1.
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
2.
Smithsonian Astrophysical Observatory
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The SAO was founded in 1890 by Samuel Pierpont Langley, the Smithsonians third Secretary, primarily for studies of the sun. Langley is remembered today as a pioneer, but he was trained as an astronomer and was the first American scientist to perceive astrophysics as a distinct field. Langley invented the bolometer and discovered infrared radiation from the sun, in 1955, the SAO moved from Washington, D. C. to Cambridge, to affiliate with HCO and to expand its staff, facilities, and most importantly, its scientific scope. Smithsonian and the USAF Project Space Track shared observations and ephemerides throughout the days of satellite tracking. In 1973, the ties between Smithsonian and Harvard were strengthened and formalized by the creation of the joint Harvard-Smithsonian CfA, SAO has operated a number of remote stations over the years. Currently, more than 300 scientists at the CfA are engaged in a program of research in astronomy, astrophysics, earth and space sciences. The Chandra X-ray Observatory is managed and operated by SAO from Cambridge, with the University of Arizona, SAO also manages the MMT Observatory. Samuel Pierpont Langley 1890–1906 Charles Greeley Abbot 1906–1942 Loyal Blaine Aldrich 1942–1955 Fred Lawrence Whipple 1955–1973 George B, field 1973–1982 Irwin I. Shapiro 1982–2004 Charles R. Alcock 2004– SAO homepage Harvard-Smithsonian Center for Astrophysics
3.
TRW Inc.
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TRW Inc. was an American corporation involved in a variety of businesses, mainly aerospace, automotive, and credit reporting. It was a pioneer in multiple fields including electronic components, integrated circuits, computers, software, TRW built many spacecraft, including Pioneer 1, Pioneer 10, and several space-based observatories. It was #57 on the Fortune 500 list, and had 122,258 employees, tRW’s roots were founded in 1901, and it lasted for more than a century until being acquired by Northrop Grumman in 2002. Persons coming from TRW were important to build up corporations like SpaceX, in 1953, the company was recruited to lead the development of the United States first ICBM. Starting with the design by Convair, the multi-corporate team launched Atlas in 1957. It flew its full range in 1958, and was adapted to fly the Mercury astronauts into orbit, TRW also led development of the Titan missile, which was later adapted to fly the Gemini missions. The company served the US Air Force as systems engineers on all subsequent ICBM development efforts, in 1960, Congress spurred the formation of the non-profit Aerospace Corporation to provide systems engineering to the US government, but TRW continued to guide the ICBM efforts. TRW originated in 1901 with the Cleveland Cap Screw Company, founded by David Kurtz and their initial products were bolts with heads electrically welded to the shafts. In 1904, a welder named Charles E. Thompson adapted their process to making automobile engine valves, and, by 1915, Charles Thompson was named General Manager of the company, which became Thompson Products in 1926. Their experimental hollow sodium-cooled valves aided Charles Lindberghs solo flight across the Atlantic, in 1937, Thompson Motor Products bought J. A. Drake and Sons. The company made high performance valves that were used in racing engines of the day. Dale Drake bought the Offy engine design with his partner Louis Meyer in 1946 and won the Indianapolis 500 twenty-seven times, more than any other engine design. During the period leading up to World War II, through the end of the Korean war, Thompson Products was a key manufacturer of component parts for aircraft engines, including aircraft valves. The TAPCO plant, owned by the U. S. Government and it employed over 16,000 workers at the peak of WW II production. They grew frustrated with Howard Hughes’ management, and formed the Ramo-Wooldridge Corporation in September 1953, the detonation of a thermonuclear bomb by the Soviet Union spurred Trevor Gardner to form the Teapot Committee in October 1953. Chaired by John von Neumann, its purpose was to study the development of ballistic missiles, Ramo and Wooldridge were committee members, and Ramo-Wooldridge Corp. became the lead contractor of the resulting ICBM development effort, reporting to the United States Air Force. With continued backing from Thompson Products, Ramo-Wooldridge diversified into computers and electronic components and they also produced scientific spacecraft such as Pioneer 1. Thompson Products and Ramo-Wooldridge merged in October 1958 to form Thompson Ramo Wooldridge Inc. unofficially known as TRW, in February 1959, Jimmy Doolittle became Chairman of the Board of Space Technology Laboratories, the division which continued to support the Air Force ICBM efforts
4.
Space Shuttle
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The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated by the U. S. National Aeronautics and Space Administration, as part of the Space Shuttle program. Its official program name was Space Transportation System, taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development, the first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982. Five complete Shuttle systems were built and used on a total of 135 missions from 1981 to 2011, the Shuttle fleets total mission time was 1322 days,19 hours,21 minutes and 23 seconds. Shuttle components included the Orbiter Vehicle, a pair of solid rocket boosters. The Shuttle was launched vertically, like a rocket, with the two SRBs operating in parallel with the OVs three main engines, which were fueled from the ET. The SRBs were jettisoned before the vehicle reached orbit, and the ET was jettisoned just before orbit insertion, at the conclusion of the mission, the orbiter fired its OMS to de-orbit and re-enter the atmosphere. The orbiter then glided as a spaceplane to a landing, usually at the Shuttle Landing Facility of KSC or Rogers Dry Lake in Edwards Air Force Base. After landing at Edwards, the orbiter was back to the KSC on the Shuttle Carrier Aircraft. The first orbiter, Enterprise, was built in 1976 for use in Approach, four fully operational orbiters were initially built, Columbia, Challenger, Discovery, and Atlantis. Of these, two were lost in accidents, Challenger in 1986 and Columbia in 2003, with a total of fourteen astronauts killed. A fifth operational orbiter, Endeavour, was built in 1991 to replace Challenger, the Space Shuttle was retired from service upon the conclusion of Atlantiss final flight on July 21,2011. Nixons post-Apollo NASA budgeting withdrew support of all components except the Shuttle. The vehicle consisted of a spaceplane for orbit and re-entry, fueled by liquid hydrogen and liquid oxygen tanks. The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982, all launched from the Kennedy Space Center, Florida. The system was retired from service in 2011 after 135 missions, the program ended after Atlantis landed at the Kennedy Space Center on July 21,2011. Major missions included launching numerous satellites and interplanetary probes, conducting space science experiments, the first orbiter vehicle, named Enterprise, was built for the initial Approach and Landing Tests phase and lacked engines, heat shielding, and other equipment necessary for orbital flight. A total of five operational orbiters were built, and of these and it was used for orbital space missions by NASA, the US Department of Defense, the European Space Agency, Japan, and Germany. The United States funded Shuttle development and operations except for the Spacelab modules used on D1, sL-J was partially funded by Japan
5.
Space Shuttle Columbia
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Space Shuttle Columbia was the first space-rated orbiter in NASAs Space Shuttle fleet. It launched for the first time on mission STS-1 on April 12,1981, construction began on Columbia in 1975 at Rockwell Internationals principal assembly facility in Palmdale, California, a suburb of Los Angeles. It is also named after the Command Module of Apollo 11, Columbia was also the female symbol of the United States. After construction, the arrived at Kennedy Space Center on March 25,1979. Columbia was originally scheduled to lift off in late 1979, however the date was delayed by problems with both the SSME components, as well as the thermal protection system. On March 19,1981, during preparations for a ground test, workers were asphyxiated while working in Columbias nitrogen-purged aft engine compartment, resulting in two or three fatalities. Columbia spent 610 days in the Orbiter Processing Facility, another 35 days in the Vehicle Assembly Building, Columbia then undertook three further research missions to test its technical characteristics and performance. Its first operational mission, with a crew, was STS-5. At this point Columbia was joined by Challenger, which flew the next three missions, while Columbia underwent modifications for the first Spacelab mission. At that time the fleet was expanded to include Discovery. Columbia returned to space on January 12,1986, with the launch of STS-61-C, the missions crew included Dr. Franklin Chang-Diaz, as well as the first sitting member of the House of Representatives to venture into space, Bill Nelson. The next shuttle mission, STS-51-L, was undertaken by Challenger and it was launched on January 28,1986, ten days after STS-61-C had landed, and ended in disaster 73 seconds after launch. In the aftermath NASAs shuttle timetable was disrupted, and Columbia was not flown again until 1989, sTS-93, launched on July 23,1999, was the first U. S. space mission with a female commander, Lt. Col. Eileen Collins. This mission deployed the Chandra X-ray Observatory, Columbias final successful mission was STS-109, the fourth servicing mission for the Hubble Space Telescope. Its next mission, STS-107, culminated in the loss when it disintegrated during reentry. Consequently, President Bush decided to retire the Shuttle orbiter fleet by 2010 in favor of the Constellation program, the Constellation program was later cancelled with the NASA Authorization Act of 2010 signed by President Obama on October 11. Due to its weight, Columbia could not have used the planned Centaur-G booster, the retention of the internal airlock allowed NASA to use Columbia for the STS-109 Hubble Space Telescope servicing mission, along with the Spacehab double module used on STS-107. The upgrade also involved replacing many of the white LRSI tiles on the surfaces with Advanced Flexible Reusable Surface Insulation blankets that had been used on Discovery
6.
STS-93
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STS-93 marked the 95th launch of the Space Shuttle, the 26th launch of Columbia, and the 21st night launch of a Space Shuttle. Eileen Collins became the first female shuttle Commander on this flight and its primary payload was the Chandra X-ray Observatory. It would also be the last mission of Columbia until March 2002, during the interim, Columbia would be out of service for upgrading, and would not fly again until STS-109. The launch was scheduled for 20 July but the launch was aborted at T−7 seconds. The successful launch of the flight occurred 3 days later and these ruptures resulted in a leak downstream of the main combustion chamber. This anomalous event and the response to the leak by the right engines controller did not violate any launch commit criteria. However, approximately 5 seconds after liftoff, an electrical short disabled the engines primary digital control unit, DCU-A. The central and right continued to operate on their remaining DCUs for the rest of powered flight to orbit. The electrical short was later discovered to have been caused by poorly routed wiring and this wiring issue led to a program-wide inspection of the wiring in all orbiters. To bring the back up to the commanded thrust level. The increased oxidizer consumption during ascent resulted in a shutdown of all three engines near the end of the projected burn due to low liquid-oxygen level sensed in the External Tank. Though the premature shutdown resulted in a velocity 15 ft/s lower than targeted and this incident brought on a maintenance practice change that required damaged oxidizer posts to be removed and replaced as opposed to being intentionally plugged, as was the practice beforehand. The primary objective of the STS-93 mission was to deploy the Chandra X-ray Observatory with its Inertial Upper Stage booster, at its launch, Chandra was the most sophisticated X-ray observatory ever built. It is designed to observe X-rays from high energy regions of the universe, the Shuttle Ionespheric Modification with Pulsed Local Exhaust payload activity researched the source of Very High Frequency radar echoes caused by the orbiter and its OMS engine firings. The Southwest Ultraviolet Imaging system was based around a Maksutov-design ultraviolet telescope, scientists can obtain sensitive photometric measurements of astronomical targets. The objective Gelation of Sols, Applied Microgravity Research experiment was to investigate the influence of microgravity on the processing of gelled sols. In particular, the purpose was to demonstrate that composite ceramic precursors composed of large particulates, the Light mass Flexible Solar Array Hinge payload consisted of several hinges fabricated from shape memory alloys. Shape memory deployment hinges offered controlled shockless deployment of solar arrays, LFSAH demonstrated this deployment capability for a number of hinge configurations
7.
Kennedy Space Center
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The John F. Kennedy Space Center is one of ten National Aeronautics and Space Administration field centers. Since December 1968, Kennedy Space Center has been NASAs primary launch center of human spaceflight, Launch operations for the Apollo, Skylab and Space Shuttle programs were carried out from Kennedy Space Center Launch Complex 39 and managed by KSC. Located on the east coast of Florida, KSC is adjacent to Cape Canaveral Air Force Station, the management of the two entities work very closely together, share resources, and even own facilities on each others property. Additionally, the center manages launch of robotic and commercial missions, researches food production and In-Situ Resource Utilization for off Earth exploration. Since 2010, the center has worked to become a multi-user spaceport through industry partnerships, there are about 700 facilities grouped across the centers 144,000 acres. There is also a Visitor Complex open to the public on site, the military had been performing launch operations since 1949 at what would become Cape Canaveral Air Force Station. In December 1959, the Department of Defense transferred 5,000 personnel, President John F. Kennedys 1961 goal of a manned lunar landing before 1970 required an expansion of launch operations. On July 1,1962, the Launch Operations Directorate was separated from MSFC to become the Launch Operations Center, therefore, the decision was made to build a new LOC site located adjacent to Cape Canaveral on Merritt Island. NASA began land acquisition in 1962, buying title to 131 square miles, the major buildings in KSCs Industrial Area were designed by architect Charles Luckman. Construction began in November 1962, and Kennedy visited the site twice in 1962, on November 29,1963, the facility was given its current name by President Lyndon B. Johnson under Executive Order 11129. Johnsons order joined both the civilian LOC and the military Cape Canaveral station under the designation John F. Kennedy Space Center, spawning some confusion joining the two in the public mind. Located on Merritt Island, Florida, the center is north-northwest of Cape Canaveral on the Atlantic Ocean and it is 34 miles long and roughly six miles wide, covering 219 square miles. KSC is a major central Florida tourist destination and is one hours drive from the Orlando area. The Kennedy Space Center Visitor Complex offers public tours of the center, Center workers can encounter bald eagles, American alligators, wild boars, eastern diamondback rattlesnakes, the endangered Florida panther and Florida manatees. From 1967 through 1973, there were 13 Saturn V launches, the first of two unmanned flights, Apollo 4 on November 9,1967, was also the first rocket launch from KSC. The Saturn Vs first manned launch on December 21,1968 was Apollo 8s lunar orbiting mission, the next two missions tested the Lunar Module, Apollo 9 and Apollo 10. Apollo 11, launched from Pad A on July 16,1969, Apollo 12 followed four months later. From 1970–1972, the Apollo program concluded at KSC with the launches of missions 13 through 17, on May 14,1973, the last Saturn V launch put the Skylab space station in orbit from Pad 39A
8.
Kennedy Space Center Launch Complex 39
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Launch Complex 39 is a rocket launch site at the John F. Kennedy Space Center on Merritt Island in Florida, United States. The site and its collection of facilities were built for the Apollo program. As of 2017, only Launch Complex 39A is active, launching SpaceXs Falcon 9. LC-39 is also being modified to support launches of the SpaceXs Dragon 2 and Falcon Heavy, as well as NASAs Space Launch System, with a new, smaller pad, C, added to support smaller launches. SpaceX leases Launch Pad 39A from NASA and has modified the pad to support Falcon Heavy launches in 2017 and beyond. NASA began modifying Launch Pad 39B in 2007 to accommodate the now defunct Project Constellation, Pad C was originally planned but never built for Apollo, and would have been a copy of pads 39A and 39B. A smaller pad, designated 39C was constructed from January to June 2015 to accommodate small-class vehicles, NASA launches from LC-39A and 39B have been supervised from the NASA Launch Control Center, located 3 miles from the launch pads. LC-39 is one of launch sites that share radar and tracking services of the Eastern Test Range. During the 1920s, Peter E. Studebaker Jr. son of the automobile magnate, in 1948, the Navy transferred the former Banana River Naval Air Station located south of Cape Canaveral, to the Air Force for use in testing captured German V-2 rockets. The sites location on the East Florida coast was ideal for this purpose in that launches would be over the ocean and this site became the Joint Long Range Proving Ground in 1949, and was renamed Patrick Air Force Base in 1950. The Air Force annexed part of Cape Canaveral to the North in 1951, forming the Air Force Missile Test Center, Missile and rocketry testing and development would take place here through the 1950s. After the creation of NASA in 1958, the CCAFS launch pads were used for NASAs civilian unmanned and manned launches, including those of Project Mercury, in 1961, President Kennedy proposed to Congress the goal of landing a man on the Moon by the end of the decade. NASA began acquisition of land in 1962, taking title to 131 square miles by outright purchase, on July 1,1962, the site was named the Launch Operations Center. At the time, the highest numbered launch pad on CCAFS was Launch Complex 37 and it was designed to handle launches of the Saturn V rocket, at the time the largest, most powerful rocket then designed, required to take Apollo to the Moon. Initial plans included four pads evenly spaced 8,700 feet apart to damage in the event of an explosion on the pad. Three were scheduled for construction and two would have built at a later date. The numbering of the pads at the time was from north to south, with the northernmost being 39A, Pad 39A was never built, and 39C became 39A in 1963. With todays numbering, 39C would have been north of 39B, Pad 39E would have been due north of the mid-distance between 39C and 39D, with 39E forming the top of a triangle, and equidistant from 39C and 39D
9.
Geocentric orbit
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A geocentric orbit or Earth orbit involves any object orbiting the Earth, such as the Moon or artificial satellites. In 1997 NASA estimated there were approximately 2,465 artificial satellite orbiting the Earth and 6,216 pieces of space debris as tracked by the Goddard Space Flight Center. Over 16,291 previously launched objects have decayed into the Earths atmosphere, altitude as used here, the height of an object above the average surface of the Earths oceans. Analemma a term in astronomy used to describe the plot of the positions of the Sun on the celestial sphere throughout one year, apogee is the farthest point that a satellite or celestial body can go from Earth, at which the orbital velocity will be at its minimum. Eccentricity a measure of how much an orbit deviates from a perfect circle, eccentricity is strictly defined for all circular and elliptical orbits, and parabolic and hyperbolic trajectories. Equatorial plane as used here, an imaginary plane extending from the equator on the Earth to the celestial sphere, escape velocity as used here, the minimum velocity an object without propulsion needs to have to move away indefinitely from the Earth. An object at this velocity will enter a parabolic trajectory, above this velocity it will enter a hyperbolic trajectory, impulse the integral of a force over the time during which it acts. Inclination the angle between a plane and another plane or axis. In the sense discussed here the reference plane is the Earths equatorial plane, orbital characteristics the six parameters of the Keplerian elements needed to specify that orbit uniquely. Orbital period as defined here, time it takes a satellite to make one orbit around the Earth. Perigee is the nearest approach point of a satellite or celestial body from Earth, sidereal day the time it takes for a celestial object to rotate 360°. For the Earth this is,23 hours,56 minutes,4.091 seconds, solar time as used here, the local time as measured by a sundial. Velocity an objects speed in a particular direction, since velocity is defined as a vector, both speed and direction are required to define it. The following is a list of different geocentric orbit classifications, Low Earth orbit - Geocentric orbits ranging in altitude from 160 kilometers to 2,000 kilometres above mean sea level. At 160 km, one revolution takes approximately 90 minutes, medium Earth orbit - Geocentric orbits with altitudes at apogee ranging between 2,000 kilometres and that of the geosynchronous orbit at 35,786 kilometres. Geosynchronous orbit - Geocentric circular orbit with an altitude of 35,786 kilometres, the period of the orbit equals one sidereal day, coinciding with the rotation period of the Earth. The speed is approximately 3,000 metres per second, high Earth orbit - Geocentric orbits with altitudes at apogee higher than that of the geosynchronous orbit. A special case of high Earth orbit is the elliptical orbit
10.
Semi-major and semi-minor axes
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In geometry, the major axis of an ellipse is its longest diameter, a line segment that runs through the center and both foci, with ends at the widest points of the perimeter. The semi-major axis is one half of the axis, and thus runs from the centre, through a focus. Essentially, it is the radius of an orbit at the two most distant points. For the special case of a circle, the axis is the radius. One can think of the axis as an ellipses long radius. The semi-major axis of a hyperbola is, depending on the convention, thus it is the distance from the center to either vertex of the hyperbola. A parabola can be obtained as the limit of a sequence of ellipses where one focus is fixed as the other is allowed to move arbitrarily far away in one direction. Thus a and b tend to infinity, a faster than b, the semi-minor axis is a line segment associated with most conic sections that is at right angles with the semi-major axis and has one end at the center of the conic section. It is one of the axes of symmetry for the curve, in an ellipse, the one, in a hyperbola. The semi-major axis is the value of the maximum and minimum distances r max and r min of the ellipse from a focus — that is. In astronomy these extreme points are called apsis, the semi-minor axis of an ellipse is the geometric mean of these distances, b = r max r min. The eccentricity of an ellipse is defined as e =1 − b 2 a 2 so r min = a, r max = a. Now consider the equation in polar coordinates, with one focus at the origin, the mean value of r = ℓ / and r = ℓ /, for θ = π and θ =0 is a = ℓ1 − e 2. In an ellipse, the axis is the geometric mean of the distance from the center to either focus. The semi-minor axis of an ellipse runs from the center of the ellipse to the edge of the ellipse, the semi-minor axis is half of the minor axis. The minor axis is the longest line segment perpendicular to the axis that connects two points on the ellipses edge. The semi-minor axis b is related to the axis a through the eccentricity e. A parabola can be obtained as the limit of a sequence of ellipses where one focus is fixed as the other is allowed to move arbitrarily far away in one direction
11.
Orbital eccentricity
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The orbital eccentricity of an astronomical object is a parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is an orbit, values between 0 and 1 form an elliptical orbit,1 is a parabolic escape orbit. The term derives its name from the parameters of conic sections and it is normally used for the isolated two-body problem, but extensions exist for objects following a rosette orbit through the galaxy. In a two-body problem with inverse-square-law force, every orbit is a Kepler orbit, the eccentricity of this Kepler orbit is a non-negative number that defines its shape. The limit case between an ellipse and a hyperbola, when e equals 1, is parabola, radial trajectories are classified as elliptic, parabolic, or hyperbolic based on the energy of the orbit, not the eccentricity. Radial orbits have zero angular momentum and hence eccentricity equal to one, keeping the energy constant and reducing the angular momentum, elliptic, parabolic, and hyperbolic orbits each tend to the corresponding type of radial trajectory while e tends to 1. For a repulsive force only the trajectory, including the radial version, is applicable. For elliptical orbits, a simple proof shows that arcsin yields the projection angle of a circle to an ellipse of eccentricity e. For example, to view the eccentricity of the planet Mercury, next, tilt any circular object by that angle and the apparent ellipse projected to your eye will be of that same eccentricity. From Medieval Latin eccentricus, derived from Greek ἔκκεντρος ekkentros out of the center, from ἐκ- ek-, eccentric first appeared in English in 1551, with the definition a circle in which the earth, sun. Five years later, in 1556, a form of the word was added. The eccentricity of an orbit can be calculated from the state vectors as the magnitude of the eccentricity vector, e = | e | where. For elliptical orbits it can also be calculated from the periapsis and apoapsis since rp = a and ra = a, where a is the semimajor axis. E = r a − r p r a + r p =1 −2 r a r p +1 where, rp is the radius at periapsis. For Earths annual orbit path, ra/rp ratio = longest_radius / shortest_radius ≈1.034 relative to center point of path, the eccentricity of the Earths orbit is currently about 0.0167, the Earths orbit is nearly circular. Venus and Neptune have even lower eccentricity, over hundreds of thousands of years, the eccentricity of the Earths orbit varies from nearly 0.0034 to almost 0.058 as a result of gravitational attractions among the planets. The table lists the values for all planets and dwarf planets, Mercury has the greatest orbital eccentricity of any planet in the Solar System. Such eccentricity is sufficient for Mercury to receive twice as much solar irradiation at perihelion compared to aphelion, before its demotion from planet status in 2006, Pluto was considered to be the planet with the most eccentric orbit
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Apsis
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An apsis is an extreme point in an objects orbit. The word comes via Latin from Greek and is cognate with apse, for elliptic orbits about a larger body, there are two apsides, named with the prefixes peri- and ap-, or apo- added to a reference to the thing being orbited. For a body orbiting the Sun, the point of least distance is the perihelion, the terms become periastron and apastron when discussing orbits around other stars. For any satellite of Earth including the Moon the point of least distance is the perigee, for objects in Lunar orbit, the point of least distance is the pericynthion and the greatest distance the apocynthion. For any orbits around a center of mass, there are the terms pericenter and apocenter, periapsis and apoapsis are equivalent alternatives. A straight line connecting the pericenter and apocenter is the line of apsides and this is the major axis of the ellipse, its greatest diameter. For a two-body system the center of mass of the lies on this line at one of the two foci of the ellipse. When one body is larger than the other it may be taken to be at this focus. Historically, in systems, apsides were measured from the center of the Earth. In orbital mechanics, the apsis technically refers to the distance measured between the centers of mass of the central and orbiting body. However, in the case of spacecraft, the family of terms are used to refer to the orbital altitude of the spacecraft from the surface of the central body. The arithmetic mean of the two limiting distances is the length of the axis a. The geometric mean of the two distances is the length of the semi-minor axis b, the geometric mean of the two limiting speeds is −2 ε = μ a which is the speed of a body in a circular orbit whose radius is a. The words pericenter and apocenter are often seen, although periapsis/apoapsis are preferred in technical usage, various related terms are used for other celestial objects. The -gee, -helion and -astron and -galacticon forms are used in the astronomical literature when referring to the Earth, Sun, stars. The suffix -jove is occasionally used for Jupiter, while -saturnium has very rarely used in the last 50 years for Saturn. The -gee form is used as a generic closest approach to planet term instead of specifically applying to the Earth. During the Apollo program, the terms pericynthion and apocynthion were used when referring to the Moon, regarding black holes, the term peri/apomelasma was used by physicist Geoffrey A. Landis in 1998 before peri/aponigricon appeared in the scientific literature in 2002
13.
Orbital inclination
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Orbital inclination measures the tilt of an objects orbit around a celestial body. It is expressed as the angle between a plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the equator, the plane of the orbit is the same as the Earths equatorial plane. The general case is that the orbit is tilted, it spends half an orbit over the northern hemisphere. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°, the inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the plane and the plane of reference, normally stated in degrees. For a satellite orbiting a planet, the plane of reference is usually the plane containing the planets equator, for planets in the Solar System, the plane of reference is usually the ecliptic, the plane in which the Earth orbits the Sun. This reference plane is most practical for Earth-based observers, therefore, Earths inclination is, by definition, zero. Inclination could instead be measured with respect to another plane, such as the Suns equator or the invariable plane, the inclination of orbits of natural or artificial satellites is measured relative to the equatorial plane of the body they orbit, if they orbit sufficiently closely. The equatorial plane is the perpendicular to the axis of rotation of the central body. An inclination of 30° could also be described using an angle of 150°, the convention is that the normal orbit is prograde, an orbit in the same direction as the planet rotates. Inclinations greater than 90° describe retrograde orbits, thus, An inclination of 0° means the orbiting body has a prograde orbit in the planets equatorial plane. An inclination greater than 0° and less than 90° also describe prograde orbits, an inclination of 63. 4° is often called a critical inclination, when describing artificial satellites orbiting the Earth, because they have zero apogee drift. An inclination of exactly 90° is an orbit, in which the spacecraft passes over the north and south poles of the planet. An inclination greater than 90° and less than 180° is a retrograde orbit, an inclination of exactly 180° is a retrograde equatorial orbit. For gas giants, the orbits of moons tend to be aligned with the giant planets equator, the inclination of exoplanets or members of multiple stars is the angle of the plane of the orbit relative to the plane perpendicular to the line-of-sight from Earth to the object. An inclination of 0° is an orbit, meaning the plane of its orbit is parallel to the sky. An inclination of 90° is an orbit, meaning the plane of its orbit is perpendicular to the sky
14.
Longitude of the ascending node
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The longitude of the ascending node is one of the orbital elements used to specify the orbit of an object in space. It is the angle from a direction, called the origin of longitude, to the direction of the ascending node. The ascending node is the point where the orbit of the passes through the plane of reference. Commonly used reference planes and origins of longitude include, For a geocentric orbit, Earths equatorial plane as the plane. In this case, the longitude is called the right ascension of the ascending node. The angle is measured eastwards from the First Point of Aries to the node, for a heliocentric orbit, the ecliptic as the reference plane, and the First Point of Aries as the origin of longitude. The angle is measured counterclockwise from the First Point of Aries to the node, the angle is measured eastwards from north to the node. pp.40,72,137, chap. In the case of a star known only from visual observations, it is not possible to tell which node is ascending. In this case the orbital parameter which is recorded is the longitude of the node, Ω, here, n=<nx, ny, nz> is a vector pointing towards the ascending node. The reference plane is assumed to be the xy-plane, and the origin of longitude is taken to be the positive x-axis, K is the unit vector, which is the normal vector to the xy reference plane. For non-inclined orbits, Ω is undefined, for computation it is then, by convention, set equal to zero, that is, the ascending node is placed in the reference direction, which is equivalent to letting n point towards the positive x-axis. Kepler orbits Equinox Orbital node perturbation of the plane can cause revolution of the ascending node
15.
Argument of periapsis
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The argument of periapsis, symbolized as ω, is one of the orbital elements of an orbiting body. Parametrically, ω is the angle from the ascending node to its periapsis. For specific types of orbits, words such as perihelion, perigee, periastron, an argument of periapsis of 0° means that the orbiting body will be at its closest approach to the central body at the same moment that it crosses the plane of reference from South to North. An argument of periapsis of 90° means that the body will reach periapsis at its northmost distance from the plane of reference. Adding the argument of periapsis to the longitude of the ascending node gives the longitude of the periapsis, however, especially in discussions of binary stars and exoplanets, the terms longitude of periapsis or longitude of periastron are often used synonymously with argument of periapsis. In the case of equatorial orbits, the argument is strictly undefined, where, ex and ey are the x- and y-components of the eccentricity vector e. In the case of circular orbits it is assumed that the periapsis is placed at the ascending node. Kepler orbit Orbital mechanics Orbital node
16.
Mean anomaly
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In celestial mechanics, the mean anomaly is an angle used in calculating the position of a body in an elliptical orbit in the classical two-body problem. Define T as the time required for a body to complete one orbit. In time T, the radius vector sweeps out 2π radians or 360°. The average rate of sweep, n, is then n =2 π T or n =360 ∘ T, define τ as the time at which the body is at the pericenter. From the above definitions, a new quantity, M, the mean anomaly can be defined M = n, because the rate of increase, n, is a constant average, the mean anomaly increases uniformly from 0 to 2π radians or 0° to 360° during each orbit. It is equal to 0 when the body is at the pericenter, π radians at the apocenter, if the mean anomaly is known at any given instant, it can be calculated at any later instant by simply adding n δt where δt represents the time difference. Mean anomaly does not measure an angle between any physical objects and it is simply a convenient uniform measure of how far around its orbit a body has progressed since pericenter. The mean anomaly is one of three parameters that define a position along an orbit, the other two being the eccentric anomaly and the true anomaly. Define l as the longitude, the angular distance of the body from the same reference direction. Thus mean anomaly is also M = l − ϖ, mean angular motion can also be expressed, n = μ a 3, where μ is a gravitational parameter which varies with the masses of the objects, and a is the semi-major axis of the orbit. Mean anomaly can then be expanded, M = μ a 3, and here mean anomaly represents uniform angular motion on a circle of radius a
17.
X-ray
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X-radiation is a form of electromagnetic radiation. Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz, X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. Spelling of X-ray in the English language includes the variants x-ray, xray, X-rays with high photon energies are called hard X-rays, while those with lower energy are called soft X-rays. Due to their ability, hard X-rays are widely used to image the inside of objects, e. g. in medical radiography. The term X-ray is metonymically used to refer to an image produced using this method. Since the wavelengths of hard X-rays are similar to the size of atoms they are useful for determining crystal structures by X-ray crystallography. By contrast, soft X-rays are easily absorbed in air, the length of 600 eV X-rays in water is less than 1 micrometer. There is no consensus for a definition distinguishing between X-rays and gamma rays, one common practice is to distinguish between the two types of radiation based on their source, X-rays are emitted by electrons, while gamma rays are emitted by the atomic nucleus. This definition has problems, other processes also can generate these high-energy photons. One common alternative is to distinguish X- and gamma radiation on the basis of wavelength, with radiation shorter than some arbitrary wavelength, such as 10−11 m and this criterion assigns a photon to an unambiguous category, but is only possible if wavelength is known. Occasionally, one term or the other is used in specific contexts due to precedent, based on measurement technique. Thus, gamma-rays generated for medical and industrial uses, for radiotherapy, in the ranges of 6–20 MeV. X-ray photons carry enough energy to ionize atoms and disrupt molecular bonds and this makes it a type of ionizing radiation, and therefore harmful to living tissue. A very high radiation dose over a period of time causes radiation sickness. In medical imaging this increased risk is generally greatly outweighed by the benefits of the examination. The ionizing capability of X-rays can be utilized in treatment to kill malignant cells using radiation therapy. It is also used for material characterization using X-ray spectroscopy, hard X-rays can traverse relatively thick objects without being much absorbed or scattered. For this reason, X-rays are widely used to image the inside of visually opaque objects, the most often seen applications are in medical radiography and airport security scanners, but similar techniques are also important in industry and research
18.
Electronvolt
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In physics, the electronvolt is a unit of energy equal to approximately 1. 6×10−19 joules. By definition, it is the amount of energy gained by the charge of an electron moving across an electric potential difference of one volt. Thus it is 1 volt multiplied by the elementary charge, therefore, one electronvolt is equal to 6981160217662079999♠1. 6021766208×10−19 J. The electronvolt is not a SI unit, and its definition is empirical, like the elementary charge on which it is based, it is not an independent quantity but is equal to 1 J/C √2hα / μ0c0. It is a unit of energy within physics, widely used in solid state, atomic, nuclear. It is commonly used with the metric prefixes milli-, kilo-, in some older documents, and in the name Bevatron, the symbol BeV is used, which stands for billion electronvolts, it is equivalent to the GeV. By mass–energy equivalence, the electronvolt is also a unit of mass and it is common in particle physics, where units of mass and energy are often interchanged, to express mass in units of eV/c2, where c is the speed of light in vacuum. It is common to express mass in terms of eV as a unit of mass. The mass equivalent of 1 eV/c2 is 1 eV / c 2 = ⋅1 V2 =1.783 ×10 −36 kg. For example, an electron and a positron, each with a mass of 0.511 MeV/c2, the proton has a mass of 0.938 GeV/c2. In general, the masses of all hadrons are of the order of 1 GeV/c2, the unified atomic mass unit,1 gram divided by Avogadros number, is almost the mass of a hydrogen atom, which is mostly the mass of the proton. To convert to megaelectronvolts, use the formula,1 u =931.4941 MeV/c2 =0.9314941 GeV/c2, in high-energy physics, the electronvolt is often used as a unit of momentum. A potential difference of 1 volt causes an electron to gain an amount of energy and this gives rise to usage of eV as units of momentum, for the energy supplied results in acceleration of the particle. The dimensions of units are LMT−1. The dimensions of units are L2MT−2. Then, dividing the units of energy by a constant that has units of velocity. In the field of particle physics, the fundamental velocity unit is the speed of light in vacuum c. Thus, dividing energy in eV by the speed of light, the fundamental velocity constant c is often dropped from the units of momentum by way of defining units of length such that the value of c is unity
19.
Great Observatories program
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NASAs series of Great Observatories satellites are four large, powerful space-based astronomical telescopes. Each of the four missions was designed to examine a specific region of the electromagnetic spectrum using very different technologies. Dr. Charles Pellerin, NASAs Director, Astrophysics invented and developed the program, the four Great Observatories were launched between 1990 and 2003, and three remain operational as of 2017. The Hubble Space Telescope primarily observes visible light and near-ultraviolet and it was launched in 1990 aboard Discovery during STS-31. A servicing mission in 1997 added capability in the range and one last mission in 2009 was to fix. The Compton Gamma Ray Observatory primarily observed gamma rays, though it extended into hard x-rays as well and it was launched in 1991 aboard Atlantis during STS-37 and was de-orbited in 2000 after failure of a gyroscope. The Chandra X-ray Observatory primarily observes soft x-rays and it was launched in 1999 aboard Columbia during STS-93 into an elliptical high-earth orbit, and was initially named the Advanced X-ray Astronomical Facility. The Spitzer Space Telescope observes the infrared spectrum and it was launched in 2003 aboard a Delta II rocket into an earth-trailing solar orbit, it was called the Space Infrared Telescope Facility before launch. Depletion of its liquid helium coolant in 2009 reduced its functionality significantly. Of these spacecraft, only the Compton Gamma Ray Observatory is not operating as of 2017, one of its gyroscopes failed, parts that survived reentry splashed into the Pacific Ocean. Hubble was originally intended to be retrieved and returned to Earth by the Space Shuttle, on October 31,2006 NASA Administrator Michael D. Griffin gave the go-ahead for a final refurbishment mission. Spitzer was the one of the Great Observatories not launched by the Space Shuttle. Titan and Atlas rockets were canceled for cost reasons, after redesign and lightening, it was launched by a Delta II rocket instead. The history of the Hubble Space Telescope can be traced back as far as 1946, Spitzer devoted much of his career to pushing for a space telescope to be developed. Congress eventually approved funding of US$36,000,000 for 1978, during the early 1980s, the telescope was named after Edwin Hubble. Gamma rays had been examined above the atmosphere by several early space missions, during its High Energy Astronomy Observatory Program in 1977, NASA announced plans to build a great observatory for gamma-ray astronomy. The Gamma Ray Observatory, renamed Compton Gamma-Ray Observatory, was designed to take advantage of the advances in detector technology during the 1980s. Following 14 years of effort, the CGRO was launched on 5 April 1991, in 1976 the Chandra X-ray Observatory was proposed to NASA by Riccardo Giacconi and Harvey Tananbaum
20.
Compton Gamma Ray Observatory
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The Compton Gamma Ray Observatory was a space observatory detecting light from 20 keV to 30 GeV in Earth orbit from 1991 to 2000. It featured four main telescopes in one spacecraft, covering X-rays and gamma rays, including various specialized sub-instruments and detectors. Following 14 years of effort, the observatory was launched from Space Shuttle Atlantis during STS-37 on April 5,1991 and it was deployed in low earth orbit at 450 km to avoid the Van Allen radiation belt. It was the heaviest astrophysical payload ever flown at that time at 17,000 kilograms, costing $617 million, the CGRO was part of NASAs Great Observatories series, along with the Hubble Space Telescope, the Chandra X-ray Observatory, and the Spitzer Space Telescope. It was the second of the series to be launched into space, CGRO was named after Arthur Holly Compton, Nobel prize winner, for work involved with gamma ray physics. CGRO was built by TRW in Redondo Beach, California, CGRO was an international collaboration and additional contributions came from the European Space Agency and various universities, as well as the U. S. Naval Research Laboratory. CGRO carried a complement of four instruments that covered an unprecedented six decades of the electromagnetic spectrum and it consisted of eight identical detector modules, one at each of the satellites corners. Each module consisted of both a NaI Large Area Detector covering the 20 keV to ~2 MeV range,50.48 cm in dia by 1.27 cm thick, and a 12.7 cm dia by 7. Sudden increases in the LAD rates triggered a high-speed data storage mode, bursts were typically detected at rates of roughly one per day over the 9-year CGRO mission. A strong burst could result in the observation of thousands of gamma rays within a time interval ranging from ~0.1 s up to about 100 s.05 to 10 MeV range. e. Particle and gamma-ray events from the rear produced slow-rise time pulses, which could be distinguished from pure NaI events from the front. Thus the CsI backing crystal acted as an active anticoincidence shield, a finder level of angular collimation was provided by a tungsten slat collimator grid within the outer CsI barrel, which collimated the response to a 3. 8° x 11. 4° FWHM rectangular FOV. A plastic scintillator across the front of each module vetoed charged particles entering from the front, the four detectors were typically operated in pairs of two. During a gamma-ray source observation, one detector would take observations of the source, the two detectors would routinely switch roles, allowing for more accurate measurements of both the source and background. The instrument had a field of view of one steradian, for cosmic gamma-ray events, the experiment required two nearly simultaneous interactions, in a set of front and rear scintillators. From these two energies, E1 and E2, the Compton scattering angle, angle θ, can be determined, along with the energy, E1 + E2. The positions of the interactions, in both the front and rear scintillators, was also measured, because of the requirement for a near coincidence between the two interactions, with the correct delay of a few nanoseconds, most modes of background production were strongly suppressed. From the collection of many event energies and event circles, a map of the positions of sources, along with their photon fluxes and spectra, could be determined
21.
Spitzer Space Telescope
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The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility, is an infrared space telescope launched in 2003. It is the fourth and final of the NASA Great Observatories program, the planned mission period was to be 2.5 years with a pre-launch expectation that the mission could extend to five or slightly more years until the onboard liquid helium supply was exhausted. This occurred on 15 May 2009, without liquid helium to cool the telescope to the very low temperatures needed to operate, most of the instruments are no longer usable. All Spitzer data, from both the primary and warm phases, are archived at the Infrared Science Archive, in keeping with NASA tradition, the telescope was renamed after its successful demonstration of operation, on 18 December 2003. Unlike most telescopes that are named after famous deceased astronomers by a board of scientists, the contest led to the telescope being named in honor of astronomer Lyman Spitzer, who had promoted the concept of space telescopes in the 1940s. Spitzer wrote a 1946 report for RAND Corporation describing the advantages of an extraterrestrial observatory, the US$720 million Spitzer was launched on 25 August 2003 at 05,35,39 UTC from Cape Canaveral SLC-17B aboard a Delta II 7920H rocket. It follows a heliocentric instead of orbit, trailing and drifting away from Earths orbit at approximately 0.1 astronomical unit per year. The primary mirror is 85 centimeters in diameter, f/12, made of beryllium and was cooled to 5.5 K, by the early 1970s, astronomers began to consider the possibility of placing an infrared telescope above the obscuring effects of Earths atmosphere. Anticipating the major results from an upcoming Explorer satellite and from the Shuttle mission, long-duration spaceflights of infrared telescopes cooled to cryogenic temperatures. Earlier infrared observations had been made by both space-based and ground-based observatories, ground-based observatories have the drawback that at infrared wavelengths or frequencies, both the Earths atmosphere and the telescope itself will radiate strongly. Additionally, the atmosphere is opaque at most infrared wavelengths and this necessitates lengthy exposure times and greatly decreases the ability to detect faint objects. It could be compared to trying to observe the stars at noon, previous space observatories were launched during the 1980s and 1990s and great advances in astronomical technology have been made since then. Most of the early concepts envisioned repeated flights aboard the NASA Space Shuttle and this approach was developed in an era when the Shuttle program was expected to support weekly flights of up to 30 days duration. A May 1983 NASA proposal described SIRTF as a Shuttle-attached mission, several flights were anticipated with a probable transition into a more extended mode of operation, possibly in association with a future space platform or space station. SIRTF would be a 1-meter class, cryogenically cooled, multi-user facility consisting of a telescope, the first flight was expected to occur about 1990, with the succeeding flights anticipated beginning approximately one year later. By September 1983 NASA was considering the possibility of a long duration SIRTF mission, Spitzer is the only one of the Great Observatories not launched by the Space Shuttle, as was originally intended. However, after the 1986 Challenger disaster, the Centaur LH2–LOX upper stage, the mission underwent a series of redesigns during the 1990s, primarily due to budget considerations. This resulted in a smaller but still fully capable mission that could use the smaller Delta II expendable launch vehicle
22.
Flagship Program
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The Flagship Program is a series of NASA missions to explore the Solar System. It is the largest and most expensive of three classes of NASA Solar System Programs, the two being the medium-cost New Frontiers Program and the lowest-cost Discovery Program. According to NASA, the cost of a Flagship-class mission is over $1 billion and these missions will be crucial in allowing humans to reach and explore high-priority targets. These critically important targets could help establish the limits of habitability, not just for the Solar System. In particular, they provide an opportunity to identify prebiotic organic molecules or even extant life beyond Earth, should it exist. The Flagship program includes the Viking probes, the Voyager probes, the Galileo spacecraft, the Cassini spacecraft, the Chandra X-Ray Observatory, proposed programs in the estimated range $1 billion and $3 billion include the Mars 2020, and Europa Multiple-Flyby Mission. And the modern NASA program which includes Flagships, in the early 1990s, NASA made the decision that instead of a centrally planned mission approach around pre-selected targets, mission ideas would compete for selection. The competitions would be based in cost categories, eventually turning into the Discovery, New Frontiers, while teams self-assemble to compete for Discovery and New Frontiers missions, Flagship programs are still strongly influenced by NASA headquarters. Other priorities included the Uranus Orbiter and Probe, the Enceladus Orbiter, at that time, all proposed NASA Flagship planetary missions were put on hold indefinitely. However, in December 2012, the Mars 2020 sample-caching rover, more recently, in June 2015, the Europa Multiple-Flyby Mission was approved by NASA and entered the formulation stage. ExoMars Jupiter Europa Orbiter Mars Science Laboratory Outer Planet Flagship Mission
23.
Space telescope
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A space telescope or space observatory is an instrument located in outer space to observe distant planets, galaxies and other astronomical objects. Space telescopes avoid many of the problems of ground-based observatories, such as pollution and distortion of electromagnetic radiation. In addition, ultraviolet frequencies, X-rays and gamma rays are blocked by the Earths atmosphere, Space telescopes are distinct from other imaging satellites pointed toward Earth for purposes of espionage, weather analysis and other types of information gathering. Spitzers proposal called for a telescope that would not be hindered by Earths atmosphere. Performing astronomy from ground-based observatories on Earth is limited by the filtering, some terrestrial telescopes can reduce atmospheric effects with adaptive optics. A telescope orbiting Earth outside the atmosphere is subject neither to twinkling nor to light pollution from artificial light sources on Earth, as a result, the angular resolution of space telescopes is often much smaller than a ground-based telescope with a similar aperture. Infrared and ultraviolet are also largely blocked, however, all these advantages do come with a price. Space telescopes are much more expensive to build than ground-based telescopes, due to their location, space telescopes are also extremely difficult to maintain. The Hubble Space Telescope was serviced by the Space Shuttle while many other space telescopes cannot be serviced at all, Space observatories can generally be divided into two classes, missions which map the entire sky, and observatories which focus on selected astronomical objects or parts of the sky. Many space observatories have already completed their missions, while others continue operating, satellites have been launched and operated by NASA, ISRO, ESA, Japanese Space Agency and the Soviet space program later succeeded by Roskosmos of Russia. Many space telescopes have been launched, as of February 2017, over 20 telescopes are known to be operational
24.
Telescope
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A telescope is an optical instrument that aids in the observation of remote objects by collecting electromagnetic radiation. The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s and they found use in both terrestrial applications and astronomy. Within a few decades, the telescope was invented, which used mirrors to collect. In the 20th century many new types of telescopes were invented, including radio telescopes in the 1930s, the word telescope now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors. The word telescope was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galileis instruments presented at a banquet at the Accademia dei Lincei, in the Starry Messenger, Galileo had used the term perspicillum. The earliest recorded working telescopes were the telescopes that appeared in the Netherlands in 1608. Their development is credited to three individuals, Hans Lippershey and Zacharias Janssen, who were spectacle makers in Middelburg, Galileo heard about the Dutch telescope in June 1609, built his own within a month, and improved upon the design in the following year. Also in 1609, Thomas Harriot became the first person known to point a telescope skyward in order to make observations of a celestial object. The idea that the objective, or light-gathering element, could be a mirror instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using parabolic mirrors—reduction of spherical aberration and no chromatic aberration—led to many proposed designs, in 1668, Isaac Newton built the first practical reflecting telescope, of a design which now bears his name, the Newtonian reflector. The invention of the lens in 1733 partially corrected color aberrations present in the simple lens and enabled the construction of shorter. The largest reflecting telescopes currently have objectives larger than 10 m, the 20th century also saw the development of telescopes that worked in a wide range of wavelengths from radio to gamma-rays. The first purpose built radio telescope went into operation in 1937, since then, a tremendous variety of complex astronomical instruments have been developed. The name telescope covers a range of instruments. Most detect electromagnetic radiation, but there are differences in how astronomers must go about collecting light in different frequency bands. The near-infrared can be collected much like light, however in the far-infrared and submillimetre range. For example, the James Clerk Maxwell Telescope observes from wavelengths from 3 μm to 2000 μm, on the other hand, the Spitzer Space Telescope, observing from about 3 μm to 180 μm uses a mirror. Also using reflecting optics, the Hubble Space Telescope with Wide Field Camera 3 can observe in the range from about 0.2 μm to 1.7 μm
25.
Satellite
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In the context of spaceflight, a satellite is an artificial object which has been intentionally placed into orbit. Such objects are called artificial satellites to distinguish them from natural satellites such as Earths Moon. In 1957 the Soviet Union launched the worlds first artificial satellite, since then, about 6,600 satellites from more than 40 countries have been launched. According to a 2013 estimate,3,600 remained in orbit, of those, about 1,000 were operational, the rest have lived out their useful lives and become space debris. Approximately 500 operational satellites are in orbit,50 are in medium-Earth orbit. A few large satellites have been launched in parts and assembled in orbit. Over a dozen space probes have been placed into orbit around other bodies and become artificial satellites to the Moon, Mercury, Venus, Mars, Jupiter, Saturn, a few asteroids, Satellites are used for many purposes. Common types include military and civilian Earth observation satellites, communications satellites, navigation satellites, weather satellites, Space stations and human spacecraft in orbit are also satellites. Satellite orbits vary greatly, depending on the purpose of the satellite, well-known classes include low Earth orbit, polar orbit, and geostationary orbit. A launch vehicle is a rocket that throws a satellite into orbit, usually it lifts off from a launch pad on land. Some are launched at sea from a submarine or a mobile maritime platform, Satellites are usually semi-independent computer-controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control, the first fictional depiction of a satellite being launched into orbit was a short story by Edward Everett Hale, The Brick Moon. The idea surfaced again in Jules Vernes The Begums Fortune, in 1903, Konstantin Tsiolkovsky published Exploring Space Using Jet Propulsion Devices, which is the first academic treatise on the use of rocketry to launch spacecraft. He calculated the speed required for a minimal orbit. In 1928, Herman Potočnik published his book, The Problem of Space Travel — The Rocket Motor. He described the use of orbiting spacecraft for observation of the ground, in a 1945 Wireless World article, the English science fiction writer Arthur C. Clarke described in detail the possible use of communications satellites for mass communications. He suggested that three geostationary satellites would provide coverage over the entire planet, the first artificial satellite was Sputnik 1, launched by the Soviet Union on October 4,1957, and initiating the Soviet Sputnik program, with Sergei Korolev as chief designer. This in turn triggered the Space Race between the Soviet Union and the United States, Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere
26.
Hubble Space Telescope
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The Hubble Space Telescope is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. Although not the first space telescope, Hubble is one of the largest and most versatile, with a 2. 4-meter mirror, Hubbles four main instruments observe in the near ultraviolet, visible, and near infrared spectra. Hubbles orbit outside the distortion of Earths atmosphere allows it to take extremely high-resolution images, Hubble has recorded some of the most detailed visible light images ever, allowing a deep view into space and time. Many Hubble observations have led to breakthroughs in astrophysics, such as determining the rate of expansion of the universe. The HST was built by the United States space agency NASA, the Space Telescope Science Institute selects Hubbles targets and processes the resulting data, while the Goddard Space Flight Center controls the spacecraft. Space telescopes were proposed as early as 1923, Hubble was funded in the 1970s, with a proposed launch in 1983, but the project was beset by technical delays, budget problems, and the Challenger disaster. When finally launched in 1990, Hubbles main mirror was found to have been ground incorrectly, the optics were corrected to their intended quality by a servicing mission in 1993. Hubble is the telescope designed to be serviced in space by astronauts. After launch by Space Shuttle Discovery in 1990, five subsequent Space Shuttle missions repaired, upgraded, the fifth mission was canceled on safety grounds following the Columbia disaster. However, after spirited public discussion, NASA administrator Mike Griffin approved the fifth servicing mission, the telescope is operating as of 2017, and could last until 2030–2040. Its scientific successor, the James Webb Space Telescope, is scheduled for launch in 2018, the history of the Hubble Space Telescope can be traced back as far as 1946, to the astronomer Lyman Spitzers paper Astronomical advantages of an extraterrestrial observatory. In it, he discussed the two advantages that a space-based observatory would have over ground-based telescopes. First, the resolution would be limited only by diffraction, rather than by the turbulence in the atmosphere. Second, a telescope could observe infrared and ultraviolet light. Spitzer devoted much of his career to pushing for the development of a space telescope, space-based astronomy had begun on a very small scale following World War II, as scientists made use of developments that had taken place in rocket technology. An orbiting solar telescope was launched in 1962 by the United Kingdom as part of the Ariel space program, oAO-1s battery failed after three days, terminating the mission. It was followed by OAO-2, which carried out observations of stars and galaxies from its launch in 1968 until 1972. The continuing success of the OAO program encouraged increasingly strong consensus within the community that the LST should be a major goal
27.
Indian Americans
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Indian Americans or Indo-Americans are Americans whose ancestry belongs to any of the many ethnic groups of the Republic of India. As the most socio-economically successful minority group in the U. S. Indian Americans comprise 4 million people. Indian Americans are the countrys third-largest Asian group alone or in combination with other races after Chinese Americans and Filipino Americans, the U. S. Census Bureau uses the term Asian Indian to avoid confusion with the indigenous peoples of the Americas commonly referred to as American Indians. In the Americas, historically, the term Indian has been most commonly used to refer to the people of the continents after European colonization in the 15th century. Qualifying terms such as American Indian and East Indian were and are used to avoid ambiguity. Since the 1980, Indian Americans have been categorized as Asian Indian by the United States Census Bureau, while East Indian remains in use, the term South Asian is often chosen instead for academic and governmental purposes. Indian Americans are a subgroup of South Asian Americans, a group also includes Bangladeshi Americans, Bhutanese Americans, Nepalese Americans, Pakistani Americans, Sri Lankan Americans. The Naturalization Act of 1790 made Asians ineligible for citizenship, with limited to whites only. Indian immigration began in the century, with more than two thousand Indians living in the United States, primarily on the West Coast, by the end of the century. The presence of Indian-Americans also helped develop interest in Eastern religions in the US, Swami Vivekananda arriving in Chicago at the Worlds Fair led to the establishment of the Vedanta Society. Many Punjabis migrated to the western US in the 19th and early 20th century followed by many other, prior to 1965, Indian immigration to the U. S. was small and isolated, with fewer than fifty thousand Indian immigrants in the country. The Bellingham riots in Bellingham, Washington on September 5,1907 epitomized the low tolerance in the U. S. for Indians, although labeled Hindu, the majority of Indians were Sikh. In the 1923 case, United States v. Bhagat Singh Thind, the Court also argued that the racial difference between Indians and whites was so great that the great body of our people would reject assimilation with Indians. It was after the Luce–Celler Act of 1946 that a quota of 100 Indians per year could immigrate to the U. S. at least twenty Indian American enclaves characterized as a Little India have emerged in the New York City Metropolitan Area. Other metropolitan areas with large Indian American populations include Atlanta, Baltimore–Washington, Boston, Chicago, worth, Detroit, Houston, Los Angeles, Philadelphia, and San Francisco–San Jose–Oakland. Please note that data for multi-racial Asian Americans has not yet released by the US Census Bureau. In 2006, of the 1,266,264 legal immigrants to the United States,58,072 were from India, between 2000 and 2006,421,006 Indian immigrants were admitted to the U. S. up from 352,278 during the 1990–1999 period. According to the 2000 U. S. census, the growth rate for Indians from 1990 to 2000 was 105.87 percent
28.
Subrahmanyan Chandrasekhar
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His mathematical treatment of stellar evolution yielded many of the best current theoretical models of the later evolutionary stages of massive stars and black holes. The Chandrasekhar limit is named after him and he showed that the mass of a white dwarf could not exceed 1.44 times that of the Sun – the Chandrasekhar limit. Chandrasekhar extended this analysis to the medium, showing that clouds of galactic gas. Chandrasekhar studied at Presidency College, Madras and the University of Cambridge and he spent most of his career at the University of Chicago, spending some time in its Yerkes Observatory, and serving as editor of The Astrophysical Journal from 1952 to 1971. He served on the University of Chicago faculty from 1937 until his death in 1995 at the age of 84, Chandrasekhar married Lalitha Doraiswamy in September 1936. He had met her as a student at Presidency College. Chandrasekhar was the nephew of Sir Chandrasekhara Venkata Raman, who was awarded the Nobel Prize for Physics in 1930 and he became a naturalized citizen of the United States in 1953. He was the eldest of their four sons and the third of their ten children and his paternal uncle was the Indian physicist and Nobel laureate C. V. Raman. His mother was devoted to intellectual pursuits, had translated Henrik Ibsens A Dolls House into Tamil and is credited with arousing Chandras intellectual curiosity at an early age. Chandrasekhar was tutored at home initially through middle school and later attended the Hindu High School, Triplicane, H. Fowler with whom he communicated his first paper. At the meetings of the Royal Astronomical Society, he met Professor E. A. Milne. On the advice of Prof. P. A. M. Dirac, he spent his year of graduate studies at the Institute for Theoretical Physics in Copenhagen. During this time, Chandrasekhar made acquaintance with British physicist Sir Arthur Eddington, in an infamous encounter in 1935, Eddington publicly ridiculed the concept of the Chandrasekhar limit. Although Eddington would later be proved wrong, this encounter caused Chandra to contemplate employment outside the UK, later in life, on multiple occasions, Chandra expressed the view that Eddingtons behavior was in part racially motivated. In January 1937, Chandrasekhar was recruited to the University of Chicago faculty as Assistant Professor by Dr. Otto Struve and President Robert Maynard Hutchins. He was to remain at the university for his career, becoming Morton D. Hull Distinguished Service Professor of Theoretical Astrophysics in 1952. Chandrasekhar did some work at Yerkes Observatory in Williams Bay, Wisconsin, after the Laboratory for Astrophysics and Space Research was built by NASA in 1966 at the University, Chandrasekhar occupied one of the four corner offices on the second floor. Chandrasekhar lived at 4800 Lake Shore Drive after the apartment complex was built in the late 1960s
29.
European Space Agency
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The European Space Agency is an intergovernmental organisation of 22 member states, dedicated to the exploration of space. Established in 1975 and headquartered in Paris, France, ESA has a staff of about 2,000. The main European launch vehicle Ariane 5 is operated through Arianespace with ESA sharing in the costs of launching, after World War II, many European scientists left Western Europe in order to work with the United States. The meeting was attended by representatives from eight countries, including Harrie Massey. The Western European nations decided to have two different agencies, one concerned with developing a system, ELDO, and the precursor of the European Space Agency. The latter was established on 20 March 1964 by an agreement signed on 14 June 1962, from 1968 to 1972, ESRO launched seven research satellites. ESA in its current form was founded with the ESA Convention in 1975, ESA has 10 founding member states, Belgium, Denmark, France, Germany, Italy, the Netherlands, Spain, Sweden, Switzerland and the United Kingdom. These signed the ESA Convention in 1975 and deposited the instruments of ratification by 1980, during this interval the agency functioned in a de facto fashion. ESA launched its first major scientific mission in 1975, Cos-B, ESA joined NASA in the IUE, the worlds first high-orbit telescope, which was launched in 1978 and operated very successfully for 18 years. A number of successful Earth-orbit projects followed, and in 1986 ESA began Giotto, its first deep-space mission, to study the comets Halley and Grigg–Skjellerup. Hipparcos, a mission, was launched in 1989 and in the 1990s SOHO, Ulysses. Recent scientific missions in co-operation with NASA include the Cassini–Huygens space probe, as the successor of ELDO, ESA has also constructed rockets for scientific and commercial payloads. Ariane 1, launched in 1979, brought mostly commercial payloads into orbit from 1984 onward, the successor launch vehicle of Ariane 5, the Ariane 6 is already in the definition stage and is envisioned to enter service in the 2020s. The beginning of the new millennium saw ESA become, along with agencies like NASA, JAXA, ISRO, CSA and Roscosmos, one of the major participants in scientific space research. Although ESA had relied on co-operation with NASA in previous decades, especially the 1990s, changed circumstances led to decisions to rely more on itself, a 2011 press issue thus stated, Russia is ESAs first partner in its efforts to ensure long-term access to space. ESA maintains its scientific and research projects mainly for astronomy-space missions such as Corot, launched on 27 December 2006 and this is the reason space exploration is an integral part of overall space activities. It has always been so, and it will be more important in the future. ESA describes its work in two overlapping ways, For the general public the various fields of work are described as Activities, Member states participate to varying degrees in the mandatory and optional space programmes
30.
XMM-Newton
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It is the second cornerstone mission of ESAs Horizon 2000 programme. Originally scheduled for a mission, the spacecraft remains in good health and has received mission extensions through 2016. As of February 2016, more than 4,300 papers have been published about either XMM-Newton or the results it has returned. In 1982, even before the launch of XMM-Newtons predecessor EXOSAT in 1983, the XMM mission was formally proposed to the ESA Science Programme Committee in 1984 and gained approval from the Agencys Council of Ministers in January 1985. That same year, several working groups were established to determine the feasibility of such a mission, at this workshop, it was proposed that the spacecraft contain 12 low-energy and 7 high-energy X-ray telescopes. In June 1988 the European Space Agency approved the mission and issued a call for investigation proposals, improvements in technology further reduced the number of X-ray telescopes needed to just three. In June 1989, the instruments had been selected and work began on spacecraft hardware. A project team was formed in January 1993 and based at the European Space Research and Technology Centre in Noordwijk, the XMM Survey Science Centre was established at the University of Leicester in 1995. The three flight mirror modules for the X-ray telescopes were delivered by Italian subcontractor Media Lario in December 1998, XMM left the ESTEC integration facility on 9 September 1999, taken by road to Katwijk then by the barge Emeli to Rotterdam. On 12 September, the spacecraft left Rotterdam for French Guiana aboard Arianespaces transport ship MN Toucan, the Toucan docked at the French Guianese town of Kourou on 23 September, and was transported to Guiana Space Centres Ariane 5 Final Assembly Building for final launch preparation. Launch of XMM took place on 10 December 1999 at 14,32 UTC from the Guiana Space Centre. XMM was lofted into space aboard an Ariane 504 rocket, and placed into an elliptical, 40-degree orbit that had a perigee of 838 km. Forty minutes after being released from the Ariane upper stage, telemetry confirmed to ground stations that the solar arrays had successfully deployed. 9-degree inclination. This resulted in the making one complete revolution of the Earth approximately every 48 hours. Immediately after launch, XMM began its Launch and Early Orbit phase of operations, on 17 and 18 December 1999, the X-ray modules and Optical Monitor doors were opened, respectively. Instrument activation started on 4 January 2000, and the Instrument Commissioning phase began on 16 January, on 3 March, the Calibration and Performance Validation phase began, and routine science operations began on 1 June. During a press conference on 9 February 2000, ESA presented the first images taken by XMM, whereas the program had formally been known as the High Throughput X-ray Spectroscopy Mission, the new name would reflect the nature of the program and the originator of the field of spectroscopy. Including all construction, spacecraft launch, and two years of operation, the project was accomplished within a budget of 689 million €, because of the spacecrafts good health and the significant returns of data, XMM-Newton has received several mission extensions by ESAs Science Programme Committee
31.
Riccardo Giacconi
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Riccardo Giacconi is an Italian Nobel Prize-winning astrophysicist who laid the foundations of X-ray astronomy. He is currently a professor at the Johns Hopkins University, born in Genoa, Italy, Giacconi received his Laurea from the University of Milan before moving to the US to pursue a career in astrophysics research. Since cosmic X-ray radiation is absorbed by the Earths atmosphere, space-based telescopes are needed for X-ray astronomy, Giacconi also applied his expertise to other fields of astronomy, becoming the first director of the Space Telescope Science Institute, the science operations center for the Hubble Space Telescope. Giacconi was awarded a share of the Nobel Prize in Physics in 2002 for pioneering contributions to astrophysics, during that time he also held the position of Director General of the European Southern Observatory. He is currently principal investigator for the Chandra Deep Field-South project with NASAs Chandra X-ray Observatory
32.
Marshall Space Flight Center
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The George C. Marshall Space Flight Center is the U. S. governments civilian rocketry and spacecraft propulsion research center. The largest NASA center, MSFCs first mission was developing the Saturn launch vehicles for the Apollo moon program, located on the Redstone Arsenal near Huntsville, Alabama, MSFC is named in honor of General of the Army George Marshall. The center also contains the Huntsville Operations Support Center, a facility that supports ISS launch, payload, the HOSC also monitors rocket launches from Cape Canaveral Air Force Station when a Marshall Center payload is on board. The largest and best-known activity was called Operation Paperclip, in August 1945,127 missile specialists led by Wernher von Braun signed work contracts with the U. S. Armys Ordnance Corps. Most of them had worked on the V-2 missile development under von Braun at Peenemünde, Von Braun and the other Germans were sent to Fort Bliss, Texas, joining the Armys newly formed Research and Development Division Sub-office. Von Braun had long had a great interest in rocketry for space science, toward this, he was allowed to use a WAC Corporal rocket as a second stage for a V-2, the combination, called Bumper, reached a record-breaking 250 miles altitude. During World War II, the production and storage of shells was conducted by three arsenals nearby to Huntsville, Alabama. After the war, these were closed, and the three areas were combined to form Redstone Arsenal, a year later, the Secretary of the Army approved the transfer of the rocket research and development activities from Fort Bliss to the new center at Redstone Arsenal. Beginning in April 1950, about 1,000 persons were involved in the transfer, at this time, R&D responsibility for guided missiles was added, and studies began on a medium-range guided missile that eventually became the Redstone rocket. Over the next decade, the development on Redstone Arsenal greatly expanded. Many small free-flight and guided rockets were developed, and work on the Redstone rocket got underway, although this rocket was primarily intended for military purposes, von Braun kept space firmly in his mind, and published a widely read article on this subject. In mid-1952, the Germans who had worked under individual contracts were converted to civil service employees. Von Braun was appointed Chief of the Guided Missile Development Division, in September 1954, von Braun proposed using the Redstone as the main booster of a multi-stage rocket for launching artificial satellites. A year later, a study for Project Orbiter was completed, detailing plans, the Armys official role in the U. S. space satellite program was delayed, however, after higher authorities elected to use the Vanguard rocket then being developed by the Naval Research Laboratory. In February 1956, the Army Ballistic Missile Agency was established, von Braun was the director of the Development Operations Division. One of the programs was a 1, 500-mile, single-stage missile that was started the previous year. The first Jupiter IRBM flight took place from Cape Canaveral in March 1957 with the first successful flight to full range on 31 May, Jupiter was eventually taken over by the U. S. Air Force. The ABMA developed Jupiter-C was composed of a Redstone rocket first stage, while the Jupiter C capability was such that it could have placed the fourth stage in orbit, that mission had been assigned to the NRL
33.
Einstein Observatory
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Einstein Observatory was the first fully imaging X-ray telescope put into space and the second of NASAs three High Energy Astrophysical Observatories. Named HEAO B before launch, the name was changed to honor Albert Einstein upon its successfully attaining orbit. Its orbital inclination orbit was 23.5 degrees, the Einstein Observatory satellite re-entered the Earths atmosphere and burned up on March 25,1982. It had instruments sensitive in the 0.2 to 3.5 keV energy range
34.
Space Shuttle program
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When its mission was complete, the orbiter would re-enter the Earths atmosphere and land like a glider at either the Kennedy Space Center or Edwards Air Force Base. The Shuttle is the only winged manned spacecraft to have achieved orbit and landing, and its missions involved carrying large payloads to various orbits, providing crew rotation for the space station, and performing service missions. The orbiter also recovered satellites and other payloads from orbit and returned them to Earth, the stalled plans for a U. S. space station evolved into the International Space Station and were formally initiated in 1983 by U. S. The first experimental orbiter Enterprise was a glider, launched from the back of a specially modified Boeing 747. The Space Shuttle program finished with its last mission, STS-135 flown by Atlantis, in July 2011, the Space Shuttle program formally ended on August 31,2011. Since the Shuttles retirement, many of its duties are performed by an assortment of government. The European ATV Automated Transfer Vehicle supplied the ISS between 2008 and 2015, classified military missions are being flown by the US Air Forces unmanned space plane, the X-37B. Crew service to the ISS is currently provided by the Russian Soyuz while work on the Commercial Crew Development program proceeds, for missions beyond low Earth orbit, NASA is building the Space Launch System and the Orion spacecraft. Before the Apollo 11 moon landing in 1969, NASA began early studies of space shuttle designs, in 1969, President Richard Nixon formed the Space Task Group, chaired by Vice President Spiro T. Agnew. Smaller goals included a variety of vehicles for moving spacecraft around in orbit. Presenting the plans to Nixon, Agnew was told that the administration would not commit to a Mars mission and he was then told to select one of the two remaining proposals. During early shuttle development there was debate about the optimal shuttle design that best balanced capability, development cost. Ultimately the current design was chosen, using a reusable winged orbiter, reusable solid rocket boosters, the shuttle program was formally launched on January 5,1972, when President Nixon announced that NASA would proceed with the development of a reusable space shuttle system. The prime contractor for the program was North American Rockwell, the company responsible for building the Apollo Command/Service Module. The contractor for the Space Shuttle Solid Rocket Boosters was Morton Thiokol, for the tank, Martin Marietta. All Space Shuttle missions were launched from the Kennedy Space Center, the weather criteria used for launch included, but were not limited to, precipitation, temperatures, cloud cover, lightning forecast, wind, and humidity. The Shuttle was not launched under conditions where it could have been struck by lightning, the first fully functional orbiter was Columbia, built in Palmdale, California. It was delivered to Kennedy Space Center on March 25,1979, Challenger was delivered to KSC in July 1982, Discovery in November 1983, Atlantis in April 1985 and Endeavour in May 1991
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Van Allen radiation belt
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A radiation belt is a zone of energetic charged particles, most of which originate from the solar wind that is captured by and held around a planet by that planets magnetic field. The Earth has two belts and sometimes others may be temporarily created. The discovery of the belts is credited to James Van Allen, Earths two main belts extend from an altitude of about 1,000 to 60,000 kilometers above the surface in which region radiation levels vary. Most of the particles form the belts are thought to come from solar wind. By trapping the solar wind, the magnetic field deflects those energetic particles, the belts are located in the inner region of the Earths magnetosphere. The belts trap energetic electrons and protons, other nuclei, such as alpha particles, are less prevalent. The belts endanger satellites, which must have their sensitive components protected with adequate shielding if they spend significant time in that zone, kristian Birkeland, Carl Størmer, and Nicholas Christofilos had investigated the possibility of trapped charged particles before the Space Age. Explorer 1 and Explorer 3 confirmed the existence of the belt in early 1958 under James Van Allen at the University of Iowa, the trapped radiation was first mapped by Explorer 4, Pioneer 3 and Luna 1. The term Van Allen belts refers specifically to the radiation belts surrounding Earth, however, the Sun does not support long-term radiation belts, as it lacks a stable, global, dipole field. The Earths atmosphere limits the belts particles to regions above 200–1,000 km, the belts are confined to a volume which extends about 65° on either side of the celestial equator. The NASA Van Allen Probes mission aims at understanding how populations of relativistic electrons and ions in space form or change in response to changes in solar activity, the Van Allen Probes mission successfully launched on August 30,2012. The primary mission is scheduled to last two years with expendables expected to last four, NASAs Goddard Space Flight Center manages the Living With a Star program of which the Van Allen Probes is a project, along with Solar Dynamics Observatory. The Applied Physics Laboratory is responsible for the implementation and instrument management for the Van Allen Probes, Radiation belts exist around other planets and moons in the solar system that have magnetic fields powerful enough to sustain them. To date, most of these belts have been poorly mapped. The Voyager Program only nominally confirmed the existence of similar belts around Uranus, the inner Van Allen Belt extends typically from an altitude of 0.2 to 2 Earth radii or 1,000 km to 6,000 km above the Earth. In certain cases when solar activity is stronger or in areas such as the South Atlantic Anomaly. The inner belt contains high concentrations of electrons in the range of hundreds of keV and energetic protons with energies exceeding 100 MeV, the source of lower energy protons is believed to be proton diffusion due to changes in the magnetic field during geomagnetic storms. Due to the offset of the belts from Earths geometric center
36.
Northrop Grumman
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Northrop Grumman Corporation is an American global aerospace and defense technology company formed by Northrops 1994 purchase of Grumman. The company was named as the fifth-largest defense contractor in the world in 2015, Northrop Grumman employs over 68,000 people worldwide. It reported revenues of $23.526 billion in 2015, Northrop Grumman ranks No.124 on the 2015 Fortune 500 list of Americas largest corporations and ranks in the top ten military-friendly employers. It is headquartered in West Falls Church, Virginia, Northrop Grumman is made up of three business sectors, Aerospace Systems, Mission Systems, and Technology Services. Aerospace Systems, headquartered in Redondo Beach, California produces aircraft, spacecraft, high-energy laser systems and microelectronics for the US and other nations. The B-2 Spirit strategic bomber, the E-8C Joint STARS surveillance aircraft, the RQ-4 Global Hawk, the US Army uses Northrop Grummans RQ-5 Hunter unmanned air vehicle, which has been in operational use since 1995. The U. S. Navy uses Northrop Grumman-built aerial vehicles such as the BQM-74 Chukar, RQ-4 Global Hawk based BAMS UAS, Grumman C-2 Greyhound, Grumman E-2 Hawkeye, and the EA-6B Prowler. Northrop Grumman provides major components and assemblies for different aircraft such as F/A-18 Hornet, F/A-18E/F Super Hornet, Electronic Systems produces and maintains the AWACS aerial surveillance systems for the U. S. the United Kingdom, NATO, Japan, and others. Northrop Grumman is the contractor for the development and integration of the Air Forces $2-billion Multi-Platform Radar Technology Insertion Program. Many other smaller products are made by Northrop Grumman, such as night vision goggles, information Systems, headquartered in McLean, Virginia, supports the U. S. Vinnell, a Technical Services Northrop Grumman subsidiary, provides training and communications for the military. In 2003, it landed a $48 million contract to train the Iraqi Army, in 2005 the company won a $2 billion contract with Virginia to overhaul most of the states IT operations. Later that year, The United Kingdom paid $1.2 billion in a contract with the company to provide maintenance of the countrys defensive radar, Northrop Grumman performs various functions in the War on Drugs. The company sends planes to spray herbicides on suspected cocaine fields in Colombia, remotec, a subsidiary, is the foremost manufacturer of remote control vehicles for explosive ordnance disposal and hazardous material handling. A UK-based subsidiary, Park Air Systems, provides VHF and UHF ground-to-air communications systems for the civil, Northrop Grumman has also worked closely with Antenna Associates, Inc. a manufacturer of Identification friend or foe /Secondary Surveillance Radar antennas located in Massachusetts. In August 2007, Northrop Grumman acquired Scaled Composites in which it had owned a 40% stake. Originally formed in California in 1939 by Jack Northrop, the Northrop Corporation was reincorporated in Delaware in 1985, in 1994, Northrop Aircraft bought Grumman Aerospace, famous for building the Apollo Lunar Module to create Northrop Grumman. In 1996, the new company acquired Westinghouse Electronic Systems, a manufacturer of radar systems. In 1997, the defense computer contractor Logicon was added, which had acquired Geodynamics Corporation in March 1996, in 1998, a merger between Northrop Grumman and competitor Lockheed Martin was considered but abandoned after resistance from the Department of Defense and Department of Justice
37.
Redondo Beach, California
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Redondo Beach is one of the three Beach Cities located in Los Angeles County, California, United States. The population was 66,748 at the 2010 census, up from 63,261 at the 2000 census, the city is located in the South Bay region of the greater Los Angeles area. Redondo Beach was originally part of the 1785 Rancho San Pedro Spanish land grant that became the South Redondo area. The citys territory has an unusual shape including an area along the beach and another strip inland from Manhattan Beach, the primary attractions include Municipal Pier and the sandy beach, popular with tourists and a variety of sports enthusiasts. The western terminus of the Metro Rail Green Line is in North Redondo Beach, the Chowigna Indians used the site of todays Hopkins Wilderness Park, formerly Nike missile site LA-57 from 1956 to 1963, in Redondo Beach, California, as a lookout place. The wetlands located at the site of todays AES power plant in Redondo Beach were a source of foods including halibut, lobster, and sea bass, and also of salt. In the 1700s, the Chowigna bartered salt from the old Redondo Salt Lake and their village by the lake was called Onoova-nga, or Place of Salt. The Chowigna were relocated to missions in 1854, when Manuel Dominguez sold 215 acres of Rancho San Pedro, including the lake, to Henry Allanson, moonstone Beach was a tourist attraction from the late 1880s to the early 1920s. Tourists gathered moonstones from the mounds that had washed ashore during storms. According to the United States Census Bureau, the city has an area of 6.2 square miles. Redondo Beach was originally part of the 1784 Rancho San Pedro Spanish land grant of the 43, the ocean side of Pacific Coast Highway has restaurants and boating activities while inland of PCH is largely residential. Redondo Breakwall is a surf spot in the South Bay. This power plant sports Whaling Wall number 31, a 586 ft ×95 ft whale mural by world-famous artist Robert Wyland titled Gray Whale Migration. Redondo Beach has a division between the north and south sections of the city with 190th, Anita, and Herondo streets forming its east-west boundary line. South Redondo is along the beachfront with the pier and marina/harbor complex, the small business district near the pier and marina was revived in the 1990s by beachgoers and new residents who wanted to sell beachwear and surfing accessories. South Redondo has wide streets, wide beaches and laid-back feel make it a prime destination for those seeking a bike to the grocery store community. The main library is located in the Civic Center, North Redondo, north of 190th Street, is an inland community separated from the beachfront by Hermosa Beach and Manhattan Beach. It is also home to the South Bay Galleria shopping center, the North Branch of the Redondo Beach Library serves this area
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California
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California is the most populous state in the United States and the third most extensive by area. Located on the western coast of the U. S, California is bordered by the other U. S. states of Oregon, Nevada, and Arizona and shares an international border with the Mexican state of Baja California. Los Angeles is Californias most populous city, and the second largest after New York City. The Los Angeles Area and the San Francisco Bay Area are the nations second- and fifth-most populous urban regions, California also has the nations most populous county, Los Angeles County, and its largest county by area, San Bernardino County. The Central Valley, an agricultural area, dominates the states center. What is now California was first settled by various Native American tribes before being explored by a number of European expeditions during the 16th and 17th centuries, the Spanish Empire then claimed it as part of Alta California in their New Spain colony. The area became a part of Mexico in 1821 following its war for independence. The western portion of Alta California then was organized as the State of California, the California Gold Rush starting in 1848 led to dramatic social and demographic changes, with large-scale emigration from the east and abroad with an accompanying economic boom. If it were a country, California would be the 6th largest economy in the world, fifty-eight percent of the states economy is centered on finance, government, real estate services, technology, and professional, scientific and technical business services. Although it accounts for only 1.5 percent of the states economy, the story of Calafia is recorded in a 1510 work The Adventures of Esplandián, written as a sequel to Amadis de Gaula by Spanish adventure writer Garci Rodríguez de Montalvo. The kingdom of Queen Calafia, according to Montalvo, was said to be a land inhabited by griffins and other strange beasts. This conventional wisdom that California was an island, with maps drawn to reflect this belief, shortened forms of the states name include CA, Cal. Calif. and US-CA. Settled by successive waves of arrivals during the last 10,000 years, various estimates of the native population range from 100,000 to 300,000. The Indigenous peoples of California included more than 70 distinct groups of Native Americans, ranging from large, settled populations living on the coast to groups in the interior. California groups also were diverse in their organization with bands, tribes, villages. Trade, intermarriage and military alliances fostered many social and economic relationships among the diverse groups, the first European effort to explore the coast as far north as the Russian River was a Spanish sailing expedition, led by Portuguese captain Juan Rodríguez Cabrillo, in 1542. Some 37 years later English explorer Francis Drake also explored and claimed a portion of the California coast in 1579. Spanish traders made unintended visits with the Manila galleons on their trips from the Philippines beginning in 1565
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Astrophysics
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Astrophysics is the branch of astronomy that employs the principles of physics and chemistry to ascertain the nature of the heavenly bodies, rather than their positions or motions in space. Among the objects studied are the Sun, other stars, galaxies, extrasolar planets, the interstellar medium and their emissions are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. In practice, modern astronomical research often involves an amount of work in the realms of theoretical and observational physics. Although astronomy is as ancient as recorded history itself, it was separated from the study of terrestrial physics. Their challenge was that the tools had not yet been invented with which to prove these assertions, for much of the nineteenth century, astronomical research was focused on the routine work of measuring the positions and computing the motions of astronomical objects. Kirchhoff deduced that the lines in the solar spectrum are caused by absorption by chemical elements in the Solar atmosphere. In this way it was proved that the elements found in the Sun. Among those who extended the study of solar and stellar spectra was Norman Lockyer and he thus claimed the line represented a new element, which was called helium, after the Greek Helios, the Sun personified. By 1890, a catalog of over 10,000 stars had been prepared that grouped them into thirteen spectral types, most significantly, she discovered that hydrogen and helium were the principal components of stars. This discovery was so unexpected that her dissertation readers convinced her to modify the conclusion before publication, however, later research confirmed her discovery. By the end of the 20th century, studies of astronomical spectra had expanded to cover wavelengths extending from radio waves through optical, x-ray and it is the practice of observing celestial objects by using telescopes and other astronomical apparatus. The majority of observations are made using the electromagnetic spectrum. Radio astronomy studies radiation with a greater than a few millimeters. The study of these waves requires very large radio telescopes, infrared astronomy studies radiation with a wavelength that is too long to be visible to the naked eye but is shorter than radio waves. Infrared observations are made with telescopes similar to the familiar optical telescopes. Objects colder than stars are studied at infrared frequencies. Optical astronomy is the oldest kind of astronomy, telescopes paired with a charge-coupled device or spectroscopes are the most common instruments used. The Earths atmosphere interferes somewhat with optical observations, so adaptive optics, in this wavelength range, stars are highly visible, and many chemical spectra can be observed to study the chemical composition of stars, galaxies and nebulae
40.
Chandrasekhar limit
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The Chandrasekhar limit is the maximum mass of a stable white dwarf star. The limit was first indicated in papers published by Wilhelm Anderson, stoner, and was named after Subrahmanyan Chandrasekhar, the Indian astrophysicist who independently discovered and improved upon the accuracy of the calculation in 1930, at the age of 19, in India. White dwarfs resist gravitational collapse primarily through electron degeneracy pressure, the Chandrasekhar limit is the mass above which electron degeneracy pressure in the stars core is insufficient to balance the stars own gravitational self-attraction. Those with masses under the limit remain stable as white dwarfs, the currently accepted value of the limit is about 1.4 M ⊙. Electron degeneracy pressure is a quantum-mechanical effect arising from the Pauli exclusion principle, since electrons are fermions, no two electrons can be in the same state, so not all electrons can be in the minimum-energy level. Rather, electrons must occupy a band of energy levels, compression of the electron gas increases the number of electrons in a given volume and raises the maximum energy level in the occupied band. Therefore, the energy of the electrons will increase upon compression, so pressure must be exerted on the gas to compress it. With sufficient compression, electrons are forced into nuclei in the process of electron capture, relieving the pressure. In the nonrelativistic case, electron degeneracy pressure gives rise to an equation of state of the form P = K1 ρ53, where P is the pressure, ρ is the mass density, and K1 is a constant. As the mass of a white dwarf increases, the typical energies to which degeneracy pressure forces the electrons are no longer negligible relative to their rest masses. The velocities of the approach the speed of light. In the strongly relativistic limit, the equation of state takes the form P = K2 ρ43 and this will yield a polytrope of index 3, which will have a total mass, Mlimit say, depending only on K2. For a fully relativistic treatment, the equation of state used will interpolate between the equations P = K1 ρ53 for small ρ and P = K2 ρ43 for large ρ. When this is done, the model radius still decreases with mass, the curves of radius against mass for the non-relativistic and relativistic models are shown in the graph. They are colored blue and green, respectively, μe has been set equal to 2. Radius is measured in standard solar radii or kilometers, and mass in standard solar masses, calculated values for the limit will vary depending on the nuclear composition of the mass. Chandrasekhar, eq. eq. eq. mH is the mass of the hydrogen atom, ω30 ≈2.018236 is a constant connected with the solution to the Lane-Emden equation. As ℏ c / G is the Planck mass, the limit is of the order of M Pl 3 m H2, lieb and Yau have given a rigorous derivation of the limit from a relativistic many-particle Schrödinger equation
. Bibcode:2004IJMPD..13.1239S. doi:10.1142/S0218271804005377.
