Aerospace is a term used to collectively refer to the atmosphere and outer space . Aerospace activity is very diverse, with a multitude of commercial, industrial, and military applications. Aerospace engineering consists of aeronautics and astronautics . Aerospace organizations research, design, manufacture, operate, maintain, and repair both aircraft and spacecraft .
124-432: The beginning of space and the ending of the air are proposed as 100km (62mi) above the ground according to the physical explanation that the air density is too low for a lifting body to generate meaningful lift force without exceeding orbital velocity. In most industrial countries, the aerospace industry is a cooperation of the public and private sectors. For example, several states have a civilian space program funded by
248-435: A boundary marked in most places by a temperature inversion (i.e. a layer of relatively warm air above a colder one), and in others by a zone that is isothermal with height. Although variations do occur, the temperature usually declines with increasing altitude in the troposphere because the troposphere is mostly heated through energy transfer from the surface. Thus, the lowest part of the troposphere (i.e. Earth's surface)
372-505: A factor of 1/ e (0.368) every 7.64 km (25,100 ft), (this is called the scale height ) -- for altitudes out to around 70 km (43 mi; 230,000 ft). However, the atmosphere is more accurately modeled with a customized equation for each layer that takes gradients of temperature, molecular composition, solar radiation and gravity into account. At heights over 100 km, an atmosphere may no longer be well mixed. Then each chemical species has its own scale height. In summary,
496-511: A layer in which temperatures rise with increasing altitude. This rise in temperature is caused by the absorption of ultraviolet radiation (UV) from the Sun by the ozone layer, which restricts turbulence and mixing. Although the temperature may be −60 °C (−76 °F; 210 K) at the tropopause, the top of the stratosphere is much warmer, and may be near 0 °C. The stratospheric temperature profile creates very stable atmospheric conditions, so
620-574: A mass of about 5.15 × 10 kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner with increasing altitude, with no definite boundary between the atmosphere and outer space . The Kármán line , at 100 km (62 mi) or 1.57% of Earth's radius, is often used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi). Several layers can be distinguished in
744-457: A military defense force stagnated as they focused on other concerns relevant to setting up the new government. President George Washington went to Congress to remind them of their duty to establish a military twice during this time. Finally, on the last day of the session, September 29, 1789, Congress created the War Department . The War Department handled naval affairs until Congress created
868-485: A million miles away, were found to be reflected light from ice crystals in the atmosphere. When light passes through Earth's atmosphere, photons interact with it through scattering . If the light does not interact with the atmosphere, it is called direct radiation and is what you see if you were to look directly at the Sun. Indirect radiation is light that has been scattered in the atmosphere. For example, on an overcast day when you cannot see your shadow, there
992-656: A more serious scientific discipline. Airmen like Otto Lilienthal , who introduced cambered airfoils in 1891, used gliders to analyze aerodynamic forces . The Wright brothers were interested in Lilienthal's work and read several of his publications. They also found inspiration in Octave Chanute , an airman and the author of Progress in Flying Machines (1894). It was the preliminary work of Cayley, Lilienthal, Chanute, and other early aerospace engineers that brought about
1116-523: A part of the general safety of a system or a piece of equipment. It implies that the system or equipment can be operated properly and without causing any danger, risk, damage or injury. Functional safety is crucial in the aerospace industry, which allows no compromises or negligence. In this respect, supervisory bodies, such as the European Aviation Safety Agency (EASA), regulate the aerospace market with strict certification standards. This
1240-451: A part. This certification guarantees that a part was repaired or overhauled to meet OEM specifications. Once a part is overhauled its value is determined from the supply and demand of the aerospace market. When an airline has an aircraft on the ground , the part that the airline requires to get the plane back into service becomes invaluable. This can drive the market for specific parts. There are several online marketplaces that assist with
1364-445: A variable amount of water vapor , on average around 1% at sea level, and 0.4% over the entire atmosphere. Air composition, temperature and atmospheric pressure vary with altitude . Within the atmosphere, air suitable for use in photosynthesis by terrestrial plants and respiration of terrestrial animals is found only within 12 kilometres (7.5 mi) from the ground. Earth's early atmosphere consisted of accreted gases from
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#17328510977621488-423: A variety of different fields including medicine, transportation, energy, consumer goods, public safety and more. NASA publishes an annual report called "Spinoffs", regarding many of the specific products and benefits to the aforementioned areas in an effort to highlight some of the ways funding is put to use. For example, in the most recent edition of this publication, "Spinoffs 2015", endoscopes are featured as one of
1612-544: Is 14 °C (57 °F; 287 K) or 15 °C (59 °F; 288 K), depending on the reference. The average atmospheric pressure at sea level is defined by the International Standard Atmosphere as 101325 pascals (760.00 Torr ; 14.6959 psi ; 760.00 mmHg ). This is sometimes referred to as a unit of standard atmospheres (atm) . Total atmospheric mass is 5.1480×10 kg (1.135×10 lb), about 2.5% less than would be inferred from
1736-408: Is about 1.2 kg/m (1.2 g/L, 0.0012 g/cm ). Density is not measured directly but is calculated from measurements of temperature, pressure and humidity using the equation of state for air (a form of the ideal gas law ). Atmospheric density decreases as the altitude increases. This variation can be approximately modeled using the barometric formula . More sophisticated models are used to predict
1860-414: Is about 28.946 or 28.96 g/mol. This is decreased when the air is humid. The relative concentration of gases remains constant until about 10,000 m (33,000 ft). In general, air pressure and density decrease with altitude in the atmosphere. However, temperature has a more complicated profile with altitude and may remain relatively constant or even increase with altitude in some regions (see
1984-442: Is because clouds (H 2 O) are strong absorbers and emitters of infrared radiation. This is also why it becomes colder at night at higher elevations. The greenhouse effect is directly related to this absorption and emission effect. Some gases in the atmosphere absorb and emit infrared radiation, but do not interact with sunlight in the visible spectrum. Common examples of these are CO 2 and H 2 O. The refractive index of air
2108-1429: Is called paleoclimatology . The three major constituents of Earth's atmosphere are nitrogen , oxygen , and argon . Water vapor accounts for roughly 0.25% of the atmosphere by mass. The concentration of water vapor (a greenhouse gas) varies significantly from around 10 ppm by mole fraction in the coldest portions of the atmosphere to as much as 5% by mole fraction in hot, humid air masses, and concentrations of other atmospheric gases are typically quoted in terms of dry air (without water vapor). The remaining gases are often referred to as trace gases, among which are other greenhouse gases , principally carbon dioxide, methane, nitrous oxide, and ozone. Besides argon, other noble gases , neon , helium , krypton , and xenon are also present. Filtered air includes trace amounts of many other chemical compounds . Many substances of natural origin may be present in locally and seasonally variable small amounts as aerosols in an unfiltered air sample, including dust of mineral and organic composition, pollen and spores , sea spray , and volcanic ash . Various industrial pollutants also may be present as gases or aerosols, such as chlorine (elemental or in compounds), fluorine compounds and elemental mercury vapor. Sulfur compounds such as hydrogen sulfide and sulfur dioxide (SO 2 ) may be derived from natural sources or from industrial air pollution. Mole fraction
2232-447: Is close to, but just greater than, 1. Systematic variations in the refractive index can lead to the bending of light rays over long optical paths. One example is that, under some circumstances, observers on board ships can see other vessels just over the horizon because light is refracted in the same direction as the curvature of Earth's surface. The refractive index of air depends on temperature, giving rise to refraction effects when
2356-512: Is composed of a layer of gas mixture that surrounds the Earth 's planetary surface (both lands and oceans ), known collectively as air , with variable quantities of suspended aerosols and particulates (which create weather features such as clouds and hazes ), all retained by Earth's gravity . The atmosphere serves as a protective buffer between the Earth's surface and outer space , shields
2480-477: Is mainly composed of extremely low densities of hydrogen, helium and several heavier molecules including nitrogen, oxygen and carbon dioxide closer to the exobase. The atoms and molecules are so far apart that they can travel hundreds of kilometres without colliding with one another. Thus, the exosphere no longer behaves like a gas, and the particles constantly escape into space . These free-moving particles follow ballistic trajectories and may migrate in and out of
2604-605: Is meant to reach and ensure the highest possible level of safety. The standards AS 9100 in America, EN 9100 on the European market or JISQ 9100 in Asia particularly address the aerospace and aviation industry. These are standards applying to the functional safety of aerospace vehicles. Some companies are therefore specialized in the certification, inspection verification and testing of the vehicles and spare parts to ensure and attest compliance with
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#17328510977622728-445: Is no direct radiation reaching you, it has all been scattered. As another example, due to a phenomenon called Rayleigh scattering , shorter (blue) wavelengths scatter more easily than longer (red) wavelengths. This is why the sky looks blue; you are seeing scattered blue light. This is also why sunsets are red. Because the Sun is close to the horizon, the Sun's rays pass through more atmosphere than normal before reaching your eye. Much of
2852-598: Is not military, such as the Department of Homeland Security, counter-terrorism spending by the FBI, and intelligence-gathering spending by the NSA. In the 2010 United States federal budget , the Department of Defense was allocated a base budget of $ 533.7 billion, with a further $ 75.5 billion adjustment in respect of 2009, and $ 130 billion for overseas contingencies. The subsequent 2010 Department of Defense Financial Report shows
2976-513: Is so tenuous that some scientists consider it to be part of interplanetary space rather than part of the atmosphere). It extends from the thermopause (also known as the "exobase") at the top of the thermosphere to a poorly defined boundary with the solar wind and interplanetary medium . The altitude of the exobase varies from about 500 kilometres (310 mi; 1,600,000 ft) to about 1,000 kilometres (620 mi) in times of higher incoming solar radiation. The upper limit varies depending on
3100-481: Is sometimes referred to as volume fraction ; these are identical for an ideal gas only. ppm: parts per million by molecular count The concentration of CO 2 has been increasing in recent decades , as has that of CH 4 . Water vapor is about 0.25% by mass over full atmosphere Water vapor varies significantly locally The average molecular weight of dry air, which can be used to calculate densities or to convert between mole fraction and mass fraction,
3224-456: Is the lowest layer of Earth's atmosphere. It extends from Earth's surface to an average height of about 12 km (7.5 mi; 39,000 ft), although this altitude varies from about 9 km (5.6 mi; 30,000 ft) at the geographic poles to 17 km (11 mi; 56,000 ft) at the Equator , with some variation due to weather. The troposphere is bounded above by the tropopause ,
3348-535: Is the secretary and their deputies, including predominantly civilian staff. OSD is the principal staff element of the Secretary of Defense in the exercise of policy development, planning, resource management, fiscal and program evaluation and oversight, and interface and exchange with other U.S. federal government departments and agencies, foreign governments, and international organizations, through formal and informal processes. OSD also performs oversight and management of
3472-412: Is too low to conduct a significant amount of energy to or from the skin. This layer is completely cloudless and free of water vapor. However, non-hydrometeorological phenomena such as the aurora borealis and aurora australis are occasionally seen in the thermosphere. The International Space Station orbits in this layer, between 350 and 420 km (220 and 260 mi). It is this layer where many of
3596-475: Is typically the warmest section of the troposphere. This promotes vertical mixing (hence, the origin of its name in the Greek word τρόπος, tropos , meaning "turn"). The troposphere contains roughly 80% of the mass of Earth's atmosphere. The troposphere is denser than all its overlying layers because a larger atmospheric weight sits on top of the troposphere and causes it to be most severely compressed. Fifty percent of
3720-724: The Central Intelligence Agency , the National Security Council , National Security Resources Board , United States Air Force , and the Joint Chiefs of Staff . The act placed the National Military Establishment under the control of a single secretary of defense . The National Military Establishment formally began operations on September 18, the day after the Senate confirmed James V. Forrestal as
3844-905: The Eisenhower School (ES) and the National War College (NWC). Faced with rising tensions between the Thirteen Colonies and the British government , one of the first actions taken by the First Continental Congress in September 1774 was to recommend that the colonies begin defensive military preparations. In mid-June 1775, after the outbreak of the Revolutionary War , the Second Continental Congress , recognizing
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3968-577: The F-layer of the ionosphere where they encounter enough atmospheric drag to require reboosts every few months, otherwise, orbital decay will occur resulting in a return to Earth. Depending on solar activity, satellites can experience noticeable atmospheric drag at altitudes as high as 700–800 km. The division of the atmosphere into layers mostly by reference to temperature is discussed above. Temperature decreases with altitude starting at sea level, but variations in this trend begin above 11 km, where
4092-718: The National Aerospace Laboratories and the Indian Space Research Organisation are headquartered. The Indian Space Research Organisation (ISRO) launched India's first Moon orbiter, Chandrayaan-1 , in October 2008. In Russia, large aerospace companies like Oboronprom and the United Aircraft Building Corporation (encompassing Mikoyan , Sukhoi , Ilyushin , Tupolev , Yakovlev , and Irkut which includes Beriev ) are among
4216-511: The Navy Department in 1798. The secretaries of each department reported directly to the president as cabinet-level advisors until 1949, when all military departments became subordinate to the Secretary of Defense. After the end of World War II , President Harry Truman proposed the creation of a unified department of national defense. In a special message to the Congress on December 19, 1945,
4340-658: The Office of the Director of National Intelligence . They fulfill the requirements of national policymakers and war planners, serve as Combat Support Agencies , and also assist and deploy alongside non-Department of Defense intelligence or law enforcement services such as the Central Intelligence Agency and the Federal Bureau of Investigation . The military services each have their intelligence elements that are distinct from but subject to coordination by national intelligence agencies under
4464-595: The United States Armed Forces . As of November 2022, the U.S. Department of Defense is the second largest employer in the world after India (and potentially China, if including the Central Military Commission), with over 1.4 million active-duty service personnel, including soldiers, marines, sailors, airmen, and guardians. The Department of Defense also maintains over 778,000 National Guard and reservists, and over 747,000 civilians, bringing
4588-688: The deputy secretary of defense . Secretaries of military departments, in turn, normally exercise authority over their forces by delegation through their respective service chiefs (i.e., Chief of Staff of the Army , Commandant of the Marine Corps , Chief of Naval Operations , Chief of Staff of the Air Force , and Chief of Space Operations ) over forces not assigned to a Combatant Command . Secretaries of Military Departments and service chiefs do not possess operational command authority over U.S. troops (this power
4712-511: The fiscal year 2024 (FY2024) presidential budget request was $ 842 billion. In January 2023 Treasury Secretary Janet Yellen announced the US government would hit its $ 31.4 trillion debt ceiling on 19 January 2023; the date on which the US government would no longer be able to use extraordinary measures such as issuance of Treasury securities is estimated to be in June 2023. On 3 June 2023,
4836-1417: The government , such as National Aeronautics and Space Administration in the United States, European Space Agency in Europe, the Canadian Space Agency in Canada, Indian Space Research Organisation in India, Japan Aerospace Exploration Agency in Japan, Roscosmos State Corporation for Space Activities in Russia, China National Space Administration in China, SUPARCO in Pakistan, Iranian Space Agency in Iran, and Korea Aerospace Research Institute in South Korea. Along with these public space programs, many companies produce technical tools and components such as spacecraft and satellites . Some known companies involved in space programs include Boeing , Cobham , Airbus , SpaceX , Lockheed Martin , RTX Corporation , MDA and Northrop Grumman . These companies are also involved in other areas of aerospace, such as
4960-588: The infrared to around 1100 nm. There are also infrared and radio windows that transmit some infrared and radio waves at longer wavelengths. For example, the radio window runs from about one centimetre to about eleven-metre waves. Emission is the opposite of absorption, it is when an object emits radiation. Objects tend to emit amounts and wavelengths of radiation depending on their " black body " emission curves, therefore hotter objects tend to emit more radiation, with shorter wavelengths. Colder objects emit less radiation, with longer wavelengths. For example,
5084-433: The magnetosphere or the solar wind. Every second, the Earth loses about 3 kg of hydrogen, 50 g of helium, and much smaller amounts of other constituents. The exosphere is too far above Earth for meteorological phenomena to be possible. However, Earth's auroras —the aurora borealis (northern lights) and aurora australis (southern lights)—sometimes occur in the lower part of the exosphere, where they overlap into
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5208-402: The mesopause that marks the top of this middle layer of the atmosphere. It is the coldest place on Earth and has an average temperature around −85 °C (−120 °F ; 190 K ). Just below the mesopause, the air is so cold that even the very scarce water vapor at this altitude can condense into polar-mesospheric noctilucent clouds of ice particles. These are the highest clouds in
5332-451: The solar nebula , but the atmosphere changed significantly over time, affected by many factors such as volcanism , impact events , weathering and the evolution of life (particularly the photoautotrophs ). Recently, human activity has also contributed to atmospheric changes , such as climate change (mainly through deforestation and fossil fuel -related global warming ), ozone depletion and acid deposition . The atmosphere has
5456-428: The temperature section). Because the general pattern of the temperature/altitude profile, or lapse rate , is constant and measurable by means of instrumented balloon soundings , the temperature behavior provides a useful metric to distinguish atmospheric layers. This atmospheric stratification divides the Earth's atmosphere into five main layers: The exosphere is the outermost layer of Earth's atmosphere (though it
5580-511: The tropopause . This layer extends from the top of the troposphere at roughly 12 km (7.5 mi; 39,000 ft) above Earth's surface to the stratopause at an altitude of about 50 to 55 km (31 to 34 mi; 164,000 to 180,000 ft). The atmospheric pressure at the top of the stratosphere is roughly 1/1000 the pressure at sea level . It contains the ozone layer , which is the part of Earth's atmosphere that contains relatively high concentrations of that gas. The stratosphere defines
5704-625: The Army , Secretary of the Navy and Secretary of the Air Force ), appointed by the president, with the advice and consent of the Senate . They have the legal authority under Title 10 of the United States Code to conduct all the affairs of their respective departments within which the military services are organized. The secretaries of the Military Departments are (by law) subordinate to the secretary of defense and (by SecDef delegation) to
5828-582: The CIA's human intelligence efforts while also focusing on military human intelligence priorities. These agencies are directly overseen by the Under Secretary of Defense for Intelligence and Security . The Joint Chiefs of Staff (JCS) is a body of senior uniformed leaders in the Department of Defense who advise the secretary of defense, the Homeland Security Council , the National Security Council and
5952-754: The Chairman of the Joint Chiefs of Staff (CJCS) as the "principal military adviser to the President, the National Security Council, the Homeland Security Council, and the Secretary of Defense". The remaining Joint Chiefs of Staff may only have their advice relayed to the President, National Security Council, the Homeland Security Council , or the Secretary of Defense after submitting it to the CJCS. By law,
6076-540: The Defense Agencies, Department of Defense Field Activities, and specialized Cross Functional Teams . OSD is a parent agency of the following defense agencies: Several defense agencies are members of the United States Intelligence Community . These are national-level intelligence services that operate under the Department of Defense jurisdiction but simultaneously fall under the authorities of
6200-514: The Department of Defense budget, such as nuclear weapons research, maintenance, cleanup, and production, which is in the Department of Energy budget, Veterans Affairs, the Treasury Department's payments in pensions to military retirees and widows and their families, interest on debt incurred in past wars, or State Department financing of foreign arms sales and militarily-related development assistance. Neither does it include defense spending that
6324-464: The Department of Defense. Department of Defense manages the nation's coordinating authorities and assets in disciplines of signals intelligence , geospatial intelligence , and measurement and signature intelligence , and also builds, launches, and operates the Intelligence Community's satellite assets. Department of Defense also has its own human intelligence service , which contributes to
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#17328510977626448-537: The European Union, aerospace companies such as Airbus SE , Safran , Thales , Dassault Aviation , Leonardo and Saab AB account for a large share of the global aerospace industry and research effort, with the European Space Agency as one of the largest consumers of aerospace technology and products. In India, Bangalore is a major center of the aerospace industry, where Hindustan Aeronautics Limited ,
6572-597: The FY 2019 budget: "The overall number you often hear is $ 716 billion. That is the amount of funding for national defense, the accounting code is 050 and includes more than simply the Department of Defense. It includes, for example, the Department of Energy and others. That large a number, if you back out the $ 30 billion for non-defense agencies, you get to $ 686 billion. That is the funding for the Department of Defense, split between $ 617 billion in base and $ 69 billion in overseas contingency ". The Department of Defense budget encompasses
6696-509: The FY2018 Budget expired and the FY2019 budget came into effect. The FY2019 Budget for the Department of Defense is approximately $ 686,074,048,000 (Including Base + Overseas Contingency Operations + Emergency Funds) in discretionary spending and $ 8,992,000,000 in mandatory spending totaling $ 695,066,000,000 Undersecretary of Defense (Comptroller) David L. Norquist said in a hearing regarding
6820-773: The Joint Chiefs of Staff ( JCS ) and the Joint Staff ( JS ), Office of the Inspector General ( DODIG ), the Combatant Commands , the Military Departments ( Department of the Army (DA), Department of the Navy (DON) & Department of the Air Force (DAF)), the Defense Agencies and Department of Defense Field Activities , the National Guard Bureau (NGB), and such other offices, agencies, activities, organizations, and commands established or designated by law, or by
6944-558: The Kármán line, significant atmospheric effects such as auroras still occur. Meteors begin to glow in this region, though the larger ones may not burn up until they penetrate more deeply. The various layers of Earth's ionosphere , important to HF radio propagation, begin below 100 km and extend beyond 500 km. By comparison, the International Space Station and Space Shuttle typically orbit at 350–400 km, within
7068-584: The NDAA on 14 December 2023. The Senate will next undertake negotiations on supplemental spending for 2024. A government shutdown was averted on 23 March 2024 with the signing of a $ 1.2 trillion bill to cover FY2024. A 2013 Reuters investigation concluded that Defense Finance & Accounting Service , the Department of Defense's primary financial management arm, implements monthly "unsubstantiated change actions"—illegal, inaccurate "plugs"—that forcibly make DoD's books match Treasury's books. Reuters reported that
7192-1013: The National Security Agency ( NSA ), the National Geospatial-Intelligence Agency ( NGA ), and the National Reconnaissance Office ( NRO ). Other Defense agencies include the Defense Advanced Research Projects Agency ( DARPA ), the Defense Logistics Agency ( DLA ), the Missile Defense Agency ( MDA ), the Defense Health Agency ( DHA ), Defense Threat Reduction Agency ( DTRA ), the Defense Counterintelligence and Security Agency ( DCSA ),
7316-467: The Pentagon was the only federal agency that had not released annual audits as required by a 1992 law. According to Reuters, the Pentagon "annually reports to Congress that its books are in such disarray that an audit is impossible". In 2015, a Pentagon consulting firm performed an audit on the Department of Defense's budget. It found that there was $ 125 billion in wasteful spending that could be saved over
7440-642: The President to the Secretary of Defense, the service chief of the Unified Combatant Commander(s), and then to the unified combatant commander(s). Also provided in this legislation was a centralized research authority, the Advanced Research Projects Agency , eventually known as DARPA . The act was written and promoted by the Eisenhower administration and was signed into law on August 6, 1958. The Secretary of Defense , appointed by
7564-458: The Space Development Agency ( SDA ) and the Pentagon Force Protection Agency ( PFPA ), all of which are subordinate to the secretary of defense. Additionally, the Defense Contract Management Agency ( DCMA ) is responsible for administering contracts for the Department of Defense. Military operations are managed by eleven regional or functional unified combatant commands . The Department of Defense also operates several joint services schools, including
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#17328510977627688-459: The Sun is approximately 6,000 K (5,730 °C ; 10,340 °F ), its radiation peaks near 500 nm, and is visible to the human eye. Earth is approximately 290 K (17 °C; 62 °F), so its radiation peaks near 10,000 nm, and is much too long to be visible to humans. Because of its temperature, the atmosphere emits infrared radiation. For example, on clear nights Earth's surface cools down faster than on cloudy nights. This
7812-468: The Swedish Air Force—especially in support of its position as a neutral country. (See Saab AB .) Other European countries either team up in making fighters (such as the Panavia Tornado and the Eurofighter Typhoon ), or else to import them from the United States. Pakistan has a developing aerospace engineering industry. The National Engineering and Scientific Commission , Khan Research Laboratories and Pakistan Aeronautical Complex are among
7936-425: The Unified Combatant Commands are responsible for military forces' actual operational command. Almost all operational U.S. forces are under the authority of a Unified Command. The Unified Commands are governed by a Unified Command Plan —a frequently updated document (produced by the DoD), which lays out the Command's mission, geographical/functional responsibilities, and force structure. During military operations,
8060-422: The United States , the latter of which is also the commander-in-chief of the United States Armed Forces . Beneath the Department of Defense are three subordinate military departments: the Department of the Army , the Department of the Navy , and the Department of the Air Force . In addition, four national intelligence services are subordinate to the Department of Defense: the Defense Intelligence Agency ( DIA ),
8184-466: The United States and Europe to fill these needs. However Canada still manufactures some military aircraft although they are generally not combat capable. Another notable example was the late 1950s development of the Avro Canada CF-105 Arrow , a supersonic fighter-interceptor whose 1959 cancellation was considered highly controversial. France has continued to make its own warplanes for its air force and navy, and Sweden continues to make its own warplanes for
8308-429: The United States. However, the UK has a very active aerospace sector, with major companies such as BAE Systems , supplying fully assembled aircraft, aircraft components, sub-assemblies and sub-systems to other manufacturers, both in Europe and all over the world. Canada has formerly manufactured some of its own designs for jet warplanes, etc. (e.g. the CF-100 fighter), but for some decades, it has relied on imports from
8432-521: The allocation for the Department of Defense was $ 585 billion, the highest level of budgetary resources among all federal agencies, and this amounts to more than one-half of the annual federal expenditures in the United States federal budget discretionary budget . On September 28, 2018, President Donald Trump signed the Department of Defense and Labor, Health and Human Services, and Education Appropriations Act, 2019, and Continuing Appropriations Act, 2019 (H.R.6157) into law. On September 30, 2018,
8556-403: The appropriate regulations. Spinoffs refer to any technology that is a direct result of coding or products created by NASA and redesigned for an alternate purpose. These technological advancements are one of the primary results of the aerospace industry, with $ 5.2 billion worth of revenue generated by spinoff technology, including computers and cellular devices. These spinoffs have applications in
8680-420: The aptly-named thermosphere above 90 km. Because in an ideal gas of constant composition the speed of sound depends only on temperature and not on pressure or density, the speed of sound in the atmosphere with altitude takes on the form of the complicated temperature profile (see illustration to the right), and does not mirror altitudinal changes in density or pressure. The density of air at sea level
8804-421: The atmosphere also cools by emitting radiation, as discussed below. The combined absorption spectra of the gases in the atmosphere leave "windows" of low opacity , allowing the transmission of only certain bands of light. The optical window runs from around 300 nm ( ultraviolet -C) up into the range humans can see, the visible spectrum (commonly called light), at roughly 400–700 nm and continues to
8928-399: The atmosphere and may be visible to the naked eye if sunlight reflects off them about an hour or two after sunset or similarly before sunrise. They are most readily visible when the Sun is around 4 to 16 degrees below the horizon. Lightning-induced discharges known as transient luminous events (TLEs) occasionally form in the mesosphere above tropospheric thunderclouds . The mesosphere is also
9052-489: The atmosphere based on characteristics such as temperature and composition, namely the troposphere , stratosphere , mesosphere , thermosphere (formally the ionosphere ) and exosphere . The study of Earth's atmosphere and its processes is called atmospheric science (aerology), and includes multiple subfields, such as climatology and atmospheric physics . Early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann . The study of historic atmosphere
9176-637: The average sea level pressure and Earth's area of 51007.2 megahectares, this portion being displaced by Earth's mountainous terrain. Atmospheric pressure is the total weight of the air above unit area at the point where the pressure is measured. Thus air pressure varies with location and weather . If the entire mass of the atmosphere had a uniform density equal to sea level density (about 1.2 kg per m ) from sea level upwards, it would terminate abruptly at an altitude of 8.50 km (27,900 ft). Air pressure actually decreases exponentially with altitude, dropping by half every 5.6 km (18,000 ft) or by
9300-414: The blue light has been scattered out, leaving the red light in a sunset. Different molecules absorb different wavelengths of radiation. For example, O 2 and O 3 absorb almost all radiation with wavelengths shorter than 300 nanometres . Water (H 2 O) absorbs at many wavelengths above 700 nm. When a molecule absorbs a photon, it increases the energy of the molecule. This heats the atmosphere, but
9424-438: The budgeted global military spending – more than the next 7 largest militaries combined. By 2019, the 27th secretary of defense had begun a line-by-line review of the defense budget; in 2020 the secretary identified items amounting to $ 5.7 billion, out of a $ 106 billion subtotal (the so-called "fourth estate" agencies such as missile defense, and defense intelligence, amounting to 16% of the defense budget), He will re-deploy to
9548-472: The capability to design and manufacture both armed and unarmed unmanned aerial vehicles . In the People's Republic of China, Beijing , Xi'an , Chengdu , Shanghai , Shenyang and Nanchang are major research and manufacture centers of the aerospace industry. China has developed an extensive capability to design, test and produce military aircraft, missiles and space vehicles. Despite the cancellation in 1983 of
9672-465: The chain of command runs from the president to the secretary of defense to the combatant commanders of the Combatant Commands. As of 2019 , the United States has eleven Combatant Commands, organized either on a geographical basis (known as " area of responsibility ", AOR) or on a global, functional basis: Department of Defense spending in 2017 was 3.15% of GDP and accounted for about 38% of
9796-430: The chairman has to present that advice whenever he is presenting his own. The chain of command goes from the president to the secretary of defense to the commanders of the Combatant Commands . Goldwater–Nichols also created the office of vice-chairman, and the chairman is now designated as the principal military adviser to the secretary of defense, the Homeland Security Council, the National Security Council and to
9920-486: The commodity selling of aircraft parts. In the aerospace and defense industry, much consolidation occurred at the end of the 20th century and in the early 21st century. Between 1988 and 2011, more than 6,068 mergers and acquisitions with a total known value of US$ 678 billion were announced worldwide. The largest transactions have been: Multiple technologies and innovations are used in aerospace, many of them pioneered around World War II : Functional safety relates to
10044-606: The construction of aircraft. Modern aerospace began with Engineer George Cayley in 1799. Cayley proposed an aircraft with a "fixed wing and a horizontal and vertical tail," defining characteristics of the modern aeroplane. The 19th century saw the creation of the Aeronautical Society of Great Britain (1866), the American Rocketry Society, and the Institute of Aeronautical Sciences , all of which made aeronautics
10168-487: The debt ceiling was suspended until 2025. The $ 886 billion National Defense Authorization Act is facing reconciliation of the House and Senate bills after passing both houses 27 July 2023; the conferees have to be chosen, next. As of September 2023, a Continuing resolution is needed to prevent a Government shutdown . A shutdown was avoided on 30 September for 45 days (until 17 November 2023), with passage of
10292-415: The definition. Various authorities consider it to end at about 10,000 kilometres (6,200 mi) or about 190,000 kilometres (120,000 mi)—about halfway to the moon, where the influence of Earth's gravity is about the same as radiation pressure from sunlight. The geocorona visible in the far ultraviolet (caused by neutral hydrogen) extends to at least 100,000 kilometres (62,000 mi). This layer
10416-438: The department were streamlined while still maintaining the ordinary jurisdiction of the Military Departments to organize, train, and equip their associated forces. The Act clarified the overall decision-making authority of the secretary of defense concerning these subordinate Military Departments. It more clearly defined the operational chain of command over U.S. military forces (created by the military departments) as running from
10540-399: The experimental Shanghai Y-10 , China is still developing its civil aerospace industry. The aircraft parts industry was born out of the sale of second-hand or used aircraft parts from the aerospace manufacture sector. Within the United States there is a specific process that parts brokers or resellers must follow. This includes leveraging a certified repair station to overhaul and "tag"
10664-596: The first crewed Moon landing. In April 1981, the Space Shuttle Columbia launched, the start of regular crewed access to orbital space. A sustained human presence in orbital space started with " Mir " in 1986 and is continued by the " International Space Station ". Space commercialization and space tourism are more recent features of aerospace. Aerospace manufacturing is a high-technology industry that produces "aircraft, guided missiles, space vehicles, aircraft engines, propulsion units, and related parts". Most of
10788-648: The first powered sustained flight at Kitty Hawk, North Carolina on December 17, 1903, by the Wright brothers. War and science fiction inspired scientists and engineers like Konstantin Tsiolkovsky and Wernher von Braun to achieve flight beyond the atmosphere. World War II inspired Wernher von Braun to create the V1 and V2 rockets. The launch of Sputnik 1 in October 1957 started the Space Age , and on July 20, 1969 Apollo 11 achieved
10912-564: The first secretary of defense. The National Military Establishment was renamed the "Department of Defense" on August 10, 1949, and absorbed the three cabinet-level military departments, in an amendment to the original 1947 law. The renaming is alleged to be due to the Establishment's abbreviation, NME, being pronounced "enemy". Under the Department of Defense Reorganization Act of 1958 ( Pub. L. 85–599 ), channels of authority within
11036-434: The gas molecules are so far apart that its temperature in the usual sense is not very meaningful. The air is so rarefied that an individual molecule (of oxygen , for example) travels an average of 1 kilometre (0.62 mi; 3300 ft) between collisions with other molecules. Although the thermosphere has a high proportion of molecules with high energy, it would not feel hot to a human in direct contact, because its density
11160-1053: The industrial sector with fresh workers, apprenticeship programs like the Aerospace Joint Apprenticeship Council (AJAC) collaborate with community colleges and aerospace firms in Washington state. Important locations of the civilian aerospace industry worldwide include Washington state ( Boeing ), California ( Boeing , Lockheed Martin , etc.) and Montreal, Quebec , Canada ( Bombardier , Pratt & Whitney Canada ) in North America ; Toulouse , France ( Airbus SE ) and Hamburg , Germany ( Airbus SE ) in Europe ; as well as São José dos Campos , Brazil ( Embraer ), Querétaro , Mexico (Bombardier Aerospace, General Electric Aviation) and Mexicali , Mexico (United Technologies Corporation, Gulfstream Aerospace ) in Latin America . In
11284-494: The industry is geared toward governmental work. For each original equipment manufacturer (OEM), the US government has assigned a Commercial and Government Entity (CAGE) code . These codes help to identify each manufacturer, repair facilities, and other critical aftermarket vendors in the aerospace industry. In the United States, the Department of Defense and the National Aeronautics and Space Administration (NASA) are
11408-404: The jurisdiction of other congressional committees. The Department of Defense is unique because it is one of the few federal entities where the majority of its funding falls into the discretionary category. The majority of the entire federal budget is mandatory, and much of the discretionary funding in the budget consists of DoD dollars. * Numbers may not add due to rounding As of 10 March 2023
11532-493: The latest Center for Effective Government analysis of 15 federal agencies which receive the most Freedom of Information Act requests, published in 2015 (using 2012 and 2013 data, the most recent years available), the DoD earned 61 out of a possible 100 points, a D− grade. While it had improved from a failing grade in 2013, it still had low scores in processing requests (55%) and disclosure rules (42%). The organization and functions of
11656-403: The layer where most meteors burn up upon atmospheric entrance. It is too high above Earth to be accessible to jet-powered aircraft and balloons, and too low to permit orbital spacecraft. The mesosphere is mainly accessed by sounding rockets and rocket-powered aircraft . The stratosphere is the second-lowest layer of Earth's atmosphere. It lies above the troposphere and is separated from it by
11780-413: The major global players in this industry. The historic Soviet Union was also the home of a major aerospace industry. The United Kingdom formerly attempted to maintain its own large aerospace industry, making its own airliners and warplanes, but it has largely turned its lot over to cooperative efforts with continental companies, and it has turned into a large import customer, too, from countries such as
11904-561: The majority of the National Defense Budget of approximately $ 716.0 billion in discretionary spending and $ 10.8 billion in mandatory spending for a $ 726.8 billion total. Of the total, $ 708.1 billion falls under the jurisdiction of the House Committee on Armed Services and Senate Armed Services Committee and is subject to authorization by the annual National Defense Authorization Act (NDAA). The remaining $ 7.9 billion falls under
12028-482: The mass of Earth's atmosphere is distributed approximately as follows: By comparison, the summit of Mount Everest is at 8,848 m (29,029 ft); commercial airliners typically cruise between 10 and 13 km (33,000 and 43,000 ft) where the lower density and temperature of the air improve fuel economy; weather balloons reach 30.4 km (100,000 ft) and above; and the highest X-15 flight in 1963 reached 108.0 km (354,300 ft). Even above
12152-503: The medical derivations of aerospace achievement. This device enables more precise and subsequently cost-effective neurosurgery by reducing complications through a minimally invasive procedure that abbreviates hospitalization. "These NASA technologies are not only giving companies and entrepreneurs a competitive edge in their own industries, but are also helping to shape budding industries, such as commercial lunar landers ," said Daniel Lockney. Air The atmosphere of Earth
12276-589: The modernization of hypersonics, artificial intelligence, and missile defense. Beyond 2021 the 27th secretary of defense is projecting the need for yearly budget increases of 3 to 5 percent to modernize. The Department of Defense accounts for the majority of federal discretionary spending. In FY 2017, the Department of Defense budgeted spending accounted for 15% of the U.S. federal budget, and 49% of federal discretionary spending , which represents funds not accounted for by pre-existing obligations. However, this does not include many military-related items that are outside
12400-633: The necessity of having a national army that could move about and fight beyond the boundaries of any particular colony, organized the Continental Army on June 14, 1775. This momentous event is commemorated in the U.S. annually as Flag Day . Later that year, Congress would charter the Continental Navy on October 13, and the Continental Marines on November 10. Upon the seating of the 1st U.S. Congress on March 4, 1789, legislation to create
12524-579: The next five years without layoffs or reduction in military personnel. In 2016, The Washington Post uncovered that rather than taking the advice of the auditing firm, senior defense officials suppressed and hid the report from the public to avoid political scrutiny. In June 2016, the Office of the Inspector General released a report stating that the Army made $ 6.5 trillion in wrongful adjustments to its accounting entries in 2015. The Department of Defense failed its fifth audit in 2022, and could not account for more than 60% of its $ 3.5 trillion in assets. In
12648-504: The orbital decay of satellites. The average mass of the atmosphere is about 5 quadrillion (5 × 10 ) tonnes or 1/1,200,000 the mass of Earth. According to the American National Center for Atmospheric Research , "The total mean mass of the atmosphere is 5.1480 × 10 kg with an annual range due to water vapor of 1.2 or 1.5 × 10 kg, depending on whether surface pressure or water vapor data are used; somewhat smaller than
12772-528: The premier organizations involved in research and development in this sector. Pakistan has the capability of designing and manufacturing guided rockets, missiles and space vehicles. The city of Kamra is home to the Pakistan Aeronautical Complex which contains several factories. This facility is responsible for manufacturing the MFI-17 , MFI-395 , K-8 and JF-17 Thunder aircraft. Pakistan also has
12896-530: The president cited wasteful military spending and interdepartmental conflicts. Deliberations in Congress went on for months focusing heavily on the role of the military in society and the threat of granting too much military power to the executive. On July 26, 1947, Truman signed the National Security Act of 1947 , which set up a unified military command known as the National Military Establishment and created
13020-603: The president following U.S. Senate confirmation. Each of the individual Military Service Chiefs, outside their Joint Chiefs of Staff obligations, works directly for the secretary of the military department concerned: the Secretary of the Army , Secretary of the Navy , and Secretary of the Air Force . Following the Goldwater–Nichols Act in 1986, the Joint Chiefs of Staff no longer maintained operational command authority individually or collectively. The act designated
13144-547: The president on military matters. The composition of the Joint Chiefs of Staff is defined by statute and consists of the chairman of the Joint Chiefs of Staff (CJCS), vice chairman of the Joint Chiefs of Staff (VCJCS), senior enlisted advisor to the chairman (SEAC), the Military Service chiefs from the Army , Marine Corps , Navy , Air Force , and Space Force , in addition to the chief of National Guard Bureau , all appointed by
13268-473: The president or by the secretary of defense. Department of Defense Directive 5100.01 describes the organizational relationships within the department and is the foundational issuance for delineating the major functions of the department. The latest version, signed by former Secretary of Defense Robert Gates in December 2010, is the first major re-write since 1987. The Office of the Secretary of Defense ( OSD )
13392-464: The president with the advice and consent of the Senate , is by federal law ( 10 U.S.C. § 113 ) the head of the Department of Defense, "the principal assistant to the President in all matters relating to Department of Defense", and has "authority, direction, and control over the Department of Defense". Because the Constitution vests all military authority in Congress and the president,
13516-560: The president. The Joint Staff (JS) is a headquarters staff at the Pentagon made up of personnel from all five services that assist the chairman and vice chairman in discharging their duties. It is managed by the Director of the Joint Staff (DJS) who is a lieutenant general or vice admiral . There are three military departments within the Department of Defense: The Military Departments are each headed by their secretary (i.e., Secretary of
13640-523: The previous estimate. The mean mass of water vapor is estimated as 1.27 × 10 kg and the dry air mass as 5.1352 ±0.0003 × 10 kg." Solar radiation (or sunlight) is the energy Earth receives from the Sun . Earth also emits radiation back into space, but at longer wavelengths that humans cannot see. Part of the incoming and emitted radiation is absorbed or reflected by the atmosphere. In May 2017, glints of light, seen as twinkling from an orbiting satellite
13764-422: The satellites orbiting the Earth are present. The mesosphere is the third highest layer of Earth's atmosphere, occupying the region above the stratosphere and below the thermosphere. It extends from the stratopause at an altitude of about 50 km (31 mi; 160,000 ft) to the mesopause at 80–85 km (50–53 mi; 260,000–280,000 ft) above sea level. Temperatures drop with increasing altitude to
13888-470: The statutory authority of the secretary of defense is derived from their constitutional authority. Since it is impractical for either Congress or the president to participate in every piece of Department of Defense affairs, the secretary of defense and the secretary's subordinate officials generally exercise military authority. The Department of Defense is composed of the Office of the Secretary of Defense ( OSD ),
14012-447: The stratosphere lacks the weather-producing air turbulence that is so prevalent in the troposphere. Consequently, the stratosphere is almost completely free of clouds and other forms of weather. However, polar stratospheric or nacreous clouds are occasionally seen in the lower part of this layer of the atmosphere where the air is coldest. The stratosphere is the highest layer that can be accessed by jet-powered aircraft . The troposphere
14136-610: The surface from most meteoroids and ultraviolet solar radiation , keeps it warm and reduces diurnal temperature variation (temperature extremes between day and night ) through heat retention ( greenhouse effect ), redistributes heat and moisture among different regions via air currents , and provides the chemical and climate conditions allowing life to exist and evolve on Earth. By mole fraction (i.e., by quantity of molecules ), dry air contains 78.08% nitrogen , 20.95% oxygen , 0.93% argon , 0.04% carbon dioxide , and small amounts of other trace gases . Air also contains
14260-419: The temperature gradient is large. An example of such effects is the mirage . United States Department of Defense The United States Department of Defense ( DoD , USDOD , or DOD ) is an executive branch department of the federal government of the United States charged with coordinating and supervising all agencies and functions of the U.S. government directly related to national security and
14384-444: The temperature stabilizes over a large vertical distance through the rest of the troposphere. In the stratosphere , starting above about 20 km, the temperature increases with height, due to heating within the ozone layer caused by the capture of significant ultraviolet radiation from the Sun by the dioxygen and ozone gas in this region. Still another region of increasing temperature with altitude occurs at very high altitudes, in
14508-442: The thermopause varies considerably due to changes in solar activity. Because the thermopause lies at the lower boundary of the exosphere, it is also referred to as the exobase . The lower part of the thermosphere, from 80 to 550 kilometres (50 to 342 mi) above Earth's surface, contains the ionosphere . The temperature of the thermosphere gradually increases with height and can rise as high as 1500 °C (2700 °F), though
14632-429: The thermosphere. The exosphere contains many of the artificial satellites that orbit Earth. The thermosphere is the second-highest layer of Earth's atmosphere. It extends from the mesopause (which separates it from the mesosphere) at an altitude of about 80 km (50 mi; 260,000 ft) up to the thermopause at an altitude range of 500–1000 km (310–620 mi; 1,600,000–3,300,000 ft). The height of
14756-456: The total budgetary resources for fiscal year 2010 were $ 1.2 trillion. Of these resources, $ 1.1 trillion were obligated and $ 994 billion were disbursed, with the remaining resources relating to multi-year modernization projects requiring additional time to procure. After over a decade of non-compliance , Congress has established a deadline of Fiscal year 2017 for the Department of Defense to achieve audit readiness . In 2015
14880-419: The total mass of the atmosphere is located in the lower 5.6 km (3.5 mi; 18,000 ft) of the troposphere. Nearly all atmospheric water vapor or moisture is found in the troposphere, so it is the layer where most of Earth's weather takes place. It has basically all the weather-associated cloud genus types generated by active wind circulation, although very tall cumulonimbus thunder clouds can penetrate
15004-471: The total to over 2.91 million employees. Headquartered at the Pentagon in Arlington County, Virginia , just outside Washington, D.C. , the Department of Defense's stated mission is "to provide the military forces needed to deter war and ensure our nation's security". The Department of Defense is headed by the secretary of defense , a cabinet-level head who reports directly to the president of
15128-430: The tropopause from below and rise into the lower part of the stratosphere. Most conventional aviation activity takes place in the troposphere, and it is the only layer accessible by propeller-driven aircraft . Within the five principal layers above, which are largely determined by temperature, several secondary layers may be distinguished by other properties: The average temperature of the atmosphere at Earth's surface
15252-632: The two largest consumers of aerospace technology and products. 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 Lockheed Martin . As talented American employees age and retire, these manufacturers face an expanding labor shortfall. In order to supply
15376-525: Was stripped from them in the Defense Reorganization Act of 1958 ), and instead, Military Departments are tasked solely with "the training, provision of equipment, and administration of troops." A unified combatant command is a military command composed of personnel/equipment from at least two Military Departments, which has a broad/continuing mission. These military departments are responsible for equipping and training troops to fight, while
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