leasing has become an effective conserver of cash flow for airlines, and the leasing companies have become the source of procurement funds for the contractors. Consistent with the high level of total funds required and with the risk in cost and market, shared investment among suppliers and prime contractors over the entire life of a program has become a more frequent practice as well.

      The world's aerospace industry undertakes research and development alone and in conjunction with governmental agencies and academia. The ultimate aim of the effort is the creation of flight vehicles more advanced than their predecessors. Because of the complexity—i.e., the “systems” nature—of the industry's end products, advancements commonly require improvements across many technological disciplines.

      Aerospace research and development comprises three main activities. Basic research involves investigations that may have no application in existing systems but provide advancement of knowledge for its potential. Applied research is the investigative effort aimed at direct applications. Development, by definition, is the use of scientific knowledge directed toward the production of useful materials, devices, systems or methods, including design and development of prototypes and processes; it is the translation into hardware and software of the results of applied research. The primary focus in the aerospace industry is on applied research and development related to the introduction and improvement of products.

      Since applied research is absolutely vital to the competitiveness of the industry, it is often supported by governments. In the United States, funds are commonly provided by agencies such as NASA and the military service laboratories that work directly with the country's industry. In Europe and the rest of the world, governments most often provide financial support for research directly to their countries' industry. The multinational European Space Agency maintains ESTEC, the European Space Research and Technology Centre, in Noordwijk, Netherlands. ESTEC is the technical development interface between European industry and the scientific community. It oversees the development of spacecraft, and it has its own technological laboratories and extensive facilities for testing spacecraft and components under simulated launch and in-space conditions. Britain, Sweden, and France also support notable government laboratories.

      Reducing the weight of aircraft structures has always been a focus of research. In addition to ongoing research into composite materials (composite material), investigation of aluminum-lithium and other alloys continues to foster advances in metals. Materials (materials science) research for supersonic and hypersonic vehicles focuses on both high-temperature polymers and lightweight metals as well as high-temperature polymer-matrix composites, adhesives, sealants, light alloys, and metal-matrix composites for structural applications (see materials science: Materials for aerospace (materials science)).

      To improve the all-weather operation of commercial aircraft, enhanced vision systems using video and infrared cameras or millimetre-wave radar are being pursued. Other areas of research include fly-by-light techniques that transmit commands through fibre-optic cables rather than electrically. The demand for longer vehicle lifetimes has made vital the development of nondestructive evaluation techniques to measure quality states and estimate the remaining lifetimes of structures.

      In the military (military aircraft) sector, research studies focus on means to enhance the maneuverability and survivability of flight vehicles. Combat survivability is defined as the capability of an aircraft to avoid or withstand a hostile environment, and related research centres on threat warning, signal jamming, radar deception, reduction of infrared signatures, threat suppression, redundancy and protection of components, passive and active damage suppression, and shielding.

      Since the first spacecraft were launched, the size and weight of satellites and probes have increased constantly, as have costs. Much of spacecraft research is focused on reversing this trend by miniaturizing instruments, propulsion systems, power sources, and other components and developing small spacecraft that can replace larger systems. Important research directions include vehicle autonomy, microelectronic and microelectromechanical systems, ion engines, modular architecture and multifunctional systems, and high-efficiency solar arrays that replace silicon cells with significantly more effective photovoltaic materials such as gallium arsenide.

Product development and testing
      Initiation of the product development process differs between the military and commercial sectors. In the United States the defense services normally provide detailed mission specifications for desired products, against which contractors submit proposals as part of a competitive process. Proposals are reviewed, and one or more development contractors are selected. In some cases contracts are awarded solely for the development of competitive prototypes. The company or team of companies that develops the winning design then may receive a full-scale development and production contract.

      In the civil aircraft sector, manufacturers conduct detailed market studies to determine the need for new vehicle designs, then define specifications, announce to potential customers their intention to develop the new product, and solicit orders. When sufficient firm orders are obtained—from the so-called launching customers—the program is officially initiated. The customers' engineers generally work together with the manufacturers to influence the final design to fit specific needs.

      The design cycle of a new flight vehicle has changed radically since the 1980s because of new methods, tools, and guidelines. Traditionally, the cycle begins with a conceptual design of the overall product followed by the preliminary design, in which most or all subsystems take shape. In most, if not all, cases, several iterations must be made before a final design is achieved. Since not all production issues are generally anticipated by design engineers, substantial design rework is common. Despite the apparent simplicity of the initial conceptual design phase, 70–80 percent of the aerospace product's cost is determined in this stage.

      Because reducing costs has become increasingly important, a new design method, concurrent engineering (CE), has been replacing the traditional cycle. CE simultaneously organizes many aspects of the design effort under the aegis of special teams of designers, engineers, and representatives of other relevant activities and processes. The method allows supporting activities such as stress analysis, aerodynamics, and materials analysis, which ordinarily would be done sequentially, to be carried out together. A step beyond CE, incorporating production, quality assurance, procurement, and marketing within the teams, is a method called integrated product and process development (IPPD). IPPD ensures that the needs of the users and those who bring the product to the customer through manufacturing and outside procurement are considered at the beginning of the design/build cycle. In cases in which maintenance plays a major role in the life cycle of a product, relevant personnel from that segment are also brought into the teams.

      CE and IPPD have resulted in numerous improvements for the industry. They have shortened the total time required to bring products to market, simplified product structures by reducing parts counts, lowered product and life-cycle costs, reduced defect rates, increased reliability, and shortened development cycles. For example, in the development of the 777, Boeing formed 238 design/build teams, which helped to reduce the number of changes necessary after release of initial designs to less than half of that for earlier models done conventionally.

      Traditionally, the design process of defense aerospace systems has been governed by military specifications and standards, which specify in detail what to build and how to build it. In June 1994 a U.S. Department of Defense memorandum substituted performance specifications describing system requirements for previously used military specifications. The policy was intended to reduce costs, shorten acquisition cycles, and allow the use of commercial off-the-shelf advanced technologies and hardware. Contractors were thus given more freedoms but were also required to accept more accountability for the success or failure of their products. Although European design processes have not yet incorporated this approach, the introduction of commercial quality standards is being progressively implemented under international commercial guidelines published by the International Organization for Standardization (ISO).

Use of computers
      The computer has also fundamentally changed the development process by permitting digital modeling and simulation as well as computer-aided design in conjunction with computer-aided manufacturing (CAD/CAM; see computer-aided engineering). In the early design stage of a flight vehicle, digital computer modeling of prospective designs enables rapid examination of several candidate configurations and thus replaces a portion of costly wind-tunnel testing. Modern systems create a three-dimensional model—a virtual flight vehicle—based on the data sets entered. All details, from the airframe to the electric subsystem, are stored in the computer. This eliminates the requirement for full-size physical models, known as mock-ups, on which the engineers verify design layouts. Widely used CAD/CAM software packages in the aerospace industry include CATIA from Dassault (Dassault Industries) Systemes/IBM, Unigraphics from Unigraphics Solutions, and CADDS and Pro/ENGINEER from Parametric Technology Corporation. Boeing used the CATIA package to develop the 777, the first aircraft to have been designed completely with computers without a mock-up.

Wind-tunnel (wind tunnel) testing
      Computer simulation has reduced the amount of wind-tunnel (wind tunnel) testing necessary, but the latter remains an important part of the development process in the aerospace industry. During development of the Boeing 777, for example, some 2,000 hours in the wind tunnel were clocked. The wind tunnel, which predates powered flight by 32 years, is a test apparatus in which air is blown over a model in a test section, creating an effect comparable to flight. Some low-speed tunnels have test sections large enough to accommodate a complete small airplane or a wing-nacelle section of a large aircraft. In high-speed tunnels, for which a large amount of energy must be supplied to provide supersonic velocities, test models are of reduced scale—for research purposes they are sometimes only centimetres in span or length. Tunnels are classified according to airflow velocity: subsonic (up to Mach 0.8), transonic (Mach 0.8–1.2), supersonic (Mach 1.2–6), hypersonic (Mach 6–12), or hypervelocity (above Mach 12).

Prototype testing and certification
      In the prototype construction phase, emphasis shifts to testing. A customary procedure is to build several test airplanes solely to verify the design. The structural integrity of the aircraft is determined in static and dynamic tests. Ground testing requires an array of facilities, including ovens for applying high temperatures to materials, acoustic chambers to permit study of the effect of high-frequency engine noise on structures, rigs for measuring landing impacts, and variable-frequency vibrators for investigations of vibration and flutter characteristics of structures. Test fixtures verify that the ultimate load factor called for in the design has been met or exceeded; for example, the wings may be loaded until they break. In dynamic or fatigue tests, the life of the aircraft is simulated in time-lapse fashion. Thus an airplane may go through more than 100,000 equivalent “flight hours” before it is taken apart and examined completely in every detail.

      While prototype airframes are being built, tests are also conducted on ancillary equipment. Because of the broad variety of this equipment, the testing process differs for each system. Structural and mechanical systems are tested in similar fashion to that described for aircraft structures, whereas electrical and electronic equipment is exhaustively checked by a battery of electronic test equipment that is often tailored to the system being examined. As the equipment is run through its performance cycle, monitors affirm or detect and isolate faults for correction. In many cases, complete systems are further checked in altitude chambers that simulate operating environments.

      Engines (jet engine) are tested in the propulsion equivalent of the wind tunnel, a test cell capable of simulating flight conditions. To qualify for installation, a new engine undergoes several hundred hours of testing that embraces the entire intended range of speed and altitude capacity of the airplane. In endurance testing, the engine must operate for more than 1,000 hours continuously, many at maximum thrust. In one unique test, dead birds are thrown into the engine to simulate its in-flight ingestion of living birds, a hazard that has caused flight failures. Test engines are heavily instrumented, and the recorded data are transmitted to a computer for processing. After the test runs, the engines are completely disassembled and inspected.

      As a general rule, flight testing of prototype aircraft is conducted over sparsely populated areas or over water because of the possibility of accident and to allow freedom for maneuvers. Flight testing is necessary to validate what has only been analysis to this stage, although modern procedures of computerized design and wind-tunnel testing are so thorough and extensive that the results of the flight-test phase rarely dictate a major design change. Because simulators allow test pilots to “fly” the aircraft well before the first prototype has been built, the behaviour of the plane tends to conform to specifications and expectations.

      Regulations for flight certification largely govern tests for commercial aircraft, and certification takes approximately one year. Military aircraft flight testing, which includes performance with many different weapons systems, takes nearly twice that time. For certification, all aircraft must demonstrate capabilities in numerous performance tests under all anticipated conditions—for example, emergency braking, stall trials, loss of engine thrust, and takeoff and landing in extremely hot, cold, high-altitude, and low-altitude environments.

      Once a civil aircraft has demonstrated its airworthiness in the flight certification program, it can enter regular service. The necessary certificates are issued in the United States by the Federal Aviation Administration (FAA) and in Europe by the Joint Airworthiness Authorities (JAA). These certifications are required for any aircraft purchased within the United States or Europe, respectively, and serve throughout the world as the basis for certifying civil aircraft that are to enter service in those countries. Russia and China have certification processes largely modeled on American and European standards. Significant aircraft suppliers from Brazil, Japan, and Indonesia use American and European certification standards.

spacecraft, launch vehicle, and missile development
      The research effort that goes into the development of missiles, launch vehicles, and spacecraft parallels that of the airplane in the design and ground-test stages but differs for the flight-test stage. For major launch vehicles and strategic missiles, the absence of a pilot on board, the great expense of a single launch, and the inability to recover and reuse the test vehicle call for rigorous test techniques, highly elaborate instrumentation both in the vehicle and on the ground, and extraordinarily intensive preflight checkout in order to prevent a costly abort.

      Unmanned spacecraft are unique in that they rarely undergo prototype test flights; rather, they are carried into orbit with their full complement of operational instrumentation on tested launch vehicles. Spacecraft instrumentation sends information about performance and operation back to the Earth, thereby providing the basis for design refinement in later models of the same family. The substitute for prototype testing is ground-based simulation, conducted in two types of simulators: the space simulator, which duplicates all the environmental conditions in which the spacecraft will operate, and the mission simulator, which permits carrying out the entire range of maneuvers and system operations that might be performed on an actual flight.

Historical context
      Understanding modern aerospace manufacturing processes requires that they be viewed in the context of the historical development of vehicle design. The spruce and fir frames of aircraft through World War I required skilled woodworkers and their equipment, coupled with crafters—often women transferring homemaking skills to the shop—who laced or sewed fabric to the frames. These “skins” for the wings and fuselages were painted with acetone-based lacquers or dopes to tighten and toughen surfaces; thus factories had large brush or spray areas with natural or induced air circulation to enhance drying and dissipation of fumes. At the same time, with the exception of the air-cooled engine designs developed by the Wright brothers and sold widely in Europe, aircraft engine manufacturing was an extension of the production of liquid-cooled automobile motors. Emphasized were refined machining techniques for the cylinder head fins, which provided the extensive cooling surfaces needed.

      The advent of metal airframes changed both the character of manufacturing processes and the skills required of production workers. At first, only the wood framework of fuselages was replaced by tubular aluminum trusses connected with mechanical fasteners or welding; coverings were still sewn and glued fabric. In the mid 1930s, as thin rolled aluminum alloys became available, all-metal structures for fuselages and then wings became prevalent. Skilled craftsmen were required to operate the metalworking machines, and new emphasis was placed on flush riveting and welding and on hard tooling of fixtures to facilitate alignment and assembly. At the same time, the forging of landing-gear components and major structural fittings and the forming of sheet metal grew to resemble processes in the automobile industry. This affinity became particularly close as all-metal bombers and transports revolutionized manufacturing of all but small private planes. It was not surprising, therefore, that the mass producers of automobiles and related equipment became manufacturers of military aircraft during World War II.

      After the war, jet propulsion and other technical advances led to further changes in manufacturing techniques and processes. The economics of high-speed transports resulted in increases in passenger capacity, which necessitated aircraft much larger than wartime bombers. This, in turn, required expanded facilities and fixtures such that by the start of the 21st century initial plant investment for modern airliners had reached as high as $2 billion, even with more than 50 percent of the work being done by suppliers to the prime contractor. Thus, a community of structural subassembly contractors building wings, sections of fuselages, and horizontal surfaces now relieve some of the space and tooling needs of prime contractors such as Boeing (Boeing Company) in the United States and Airbus Industrie in Europe. Russian companies, however, still operate in a more vertically integrated mode, keeping all aspects of component manufacture and assembly within one organization.

      Modern aircraft manufacture has been described as “a craft process with a mass production mentality.” With the exception of experimental and very specialized airplanes, this has generally been true. Large aircraft consist of the assembly of one million to five million separate parts, and complex spacecraft of several hundred thousand parts. Each different type demands unique skills and manufacturing methods.

      Because of the extensive range of skills and facilities required, no single company builds an entire flight vehicle. Manufacturing in the aerospace industry crosses nearly all construction boundaries—for example, conventional machine shops for mechanical components, clean rooms for electronic parts, and unusually large final-assembly facilities for multi-hundred-ton aircraft, space vehicles, and missiles. In every developed country of the world, major aerospace production programs incorporate a complete range of hardware and software from suppliers that operate as subcontractors to the prime contractor or systems integrator. Subcontracting covers not only the onboard equipment but also, in most large projects, major elements of the airframe itself. In Europe, where large developments occur in multinational cooperative efforts, the distribution of the production is especially broad.

Fabrication processes and materials
      Fabrication involves the manufacture of individual components that make up larger assemblies or end products. This activity encompasses the working of metals and the incorporation of electrical and electronic devices into processors, circuit boards, and subassemblies for the components of navigation, communication, and control systems. Most of the basic metal-fabrication methods have been employed since World War II. Modern differences, such as tighter metal-cutting tolerances, are related to advances in the capabilities of machines and tools (see metallurgy: Metalworking (metallurgy)). In electronic fabrication, changes have mirrored those of the semiconductor and computer industries. In past decades, electronic elements having single functions were linked with wiring to make up the multiple functions necessary for systems. In modern systems, hundreds of functions are performed by a single microchip or, in conjunction with microminiaturized elements, by printed circuit boards (see integrated circuit).

Working of materials
      Metals are cut, shaped, bored, bent, and formed by tools and machines operated manually or, increasingly, under the control of computers programmed to guide the necessary operations consistently and with greater precision than can normally be provided by humans. The parallels for electrical and electronic fabrication are robotic tools for insertion of components into circuit boards, wave soldering (an automated process for securing components to circuit boards with a standing wave of molten solder) for rapid, uniform connections, and photolithography (photographic transfer of a pattern to a surface for etching) for making circuit boards and multichip modules.

      Materials play an important role not only in the fabrication methods used but also in the safety measures employed. For example, beryllium, whose combination of light weight, high strength, and high melting point makes it a valuable structural material, yields dust and chips during machining. Because exposure to beryllium particles can cause adverse health effects, special care is required to preclude their contamination of personnel or atmosphere. Polymer-matrix composites also require special contamination protection because of the toxic character of the resins involved.

      In the production of components that must bear high loads yet be as light as possible, aerospace fabricators have evolved engineering techniques for modifying the characteristics of a material. The most notable example is the so-called honeycomb sandwich, which is far lighter than a metal plate of comparable thickness and has greater resistance to bending. The sandwich consists of a honeycomb core, composed of rows of hollow hexagonal cells, bonded between extremely thin metal face sheets. Aluminum is the most extensively used metal in both core and face sheets, but the technique is applicable to a large variety of metallic and nonmetallic materials. Sandwich construction is now employed to some degree in almost every type of flight vehicle.

      Polymer-matrix composites are valued in the aerospace industry for their stiffness, lightness, and heat resistance (see materials science: Polymer-matrix composites (materials science)). They are fabricated materials in which carbon or hydrocarbon fibres (and sometimes metallic strands, filaments, or particles) are bonded together by polymer resins in either sheet or fibre-wound form. In the former, individual sheet elements are layered in metal, wood, or plastic molds and joined with adhesives. Applications for sheet composites include wing skins and fuselage bulkheads in aircraft and the underlying support for solar arrays in satellites. In fibre-wound forms, tubular or spherical shapes are fabricated by winding continuous fibre on a spinning mold (mandrel) with high-speed, computer-programmed precision, injecting liquid resin as the part is formed, and then curing the resin. This process is used for forming rocket motor casings; spherical containers for fuels, lubricants, and gases; and ducts for aircraft environmental systems.

Special requirements of military aircraft
      Military aircraft demand lightweight structures to achieve high performance. Moreover, the materials used must be able to withstand the temperatures created by air friction when the vehicle is flying at high speeds. These requirements have fostered the use of new metals such as aluminum-magnesium alloys and titanium, as well as composites and polymers for many surfaces—as much as 35 percent of the structure (see materials science: Materials for aerospace (materials science)). The manufacture of these materials and their products has created new challenges. titanium, although a relatively brittle material, has high strength-to-weight properties at operating temperatures as high as 480 °C (900 °F). Forming it into sheets generally requires heated dies and specialized machining and grinding. Titanium is therefore usually limited to applications, such as leading edges for wings and tails and related fittings, where its characteristics excel. Composites, on the other hand, are increasingly becoming staples of aircraft outer surfaces; thus, most structure manufacturers incorporate the necessary fabrication technology in their factories. To achieve required strengths, composite materials must be bonded in either hot- or cold-cure processes. Bonding is achieved within a vacuum, supplied either within evacuated rubberized bags or in autoclaves (temperature- and pressure-controlled chambers). Complementing the fabrication of composite sheets and fibre-wound forms is a comparatively recent method called pultrusion, which extrudes composite shapes in much the same fashion as molten metals are forced through a die. Other composite-making techniques incorporate the kind of ultralight structural practices used with metals and fibreglass, such as sandwich construction.

Engine and avionics manufacture
      Although the airframe manufacturers remain the major integrators and sellers of aircraft, costs of production have shifted increasingly toward the key subsystems of propulsion and avionics and auxiliary equipment such as landing gear and, in the case of military airplanes, armament. Typically, for civil transports the costs average 50 percent for structure and integration, 20 percent for engines, and 30 percent for avionics. For military aircraft, the cost of avionics, including systems associated with self-protection and weapons management, can reach 50 percent, with 20 percent for engines and 30 percent for airframe and integration. In fact, the classic final assembly and test phases represent a mere 7–10 percent of the cost of modern fighter aircraft.

      With the exception of lightweight piston engines for private craft, jet engines account for the largest production lines. The manufacture of jet engines (jet engine), including turboprops and turboshafts, requires critical attention to close tolerances, which in turn demands precision forgings, castings, and machinery from the suppliers of the engine makers. Quality issues clearly drive this production and have stimulated inspection and alignment methods employing laser instrumentation and computer techniques that enhance the application of quality-control methods such as statistical process control.

       avionics production involves not only the precision manufacture of computer processors but also extra safety and reliability issues. This has resulted in extended test requirements and tightened limits on performance parameters and has stimulated the development of new processes for circuit-board assembly.

      An increasingly important element of avionics production is the operating software. This is evidenced by the rise in software cost for U.S. defense programs from $5 billion to $35 billion between 1985 and 1995. Modern production methods for software employ “factory” techniques that translate requirements directly to code through an automated process. These have reduced the rate of software defects and substantially cut development time. Such gains are particularly significant in the context of the several million lines of code required by modern fighters and commercial transports, compared with the 20,000 lines associated with military aircraft of the 1960s.

Satellite, launch vehicle, and missile manufacture
      The manufacturing processes for aircraft are largely paralleled in the production of satellites, their launch vehicles, and missiles. Because minimum weight is critical for all three kinds of products, the use of composites has grown such that it can include the entire structure for satellites and smaller missiles. For these vehicles, electronics production plays an increased role in manufacture, accounting for as much as 70 percent of the total cost. Nevertheless, the small quantity of satellites necessary, even for large constellations in communications systems, limits some of the benefits of volume production, such as reduced costs, although this is not necessarily true of component products that are common to several satellite designs—for example, sensors, instruments, small rocket motors, and communications equipment.

Assembly methods and facilities

Building of subassemblies
      Assembly of aerospace vehicles at the prime contractor or systems integrator begins with the accumulation of subassemblies. An example of a typical subassembly for a transport aircraft is the rear fuselage section, which is itself composed of several segments. (These segments are often built by subcontractors, who in turn deal with their own suppliers of the segments' constituent elements.) The segments are taken to the subassembly area, where teams of workers fit them into support jigs or fixtures and join them into a unit, within which the interior equipment is then installed. In similar manner, teams put together other subassemblies such as the remaining fuselage sections, wing sections, tail sections, and engine nacelles. The various subassemblies then are taken to the main assembly line, where final integration takes place.

      Similarly, spacecraft comprise subassemblies (typically the structural, propulsion, guidance and control, communication, and payload modules, plus solar arrays when required), each of which is made up of many components. These modules may be built within the plant of the spacecraft integrator or by subcontractors, with final assembly and testing being the usual responsibilities and concentration of the former.

      In both aircraft and spacecraft, integration of a subassembly's components is most often effected in black boxes. In addition to enclosing electronic and electrical subelements, these housings have connectors that interface with various systems in the vehicles.

      The performance of subassemblies as units is verified prior to their integration into final assemblies. In the case of structural subassemblies, verification usually is confined to load testing, alignment and assurance of dimensions and tolerances, and electrical conformity checks for installed cabling. For subassemblies with electrical and electronic, hydraulic, and mechanically actuated components, extensive tests are usually performed in simulated flight environments incorporating vacuum, temperature, and vibration excursions. The required time, test equipment, and related computer software represent a significant portion of the cost of these elements, some 10–25 percent.

Final assembly
      The final assembly of complete aircraft usually requires a facility furnished with a network of overhead rails on which ride heavy-lift cranes capable of moving large portions of vehicles. Facility size is governed by vehicle dimensions; for example, Boeing (Boeing Company)'s plant in Everett, Washington, is the world's largest building by volume, containing some 13.4 million cubic metres (473 million cubic feet) and covering an area of 405,000 square metres (4.4 million square feet). Airbus Industrie's Final Assembly Complex Clément Ader, near Toulouse, France, although smaller, with 5.3 million cubic metres (187 million cubic feet), is Europe's largest industrial building.

      Aircraft assembly normally starts with the joining, or mating, of fuselage subassemblies that have been craned into a supporting jig or fixture. As the vehicle is assembled, it is moved through a succession of work stations, acquiring additional subassemblies and accumulating its onboard systems, ducts, control cables, and other interior plumbing. Light- and medium-weight aircraft may be moved on wheeled fixtures; heavier aircraft are craned. Modern large planes and spacecraft often are moved via an adaptation of the air-cushion technique. Highly compressed air is pumped into the assembly fixture supports and escapes downward through holes. The powerful thrust of the escaping air lifts the entire fixture and vehicle assembly several millimetres off the floor, enough to permit movement by tractor or human power. Major assembly steps include the additions of nose and tail sections, wings, engines, and landing gear. On completion of work at the last station, the airplane is rolled out of the assembly plant to the flight line for its production flight test, a process that involves a thorough checkout of specified performance.

      Many types of small missiles (missile) require no such elaborate techniques or facilities. Composed basically of a cylindrical shell, a warhead, a guidance system, and a rocket motor, they are readily assembled in a low-bay plant. Larger missiles of the ballistic type and space launch vehicles are assembled in high-bay facilities with their longitudinal axes vertical. In the case of the space shuttle, for example, the mating of the orbiter with the external tank and solid rocket boosters is conducted with tail down in the 160-metre- (525-foot-) high Vehicle Assembly Building at the Kennedy Space Center in Florida.

       spacecraft are unique among flight vehicles in that their final assembly generally takes place under clean-room conditions. A typical clean room has an atmosphere-control system that rigidly regulates temperature and humidity and bars entrance, by means of filters, of all but minuscule contamination. Walls and ceilings are typically of one-piece plastic, lacking cracks where dust might collect, and are washed and vacuumed daily. Maintenance of spacecraft or faulty equipment cannot be done within the room without a subsequent thorough environmental “scrubbing.”

      Some spacecraft are assembled at successive work stations; others remain in a fixed position while teams of specialists successively install the myriad onboard systems. Because spacecraft have no opportunity for flight testing, an intensely detailed acceptance checkout is handled in the clean room by automatic test equipment. The spacecraft is then encased in a sterile container for shipment.

      Critical for all aerospace vehicles, once they are assembled, are the methods for ensuring the quality of the manufacturing and assembly processes. In the case of aircraft this involves extensive inspections of structural and mechanical items, including functional verification of equipment such as control surfaces and systems, landing-gear operation, avionics performance, weapons-systems interfaces, and personnel (crew and passenger) environmental conditioning. Helicopters, as a special class of aircraft, receive inspections that incorporate verification of rotor drive systems and associated gear trains.

      For spacecraft, even greater emphasis is placed on functional verification including, in most cases, assurance of the performance of all critical operations in thermal vacuum chambers that simulate space. In addition, since most of its operations are not modifiable to a significant extent once a spacecraft is in orbit, those that are automatically programmed or controlled by computers require highly detailed validation. This is preferably carried out with accurate simulations, if not actual use, of the communication and command links that will be used during the space mission.

      Launch vehicles (launch vehicle) are verified in somewhat similar fashion. They are tested fully assembled, most often at the launch pad or in a proximate assembly facility where the final elements, including upper-stage rockets and payloads, are installed. The size of most launch vehicles precludes environmental testing at the fully assembled level; rather they are given such testing at the highest possible levels of subassembly. Missiles often follow the spacecraft mode, with emphasis on alignments and testing of sensors and target seekers or other guidance systems being paramount, since they are often adjusted just prior to flight.

Lean manufacturing
      Consistent with improving the economics of aerospace vehicles is the transition to a new paradigm for the entire industry, from concept development to operations. This approach involves all processes pertaining to the acquisition, design, development, and manufacturing of a product or system and has been variously called “lean,” “agile,” or “synchronous” manufacturing. It strives to eliminate non-value-added or wasteful resources, including material, space, tooling, and labour. It applies such principles as waste minimization, flexibility, and responsiveness to change; these are supported by efforts to optimize the flow of material and information and to achieve superior quality in order to eliminate scrap and rework.

      Lean manufacturing was derived from studies of the automobile industry, which showed that the best Japanese carmakers had achieved competitive advantages by using practices rooted in the principles noted. For the aerospace industry, its implementation involves major cultural changes emphasizing integrated teams of workers having decision-making responsibility at levels closest to where work is performed, in contrast to the conventional system in which responsibility is transferred upward through multiple layers of management. It is estimated that full implementation of this paradigm can reduce costs and product cycle times by 50 percent.

      In 1992 the U.S. Air Force funded a study to evaluate the applicability of lean manufacturing to aerospace products. From that effort was established the Lean Aerospace Initiative, a consortium of 20 companies and several government agencies. With federal funding, the participating firms undertook pilot programs, some of which led to the incorporation of commercial lean manufacturing practices in the manufacture of defense products. Although these changes have produced major benefits in local stages of production, their translation to entire product enterprises has been slow. Part of the reason is that a complete enterprise comprises not only design and production but also the overhead functions of administration and support as well as customers and suppliers. Nevertheless, progress was being made with the expansion of lean initiative programs to these elements.

      The maintenance support provided by aerospace-industry firms is applied primarily to corporate, commercial, and military aircraft. Light-plane maintenance is generally handled by local fixed-base operators, which are not considered part of the aerospace industrial complex. Launch vehicles and unmanned spacecraft, although maintained throughout their prelaunch life by constant checking and correction, are single-use systems. For manned spacecraft the paramount concern is crew safety. The space shuttle, for example, is thoroughly overhauled by NASA and contractor personnel after every flight. Small military missiles are maintained in the field by specialists in their operating units. Ballistic missiles similarly undergo routine maintenance at their field installations, but certain types of work, for example, realignment of structure and sensors, require return of the missile to the originating plant.

      Routine maintenance of aircraft is normally carried out by the civil or military operator. It includes frequent inspections, either after every flight or a designated series of flights or after a time interval, and minor maintenance such as replacement of a part or repair of a faulty item of equipment. This type of maintenance can be handled at most airline terminals and military bases. Major maintenance work involves complete rework of an airplane or engine that has had considerable service time. Larger airlines have their own extensive technical facilities for major overhaul, and major military air forces are similarly equipped. Usually these facilities specialize in servicing specific models to achieve a high degree of proficiency and efficiency. Despite their competition in the air, smaller airlines often cooperate on the ground and contract for the technical services of other carriers to do their maintenance work. Some manufacturers offer maintenance service through subsidiaries that specialize in this business. The costs involved in the maintenance of aerospace systems are substantial. For example, over the lifetime of a normal jet engine, an operator will spend about two to three times its original acquisition cost on maintenance.

      The role of the actual manufacturer in the maintenance of its products is principally that of a supplier of parts, documentation, and advice. Provision of spare parts is a particularly important source of revenue for the original equipment manufacturers. Boeing, for example, sends out some 650,000 spare parts per year to about 400 airlines. The firm's key spare-parts centre holds 410,000 different parts—50,000,000 items altogether—and operates 24 hours a day. The supplying of documentation in electronic form is now a routine feature. Documentation for the Airbus A320 jetliner, which originally involved 60,000 text pages, 16,000 figures, and legions of microfilms and which weighed 100 kg (220 pounds), has been replaced by several CD-ROMs, which include the maintenance manual, an illustrated spare-parts catalog, a troubleshooting manual, and a product management database.

Inspection technologies
      The most critical portion of maintenance work is inspection to detect cracks, flaws, debonds, delamination, corrosion, and other detrimental changes before they threaten the aircraft. Inspectors do much of their work visually, often using nothing more sophisticated than a flashlight and a mirror. For most of the remainder, they use ultrasound, X-rays, eddy currents, and other nondestructive evaluation (NDE) methods (see materials testing: Nondestructive testing (materials testing)). Current research efforts in NDE techniques seek ultimately to probe entire aircraft with no disassembly. A number of newer NDE technologies including holography, pulsed thermometry, shearography, and neutron radiation are used routinely by manufacturers, especially for such critical elements as turbine components and composites, but they have as yet only limited applications in maintenance.

Airframe and engine overhaul
      To ensure the safe operation of airliners, airframes and engines of civil and military aircraft have obligatory major overhauls after specified time intervals. For the airframes (airframe) of commercial airliners, this is required after about five years (22,000 flight hours) of operation. In such a major overhaul, the first phase is an evaluation of the technical “health” of the aircraft and its engines. To do this, the entire structure is disassembled, and each component is visually inspected for wear and damage. Additionally, structures are examined by X-ray, fluorescent, ultrasonic, and dye-penetrant methods to detect defects not visible to the eye. Corrosion is removed by sandblasting or vacuum blasting. Defective components are repaired or replaced, sometimes requiring machining operations to make a part not carried as a spare. With delamination being the most frequent problem faced during maintenance of composites, specialized shops have been established as part of maintenance facilities to make required repairs.

      The second phase of overhaul consists of modifications to an aircraft, either because they are recommended by the manufacturer (through service bulletins) on the basis of service experience or because performance can be improved. An example of the latter is the strengthening of structural components to increase the maximum takeoff weight.

      Engines (jet engine), on a more frequent cycle, are completely disassembled, and individual parts are inspected and cleaned. Precision measurement equipment verifies conformance to the tight tolerance limits set by the manufacturers, and those components that are even marginally off are repaired or replaced. Engines are then reassembled, mounted in a test cell, and run through a lengthy series of tests. In all maintenance and overhaul operations, whether airframe, engine, or accessories, technicians are required to follow the same quality-control procedures that were in effect during original manufacture.

Remanufacture and upgrading
      The most elaborate type of program under the general heading of maintenance is the remanufacturing process. Performed at aircraft-manufacturing facilities, remanufacture is a measure that combines a general overhaul with an upgrade of some of the aircraft's systems. The latter process often paces the progressive development of a basic airplane type through several models, and it incorporates design changes and improved onboard systems dictated by service experience with the original model. Thus, if a particular model in service still has years of useful life, it is more economical to upgrade its systems by remanufacture than to build an entirely new aircraft.

      A second reason for upgrades is the increasing in-service time being demanded from all aircraft. Factors such as the escalating prices of new military fighters and declining defense budgets have forced most countries to modernize their existing aircraft in order to prolong their useful life until newer craft can be afforded. The jet-fighter (fighter aircraft) upgrade market has become increasingly significant, spawning an industry ranging from independent small firms to large national aircraft conglomerates, including the original manufacturers, which often team with the industry of the potential customer country to make a sales offer more attractive. The leading company in the fighter upgrade market is Israel Aircraft Industries, which transformed an aborted airplane-development program into this lucrative market. Fighter upgrades most often target three areas: avionics, engines, and armament, all of which can greatly improve the performance of the vehicle. Following reassembly, painting, and production testing, upgraded fighters frequently come close in performance to that of later models.

      For commercial aircraft the upgrade process is analogous. Here, too, the emphasis is on avionics and engines, especially the latter. These upgrades can prolong the profitable operation of the aircraft or allow it to meet the latest noise and emission regulations.

Stanley I. Weiss Amir R. Amir

Additional Reading

General works
Roger E. Bilstein, Flight in America: From the Wrights to the Astronauts, rev. ed. (1994), is a general treatise on the development of aviation and spaceflight for the layperson, and his The American Aerospace Industry: From Workshop to Global Enterprise (1996) provides an account of the development of the American aerospace industry. The best source for historical aerospace data is Charles Harvard Gibbs-Smith, The Aeroplane: An Historical Survey of Its Origins and Development (1960). An excellent source on the development of the American aircraft industry to the 1940s is Grover Loening, Takeoff Into Greatness (1968). Charles D. Bright, The Jet Makers: The Aerospace Industry from 1945 to 1972 (1978), details the aerospace industry in the United States after World War II. T.A. Heppenheimer, Turbulent Skies: The History of Commercial Aviation (1995), traces the ascent of the airline business from the biplane era to modern jetliners, and Countdown: A History of Space Flight (1997) includes excellent coverage on the development of the space industry. Bill Gunston, World Encyclopedia of Aircraft Manufacturers (1993), provides a brief listing of the world's aircraft manufacturers from the pioneers to the early 1990s. Daniel Todd and Jamie Simpson, The World Aircraft Industry (1986), discusses the state of the aerospace industry by country and technology and provides statistical data in the appendix.

Aerospace companies and projects
David Weldon Thornton, Airbus Industrie: The Politics of an International Industrial Collaboration (1995), describes the integration of Europe's disparate aerospace industries into an industrial power that ended the American monopoly in the commercial airliner business. Additional accounts of the Airbus consortium are found in Guy Norris and Mark Wagner, Airbus (1999); and Matthew Lynn, Birds of Prey: Boeing vs. Airbus, a Battle for the Skies, rev. ed. (1997). Brian Trubshaw, Concorde: The Inside Story (2000); and Christopher Orlebar, The Concorde Story, new ed. (1997), cover the development of the British-French supersonic passenger transport. The collapse and recovery of Britain's aerospace business in the last decades of the 20th century is recounted in Richard Evans and Colin Price, Vertical Take-Off: The Inside Story of British Aerospace's Comeback from Crisis to World Class (1999). Specific American aerospace companies are examined in Eugene E. Bauer, Boeing: The First Century (2000); Robert Redding and Bill Yenne, Boeing: Planemaker to the World, rev. and updated ed. (1997); Bill Yenne, McDonnell Douglas: A Tale of Two Giants (1985), and Rockwell: The Heritage of North American (1989); and Walter J. Boyne, Beyond the Horizons: The Lockheed Story (1998). Accounts of individual Soviet design bureaus and the men who shaped them are found in R.A. Belyakov (R.A. Belíàkov) and J. Marmain, MiG: Fifty Years of Secret Aircraft Design, trans. from Russian (1994); Vladimir Antonov et al., OKB Sukhoi: A History of the Design Bureau and Its Aircraft (1996); Paul Duffy and Andrei Kandalov, Tupolev: The Man and His Aircraft (1996); and James Harford, Korolev: How One Man Masterminded the Soviet Drive to Beat America to the Moon (1997).

The best reference work for aircraft production data on types produced is Jane's All the World's Aircraft (annual). The best reference work on space hardware produced, the space industry, and space-related organizations is Jane's Space Directory (annual). Aerospace Facts and Figures (annual), prepared by the Aerospace Industries Association of America (AIA), is a standard reference source for figures on the American aerospace industry. Aerospace Yearbook (1919–70), compiled by the AIA and its predecessors, is a standard reference source on the U.S aerospace industry to 1970. Aviation Week & Space Technology (weekly) is the best source for the latest information on the aerospace industry. Space News (weekly) covers the business news of the space industry. Flight International (weekly) is an aerospace news magazine published in the United Kingdom. An informative German-language aerospace magazine is Flug Revue (monthly).Stanley I. Weiss Amir R. Amir

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Universalium. 2010.

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