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TDF 2
TDF 2 or TDF-2 was a French communications satellite which was to have been operated by Télévision de France (France Télécom). It was intended to be used to provide television broadcast services to Europe, however it failed before entering service. It was constructed by Aérospatiale, based on the Spacebus 300 satellite bus, and carried five Ku-band transponders. At launch it had a mass of , and an expected operational lifespan of eight years. Launch TDF 2 was launched by Arianespace using an Ariane 44L H10 launch vehicle flying from ELA-2 at Centre Spatial Guyanais, Kourou, French Guiana. The launch took place at 22:25:00 UTC on 24 July 1990. It was a Spacebus 300 satellite bus. Mission TDF 2 was placed into a geostationary orbit at a longitude of 19.2° West. In August 1997, at 36° East, the bird joined the Eutelsat fleet. TDF 2 is expected to remain in service at least until early 1999. See also * 1990 in spaceflight The following is an outline of 1990 ... [...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; it creates a communication channel between a source transmitter and a 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 high frequency radio waves used for telecommunications links travel by line of sight and so are obstructed by the curve of the Earth. The purpose of communicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ku Band
The Ku band () is the portion of the electromagnetic spectrum in the microwave range of frequencies from 12 to 18 gigahertz (GHz). The symbol is short for "K-under" (originally german: Kurz-unten), because it is the lower part of the original NATO K band, which was split into three bands (Ku, K, and Ka) because of the presence of the atmospheric water vapor resonance peak at 22.24 GHz, (1.35 cm) which made the center unusable for long range transmission. In radar applications, it ranges from 12 to 18 GHz according to the formal definition of radar frequency band nomenclature in IEEE Standard 521–2002. Ku band is primarily used for satellite communications, most notably the downlink used by direct broadcast satellites to broadcast satellite television, and for specific applications such as NASA's Tracking Data Relay Satellite used for International Space Station (ISS) communications and SpaceX Starlink satellites. Ku band satellites are also u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutelsat
Eutelsat S.A. is a French satellite operator. Providing coverage over the entire European continent, the Middle East, Africa, Asia and the Americas, it is the world's third-largest satellite operator in terms of revenues. Eutelsat's satellites are used for broadcasting nearly 7,000 television stations, of which 1,400 are in high-definition television, and 1,100 radio stations to over 274 million cable and satellite homes. They also serve requirements for TV contribution services, corporate networks, mobile communications, Internet backbone connectivity and broadband access for terrestrial, maritime and in-flight applications. EUTELSAT is headquartered in Paris, France. Eutelsat Communications Chief Executive Officer is currently Eva Berneke. In October 2017, Eutelsat acquired Noorsat, one of the leading satellite service providers in the Middle East, from Bahrain's Orbit Holding Group. Noorsat is the premier distributor of Eutelsat capacity in the Middle East, serving blue-c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitude
Longitude (, ) is a geographic coordinate that specifies the east– west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter lambda (λ). Meridians are semicircular lines running from pole to pole that connect points with the same longitude. The prime meridian defines 0° longitude; by convention the International Reference Meridian for the Earth passes near the Royal Observatory in Greenwich, England on the island of Great Britain. Positive longitudes are east of the prime meridian, and negative ones are west. Because of the Earth's rotation, there is a close connection between longitude and time measurement. Scientifically precise local time varies with longitude: a difference of 15° longitude corresponds to a one-hour difference in local time, due to the differing position in relation to the Sun. Comparing local time to an absolute measure of ti ... [...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 geosynchronous orbit in altitude above Earth's equator ( in radius from Earth's center) and following the direction of Earth's rotation. An object in such an orbit has an orbital period equal to Earth's rotational period, one 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 antennas do not have to rotate to track them but can be pointed permanently at the position in the sky where the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
French Guiana
French Guiana ( or ; french: link=no, Guyane ; gcr, label=French Guianese Creole, Lagwiyann ) is an overseas departments and regions of France, overseas department/region and single territorial collectivity of France on the northern Atlantic Ocean, Atlantic coast of South America in the Guianas. It borders Brazil to the east and south and Suriname to the west. With a land area of , French Guiana is the second-largest Regions of France, region of France (more than one-seventh the size of Metropolitan 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 . (Its population is less than that of Metropolitan France.) Half of its 294,436 inhabitants in 2022 lived in the metropolitan area of Cayenne, its Prefectures in France, capital. 98.9% of the land territory of French Guiana is covered by forests, a large part of which is Old-growth forest, primeval Tropical r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Launch Vehicle
A launch vehicle or carrier rocket is a rocket designed to carry a payload (spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and systems such as vehicle assembly and fueling. Launch vehicles are engineered with advanced aerodynamics and technologies, which contribute to large operating costs. An orbital launch vehicle must lift its payload at least to the boundary of space, approximately and accelerate it to a horizontal velocity of at least . Suborbital vehicles launch their payloads to lower velocity or are launched at elevation angles greater than horizontal. Practical orbital launch vehicles are multistage rockets which use chemical propellants such as solid fuel, liquid hydrogen, kerosene, liquid oxygen, or Hypergolic propellants. Launch vehicles are classified by their orbital payload capacity, ranging from small-, medium-, heavy- to super-heavy lift ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transponder (satellite Communications)
A communications satellite's transponder is the series of interconnected units that form a communications channel between the receiving and the transmitting antennas. It is mainly used in satellite communication to transfer the received signals. A transponder is typically composed of: * an input band-limiting device (an input band-pass filter), * an input low-noise amplifier (LNA), designed to amplify the signals received from the Earth station (normally very weak, because of the large distances involved), * a frequency translator (normally composed of an oscillator and a frequency mixer) used to convert the frequency of the received signal to the frequency required for the transmitted signal, * an output band-pass filter, * a power amplifier (this can be a traveling-wave tube or a solid-state amplifier). Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Most transponders operate on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Bus
A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are opposed to specially produced satellites. Bus-derived satellites are usually customized to customer requirements, for example with specialized sensors or transponders, in order to achieve a specific mission. They are commonly used for geosynchronous satellites, particularly communications satellites, but are also used in spacecraft which occupy lower orbits, occasionally including low Earth orbit missions. Examples Some satellite bus examples include: * Boeing DS&S 702 * Lockheed Martin Space Systems A2100 * Alphabus * INVAP ARSAT-3K * Airbus D&S Eurostar * ISRO's I-1K, I-2K, I-3K, I-4K, I-6K, and Indian Mini Satellite bus * NASA Ames MCSB * SSL 1300 * Orbital ATK GEOStar * Mitsubishi Electric DS2000 * Spacecraft bus of the James Webb Space Telescope * SP ... [...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; it creates a communication channel between a source transmitter and a 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 high frequency radio waves used for telecommunications links travel by line of sight and so are obstructed by the curve of the Earth. The purpose of communicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TDF 1
TDF 1 or TDF-1 was a French communications satellite which was to have been operated by Télévision de France (France Télécom). It was intended to be used to provide television broadcast services to Europe, however it failed before entering service. It was constructed by Aérospatiale, based on the Spacebus 300 satellite bus, and carried five Ku-band transponders. At launch it had a mass of , and an expected operational lifespan of eight years. Launch TDF 1 was launched by Arianespace using an Ariane 2 launch vehicle flying from ELA-1 at Centre Spatial Guyanais, Kourou, French Guiana. The launch took place at 02:17:00 UTC on 28 October 1988. It was a Spacebus 300 satellite bus. Mission TDF 1 was placed into a geostationary orbit at a longitude of 19.2° West. See also * 1988 in spaceflight The following is an outline of 1988 in spaceflight. Launches Deep-space rendezvous There were no deep-space rendezvous in 1988. References Footnote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
France Telecom
Orange S.A. (), formerly France Télécom S.A. (stylized as france telecom) is a French multinational telecommunications corporation. It has 266 million customers worldwide and employs 89,000 people in France, and 59,000 elsewhere. In 2015, the group had revenue of €40 billion. The company's head office is located in the 15th arrondissement of Paris. Orange has been the company's main brand for mobile, landline, internet and Internet Protocol television (IPTV) services since 2006. The Orange brand originated in the United Kingdom in 1994 after Hutchison Whampoa acquired a controlling stake in Microtel Communications: that company became a subsidiary of Mannesmann in 1999 and then was acquired by France Télécom in 2000. The France Télécom company was rebranded to Orange on 1 July 2013. The company has faced criticism due to the Orange S.A. suicides. History Nationalised service (1878–1980s) In 1792, under the French Revolution, the first communication ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
