1.
Apollo 13
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Apollo 13 was the seventh manned mission in the American Apollo space program and the third intended to land on the Moon. The mission was commanded by James A. Lovell with John L. Jack Swigert as Command Module Pilot, Swigert was a late replacement for the original CM pilot Ken Mattingly, who was grounded by the flight surgeon after exposure to German measles. The story of the Apollo 13 mission has been dramatized multiple times and that crew was composed of L. Gordon Cooper, Jr, Donn F. Eisele, Edgar D. Mitchell. Deke Slayton, NASAs Director of Flight Crew Operations, never intended to rotate Cooper and Eisele to another mission and he assigned them to the backup crew simply because of a lack of flight-qualified manpower in the Astronaut Office at the time the assignment needed to be made. Slayton felt Cooper had no more than a small chance of receiving the Apollo 13 command, if he did an outstanding job with the assignment. Thus, the original assignment Slayton submitted to his superiors for this flight was, shepard, Jr, Stuart A. Roosa, Edgar D. Mitchell. Seven days before launch, the Backup Lunar Module Pilot, Charlie Duke and this exposed both the prime and backup crews, who trained together. Mattingly was found to be the one of the other five who had not had rubella as a child. Three days before launch, at the insistence of the Flight Surgeon, Mattingly never contracted rubella and was assigned after the mission as Command Module Pilot to Youngs crew, which later flew Apollo 16, the fifth mission to land on the Moon. Vance D. Brand, Jack R. Lousma, Joseph P. Kerwin, Gene Kranz – White Team, Glynn Lunney – Black Team, Milt Windler – Maroon Team, Gerry Griffin – Gold Team. The astronauts mission insignia was sculpted as a medallion titled Steeds of Apollo by Lumen Martin Winter and was struck by the Franklin Mint. Mass, CSM Odyssey 63,470 pounds, LM Aquarius 33,490 pounds, Perigee,99.3 nautical miles, Apogee,100.3 nautical miles, Inclination,31. 817°, Period,88.19 min. The Apollo 13 mission was to explore the Fra Mauro formation, or Fra Mauro highlands and it is a widespread, hilly selenological area thought to be composed of ejecta from the impact that formed Mare Imbrium. The next Apollo mission, Apollo 14, eventually made a flight to Fra Mauro. April 14,1970 UTC Oxygen tank explosion,03,07,53 UTC,173,790.5 nmi from Earth CSM power down, Crew was on board the USS Iwo Jima 45 minutes later. The mission was launched at the time,02,13,00 PM EST on April 11. An anomaly occurred when the second-stage, center engine shut down two minutes early. The engine shutdown was determined to be caused by severe pogo oscillations measured at a strength of 68 g, the vehicles guidance system shut the engine down in response to sensed thrust chamber pressure fluctuations
2.
Profession
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The term is a truncation of the term liberal profession, which is, in turn, an Anglicization of the French term profession libérale. Medieval and early modern tradition recognized only four professions, divinity, medicine, the military officer, just as some professions rise in status and power through various stages, others may decline. Disciplines formalized more recently, such as architecture, now have equally long periods of study associated with them, originally, any regulation of the professions was self-regulation through bodies such as the College of Physicians or the Inns of Court. With the growing role of government, statutory bodies have taken on this role. It may be resisted as limiting the freedom to innovate or to practice as in their professional judgement they consider best. An example was in 2008, when the British government proposed wide statutory regulation of psychologists, besides regulating access to a profession, professional bodies may set examinations of competence and enforce adherence to an ethical code. Typically, individuals are required by law to be qualified by a professional body before they are permitted to practice in that profession. However, in countries, individuals may not be required by law to be qualified by such a professional body in order to practice. This requirement is set out by the Educational Department Bureau of Hong Kong, Professions tend to be autonomous, which means they have a high degree of control of their own affairs, professionals are autonomous insofar as they can make independent judgments about their work. This usually means the freedom to exercise their professional judgement, however, it also has other meanings. Professional autonomy is often described as a claim of professionals that has to serve primarily their own interests, one major implication of professional autonomy is the traditional ban on corporate practice of the professions, especially accounting, architecture, medicine, and law. This means that in many jurisdictions, these professionals cannot do business through regular for-profit corporations, the obvious implication of this is that all equity owners of the professional business entity must be professionals themselves. This avoids the possibility of an owner of the firm telling a professional how to do his or her job. But because professional business entities are locked out of the stock market. Professions enjoy a social status, regard and esteem conferred upon them by society. This high esteem arises primarily from the social function of their work. All professions involve technical, specialized and highly skilled work often referred to as professional expertise, training for this work involves obtaining degrees and professional qualifications without which entry to the profession is barred. Updating skills through continuing education is required through training and this power is used to control its own members, and also its area of expertise and interests
3.
Aeronautics
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Aeronautics is the science or art involved with the study, design, and manufacturing of air flight capable machines, and the techniques of operating aircraft and rockets within the atmosphere. The British Royal Aeronautical Society identifies the aspects of aeronautical Art, Science and Engineering and the profession of Aeronautics. A significant part of science is a branch of dynamics called aerodynamics, which deals with the motion of air. Attempts to fly without any real aeronautical understanding have been made from the earliest times, typically by constructing wings, wiser investigators sought to gain some rational understanding through the study of bird flight. An early example appears in ancient Egyptian texts, later medieval Islamic scientists also made such studies. The founders of modern aeronautics, Leonardo da Vinci in the Renaissance and Cayley in 1799, man-carrying kites are believed to have been used extensively in ancient China. In 1282 the European explorer Marco Polo described the Chinese techniques then current, the Chinese also constructed small hot air balloons, or lanterns, and rotary-wing toys. The lifting medium for his balloon would be an aether whose composition he did not know, although his designs were rational, they were not based on particularly good science. Many of his designs, such as a four-person screw-type helicopter, have severe flaws and he did at least understand that An object offers as much resistance to the air as the air does to the object. His analysis led to the realisation that manpower alone was not sufficient for sustained flight, da Vincis work was lost after his death and did not reappear until it had been overtaken by the work of George Cayley. The modern era of lighter-than-air flight began early in the 17th century with Galileos experiments in which he showed that air has weight and these would be lighter than the displaced air and able to lift an airship. His proposed methods of controlling height are still in use today, by carrying ballast which may be dropped overboard to gain height, in practice de Terzis spheres would have collapsed under air pressure, and further developments had to wait for more practicable lifting gases. From the mid-18th century the Montgolfier brothers in France began experimenting with balloons and their balloons were made of paper, and early experiments using steam as the lifting gas were short-lived due to its effect on the paper as it condensed. Meanwhile, the discovery of hydrogen led Joseph Black in c.1780 to propose its use as a lifting gas, on hearing of the Montgolfier Brothers invitation, the French Academy member Jacques Charles offered a similar demonstration of a hydrogen balloon. Charles and two craftsmen, the Robert brothers, developed a material of rubberised silk for the envelope. The hydrogen gas was to be generated by chemical reaction during the filling process, the Montgolfier designs had several shortcomings, not least the need for dry weather and a tendency for sparks from the fire to set light to the paper balloon. The manned design had a gallery around the base of the rather than the hanging basket of the first, unmanned design. On their free flight, De Rozier and dArlandes took buckets of water, on the other hand, the manned design of Charles was essentially modern
4.
Astronautics
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Astronautics is the theory and practice of navigation beyond Earths atmosphere. The term astronautics was coined in the 1920s by J. H. Rosny, president of the Goncourt academy, because there is a degree of technical overlap between the two fields, the term aerospace is often used to describe both at once. In 1930, Robert Esnault-Pelterie publishes the first book on the new research field, space launch vehicles must withstand titanic forces, while satellites can experience huge variations in temperature in very brief periods. Extreme constraints on mass cause astronautical engineers to face the constant need to save mass in the design in order to maximize the payload that reaches orbit. The early history of astronautics is theoretical, the mathematics of space travel was established by Isaac Newton in his 1687 treatise Philosophiae Naturalis Principia Mathematica. Other mathematicians, such as Swiss Leonhard Euler and Franco-Italian Joseph Louis Lagrange also made contributions in the 18th and 19th centuries. In spite of this, astronautics did not become a discipline until the mid-20th century. On the other hand, the question of spaceflight puzzled the literary imaginations of such figures as Jules Verne and H. G. Wells. Δ v = v e ln m 0 m 1 In fact this equation was derived earlier by William Moore, for more information on the mathematical basis of space travel, see Orbital mechanics. The Prix dAstronautique awarded by the Société astronomique de France, the French astronomical society, was the first prize on this subject, although many regard astronautics itself as a rather specialized subject, engineers and scientists working in this area must be knowledgeable in many distinct fields. Astrodynamics, the study of orbital motion and those specializing in this field examine topics such as spacecraft trajectories, ballistics and celestial mechanics. Spacecraft propulsion, how spacecraft change orbits, and how they are launched, most spacecraft have some variety of rocket engine, and thus most research efforts focus on some variety of rocket propulsion, such as chemical, nuclear or electric. Spacecraft design, a form of systems engineering that centers on combining all the necessary subsystems for a particular launch vehicle or satellite. Controls, keeping a satellite or rocket in its desired orbit and orientation
5.
Science
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Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. The formal sciences are often excluded as they do not depend on empirical observations, disciplines which use science, like engineering and medicine, may also be considered to be applied sciences. However, during the Islamic Golden Age foundations for the method were laid by Ibn al-Haytham in his Book of Optics. In the 17th and 18th centuries, scientists increasingly sought to formulate knowledge in terms of physical laws, over the course of the 19th century, the word science became increasingly associated with the scientific method itself as a disciplined way to study the natural world. It was during this time that scientific disciplines such as biology, chemistry, Science in a broad sense existed before the modern era and in many historical civilizations. Modern science is distinct in its approach and successful in its results, Science in its original sense was a word for a type of knowledge rather than a specialized word for the pursuit of such knowledge. In particular, it was the type of knowledge which people can communicate to each other, for example, knowledge about the working of natural things was gathered long before recorded history and led to the development of complex abstract thought. This is shown by the construction of calendars, techniques for making poisonous plants edible. For this reason, it is claimed these men were the first philosophers in the strict sense and they were mainly speculators or theorists, particularly interested in astronomy. In contrast, trying to use knowledge of nature to imitate nature was seen by scientists as a more appropriate interest for lower class artisans. A clear-cut distinction between formal and empirical science was made by the pre-Socratic philosopher Parmenides, although his work Peri Physeos is a poem, it may be viewed as an epistemological essay on method in natural science. Parmenides ἐὸν may refer to a system or calculus which can describe nature more precisely than natural languages. Physis may be identical to ἐὸν and he criticized the older type of study of physics as too purely speculative and lacking in self-criticism. He was particularly concerned that some of the early physicists treated nature as if it could be assumed that it had no intelligent order, explaining things merely in terms of motion and matter. The study of things had been the realm of mythology and tradition, however. Aristotle later created a less controversial systematic programme of Socratic philosophy which was teleological and he rejected many of the conclusions of earlier scientists. For example, in his physics, the sun goes around the earth, each thing has a formal cause and final cause and a role in the rational cosmic order. Motion and change is described as the actualization of potentials already in things, while the Socratics insisted that philosophy should be used to consider the practical question of the best way to live for a human being, they did not argue for any other types of applied science
6.
Technology
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Technology is the collection of techniques, skills, methods and processes used in the production of goods or services or in the accomplishment of objectives, such as scientific investigation. Technology can be the knowledge of techniques, processes, and the like, the human species use of technology began with the conversion of natural resources into simple tools. The steady progress of technology has brought weapons of ever-increasing destructive power. It has helped develop more advanced economies and has allowed the rise of a leisure class, many technological processes produce unwanted by-products known as pollution and deplete natural resources to the detriment of Earths environment. Various implementations of technology influence the values of a society and raise new questions of the ethics of technology, examples include the rise of the notion of efficiency in terms of human productivity, and the challenges of bioethics. Philosophical debates have arisen over the use of technology, with disagreements over whether technology improves the condition or worsens it. The use of the technology has changed significantly over the last 200 years. Before the 20th century, the term was uncommon in English, the term was often connected to technical education, as in the Massachusetts Institute of Technology. The term technology rose to prominence in the 20th century in connection with the Second Industrial Revolution, the terms meanings changed in the early 20th century when American social scientists, beginning with Thorstein Veblen, translated ideas from the German concept of Technik into technology. In German and other European languages, a distinction exists between technik and technologie that is absent in English, which translates both terms as technology. By the 1930s, technology referred not only to the study of the industrial arts, dictionaries and scholars have offered a variety of definitions. Ursula Franklin, in her 1989 Real World of Technology lecture, gave another definition of the concept, it is practice, the way we do things around here. The term is used to imply a specific field of technology, or to refer to high technology or just consumer electronics. Bernard Stiegler, in Technics and Time,1, defines technology in two ways, as the pursuit of life by other than life, and as organized inorganic matter. Technology can be most broadly defined as the entities, both material and immaterial, created by the application of mental and physical effort in order to some value. In this usage, technology refers to tools and machines that may be used to solve real-world problems and it is a far-reaching term that may include simple tools, such as a crowbar or wooden spoon, or more complex machines, such as a space station or particle accelerator. Tools and machines need not be material, virtual technology, such as software and business methods. W. Brian Arthur defines technology in a broad way as a means to fulfill a human purpose
7.
Space exploration
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Space exploration is the ongoing discovery and exploration of celestial structures in outer space by means of continuously evolving and growing space technology. While the study of space is carried out mainly by astronomers with telescopes, Space exploration has often been used as a proxy competition for geopolitical rivalries such as the Cold War. The early era of exploration was driven by a Space Race between the Soviet Union and the United States. With the substantial completion of the ISS following STS-133 in March 2011, constellation, a Bush Administration program for a return to the Moon by 2020 was judged inadequately funded and unrealistic by an expert review panel reporting in 2009. In the 2000s, the Peoples Republic of China initiated a successful manned spaceflight program, while the European Union, Japan, from the 1990s onwards, private interests began promoting space tourism and then public space exploration of the Moon. After the war, the U. S. used German scientists, the first scientific exploration from space was the cosmic radiation experiment launched by the U. S. on a V-2 rocket on 10 May 1946. The first images of Earth taken from space followed the year while the first animal experiment saw fruit flies lifted into space in 1947. Starting in 1947, the Soviets, also with the help of German teams, launched sub-orbital V-2 rockets and their own variant and these suborbital experiments only allowed a very short time in space which limited their usefulness. The first successful launch was of the Soviet unmanned Sputnik 1 mission on 4 October 1957. The satellite weighed about 83 kg, and is believed to have orbited Earth at a height of about 250 km and it had two radio transmitters, which emitted beeps that could be heard by radios around the globe. Analysis of the signals was used to gather information about the electron density of the ionosphere. The results indicated that the satellite was not punctured by a meteoroid, Sputnik 1 was launched by an R-7 rocket. It burned up upon re-entry on 3 January 1958, the second one was Sputnik 2. Launched by the USSR on November 3,1957, it carried the dog Laika and this success led to an escalation of the American space program, which unsuccessfully attempted to launch a Vanguard satellite into orbit two months later. On 31 January 1958, the U. S. successfully orbited Explorer 1 on a Juno rocket, the first successful human spaceflight was Vostok 1, carrying 27-year-old Russian cosmonaut Yuri Gagarin on 12 April 1961. The spacecraft completed one orbit around the globe, lasting about 1 hour and 48 minutes, gagarins flight resonated around the world, it was a demonstration of the advanced Soviet space program and it opened an entirely new era in space exploration, human spaceflight. The U. S. first launched a person into space within a month of Vostok 1 with Alan Shepards suborbital flight in Mercury-Redstone 3, orbital flight was achieved by the United States when John Glenns Mercury-Atlas 6 orbited Earth on 20 February 1962. Valentina Tereshkova, the first woman in space, orbited Earth 48 times aboard Vostok 6 on 16 June 1963
8.
Military
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The armed forces of a country are its government-sponsored defense, fighting forces, and organizations. They exist to further the foreign and domestic policies of their body and to defend that body. Armed force is the use of armed forces to achieve political objectives, the study of the use of armed forces is called military science. Broadly speaking, this involves considering offense and defense at three levels, strategy, operational art, and tactics, all three levels study the application of the use of force in order to achieve a desired objective. In most countries the basis of the forces is the military. However, armed forces can include other paramilitary structures, the obvious benefit to a country in maintaining armed forces is in providing protection from foreign threats and from internal conflict. In recent decades armed forces personnel have also used as emergency civil support roles in post-disaster situations. On the other hand, they may harm a society by engaging in counter-productive warfare. Expenditure on science and technology to develop weapons and systems sometimes produces side benefits, although some claim that greater benefits could come from targeting the money directly
9.
Engineering
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The term Engineering is derived from the Latin ingenium, meaning cleverness and ingeniare, meaning to contrive, devise. Engineering has existed since ancient times as humans devised fundamental inventions such as the wedge, lever, wheel, each of these inventions is essentially consistent with the modern definition of engineering. The term engineering is derived from the engineer, which itself dates back to 1390 when an engineer originally referred to a constructor of military engines. In this context, now obsolete, a referred to a military machine. Notable examples of the obsolete usage which have survived to the present day are military engineering corps, the word engine itself is of even older origin, ultimately deriving from the Latin ingenium, meaning innate quality, especially mental power, hence a clever invention. The earliest civil engineer known by name is Imhotep, as one of the officials of the Pharaoh, Djosèr, he probably designed and supervised the construction of the Pyramid of Djoser at Saqqara in Egypt around 2630–2611 BC. Ancient Greece developed machines in both civilian and military domains, the Antikythera mechanism, the first known mechanical computer, and the mechanical inventions of Archimedes are examples of early mechanical engineering. In the Middle Ages, the trebuchet was developed, the first steam engine was built in 1698 by Thomas Savery. The development of this gave rise to the Industrial Revolution in the coming decades. With the rise of engineering as a profession in the 18th century, similarly, in addition to military and civil engineering, the fields then known as the mechanic arts became incorporated into engineering. The inventions of Thomas Newcomen and the Scottish engineer James Watt gave rise to mechanical engineering. The development of specialized machines and machine tools during the revolution led to the rapid growth of mechanical engineering both in its birthplace Britain and abroad. John Smeaton was the first self-proclaimed civil engineer and is regarded as the father of civil engineering. He was an English civil engineer responsible for the design of bridges, canals, harbours and he was also a capable mechanical engineer and an eminent physicist. Smeaton designed the third Eddystone Lighthouse where he pioneered the use of hydraulic lime and his lighthouse remained in use until 1877 and was dismantled and partially rebuilt at Plymouth Hoe where it is known as Smeatons Tower. The United States census of 1850 listed the occupation of engineer for the first time with a count of 2,000, there were fewer than 50 engineering graduates in the U. S. before 1865. In 1870 there were a dozen U. S. mechanical engineering graduates, in 1890 there were 6,000 engineers in civil, mining, mechanical and electrical. There was no chair of applied mechanism and applied mechanics established at Cambridge until 1875, the theoretical work of James Maxwell and Heinrich Hertz in the late 19th century gave rise to the field of electronics
10.
Aircraft
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An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the lift of an airfoil. The human activity that surrounds aircraft is called aviation, crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as type, aircraft propulsion, usage. Each of the two World Wars led to technical advances. Consequently, the history of aircraft can be divided into five eras, Pioneers of flight, first World War,1914 to 1918. Aviation between the World Wars,1918 to 1939, Second World War,1939 to 1945. Postwar era, also called the jet age,1945 to the present day, aerostats use buoyancy to float in the air in much the same way that ships float on the water. They are characterized by one or more large gasbags or canopies, filled with a relatively low-density gas such as helium, hydrogen, or hot air, which is less dense than the surrounding air. When the weight of this is added to the weight of the aircraft structure, a balloon was originally any aerostat, while the term airship was used for large, powered aircraft designs – usually fixed-wing. In 1919 Frederick Handley Page was reported as referring to ships of the air, in the 1930s, large intercontinental flying boats were also sometimes referred to as ships of the air or flying-ships. – though none had yet been built, the advent of powered balloons, called dirigible balloons, and later of rigid hulls allowing a great increase in size, began to change the way these words were used. Huge powered aerostats, characterized by an outer framework and separate aerodynamic skin surrounding the gas bags, were produced. There were still no fixed-wing aircraft or non-rigid balloons large enough to be called airships, then several accidents, such as the Hindenburg disaster in 1937, led to the demise of these airships. Nowadays a balloon is an aerostat and an airship is a powered one. A powered, steerable aerostat is called a dirigible, sometimes this term is applied only to non-rigid balloons, and sometimes dirigible balloon is regarded as the definition of an airship. Non-rigid dirigibles are characterized by a moderately aerodynamic gasbag with stabilizing fins at the back and these soon became known as blimps. During the Second World War, this shape was adopted for tethered balloons, in windy weather
11.
Spacecraft
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A spacecraft is a vehicle, or machine designed to fly in outer space. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, space colonization, planetary exploration, on a sub-orbital spaceflight, a spacecraft enters space and then returns to the surface, without having gone into an orbit. For orbital spaceflights, spacecraft enter closed orbits around the Earth or around other celestial bodies, robotic spacecraft used to support scientific research are space probes. Robotic spacecraft that remain in orbit around a body are artificial satellites. Only a handful of interstellar probes, such as Pioneer 10 and 11, Voyager 1 and 2, orbital spacecraft may be recoverable or not. By method of reentry to Earth they may be divided in non-winged space capsules, Sputnik 1 was the first artificial satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957, the launch ushered in new political, military, technological, and scientific developments, while the Sputnik launch was a single event, it marked the start of the Space Age. Apart from its value as a technological first, Sputnik 1 also helped to identify the upper atmospheric layers density and it also provided data on radio-signal distribution in the ionosphere. Pressurized nitrogen in the satellites false body provided the first opportunity for meteoroid detection, Sputnik 1 was launched during the International Geophysical Year from Site No. 1/5, at the 5th Tyuratam range, in Kazakh SSR. The satellite travelled at 29,000 kilometers per hour, taking 96.2 minutes to complete an orbit and this altitude is called the Kármán line. In particular, in the 1940s there were several test launches of the V-2 rocket, as of 2016, only three nations have flown manned spacecraft, USSR/Russia, USA, and China. The first manned spacecraft was Vostok 1, which carried Soviet cosmonaut Yuri Gagarin into space in 1961, there were five other manned missions which used a Vostok spacecraft. The second manned spacecraft was named Freedom 7, and it performed a sub-orbital spaceflight in 1961 carrying American astronaut Alan Shepard to an altitude of just over 187 kilometers, there were five other manned missions using Mercury spacecraft. Other Soviet manned spacecraft include the Voskhod, Soyuz, flown unmanned as Zond/L1, L3, TKS, China developed, but did not fly Shuguang, and is currently using Shenzhou. Except for the shuttle, all of the recoverable manned orbital spacecraft were space capsules. Manned space capsules The International Space Station, manned since November 2000, is a joint venture between Russia, the United States, Canada and several other countries, some reusable vehicles have been designed only for manned spaceflight, and these are often called spaceplanes. The first example of such was the North American X-15 spaceplane, the first reusable spacecraft, the X-15, was air-launched on a suborbital trajectory on July 19,1963. The first partially reusable spacecraft, a winged non-capsule, the Space Shuttle, was launched by the USA on the 20th anniversary of Yuri Gagarins flight
12.
Avionics
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Avionics are the electronic systems used on aircraft, artificial satellites, and spacecraft. Avionic systems include communications, navigation, the display and management of systems. These can be as simple as a searchlight for a helicopter or as complicated as the tactical system for an airborne early warning platform. The term avionics is a portmanteau of the aviation and electronics. The term avionics was coined by the journalist Philip J. Klass as a portmanteau of aviation electronics, many modern avionics have their origins in World War II wartime developments. For example, autopilot systems that are today were started to help bomber planes fly steadily enough to hit precision targets from high altitudes. Famously, radar was developed in the UK, Germany, modern avionics is a substantial portion of military aircraft spending. Aircraft like the F‑15E and the now retired F‑14 have roughly 20 percent of their budget spent on avionics, most modern helicopters now have budget splits of 60/40 in favour of avionics. The civilian market has seen a growth in cost of avionics. Flight control systems and new navigation needs brought on by tighter airspaces, have pushed up development costs, the major change has been the recent boom in consumer flying. As more people begin to use planes as their method of transportation. The majority of power their avionics using 14- or 28‑volt DC electrical systems, however, larger. One source of international standards for equipment are prepared by the Airlines Electronic Engineering Committee. Communications connect the deck to the ground and the flight deck to the passengers. On‑board communications are provided by systems and aircraft intercoms. The VHF aviation communication system works on the airband of 118.000 MHz to 136.975 MHz, each channel is spaced from the adjacent ones by 8.33 kHz in Europe,25 kHz elsewhere. VHF is also used for line of communication such as aircraft-to-aircraft. Amplitude modulation is used, and the conversation is performed in simplex mode, aircraft communication can also take place using HF or satellite communication
13.
Electronic engineering
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The discipline typically also designs passive electrical components, usually based on printed circuit boards. The Institute of Electrical and Electronics Engineers is one of the most important, Electronics is a subfield within the wider electrical engineering academic subject. An academic degree with a major in engineering can be acquired from some universities. The term electrical engineer is used in the academic world to include electronic engineers. The term power engineering is used as a descriptor in that industry, Electronic engineering as a profession sprang from technological improvements in the telegraph industry in the late 19th century and the radio and the telephone industries in the early 20th century. People were attracted to radio by the fascination it inspired, first in receiving. Many who went into broadcasting in the 1920s were only amateurs in the period before World War I, in the interwar years, the subject was known as radio engineering and it was only in the late 1950s that the term electronic engineering started to emerge. The tuner circuit, which allows the user of a radio to filter out all, in designing an integrated circuit, electronics engineers first construct circuit schematics that specify the electrical components and describe the interconnections between them. When completed, VLSI engineers convert the schematics into actual layouts, the conversion from schematics to layouts can be done by software but very often requires human fine-tuning to decrease space and power consumption. Once the layout is complete, it can be sent to a plant for manufacturing. Today, printed circuit boards are found in most electronic devices including televisions, computers, signal processing deals with the analysis and manipulation of signals. For analog signals, signal processing may involve the amplification and filtering of signals for audio equipment or the modulation and demodulation of signals for telecommunications. For digital signals, signal processing may involve the compression, error checking, telecommunications engineering deals with the transmission of information across a channel such as a co-axial cable, optical fiber or free space. Transmissions across free space require information to be encoded in a wave in order to shift the information to a carrier frequency suitable for transmission. Popular analog modulation techniques include amplitude modulation and frequency modulation, the choice of modulation affects the cost and performance of a system and these two factors must be balanced carefully by the engineer. Once the transmission characteristics of a system are determined, telecommunication engineers design the transmitters and receivers needed for such systems and these two are sometimes combined to form a two-way communication device known as a transceiver. A key consideration in the design of transmitters is their consumption as this is closely related to their signal strength. If the signal strength of a transmitter is insufficient the signals information will be corrupted by noise, control engineering has a wide range of applications from the flight and propulsion systems of commercial airplanes to the cruise control present in many modern cars
14.
Outer space
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Outer space or just space, is the void that exists between celestial bodies, including Earth. The baseline temperature, as set by the radiation from the Big Bang, is 2.7 kelvins. In most galaxies, observations provide evidence that 90% of the mass is in a form, called dark matter. Data indicates that the majority of the mass-energy in the universe is a poorly understood vacuum energy of space which astronomers label dark energy. Intergalactic space takes up most of the volume of the Universe, there is no firm boundary where outer space starts. However the Kármán line, at an altitude of 100 km above sea level, is used as the start of outer space in space treaties. The framework for international law was established by the Outer Space Treaty. This treaty precludes any claims of sovereignty and permits all states to freely explore outer space. Despite the drafting of UN resolutions for the uses of outer space. Humans began the exploration of space during the 20th century with the advent of high-altitude balloon flights. Earth orbit was first achieved by Yuri Gagarin of the Soviet Union in 1961, due to the high cost of getting into space, manned spaceflight has been limited to low Earth orbit and the Moon. Outer space represents an environment for human exploration because of the dual hazards of vacuum. Microgravity also has an effect on human physiology that causes both muscle atrophy and bone loss. In addition to health and environmental issues, the economic cost of putting objects, including humans. In 350 BCE, Greek philosopher Aristotle suggested that nature abhors a vacuum and this concept built upon a 5th-century BCE ontological argument by the Greek philosopher Parmenides, who denied the possible existence of a void in space. Based on this idea that a vacuum could not exist, in the West it was held for many centuries that space could not be empty. As late as the 17th century, the French philosopher René Descartes argued that the entirety of space must be filled, in ancient China, there were various schools of thought concerning the nature of the heavens, some of which bear a resemblance to the modern understanding. In the 2nd century, astronomer Zhang Heng became convinced that space must be infinite, extending well beyond the mechanism that supported the Sun, the surviving books of the Hsüan Yeh school said that the heavens were boundless, empty and void of substance
15.
Aerospace
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Aerospace is the human effort in science, engineering and business to fly in the atmosphere of Earth and surrounding space. Aerospace organisations research, design, manufacture, operate, or maintain aircraft and/or spacecraft, Aerospace activity is very diverse, with a multitude of commercial, industrial and military applications. Aerospace is not the same as airspace, which is the air space directly above a location on the ground. In most industrial countries, the industry is a cooperation of public. Along with these public space programs, many companies produce technical tools and components such as spaceships, some known companies involved in space programs include Boeing, Airbus Group, SpaceX, Lockheed Martin, MacDonald Dettwiler and Northrop Grumman. These companies are involved in other areas of aerospace such as the construction of aircraft. Modern aerospace began with George Cayley in 1799, Cayley proposed an aircraft with a fixed wing and a horizontal and vertical tail, defining characteristics of the modern airplane. Airmen like Otto Lilienthal, who introduced cambered airfoils in 1891, the Wright brothers were interested in Lilienthals work and read several of his publications. They also found inspiration in Octave Chanute, an airman and the author of Progress in Flying Machines, war and science fiction inspired great minds like Konstantin Tsiolkovsky and Wernher von Braun to achieve flight beyond the atmosphere. The launch of Sputnik 1 in October 1957 started the Space Age, in April 1981, the Space Shuttle Columbia launched, the start of regular manned access to orbital space. A sustained human presence in space started with Mir in 1986 and is continued by the International Space Station. Space commercialization and space tourism are more recent focuses in aerospace, Aerospace manufacturing is a high-technology industry that produces aircraft, guided missiles, space vehicles, aircraft engines, propulsion units, and related parts. Most of the industry is geared toward governmental work, for each original equipment manufacturer, the US government has assigned a Commercial and Government Entity code. These codes help to each manufacturer, repair facilities. In the United States, the Department of Defense and the National Aeronautics, others include the very large airline industry. The aerospace industry employed 472,000 wage and salary workers in 2006, most of those jobs were in Washington state and in California, with Missouri, New York and Texas also being important. The leading aerospace manufacturers in the U. S. are Boeing, United Technologies Corporation, SpaceX, Northrop Grumman and these manufacturers are facing an increasing labor shortage as skilled U. S. workers age and retire. In India, Bangalore is a center of the aerospace industry, where Hindustan Aeronautics Limited, the National Aerospace Laboratories
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Atmospheric pressure
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Atmospheric pressure, sometimes also called barometric pressure, is the pressure exerted by the weight of air in the atmosphere of Earth. In most circumstances atmospheric pressure is approximated by the hydrostatic pressure caused by the weight of air above the measurement point. As elevation increases, there is less overlying atmospheric mass, so that atmospheric pressure decreases with increasing elevation. On average, a column of air one square centimetre in cross-section, measured from sea level to the top of the atmosphere, has a mass of about 1.03 kilograms and that force is a pressure of 10.1 N/cm2 or 101 kN/m2. A column 1 square inch in cross-section would have a weight of about 14.7 lb or about 65.4 N and it is modified by the planetary rotation and local effects such as wind velocity, density variations due to temperature and variations in composition. The standard atmosphere is a unit of pressure defined as 101325 Pa, the mean sea level pressure is the average atmospheric pressure at sea level. This is the pressure normally given in weather reports on radio, television. When barometers in the home are set to match the weather reports, they measure pressure adjusted to sea level. The altimeter setting in aviation, is an atmospheric pressure adjustment, average sea-level pressure is 1013.25 mbar. In aviation weather reports, QNH is transmitted around the world in millibars or hectopascals, except in the United States, Canada, however, in Canadas public weather reports, sea level pressure is instead reported in kilopascals. The highest sea-level pressure on Earth occurs in Siberia, where the Siberian High often attains a sea-level pressure above 1050 mbar, the lowest measurable sea-level pressure is found at the centers of tropical cyclones and tornadoes, with a record low of 870 mbar. Pressure varies smoothly from the Earths surface to the top of the mesosphere, although the pressure changes with the weather, NASA has averaged the conditions for all parts of the earth year-round. As altitude increases, atmospheric pressure decreases, one can calculate the atmospheric pressure at a given altitude. Temperature and humidity affect the atmospheric pressure, and it is necessary to know these to compute an accurate figure. The graph at right was developed for a temperature of 15 °C, at low altitudes above the sea level, the pressure decreases by about 1.2 kPa for every 100 meters. See pressure system for the effects of air pressure variations on weather, Atmospheric pressure shows a diurnal or semidiurnal cycle caused by global atmospheric tides. This effect is strongest in tropical zones, with an amplitude of a few millibars and these variations have two superimposed cycles, a circadian cycle and semi-circadian cycle. The highest adjusted-to-sea level barometric pressure recorded on Earth was 1085.7 hPa measured in Tosontsengel
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Temperature
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A temperature is an objective comparative measurement of hot or cold. It is measured by a thermometer, several scales and units exist for measuring temperature, the most common being Celsius, Fahrenheit, and, especially in science, Kelvin. Absolute zero is denoted as 0 K on the Kelvin scale, −273.15 °C on the Celsius scale, the kinetic theory offers a valuable but limited account of the behavior of the materials of macroscopic bodies, especially of fluids. Temperature is important in all fields of science including physics, geology, chemistry, atmospheric sciences, medicine. The Celsius scale is used for temperature measurements in most of the world. Because of the 100 degree interval, it is called a centigrade scale.15, the United States commonly uses the Fahrenheit scale, on which water freezes at 32°F and boils at 212°F at sea-level atmospheric pressure. Many scientific measurements use the Kelvin temperature scale, named in honor of the Scottish physicist who first defined it and it is a thermodynamic or absolute temperature scale. Its zero point, 0K, is defined to coincide with the coldest physically-possible temperature and its degrees are defined through thermodynamics. The temperature of zero occurs at 0K = −273. 15°C. For historical reasons, the triple point temperature of water is fixed at 273.16 units of the measurement increment, Temperature is one of the principal quantities in the study of thermodynamics. There is a variety of kinds of temperature scale and it may be convenient to classify them as empirically and theoretically based. Empirical temperature scales are historically older, while theoretically based scales arose in the middle of the nineteenth century, empirically based temperature scales rely directly on measurements of simple physical properties of materials. For example, the length of a column of mercury, confined in a capillary tube, is dependent largely on temperature. Such scales are only within convenient ranges of temperature. For example, above the point of mercury, a mercury-in-glass thermometer is impracticable. A material is of no use as a thermometer near one of its phase-change temperatures, in spite of these restrictions, most generally used practical thermometers are of the empirically based kind. Especially, it was used for calorimetry, which contributed greatly to the discovery of thermodynamics, nevertheless, empirical thermometry has serious drawbacks when judged as a basis for theoretical physics. Theoretically based temperature scales are based directly on theoretical arguments, especially those of thermodynamics, kinetic theory and they rely on theoretical properties of idealized devices and materials
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Structural load
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Structural loads or actions are forces, deformations, or accelerations applied to a structure or its components. Loads cause stresses, deformations, and displacements in structures, assessment of their effects is carried out by the methods of structural analysis. Excess load or overloading may cause failure, and hence such possibility should be either considered in the design or strictly controlled. Mechanical structures, such as aircraft, satellites, rockets, space stations, ships, engineers often evaluate structural loads based upon published regulations, contracts, or specifications. Accepted technical standards are used for testing and inspection. Dead loads are static forces that are constant for an extended time. They can be in tension or compression, the term can refer to a laboratory test method or to the normal usage of a material or structure. Live loads are usually unstable or moving loads and these dynamic loads may involve considerations such as impact, momentum, vibration, slosh dynamics of fluids, etc. An impact load is one time of application on a material is less than one-third of the natural period of vibration of that material. Cyclic loads on a structure can lead to damage, cumulative damage. These loads can be repeated loadings on a structure or can be due to vibration, structural loads are an important consideration in the design of buildings. Building codes require that structures be designed and built to safely resist all actions that they are likely to face during their service life, minimum loads or actions are specified in these building codes for types of structures, geographic locations, usage and materials of construction. Structural loads are split into categories by their originating cause, in terms of the actual load on a structure, there is no difference between dead or live loading, but the split occurs for use in safety calculations or ease of analysis on complex models. To meet the requirement that design strength be higher than maximum loads, building codes prescribe that, for structural design and these load factors are, roughly, a ratio of the theoretical design strength to the maximum load expected in service. The dead load includes loads that are constant over time, including the weight of the structure itself. The roof is also a dead load, dead loads are also known as permanent or static loads. Building materials are not dead loads until constructed in permanent position, iS875-1987 give unit weight of building materials, parts, components. Live loads, or imposed loads, are temporary, of short duration and these dynamic loads may involve considerations such as impact, momentum, vibration, slosh dynamics of fluids and material fatigue
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Aerodynamics
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Aerodynamics, from Greek ἀήρ aer + δυναμική, the study of the motion of air, particularly its interaction with a solid object, such as an airplane wing. Aerodynamics is a sub-field of fluid dynamics and gas dynamics, the term aerodynamics is often used synonymously with gas dynamics, the difference being that gas dynamics applies to the study of the motion of all gases, and is not limited to air. The formal study of aerodynamics began in the sense in the eighteenth century. Most of the efforts in aerodynamics were directed toward achieving heavier-than-air flight. Recent work in aerodynamics has focused on issues related to flow, turbulence. Fundamental concepts of continuum, drag, and pressure gradients appear in the work of Aristotle, in 1726, Sir Isaac Newton became the first person to develop a theory of air resistance, making him one of the first aerodynamicists. In 1757, Leonhard Euler published the more general Euler equations which could be applied to both compressible and incompressible flows, the Euler equations were extended to incorporate the effects of viscosity in the first half of the 1800s, resulting in the Navier-Stokes equations. The Navier-Stokes equations are the most general governing equations of fluid flow, in 1871, Francis Herbert Wenham constructed the first wind tunnel, allowing precise measurements of aerodynamic forces. Drag theories were developed by Jean le Rond dAlembert, Gustav Kirchhoff, in 1889, Charles Renard, a French aeronautical engineer, became the first person to reasonably predict the power needed for sustained flight. Otto Lilienthal, the first person to become successful with glider flights, was also the first to propose thin, curved airfoils that would produce high lift. Building on these developments as well as carried out in their own wind tunnel. During the time of the first flights, Frederick W. Lanchester, Martin Wilhelm Kutta, Kutta and Zhukovsky went on to develop a two-dimensional wing theory. Expanding upon the work of Lanchester, Ludwig Prandtl is credited with developing the mathematics behind thin-airfoil, as aircraft speed increased, designers began to encounter challenges associated with air compressibility at speeds near or greater than the speed of sound. The differences in air flows under such conditions leds to problems in control, increased drag due to shock waves. The ratio of the speed to the speed of sound was named the Mach number after Ernst Mach who was one of the first to investigate the properties of supersonic flow. Theodore von Kármán and Hugh Latimer Dryden introduced the term transonic to describe flow speeds around Mach 1 where drag increases rapidly, by the time the sound barrier was broken, aerodynamicists understanding of the subsonic and low supersonic flow had matured. The Cold War prompted the design of an line of high performance aircraft. Understanding the motion of air around an object enables the calculation of forces, in many aerodynamics problems, the forces of interest are the fundamental forces of flight, lift, drag, thrust, and weight
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Propulsion
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Propulsion is a means of creating force leading to movement. The term is derived from two Latin words, pro, meaning before or forward, and pellere, meaning to drive, a propulsion system consists of a source of mechanical power, and a propulsor. A technological system uses an engine or motor as the power source, components such as clutches or gearboxes may be needed to connect the motor to axles, wheels, or propellors. Biological propulsion systems use an animals muscles as the power source, an aircraft propulsion system generally consists of an aircraft engine and some means to generate thrust, such as a propeller or a propulsive nozzle. An aircraft propulsion system must achieve two things, first, the thrust from the propulsion system must balance the drag of the airplane when the airplane is cruising. And second, the thrust from the system must exceed the drag of the airplane for the airplane to accelerate. In fact, the greater the difference between the thrust and the drag, called the excess thrust, the faster the airplane will accelerate, some aircraft, like airliners and cargo planes, spend most of their life in a cruise condition. For these airplanes, excess thrust is not as important as high engine efficiency, some aircraft, like fighter planes or experimental high speed aircraft, require very high excess thrust to accelerate quickly and to overcome the high drag associated with high speeds. For these airplanes, engine efficiency is not as important as very high thrust, modern military aircraft typically employ afterburners on a low bypass turbofan core. Future hypersonic aircraft will employ some type of ramjet or rocket propulsion, ground propulsion is any mechanism for propelling solid bodies along the ground, usually for the purposes of transportation. The propulsion system consists of a combination of an engine or motor. Maglev is a system of transportation that uses magnetic levitation to suspend, guide and propel vehicles with magnets rather than using mechanical methods, such as wheels, axles and bearings. With maglev a vehicle is levitated a short distance away from a guide way using magnets to create lift and thrust. Maglev vehicles are claimed to move smoothly and quietly and to require less maintenance than wheeled mass transit systems. It is claimed that non-reliance on friction also means that acceleration and deceleration can far surpass that of existing forms of transport, marine propulsion is the mechanism or system used to generate thrust to move a ship or boat across water. Recent development in liquified natural gas fueled engines are gaining recognition for their low emissions, spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. Each method has drawbacks and advantages, and spacecraft propulsion is an area of research. However, most spacecraft today are propelled by forcing a gas from the back/rear of the vehicle at high speed through a supersonic de Laval nozzle
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Materials science
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The interdisciplinary field of materials science, also commonly termed materials science and engineering, involves the discovery and design of new materials, with an emphasis on solids. Materials science still incorporates elements of physics, chemistry, and engineering, as such, the field was long considered by academic institutions as a sub-field of these related fields. Materials science is a syncretic discipline hybridizing metallurgy, ceramics, solid-state physics and it is the first example of a new academic discipline emerging by fusion rather than fission. Many of the most pressing scientific problems humans currently face are due to the limits of the materials that are available, thus, breakthroughs in materials science are likely to affect the future of technology significantly. Materials scientists emphasize understanding how the history of a material influences its structure, the understanding of processing-structure-properties relationships is called the § materials paradigm. This paradigm is used to advance understanding in a variety of areas, including nanotechnology, biomaterials. Such investigations are key to understanding, for example, the causes of various accidents and incidents. The material of choice of a given era is often a defining point, phrases such as Stone Age, Bronze Age, Iron Age, and Steel Age are great examples. Originally deriving from the manufacture of ceramics and its putative derivative metallurgy, materials science is one of the oldest forms of engineering, modern materials science evolved directly from metallurgy, which itself evolved from mining and ceramics and the use of fire. Materials science has driven, and been driven by, the development of technologies such as rubbers, plastics, semiconductors. Before the 1960s, many materials science departments were named metallurgy departments, reflecting the 19th, a material is defined as a substance that is intended to be used for certain applications. There are a myriad of materials around us—they can be found in anything from buildings to spacecraft, Materials can generally be divided into two classes, crystalline and non-crystalline. The traditional examples of materials are metals, semiconductors, ceramics, New and advanced materials that are being developed include nanomaterials and biomaterials, etc. The basis of science involves studying the structure of materials. Once a materials scientist knows about this structure-property correlation, they can go on to study the relative performance of a material in a given application. The major determinants of the structure of a material and thus of its properties are its constituent chemical elements and these characteristics, taken together and related through the laws of thermodynamics and kinetics, govern a materials microstructure, and thus its properties. As mentioned above, structure is one of the most important components of the field of materials science, Materials science examines the structure of materials from the atomic scale, all the way up to the macro scale. Characterization is the way materials scientists examine the structure of a material, structure is studied at various levels, as detailed below
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Structural analysis
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Structural analysis is the determination of the effects of loads on physical structures and their components. Structures subject to this type of analysis include all that must withstand loads, such as buildings, bridges, vehicles, machinery, furniture, attire, soil strata, prostheses and biological tissue. The results of the analysis are used to verify a structures fitness for use, structural analysis is thus a key part of the engineering design of structures. A structure refers to a body or system of connected parts used to support a load, other branches of engineering work on a wide variety of non-building structures. A structural system is the combination of elements and their materials. It is important for an engineer to be able to classify a structure by either its form or its function. Once the dimensional requirement for a structure have been defined, it necessary to determine the loads the structure must support. In order to design a structure, it is necessary to first specify the loads that act on it. The design loading for a structure is specified in building codes. There are two types of codes, general building codes and design codes, engineer must satisfy all the requirements for a reliable structure. There are two types of loads that structure engineering must encounter in the design, first type of load is called Dead loads that consist of the weights of the various structural members and the weights of any objects that are permanently attached to the structure. For example, columns, beams, girders, the slab, roofing, walls, windows, plumbing, electrical fixtures. Second type of load is Live Loads which vary in their magnitude, there are many different types of live loads like building loads, highway bridge Loads, railroad bridge Loads, impact loads, wind loads, snow loads, earthquake loads, and other natural loads. To perform an accurate analysis a structural engineer must determine such information as structural loads, geometry, support conditions, the results of such an analysis typically include support reactions, stresses and displacements. This information is compared to criteria that indicate the conditions of failure. Advanced structural analysis may examine dynamic response, stability and non-linear behavior, there are three approaches to the analysis, the mechanics of materials approach, the elasticity theory approach, and the finite element approach. The first two make use of analytical formulations which apply mostly to simple linear elastic models, lead to closed-form solutions, the by and finite element approach is actually a numerical method for solving differential equations generated by theories of mechanics such as elasticity theory and strength of materials. However, the finite-element method depends heavily on the power of computers and is more applicable to structures of arbitrary size
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Manufacturing
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Manufacturing is the value added to production of merchandise for use or sale using labour and machines, tools, chemical and biological processing, or formulation. Manufacturing engineering or manufacturing process are the steps through which raw materials are transformed into a final product, the manufacturing process begins with the product design, and materials specification from which the product is made. These materials are modified through manufacturing processes to become the required part. Manufacturing takes turns under all types of economic systems, in a free market economy, manufacturing is usually directed toward the mass production of products for sale to consumers at a profit. In a collectivist economy, manufacturing is more directed by the state to supply a centrally planned economy. In mixed market economies, manufacturing occurs under some degree of government regulation, modern manufacturing includes all intermediate processes required the production and integration of a products components. Some industries, such as semiconductor and steel manufacturers use the term fabrication instead, the manufacturing sector is closely connected with engineering and industrial design. Examples of major manufacturers in North America include General Motors Corporation, General Electric, Procter & Gamble, General Dynamics, Boeing, Pfizer, examples in Europe include Volkswagen Group, Siemens, and Michelin. Examples in Asia include Sony, Huawei, Lenovo, Toyota, Samsung, in its earliest form, manufacturing was usually carried out by a single skilled artisan with assistants. In much of the world, the guild system protected the privileges. Before the Industrial Revolution, most manufacturing occurred in rural areas, entrepreneurs organized a number of manufacturing households into a single enterprise through the putting-out system. Toll manufacturing is an arrangement whereby a first firm with specialized equipment processes raw materials or semi-finished goods for a second firm, manufacturing provides important material support for national infrastructure and for national defense. On the other hand, most manufacturing may involve significant social and environmental costs, the clean-up costs of hazardous waste, for example, may outweigh the benefits of a product that creates it. Hazardous materials may expose workers to health risks and these costs are now well known and there is effort to address them by improving efficiency, reducing waste, using industrial symbiosis, and eliminating harmful chemicals. The negative costs of manufacturing can also be addressed legally, developed countries regulate manufacturing activity with labor laws and environmental laws. Across the globe, manufacturers can be subject to regulations and pollution taxes to offset the costs of manufacturing activities. Labor unions and craft guilds have played a role in the negotiation of worker rights. Environment laws and labor protections that are available in developed nations may not be available in the third world, tort law and product liability impose additional costs on manufacturing
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History of aviation
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Kite flying in China dates back to several hundred years BC and slowly spread around the world. It is thought to be the earliest example of man-made flight, Leonardo da Vincis 15th-century dream of flight found expression in several rational but unscientific designs, though he did not attempt to construct any of them. Balloons, both free-flying and tethered, began to be used for military purposes from the end of the 18th century, with the French government establishing Balloon Companies during the Revolution. The modern aeroplane with its tail was established by 1909. After World War II, the boats were in their turn replaced by land planes. In the latter part of the 20th century the advent of digital electronics produced great advances in flight instrumentation, the 21st century saw the large-scale use of pilotless drones for military, civilian and leisure use. With digital controls, inherently unstable aircraft such as flying wings became possible, the origin of mankinds desire to fly is lost in the distant past. From the earliest legends there have been stories of men strapping birdlike wings, stiffened cloaks or other devices to themselves, the Greek legend of Daedalus and Icarus is one of the earliest known, others originated from India, China and the European Dark Ages. During this early period the issues of lift, stability and control were not understood, eilmer of Malmesbury soon followed and many others have continued to do so over the centuries. As late as 1811, Albrecht Berblinger constructed an ornithopter and jumped into the Danube at Ulm, the kite may have been the first form of man-made aircraft. It was invented in China possibly as far back as the 5th century BC by Mozi, later designs often emulated flying insects, birds, and other beasts, both real and mythical. Some were fitted with strings and whistles to make sounds while flying. Ancient and medieval Chinese sources describe kites being used to measure distances, test the wind, lift men, signal, Kites spread from China around the world. After its introduction into India, the further evolved into the fighter kite. Man-carrying kites are believed to have been used extensively in ancient China, an early recorded flight was that of the prisoner Yuan Huangtou, a Chinese prince, in the 6th Century AD. Stories of man-carrying kites also occur in Japan, following the introduction of the kite from China around the seventh century AD and it is said that at one time there was a Japanese law against man-carrying kites. The use of a rotor for vertical flight has existed since 400 BC in the form of the bamboo-copter, the similar moulinet à noix appeared in Europe in the 14th century AD. From ancient times the Chinese have understood that hot air rises and have applied the principle to a type of hot air balloon called a sky lantern
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Wright brothers
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They made the first controlled, sustained flight of a powered, heavier-than-air aircraft on December 17,1903, four miles south of Kitty Hawk, North Carolina. In 1904–05 the brothers developed their flying machine into the first practical fixed-wing aircraft, although not the first to build and fly experimental aircraft, the Wright brothers were the first to invent aircraft controls that made fixed-wing powered flight possible. The brothers fundamental breakthrough was their invention of three-axis control, which enabled the pilot to steer the aircraft effectively and this method became and remains standard on fixed-wing aircraft of all kinds. From the beginning of their work, the Wright brothers focused on developing a reliable method of pilot control as the key to solving the flying problem. This approach differed significantly from other experimenters of the time who put emphasis on developing powerful engines. Using a small wind tunnel, the Wrights also collected more accurate data than any before, enabling them to design and build wings. Their first U. S. patent,821,393, did not claim invention of a machine, but rather. They gained the skills essential for their success by working for years in their shop with printing presses, bicycles, motors. Their work with bicycles in particular influenced their belief that a vehicle like a flying machine could be controlled and balanced with practice. From 1900 until their first powered flights in late 1903, they conducted extensive tests that also developed their skills as pilots. Their bicycle shop employee Charlie Taylor became an important part of the team, the Wright brothers status as inventors of the airplane has been subject to counter-claims by various parties. Much controversy persists over the competing claims of early aviators. The Wright brothers were two of seven born to Milton Wright, of English and Dutch ancestry, and Susan Catherine Koerner, of German. Wilbur was born near Millville, Indiana, in 1867, Orville in Dayton, Ohio, the other Wright siblings were Reuchlin, Lorin, Katharine, and twins Otis and Ida. In elementary school, Orville was given to mischief and was once expelled, the direct paternal ancestry goes back to a Samuel Wright who sailed to America and settled in Massachusetts in 1636. In 1878 their father, who traveled often as a bishop in the Church of the United Brethren in Christ, the device was based on an invention of French aeronautical pioneer Alphonse Pénaud. Made of paper, bamboo and cork with a band to twirl its rotor. Wilbur and Orville played with it until it broke, and then built their own, in later years, they pointed to their experience with the toy as the spark of their interest in flying
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Wright Flyer
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The Wright Flyer was the first successful heavier-than-air powered aircraft. It was designed and built by the Wright brothers and they flew it four times on December 17,1903, near Kill Devil Hills, about four miles south of Kitty Hawk, North Carolina, US. Today, the airplane is exhibited in the National Air and Space Museum in Washington D. C, the U. S. Smithsonian Institution describes the aircraft as the first powered, heavier-than-air machine to achieve controlled, sustained flight with a pilot aboard. The flight of Flyer I marks the beginning of the era of aviation. The Flyer was based on the Wrights experience testing gliders at Kitty Hawk between 1900 and 1902 and their last glider, the 1902 Glider, led directly to the design of the Flyer. The Wrights built the aircraft in 1903 using giant spruce wood as their construction material, the wings were designed with a 1-in-20 camber. Since they could not find a suitable engine for the task, they commissioned their employee Charlie Taylor to build a new design from scratch. A sprocket chain drive, borrowing from bicycle technology, powered the twin propellers, the Flyer was a canard biplane configuration. As with the gliders, the pilot flew lying on his stomach on the wing with his head toward the front of the craft in an effort to reduce drag. He steered by moving a cradle attached to his hips, the cradle pulled wires which warped the wings and turned the rudder simultaneously. The Flyers runway was a track of 2x4s stood on their narrow edge, the Flyer was conceived as a control-canard, as the Wrights were more concerned with control than stability. However, it was found to be so unstable that it was barely controllable. Following the first flight, ballast was added to the nose to move the center of gravity forward, however the basics of pitch stability of the canard configuration were not understood by the Wright Brothers. Culick stated, The backward state of the theory and understanding of flight mechanics hindered them. Indeed, the most serious gap in their knowledge was probably the reason for their unwitting mistake in selecting their canard configuration. Upon returning to Kitty Hawk in 1903, the Wrights completed assembly of the Flyer while practicing on the 1902 Glider from the previous season, on December 14,1903, they felt ready for their first attempt at powered flight. The brothers tossed a coin to decide who would get the first chance at piloting, the airplane left the rail, but Wilbur pulled up too sharply, stalled, and came down in about three seconds with minor damage. Repairs after the abortive first flight took three days, when they were ready again on December 17, the wind was averaging more than 20 mph, so the brothers laid the launching rail on level ground, pointed into the wind, near their camp
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George Cayley
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Sir George Cayley, 6th Baronet was a prolific English engineer and is one of the most important people in the history of aeronautics. Many consider him to be the first true scientific aerial investigator, in 1799 he set forth the concept of the modern aeroplane as a fixed-wing flying machine with separate systems for lift, propulsion, and control. He was a pioneer of engineering and is sometimes referred to as the father of aviation. He discovered and identified the four forces which act on a flying vehicle, weight, lift, drag. Modern aeroplane design is based on discoveries and on the importance of cambered wings. He constructed the first flying model aeroplane and also diagrammed the elements of vertical flight and he designed the first glider reliably reported to carry a human aloft. He correctly predicted that sustained flight would not occur until an engine was developed to provide adequate thrust. The Wright brothers acknowledged his importance to the development of aviation and he was a founding member of the British Association for the Advancement of Science and was a distant cousin of the mathematician Arthur Cayley. Cayley, from Brompton-by-Sawdon, near Scarborough in Yorkshire, inherited Brompton Hall and Wydale Hall and other estates on the death of his father, captured by the optimism of the times, he engaged in a wide variety of engineering projects. He suggested that a practical engine might be made using gaseous vapours rather than gunpowder. He is mainly remembered for his studies and experiments with flying machines, including the working, piloted glider that he designed. He wrote a landmark three-part treatise titled On Aerial Navigation, which was published in Nicholsons Journal of Natural Philosophy, Chemistry, the 2007 discovery of sketches in Cayleys school notebooks revealed that even at school Cayley was developing his ideas on the theories of flight. It has been claimed that these images indicate that Cayley identified the principle of an inclined plane as early as 1792. To measure the drag on objects at different speeds and angles of attack, he built a whirling-arm apparatus. He also experimented with rotating wing sections of various forms in the stairwells at Brompton Hall and these scientific experiments led him to develop an efficient cambered airfoil and to identify the four vector forces that influence an aircraft, thrust, lift, drag, and gravity. As a result of his investigations into many other aspects of flight. His emphasis on lightness led him to invent a new method of constructing lightweight wheels which is in use today. For his landing wheels, he shifted the forces from compression to tension by making them from tightly-stretched string
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Lift (force)
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A fluid flowing past the surface of a body exerts a force on it. Lift is the component of force that is perpendicular to the oncoming flow direction. It contrasts with the force, which is the component of the surface force parallel to the flow direction. If the fluid is air, the force is called an aerodynamic force, in water, it is called a hydrodynamic force. Lift is also exploited in the world, and even in the plant world by the seeds of certain trees. When an aircraft is flying straight and level most of the lift opposes gravity, however, when an aircraft is climbing, descending, or banking in a turn the lift is tilted with respect to the vertical. Lift may also be entirely downwards in some aerobatic manoeuvres, or on the wing on a racing car, in this last case, the term downforce is often used. Lift may also be horizontal, for instance on a sail on a sailboat. Aerodynamic lift is distinguished from other kinds of lift in fluids, Aerodynamic lift requires relative motion of the fluid which distinguishes it from aerostatic lift or buoyancy lift as used by balloons, blimps, and dirigibles. An airfoil is a shape that is capable of generating significantly more lift than drag. A flat plate can generate lift, but not as much as a streamlined airfoil, there are several ways to explain how an airfoil generates lift. Some are more complicated or more rigorous than others, some have been shown to be incorrect. For example, there are based directly on Newton’s laws of motion. Either can be used to explain lift, an airfoil generates lift by exerting a downward force on the air as it flows past. According to Newtons third law, the air must exert an equal and opposite force on the airfoil, the air flow changes direction as it passes the airfoil and follows a path that is curved downward. According to Newtons second law, this change in flow direction requires a force applied to the air by the airfoil. Then, according to Newtons third law, the air must exert a force on the airfoil. The overall result is that a force, the lift, is generated opposite to the directional change
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Drag (physics)
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In fluid dynamics, drag is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two layers or a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are independent of velocity. Drag force is proportional to the velocity for a laminar flow, even though the ultimate cause of a drag is viscous friction, the turbulent drag is independent of viscosity. Drag forces always decrease fluid velocity relative to the object in the fluids path. In the case of viscous drag of fluid in a pipe, in physics of sports, the drag force is necessary to explain the performance of runners, particularly of sprinters. Types of drag are generally divided into the categories, parasitic drag, consisting of form drag, skin friction, interference drag, lift-induced drag. The phrase parasitic drag is used in aerodynamics, since for lifting wings drag it is in general small compared to lift. For flow around bluff bodies, form and interference drags often dominate, further, lift-induced drag is only relevant when wings or a lifting body are present, and is therefore usually discussed either in aviation or in the design of semi-planing or planing hulls. Wave drag occurs either when an object is moving through a fluid at or near the speed of sound or when a solid object is moving along a fluid boundary. Drag depends on the properties of the fluid and on the size, shape, at low R e, C D is asymptotically proportional to R e −1, which means that the drag is linearly proportional to the speed. At high R e, C D is more or less constant, the graph to the right shows how C D varies with R e for the case of a sphere. As mentioned, the equation with a constant drag coefficient gives the force experienced by an object moving through a fluid at relatively large velocity. This is also called quadratic drag, the equation is attributed to Lord Rayleigh, who originally used L2 in place of A. Sometimes a body is a composite of different parts, each with a different reference areas, in the case of a wing the reference areas are the same and the drag force is in the same ratio to the lift force as the ratio of drag coefficient to lift coefficient. Therefore, the reference for a wing is often the area rather than the frontal area. For an object with a surface, and non-fixed separation points—like a sphere or circular cylinder—the drag coefficient may vary with Reynolds number Re. For an object with well-defined fixed separation points, like a disk with its plane normal to the flow direction
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Fluid dynamics
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In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids. It has several subdisciplines, including aerodynamics and hydrodynamics, before the twentieth century, hydrodynamics was synonymous with fluid dynamics. This is still reflected in names of some fluid dynamics topics, like magnetohydrodynamics and hydrodynamic stability, the foundational axioms of fluid dynamics are the conservation laws, specifically, conservation of mass, conservation of linear momentum, and conservation of energy. These are based on mechanics and are modified in quantum mechanics. They are expressed using the Reynolds transport theorem, in addition to the above, fluids are assumed to obey the continuum assumption. Fluids are composed of molecules that collide with one another and solid objects, however, the continuum assumption assumes that fluids are continuous, rather than discrete. The fact that the fluid is made up of molecules is ignored. The unsimplified equations do not have a general solution, so they are primarily of use in Computational Fluid Dynamics. The equations can be simplified in a number of ways, all of which make them easier to solve, some of the simplifications allow some simple fluid dynamics problems to be solved in closed form. Three conservation laws are used to solve fluid dynamics problems, the conservation laws may be applied to a region of the flow called a control volume. A control volume is a volume in space through which fluid is assumed to flow. The integral formulations of the laws are used to describe the change of mass, momentum. Mass continuity, The rate of change of fluid mass inside a control volume must be equal to the net rate of flow into the volume. Mass flow into the system is accounted as positive, and since the vector to the surface is opposite the sense of flow into the system the term is negated. The first term on the right is the net rate at which momentum is convected into the volume, the second term on the right is the force due to pressure on the volumes surfaces. The first two terms on the right are negated since momentum entering the system is accounted as positive, the third term on the right is the net acceleration of the mass within the volume due to any body forces. Surface forces, such as forces, are represented by F surf. The following is the form of the momentum conservation equation
31.
World War I
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World War I, also known as the First World War, the Great War, or the War to End All Wars, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. More than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history and it was one of the deadliest conflicts in history, and paved the way for major political changes, including revolutions in many of the nations involved. The war drew in all the worlds great powers, assembled in two opposing alliances, the Allies versus the Central Powers of Germany and Austria-Hungary. These alliances were reorganised and expanded as more nations entered the war, Italy, Japan, the trigger for the war was the assassination of Archduke Franz Ferdinand of Austria, heir to the throne of Austria-Hungary, by Yugoslav nationalist Gavrilo Princip in Sarajevo on 28 June 1914. This set off a crisis when Austria-Hungary delivered an ultimatum to the Kingdom of Serbia. Within weeks, the powers were at war and the conflict soon spread around the world. On 25 July Russia began mobilisation and on 28 July, the Austro-Hungarians declared war on Serbia, Germany presented an ultimatum to Russia to demobilise, and when this was refused, declared war on Russia on 1 August. Germany then invaded neutral Belgium and Luxembourg before moving towards France, after the German march on Paris was halted, what became known as the Western Front settled into a battle of attrition, with a trench line that changed little until 1917. On the Eastern Front, the Russian army was successful against the Austro-Hungarians, in November 1914, the Ottoman Empire joined the Central Powers, opening fronts in the Caucasus, Mesopotamia and the Sinai. In 1915, Italy joined the Allies and Bulgaria joined the Central Powers, Romania joined the Allies in 1916, after a stunning German offensive along the Western Front in the spring of 1918, the Allies rallied and drove back the Germans in a series of successful offensives. By the end of the war or soon after, the German Empire, Russian Empire, Austro-Hungarian Empire, national borders were redrawn, with several independent nations restored or created, and Germanys colonies were parceled out among the victors. During the Paris Peace Conference of 1919, the Big Four imposed their terms in a series of treaties, the League of Nations was formed with the aim of preventing any repetition of such a conflict. This effort failed, and economic depression, renewed nationalism, weakened successor states, and feelings of humiliation eventually contributed to World War II. From the time of its start until the approach of World War II, at the time, it was also sometimes called the war to end war or the war to end all wars due to its then-unparalleled scale and devastation. In Canada, Macleans magazine in October 1914 wrote, Some wars name themselves, during the interwar period, the war was most often called the World War and the Great War in English-speaking countries. Will become the first world war in the sense of the word. These began in 1815, with the Holy Alliance between Prussia, Russia, and Austria, when Germany was united in 1871, Prussia became part of the new German nation. Soon after, in October 1873, German Chancellor Otto von Bismarck negotiated the League of the Three Emperors between the monarchs of Austria-Hungary, Russia and Germany
32.
Sputnik 1
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Sputnik 1 was the first artificial Earth satellite. The Soviet Union launched it into an elliptical low Earth orbit on 4 October 1957 and it was a 58 cm diameter polished metal sphere, with four external radio antennas to broadcast radio pulses. It was visible all around the Earth and its radio pulses were detectable and this surprise success precipitated the American Sputnik crisis and triggered the Space Race, a part of the larger Cold War. The launch ushered in new political, military, technological, tracking and studying Sputnik 1 from Earth provided scientists with valuable information, even though the satellite itself wasnt equipped with sensors. The density of the atmosphere could be deduced from its drag on the orbit. Sputnik 1 was launched during the International Geophysical Year from Site No. 1/5, at the 5th Tyuratam range, the satellite travelled at about 29,000 kilometres per hour, taking 96.2 minutes to complete each orbit. It transmitted on 20.005 and 40.002 MHz, the signals continued for 21 days until the transmitter batteries ran out on 26 October 1957. Sputnik burned up on 4 January 1958 while reentering Earths atmosphere, after travelling about 70 million km, on 17 December 1954, chief Soviet rocket scientist Sergei Korolev addressed Dimitri Ustinov and proposed a developmental plan for an artificial satellite. Korolev forwarded a report by Mikhail Tikhonravov with an overview of similar projects abroad, Tikhonravov had emphasized that the launch of an orbital satellite was an inevitable stage in the development of rocket technology. On 29 July 1955, U. S. President Dwight D. Eisenhower announced through his press secretary that the United States would launch an artificial satellite during the International Geophysical Year. A week later, on 8 August, the Politburo of the Communist Party of the Soviet Union approved the proposal to create an artificial satellite. On 30 August Vasily Ryabikov – the head of the State Commission on R-7 rocket test launches – held a meeting where Korolev presented calculation data for a trajectory to the Moon. They decided to develop a version of the R-7 rocket for satellite launches. On 30 January 1956 the Council of Ministers approved practical work on an artificial Earth-orbiting satellite. This satellite, named Object D, was planned to be completed in 1957–58, it would have a mass of 1,000 to 1,400 kg, the first test launch of Object D was scheduled for 1957. These included measuring the density of the atmosphere and its ion composition, the wind, magnetic fields. These data would be valuable in the creation of artificial satellites. A system of stations was to be developed to collect data transmitted by the satellite, observe the satellites orbit
33.
Explorer 1
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Explorer 1 was the first satellite of the United States, launched as part of its participation in the International Geophysical Year. The mission followed the first two satellites the previous year, the Soviet Unions Sputnik 1 and 2, beginning the Cold War Space Race between the two nations. Explorer 1 was launched on January 31,1958 at 22,48 Eastern Time atop the first Juno booster from LC-26 at the Cape Canaveral Missile Annex, Florida. It was the first spacecraft to detect the Van Allen radiation belt and it remained in orbit until 1970, and has been followed by more than 90 scientific spacecraft in the Explorer series. Explorer 1 was given Satellite Catalog Number 4, and the Harvard designation 1958 Alpha 1, the forerunner to the modern International Designator. Earth satellite program began in 1954 as a joint U. S. Army and U. S. Navy proposal, called Project Orbiter, to put a scientific satellite into orbit during the International Geophysical Year. The proposal, using a military Redstone missile, was rejected in 1955 by the Eisenhower administration in favor of the Navys Project Vanguard, using a booster advertised as more civilian in nature. Following the launch of the Soviet satellite Sputnik 1 on October 4,1957, the Jupiter-C design used for the launch had already been flight-tested in nose cone reentry tests for the Jupiter IRBM, and was modified into Juno I. Working closely together, ABMA and JPL completed the job of modifying the Jupiter-C, however, before work was completed, the Soviet Union launched a second satellite, Sputnik 2, on November 3,1957. The U. S. Navys attempt to put the first U. S. satellite into orbit failed with the launch of the Vanguard TV3 on December 6,1957. Explorer 1 was designed and built by the California Institute of Technologys JPL under the direction of Dr. William H. Pickering and it was the second satellite to carry a mission payload. The total weight of the satellite was 13.37 kilograms, in comparison, the first Soviet satellite Sputnik 1 weighed 83.6 kg. The instrument section at the front end of the satellite and the empty scaled-down fourth-stage rocket casing orbited as a single unit, data from the scientific instruments was transmitted to the ground by two antennas. This was an early time frame in the development of transistor technology. A total of 29 transistors were used in Explorer 1, plus additional ones in the Armys micrometeorite amplifier, electrical power was provided by mercury chemical batteries that made up approximately 40 percent of the payload weight. The external skin of the instrument section was sandblasted stainless steel with white stripes, the final coloration was determined by studies of shadow–sunlight intervals based on firing time, trajectory, orbit, and inclination. The Explorer 1 payload consisted of the Iowa Cosmic Ray Instrument without a data recorder which was not modified in time to make it onto the spacecraft. The real-time data received on the ground was very sparse and puzzling showing normal counting rates
34.
NASA
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President Dwight D. Eisenhower established NASA in 1958 with a distinctly civilian orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29,1958, disestablishing NASAs predecessor, the new agency became operational on October 1,1958. Since that time, most US space exploration efforts have led by NASA, including the Apollo Moon landing missions, the Skylab space station. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle, the agency is also responsible for the Launch Services Program which provides oversight of launch operations and countdown management for unmanned NASA launches. NASA shares data with various national and international such as from the Greenhouse Gases Observing Satellite. Since 2011, NASA has been criticized for low cost efficiency, from 1946, the National Advisory Committee for Aeronautics had been experimenting with rocket planes such as the supersonic Bell X-1. In the early 1950s, there was challenge to launch a satellite for the International Geophysical Year. An effort for this was the American Project Vanguard, after the Soviet launch of the worlds first artificial satellite on October 4,1957, the attention of the United States turned toward its own fledgling space efforts. This led to an agreement that a new federal agency based on NACA was needed to conduct all non-military activity in space. The Advanced Research Projects Agency was created in February 1958 to develop technology for military application. On July 29,1958, Eisenhower signed the National Aeronautics and Space Act, a NASA seal was approved by President Eisenhower in 1959. Elements of the Army Ballistic Missile Agency and the United States Naval Research Laboratory were incorporated into NASA, earlier research efforts within the US Air Force and many of ARPAs early space programs were also transferred to NASA. In December 1958, NASA gained control of the Jet Propulsion Laboratory, NASA has conducted many manned and unmanned spaceflight programs throughout its history. Some missions include both manned and unmanned aspects, such as the Galileo probe, which was deployed by astronauts in Earth orbit before being sent unmanned to Jupiter, the experimental rocket-powered aircraft programs started by NACA were extended by NASA as support for manned spaceflight. This was followed by a space capsule program, and in turn by a two-man capsule program. This goal was met in 1969 by the Apollo program, however, reduction of the perceived threat and changing political priorities almost immediately caused the termination of most of these plans. NASA turned its attention to an Apollo-derived temporary space laboratory, to date, NASA has launched a total of 166 manned space missions on rockets, and thirteen X-15 rocket flights above the USAF definition of spaceflight altitude,260,000 feet. The X-15 was an NACA experimental rocket-powered hypersonic research aircraft, developed in conjunction with the US Air Force, the design featured a slender fuselage with fairings along the side containing fuel and early computerized control systems
35.
Wernher von Braun
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He was one of the leading figures in the development of rocket technology in Nazi Germany, where he was a member of the Nazi Party and the SS. In his twenties and early thirties, von Braun worked in Germanys rocket development program, following the war, von Braun worked for the United States Army on an intermediate-range ballistic missile program before his group was assimilated into NASA. In 1975, he received the National Medal of Science and he continued insisting on the human mission to Mars throughout his life. Wernher von Braun was born on 23 March 1912 in the town of Wirsitz, in the Posen Province. He was the second of three sons and he belonged to a noble family, inheriting the German title of Freiherr. His father, conservative civil servant Magnus Freiherr von Braun, served as a Minister of Agriculture in the Reich Cabinet during the Weimar Republic, Von Braun had an older brother, Sigismund, and a younger brother, also named Magnus. After Wernher von Brauns Lutheran confirmation, his mother gave him a telescope, the family moved to Berlin in 1915 where his father worked at the Ministry of the Interior. He was taken into custody by the police until his father came to collect him. Wernher von Braun was an amateur pianist who could play Beethoven. He learned to both the cello and the piano at an early age and at one time wanted to become a composer. He took lessons from the composer Paul Hindemith, the few pieces of von Braun’s youthful compositions that exist are reminiscent of Hindemith’s style. Beginning in 1925, von Braun attended a school at Ettersburg Castle near Weimar. There he acquired a copy of By Rocket into Planetary Space by rocket pioneer Hermann Oberth, in 1928, his parents moved him to the Hermann-Lietz-Internat on the East Frisian North Sea island of Spiekeroog. Space travel had always fascinated von Braun, and from then on he applied himself to physics and mathematics to pursue his interest in rocket engineering. In 1930, he attended the Technische Hochschule Berlin, where he joined the Spaceflight Society, in spring 1932, he graduated from the Technische Hochschule Berlin, with a diploma in mechanical engineering. His early exposure to rocketry convinced him that the exploration of space would require far more applications of the current engineering technology. He also studied at ETH Zürich, although he worked mainly on military rockets in his later years there, space travel remained his primary interest. In 1930, von Braun attended a presentation given by Auguste Piccard, after the talk the young student approached the famous pioneer of high-altitude balloon flight, and stated to him, You know, I plan on traveling to the Moon at some time
36.
Rocketdyne F-1
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The F-1 is a gas-generator cycle rocket engine developed in the United States by Rocketdyne in the late 1950s and used in the Saturn V rocket in the 1960s and early 1970s. Five F-1 engines were used in the S-IC first stage of each Saturn V, the F-1 remains the most powerful single-combustion chamber liquid-propellant rocket engine ever developed. The F-1 was originally developed by Rocketdyne to meet a 1955 U. S. Air Force requirement for a large rocket engine. The eventual result of requirement was two engines, the E-1 and the much larger F-1. The E-1, although tested in static firing, was quickly seen as a technological dead-end. The Air Force eventually halted development of the F-1 because of a lack of requirement for such a large engine, however, the recently created National Aeronautics and Space Administration appreciated the usefulness of an engine with so much power, and contracted Rocketdyne to complete its development. Test firings of F-1 components had performed as early as 1957. The first static firing of a full-stage developmental F-1 was performed in March 1959, the first F-1 was delivered to NASA MSFC in October 1963. In December 1964, the F-1 completed flight-rating tests, testing continued at least through 1965. Early development tests revealed serious combustion instability problems which caused catastrophic failure. Initially, progress on this problem was slow, as it was intermittent, oscillations of 4 kHz with harmonics to 24 kHz were observed. Eventually, engineers developed a technique of detonating small explosive charges outside the combustion chamber. This allowed them to exactly how the running chamber responded to variations in pressure. The designers could then quickly experiment with different co-axial fuel-injector designs to obtain the one most resistant to instability and these problems were addressed from 1959 through 1961. Eventually, engine combustion was so stable, it would self-damp artificially induced instability within 1/10 of a second, the Rocketdyne-developed F-1 engine is the most powerful single-nozzle liquid-fueled rocket engine ever flown. The M-1 rocket engine was designed to have more thrust, however it was tested at the component level. The F-1 was a rocket motor, burning RP-1 as fuel. A turbopump was used to fuel and oxygen into the combustion chamber
37.
Saturn V
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The Saturn V was an American human-rated expendable rocket used by NASA between 1967 and 1973. The Saturn V was launched 13 times from the Kennedy Space Center in Florida with no loss of crew or payload, to date, the Saturn V remains the only launch vehicle to launch missions to carry humans beyond low Earth orbit. A total of 15 flight-capable vehicles were built, but only 13 were flown, an additional three vehicles were built for ground testing purposes. A total of 24 astronauts were launched to the Moon, three of them twice, in the four years spanning December 1968 through December 1972 and it was known that Americas rival, the Soviet Union, would also try to secure some of the Germans. Von Braun was put into the design division of the Army due to his prior direct involvement in the creation of the V-2 rocket. Between 1945 and 1958, his work was restricted to conveying the ideas, finally, they turned to von Braun and his team, who during these years created and experimented with the Jupiter series of rockets. The Juno I was the rocket launched the first American satellite in January 1958. The Jupiter series was one step in von Brauns journey to the Saturn V. The Saturn Vs design stemmed from the designs of the Jupiter series rockets, as the success of the Jupiter series became evident, the Saturn series emerged. Between 1960 and 1962, the Marshall Space Flight Center designed a series of Saturn rockets that could be used for various Earth orbit or lunar missions. NASA planned to use the C-3 as part of the Earth Orbit Rendezvous concept, the C-4 would need only two launches to carry out an EOR lunar mission. On January 10,1962, NASA announced plans to build the C-5. The three-stage rocket would consist of, the S-IC first stage, with five F-1 engines, the S-II second stage, with five J-2 engines, the C-5 was designed for a 90, 000-pound payload capacity to the Moon. The C-5 would undergo component testing even before the first model was constructed, by testing all components at once, far fewer test flights would be required before a manned launch. The C-5 was confirmed as NASAs choice for the Apollo program in early 1963, the C-1 became the Saturn I, and C-1B became Saturn IB. Von Braun headed a team at the Marshall Space Flight Center in building a vehicle capable of launching a spacecraft on a trajectory to the Moon. Before they moved under NASAs jurisdiction, von Brauns team had begun work on improving the thrust, creating a less complex operating system. It was during these revisions that the decision to reject the single engine of the V-2s design came about, the Saturn I and IB reflected these changes, but were not large enough to send a manned spacecraft to the Moon
38.
U.S. Space & Rocket Center
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Space & Rocket Center in Huntsville, Alabama is a museum operated by the government of Alabama, showcasing rockets, achievements, and artifacts of the U. S. space program. The center offers bus tours of nearby Marshall Space Flight Center, two camp programs offer visitors the opportunity to stay on the grounds and learn more about their respective subject matter. Space Camp gives an in-depth exposure to the program through participant use of simulators, lectures. Similarly, Aviation Challenge offers a taste of military pilot training including simulations, lectures. Both camps provide residential and day camp programs for children. Space & Rocket Center has one of the most extensive collections of space artifacts, displays include rockets, engines, spacecraft, simulators, and hands-on exhibits. The rocketry collection includes numerous engines, as well, engines from the V-2 engine to NERVA to the Space Shuttle Main Engine are on display as well. The Apollo program gets full coverage in the Davidson Center for Space Exploration with artifacts outlining Apollo missions. Astronauts crossed the service structures red walkway to the White Room, both on display, and climbed in the Command Module atop a Saturn V which was their cabin for the trip to the moon, Apollo 16s command module is on display. The Saturn V Instrument Unit controlled five F-1 engines in the first stage of the rocket as it lifted off the pad, several exhibits relate the complexity and magnitude of that phase of the journey. They took a Lunar Module to the surface where they collected moon rocks such as the Apollo 12 specimen at the museum. Later moon trips took a Lunar Rover, the first few moon trips ended at a Mobile Quarantine Facility where astronauts stayed to ensure containment of any moon bugs after that mission. A restored engineering mock-up of Skylab is also on display, showing the Apollo projects post-lunar efforts, various simulators help visitors understand the spaceflight experience. Space Shot lets the rider experience launch-like 4 gs and 2–3 seconds of weightlessness, g-Force Accelerator offers 3 gs of acceleration for an extended period by means of a centrifuge. Several other simulators entertain and educate visitors, other exhibits offer a hands-on understanding of concepts related to rocketry or space travel. A bell jar demonstrates the reason for using a rocket instead of a propeller in the vacuum of space, a wind tunnel offers visitors the opportunity to manipulate a model to see how forces change with its orientation, and The Mind of Saturn exhibit demonstrates gyroscopic force. An Apollo trainer offers visitors the opportunity to climb in, some simulators on exhibit were used for astronaut training. A Project Mercury simulator shows the conditions endured by the first Americans in space
39.
Soyuz TMA-14M
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Soyuz TMA-14M was a 2014 flight to the International Space Station. It transported three members of the Expedition 41 crew to the International Space Station, TMA-14M is the 123rd flight of a Soyuz spacecraft, the first flight launching in 1967. The Soyuz remained docked to the station for the Expedition 42 increment to serve as an emergency escape vehicle until undocking and landing as scheduled in March 2015. Soyuz TMA-14M successfully launched aboard a Soyuz-FG rocket from the Baikonur Cosmodrome in Kazakhstan at 20,25 UTC on Thursday,25 September 2014, the spacecraft reached low Earth orbit approximately nine minutes after lift-off. After reaching orbit, the Soyuz spacecrafts port solar array failed to deploy, according to NASA and the Russian Federal Space Agency, the solar array does not pose a threat to the success of the mission. Following a four-orbit rendezvous, the spacecraft docked with the Poisk module of the International Space Station just under six hours after launch, hatches between the two spacecraft were opened at 04,06 UTC. At this time, the crew of TMA-14M joined the crew of Expedition 41, Samokutyayev, Serova and Wilmore transferred to the crew of Expedition 42 at that time. TMA-14M remained docked to the ISS—serving as an emergency escape vehicle—until March 11,2015, when it departed and returned Samokutyayev, Serova and Wilmore to Earth. After undocking from the ISS at 22,44 UTC on 11 March, in the 2014 film Gravity, STS-157 Mission Specialist Dr. Ryan Stone pilots the Soyuz TMA-14M spacecraft in her travel from the ISS to the Chinese Tiangong station
40.
Radar cross-section
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Radar cross-section is a measure of how detectable an object is with a radar. A larger RCS indicates that an object is more easily detected, an object reflects a limited amount of radar energy back to the source. Radar cross-section is used to detect planes in a variation of ranges. For example, an aircraft will have design features that give it a low RCS. RCS is integral to the development of stealth technology, particularly in applications involving aircraft. RCS data for current military aircraft is most highly classified, in some cases, it is of interest to look at an area on the ground that includes many objects. Informally, the RCS of an object is the area of a perfectly reflecting sphere that would produce the same strength reflection as would the object in question. Somewhat less informally, the RCS of a target is an effective area that intercepts the transmitted radar power. This power density is intercepted by the target with radar cross-section σ, thus, the product P t G t 4 π r 2 σ has the dimensions of power, and represents a hypothetical total power intercepted by the radar target. The second 14 π r 2 term represents isotropic spreading of this power from the target back to the radar receiver. Thus, the product P t G t 4 π r 2 σ14 π r 2 represents the power density at the radar receiver. The receiver antenna then collects this power density with effective area A e f f, the scattering of incident radar power by a radar target is never isotropic, and the RCS is a hypothetical area. In this light, RCS can be viewed simply as a factor that makes the radar equation work out right for the experimentally observed ratio of P r / P t. However, RCS is an extremely valuable concept because it is a property of the target alone, thus, RCS allows the performance of a radar system with a given target to be analysed independent of the radar and engagement parameters. In general, RCS is a function of the orientation of the radar and target, or, for the bistatic. A targets RCS depends on its size, reflectivity of its surface, as a rule, the larger an object, the stronger its radar reflection and thus the greater its RCS. Also, radar of one band may not even detect certain size objects, for example,10 cm can detect rain drops but not clouds whose droplets are too small. Materials such as metal are strongly radar reflective and tend to produce strong signals, wood and cloth or plastic and fibreglass are less reflective or indeed transparent to radar making them suitable for radomes
41.
Radar
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Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, Radio waves from the transmitter reflect off the object and return to the receiver, giving information about the objects location and speed. Radar was developed secretly for military use by several nations in the period before, the term RADAR was coined in 1940 by the United States Navy as an acronym for RAdio Detection And Ranging or RAdio Direction And Ranging. The term radar has since entered English and other languages as a common noun, high tech radar systems are associated with digital signal processing, machine learning and are capable of extracting useful information from very high noise levels. Other systems similar to make use of other parts of the electromagnetic spectrum. One example is lidar, which uses ultraviolet, visible, or near infrared light from lasers rather than radio waves, as early as 1886, German physicist Heinrich Hertz showed that radio waves could be reflected from solid objects. In 1895, Alexander Popov, an instructor at the Imperial Russian Navy school in Kronstadt. The next year, he added a spark-gap transmitter, in 1897, while testing this equipment for communicating between two ships in the Baltic Sea, he took note of an interference beat caused by the passage of a third vessel. In his report, Popov wrote that this phenomenon might be used for detecting objects, the German inventor Christian Hülsmeyer was the first to use radio waves to detect the presence of distant metallic objects. In 1904, he demonstrated the feasibility of detecting a ship in dense fog and he obtained a patent for his detection device in April 1904 and later a patent for a related amendment for estimating the distance to the ship. He also got a British patent on September 23,1904 for a radar system. It operated on a 50 cm wavelength and the radar signal was created via a spark-gap. In 1915, Robert Watson-Watt used radio technology to advance warning to airmen. Watson-Watt became an expert on the use of direction finding as part of his lightning experiments. As part of ongoing experiments, he asked the new boy, Arnold Frederic Wilkins, Wilkins made an extensive study of available units before selecting a receiver model from the General Post Office. Its instruction manual noted that there was fading when aircraft flew by, in 1922, A. Hoyt Taylor and Leo C. Taylor submitted a report, suggesting that this might be used to detect the presence of ships in low visibility, eight years later, Lawrence A. Australia, Canada, New Zealand, and South Africa followed prewar Great Britain, and Hungary had similar developments during the war. Hugon, began developing a radio apparatus, a part of which was installed on the liner Normandie in 1935
42.
Remote sensing
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Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object and thus in contrast to on-site observation. It may be split into active remote sensing and passive remote sensing, passive sensors gather radiation that is emitted or reflected by the object or surrounding areas. Reflected sunlight is the most common source of radiation measured by passive sensors, examples of passive remote sensors include film photography, infrared, charge-coupled devices, and radiometers. Active collection, on the hand, emits energy in order to scan objects and areas whereupon a sensor then detects. RADAR and LiDAR are examples of remote sensing where the time delay between emission and return is measured, establishing the location, speed and direction of an object. Remote sensing makes it possible to data of dangerous or inaccessible areas. Remote sensing applications include monitoring deforestation in areas such as the Amazon Basin, glacial features in Arctic and Antarctic regions, military collection during the Cold War made use of stand-off collection of data about dangerous border areas. Remote sensing also replaces costly and slow data collection on the ground, the basis for multispectral collection and analysis is that of examined areas or objects that reflect or emit radiation that stand out from surrounding areas. For a summary of major remote sensing satellite systems see the overview table, conventional radar is mostly associated with aerial traffic control, early warning, and certain large scale meteorological data. Other types of active collection includes plasmas in the ionosphere, interferometric synthetic aperture radar is used to produce precise digital elevation models of large scale terrain. Laser and radar altimeters on satellites have provided a range of data. By measuring the bulges of water caused by gravity, they map features on the seafloor to a resolution of a mile or so, by measuring the height and wavelength of ocean waves, the altimeters measure wind speeds and direction, and surface ocean currents and directions. Ultrasound and radar tide gauges measure sea level, tides and wave direction in coastal, light detection and ranging is well known in examples of weapon ranging, laser illuminated homing of projectiles. Vegetation remote sensing is an application of LIDAR. Radiometers and photometers are the most common instrument in use, collecting reflected and emitted radiation in a range of frequencies. The most common are visible and infrared sensors, followed by microwave, gamma ray and rarely and they may also be used to detect the emission spectra of various chemicals, providing data on chemical concentrations in the atmosphere. Simultaneous multi-spectral platforms such as Landsat have been in use since the 1970s and these thematic mappers take images in multiple wavelengths of electro-magnetic radiation and are usually found on Earth observation satellites, including the Landsat program or the IKONOS satellite. Landsat images are used by agencies such as KYDOW to indicate water quality parameters including Secchi depth, chlorophyll a density
43.
Fluid mechanics
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Fluid mechanics is a branch of physics concerned with the mechanics of fluids and the forces on them. Fluid mechanics has a range of applications, including for mechanical engineering, civil engineering, chemical engineering, geophysics, astrophysics. Fluid mechanics can be divided into fluid statics, the study of fluids at rest, and fluid dynamics, fluid mechanics, especially fluid dynamics, is an active field of research with many problems that are partly or wholly unsolved. Fluid mechanics can be complex, and can best be solved by numerical methods. A modern discipline, called computational fluid dynamics, is devoted to this approach to solving fluid mechanics problems, Particle image velocimetry, an experimental method for visualizing and analyzing fluid flow, also takes advantage of the highly visual nature of fluid flow. Inviscid flow was further analyzed by mathematicians and viscous flow was explored by a multitude of engineers including Jean Léonard Marie Poiseuille. Fluid statics or hydrostatics is the branch of mechanics that studies fluids at rest. It embraces the study of the conditions under which fluids are at rest in stable equilibrium, and is contrasted with fluid dynamics, hydrostatics is fundamental to hydraulics, the engineering of equipment for storing, transporting and using fluids. It is also relevant to some aspect of geophysics and astrophysics, to meteorology, to medicine, fluid dynamics is a subdiscipline of fluid mechanics that deals with fluid flow—the science of liquids and gases in motion. The solution to a fluid dynamics problem typically involves calculating various properties of the fluid, such as velocity, pressure, density and it has several subdisciplines itself, including aerodynamics and hydrodynamics. Some fluid-dynamical principles are used in engineering and crowd dynamics. Fluid mechanics is a subdiscipline of continuum mechanics, as illustrated in the following table, in a mechanical view, a fluid is a substance that does not support shear stress, that is why a fluid at rest has the shape of its containing vessel. A fluid at rest has no shear stress, the assumptions inherent to a fluid mechanical treatment of a physical system can be expressed in terms of mathematical equations. This can be expressed as an equation in integral form over the control volume, the continuum assumption is an idealization of continuum mechanics under which fluids can be treated as continuous, even though, on a microscopic scale, they are composed of molecules. Fluid properties can vary continuously from one element to another and are average values of the molecular properties. The continuum hypothesis can lead to results in applications like supersonic speed flows. Those problems for which the continuum hypothesis fails, can be solved using statistical mechanics, to determine whether or not the continuum hypothesis applies, the Knudsen number, defined as the ratio of the molecular mean free path to the characteristic length scale, is evaluated. Problems with Knudsen numbers below 0.1 can be evaluated using the continuum hypothesis, the Navier–Stokes equations are differential equations that describe the force balance at a given point within a fluid
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Wing
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A wing is a type of fin that produces lift, while moving through air or some other fluid. As such, wings have a shape, a streamlined cross-sectional shape. A wings aerodynamic efficiency is expressed as its lift-to-drag ratio, the lift a wing generates at a given speed and angle of attack can be one to two orders of magnitude greater than the total drag on the wing. A high lift-to-drag ratio requires a significantly smaller thrust to propel the wings through the air at sufficient lift, lifting structures used in water, include various foils, including hydrofoils. Hydrodynamics is the science, rather than aerodynamics. Applications of underwater foils occur in hydroplanes, sailboats and submarines, the word wing from the Old Norse vængr for many centuries referred mainly to the foremost limbs of birds. In nature wings have evolved in dinosaurs, birds, mammals, fish, reptiles, Wing forms in nature The design and analysis of the wings of aircraft is one of the principal applications of the science of aerodynamics, which is a branch of fluid mechanics. The properties of the airflow around any moving object can - in principle - be found by solving the Navier-Stokes equations of fluid dynamics, however, except for simple geometries these equations are notoriously difficult to solve. Fortunately, simpler explanations can be described, for a wing to produce lift, it must be oriented at a suitable angle of attack relative to the flow of air past the wing. When this occurs the wing deflects the airflow downwards, turning the air as it passes the wing, since the wing exerts a force on the air to change its direction, the air must exert a force on the wing, equal in size but opposite in direction. This force manifests itself as differing air pressures at different points on the surface of the wing, a region of lower-than-normal air pressure is generated over the top surface of the wing, with a higher pressure on the bottom of the wing. The lower air pressure on the top of the wing generates a smaller force on the top of the wing than the upward force generated by the higher air pressure on the bottom of the wing. Hence, a net force acts on the wing. This force is called the lift generated by the wing, the different velocities of the air passing by the wing, the air pressure differences, the change in direction of the airflow, and the lift on the wing are intrinsically one phenomenon. It is, therefore, possible to lift from any of the other three. For example, the lift can be calculated from the differences, or from different velocities of the air above and below the wing. Fluid dynamics offers other approaches to solving these problems—and all produce the same answers if done correctly, air velocity on the bottom of a wing is higher than that on the top, while the wing is generating lift. Wings with a cross section are the norm in subsonic flight
45.
Wind tunnel
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A wind tunnel is a tool used in aerodynamic research to study the effects of air moving past solid objects. A wind tunnel consists of a passage with the object under test mounted in the middle. Air is made to move past the object by a fan system or other means. The test object, often called a wind tunnel model, is instrumented with sensors to measure aerodynamic forces, pressure distribution. The earliest wind tunnels were invented towards the end of the 19th century, in the days of aeronautic research. In that way an observer could study the flying object in action. The development of wind tunnels accompanied the development of the airplane, large wind tunnels were built during World War II. Wind tunnel testing was considered of importance during the Cold War development of supersonic aircraft. Determining such forces was required before building codes could specify the required strength of such buildings, in these studies, the interaction between the road and the vehicle plays a significant role, and this interaction must be taken into consideration when interpreting the test results. The advances in fluid dynamics modelling on high speed digital computers has reduced the demand for wind tunnel testing. However, CFD results are not completely reliable and wind tunnels are used to verify CFD predictions. Air velocity and pressures are measured in several ways in wind tunnels, air velocity through the test section is determined by Bernoullis principle. Measurement of the pressure, the static pressure, and the temperature rise in the airflow. The direction of airflow around a model can be determined by tufts of yarn attached to the aerodynamic surfaces, the direction of airflow approaching a surface can be visualized by mounting threads in the airflow ahead of and aft of the test model. Smoke or bubbles of liquid can be introduced into the upstream of the test model. Aerodynamic forces on the test model are usually measured with beam balances, connected to the test model with beams, strings, or cables. Pressure distributions can more conveniently be measured by the use of pressure-sensitive paint, the strip is attached to the aerodynamic surface with tape, and it sends signals depicting the pressure distribution along its surface. The aerodynamic properties of an object can not all remain the same for a scaled model, however, by observing certain similarity rules, a very satisfactory correspondence between the aerodynamic properties of a scaled model and a full-size object can be achieved
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Astrodynamics
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Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft. The motion of objects is usually calculated from Newtons laws of motion. It is a discipline within space mission design and control. General relativity is an exact theory than Newtons laws for calculating orbits. Until the rise of space travel in the century, there was little distinction between orbital and celestial mechanics. At the time of Sputnik, the field was termed space dynamics, the fundamental techniques, such as those used to solve the Keplerian problem, are therefore the same in both fields. Furthermore, the history of the fields is almost entirely shared, johannes Kepler was the first to successfully model planetary orbits to a high degree of accuracy, publishing his laws in 1605. Isaac Newton published more general laws of motion in his 1687 book. The following rules of thumb are useful for situations approximated by classical mechanics under the assumptions of astrodynamics outlined below the rules. The specific example discussed is of a satellite orbiting a planet, Keplers laws of planetary motion, Orbits are elliptical, with the heavier body at one focus of the ellipse. Special case of this is an orbit with the planet at the center. A line drawn from the planet to the satellite sweeps out equal areas in equal times no matter which portion of the orbit is measured, the square of a satellites orbital period is proportional to the cube of its average distance from the planet. Without applying force, the period and shape of the satellites orbit wont change, a satellite in a low orbit moves more quickly with respect to the surface of the planet than a satellite in a higher orbit, due to the stronger gravitational attraction closer to the planet. If thrust is applied at one point in the satellites orbit, it will return to that same point on each subsequent orbit. Thus one cannot move from one orbit to another with only one brief application of thrust. Thrust applied in the direction of the satellites motion creates an elliptical orbit with an apoapse 180 degrees away from the firing point, the consequences of the rules of orbital mechanics are sometimes counter-intuitive. For example, if two spacecraft are in the circular orbit and wish to dock, unless they are very close. This will change the shape of its orbit, causing it to gain altitude and actually slow down relative to the leading craft, the space rendezvous before docking normally takes multiple precisely calculated engine firings in multiple orbital periods requiring hours or even days to complete
47.
Orbital mechanics
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Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft. The motion of objects is usually calculated from Newtons laws of motion. It is a discipline within space mission design and control. General relativity is an exact theory than Newtons laws for calculating orbits. Until the rise of space travel in the century, there was little distinction between orbital and celestial mechanics. At the time of Sputnik, the field was termed space dynamics, the fundamental techniques, such as those used to solve the Keplerian problem, are therefore the same in both fields. Furthermore, the history of the fields is almost entirely shared, johannes Kepler was the first to successfully model planetary orbits to a high degree of accuracy, publishing his laws in 1605. Isaac Newton published more general laws of motion in his 1687 book. The following rules of thumb are useful for situations approximated by classical mechanics under the assumptions of astrodynamics outlined below the rules. The specific example discussed is of a satellite orbiting a planet, Keplers laws of planetary motion, Orbits are elliptical, with the heavier body at one focus of the ellipse. Special case of this is an orbit with the planet at the center. A line drawn from the planet to the satellite sweeps out equal areas in equal times no matter which portion of the orbit is measured, the square of a satellites orbital period is proportional to the cube of its average distance from the planet. Without applying force, the period and shape of the satellites orbit wont change, a satellite in a low orbit moves more quickly with respect to the surface of the planet than a satellite in a higher orbit, due to the stronger gravitational attraction closer to the planet. If thrust is applied at one point in the satellites orbit, it will return to that same point on each subsequent orbit. Thus one cannot move from one orbit to another with only one brief application of thrust. Thrust applied in the direction of the satellites motion creates an elliptical orbit with an apoapse 180 degrees away from the firing point, the consequences of the rules of orbital mechanics are sometimes counter-intuitive. For example, if two spacecraft are in the circular orbit and wish to dock, unless they are very close. This will change the shape of its orbit, causing it to gain altitude and actually slow down relative to the leading craft, the space rendezvous before docking normally takes multiple precisely calculated engine firings in multiple orbital periods requiring hours or even days to complete
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