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Telstar 402R
Telstar 4 (also called Telstar 402R and Telstar 403) was a communications satellite owned by AT&T Corporation. Telstar 4 was successfully launched into space on September 24, 1995, by means of an Ariane-42L vehicle from the Kourou Space Center, French Guiana. It had a launch mass of 3,410 kg. Telstar 4 stopped operating on September 19, 2003, after a short circuit A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit ... in the primary power bus. TSE. Retrieved June 3, 2018. References External links [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Satellite
A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a Transponder (satellite communications), transponder; it creates a communication channel between a source transmitter and a Radio receiver, receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. Many communications satellites are in geostationary orbit above the equator, so that the satellite appears stationary at the same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Others form satellite constellations in low Earth orbit, where antennas on the ground have to follow the position of the satellites and switch between satellites frequently. The radio waves used for telecommunications links travel by Line-of-sight propagation, line of sight and so are obstructe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telstar 402
Telstar 402 was a communications satellite owned by AT&T Corporation. Telstar 402 was successfully launched into space on September 9, 1994, by means of an Ariane-42L vehicle from the Kourou Space Center, French Guiana French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west .... It had a launch mass of 3,775 kg. The satellite was lost shortly after launch due to an explosion that occurred in the propulsion system that was caused by leakage of hot gases. References External links Gunter's Space Page - Telstar 401, 402, 402RNasa NSSDC Entry Communications satellites in geostationary orbit Spacecraft launched in 1994 Satellite launch failures {{US-spacecraft-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short Circuit
A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit. The opposite of a short circuit is an open circuit, which is an infinite resistance (or very high impedance) between two nodes. Definition A short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. This results in an electric current limited only by the Thévenin equivalent resistance of the rest of the network which can cause circuit damage, overheating, fire or explosion. Although usually the result of a fault, there are cases where short circuits are caused intentionally, for example, for the purpose of voltage-sensing crowbar circuit protectors. In circuit analysis, a ''short circuit'' is defined as a connection between two nodes that forces them to be at the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
French Guiana
French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west and Brazil to the east and south, French Guiana covers a total area of and a land area of . As of January 2025, it is home to 292,354 people. French Guiana is the second-largest Regions of France, region in France, being approximately one-seventh the size of metropolitan France, European France, and the largest Special member state territories and the European Union, outermost region within the European Union. It has a very low population density, with only . About half of its residents live in its capital, Cayenne. Approximately 98.9% of French Guiana is covered by forests, much of it Old-growth forest, primeval Tropical rainforest, rainforest. Guiana Amazonian Park, the largest national park in the European Union covers 41% of French ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kourou Space Center
The Guiana Space Centre (; CSG), also called Europe's Spaceport, is a spaceport to the northwest of Kourou in French Guiana, an overseas region of France in South America. Kourou is located approximately north of the equator at a latitude of 5°. In operation since 1968, it is a suitable location for a spaceport because of its near equatorial location and open sea to the east and north. At CSG, space launches are conducted by several European private companies and government agencies working together. The CSG land itself is managed by CNES, the French national space agency. The launch infrastructure built on the CSG land is owned by the European Space Agency. The private company Arianespace operates the launches including planning missions, handling customer relationships and overseeing the team at CSG that integrates and prepares vehicles for launch. The rockets themselves are designed and produced by other companies, ArianeGroup for the Ariane 6 and Avio for the Vega. Hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AT&T Corporation
AT&T Corporation, an abbreviation for its former name, the American Telephone and Telegraph Company, was an American telecommunications company that provided voice, video, data, and Internet telecommunications and professional services to businesses, consumers, and government agencies. During the Bell System's long history, AT&T was at times the world's largest telecommunications company, the world's largest cable television operator, and a regulated monopoly. At its peak in the 1950s and 1960s, it employed one million people and its revenue ranged between US$3 billion in 1950 ($ in present-day terms) and $12 billion in 1966 ($ in present-day terms). In 2005, AT&T was acquired by " Baby Bell" and former subsidiary SBC Communications for more than $16 billion ($ in present-day terms). SBC then changed its name to AT&T Inc., with AT&T Corporation continuing to exist as a long-distance calling subsidiary until its dissolution on May 1, 2024. History Origins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite
A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which are small CubeSats. Similar satellites can work together as groups, forming constellatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TelStar 5
Galaxy 25 (G-25) launched in 1997, contracted by International Launch Services (ILS), formerly known as Intelsat Americas 5 (IA-5) until 15 February 2007 when it was renamed as result of the merger between owner Intelsat and PanAmSat for Telstar 5, is a medium-powered communications satellite formerly in a geostationary orbit at 97° West, above a point in the Pacific Ocean several hundred miles west of the Galapagos Islands. It was manufactured by Space Systems/Loral using its LS-1300 satellite bus and is currently owned and operated by Intelsat. The satellite's main C-band transponder cluster covers the United States, Canada, and Mexico; its main Ku-band transponder cluster covers the United States, Mexico, and the Northern Caribbean Sea. An additional C-band and a Ku-band transponder pair targets Hawaii. Galaxy 25 has a projected life of 12 years. It was replaced by Galaxy 19 (formerly IA-9) in late 2008. When it was last in service at 97.1° West, Galaxy 25 transmitted both ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telstar
Telstar refers to a series of communications satellites. The first two, Telstar 1 and Telstar 2, were experimental and nearly identical. Telstar 1 launched atop of a Thor-Delta rocket on July 10, 1962, successfully relayed the first television pictures, telephone calls, and Radiofax, telegraph images through space. It also provided the first live transatlantic television feed. Telstar 2 was launched May 7, 1963. Telstar 1 and 2—though no longer functional—still orbit the Earth. Description Belonging to AT&T Corporation, AT&T, the original Telstar was part of a multi-national agreement among AT&T (USA), Bell Labs, Bell Telephone Laboratories (USA), National Aeronautics and Space Administration, NASA (USA), General Post Office, GPO (United Kingdom) and the Orange S.A., direction générale des Télécommunications (France) to develop experimental communications satellite, satellite communications over the Atlantic Ocean. Bell Labs held a contract with NASA, paying the ag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AT&T
AT&T Inc., an abbreviation for its predecessor's former name, the American Telephone and Telegraph Company, is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's List of telecommunications companies, third largest telecommunications company by revenue and the List of mobile network operators in the United States, third largest wireless carrier in the United States behind T-Mobile US, T-Mobile and Verizon. As of 2023, AT&T was ranked 32nd on the Fortune 500, ''Fortune'' 500 rankings of the largest United States corporations, with revenues of $122.4 billion. The modern company to bear the AT&T name began its history as the American District Telegraph Company, formed in St. Louis in 1878. After expanding services to Arkansas, Kansas, Oklahoma and Texas through a series of mergers, it became the Southwestern Bell Telephone Company in 1920. Southwestern Bell was a subsidiary of AT&T Corporation, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geostationary Orbit
A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular orbit, circular geosynchronous orbit in altitude above Earth's equator, in radius from Earth's center, and following the retrograde and prograde motion, direction of Earth's rotation. An object in such an orbit has an orbital period equal to Earth's rotational period, one sidereal time, sidereal day, and so to ground observers it appears motionless, in a fixed position in the sky. The concept of a geostationary orbit was popularised by the science fiction writer Arthur C. Clarke in the 1940s as a way to revolutionise telecommunications, and the first satellite to be placed in this kind of orbit was launched in 1963. Communications satellites are often placed in a geostationary orbit so that Earth-based satellite dish, satellite antennas do not have to rotate to track t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geocentric Orbit
A geocentric orbit, Earth-centered orbit, or Earth orbit involves any object orbiting Earth, such as the Moon or artificial satellites. In 1997, NASA estimated there were approximately 2,465 artificial satellite payloads orbiting Earth and 6,216 pieces of space debris as tracked by the Goddard Space Flight Center. More than 16,291 objects previously launched have undergone orbital decay and entered Earth's atmosphere. A spacecraft enters orbit when its centripetal acceleration due to gravity is less than or equal to the centrifugal acceleration due to the horizontal component of its velocity. For a low Earth orbit, this velocity is about ; by contrast, the fastest crewed airplane speed ever achieved (excluding speeds achieved by deorbiting spacecraft) was in 1967 by the North American X-15. The energy required to reach Earth orbital velocity at an altitude of is about 36 MJ/kg, which is six times the energy needed merely to climb to the corresponding altitude. Spa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
