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Badr 4
Badr-4 (a.k.a. Arabsat 4B) is an EADS Astrium-built communications satellite operated by Arabsat, launched 8 November 2006 on a Proton-M/Briz-M rocket. It provides fixed satellite communications services in C- and Ku-bands from the 26° East orbital position. The satellite is based on the Eurostar E2000+ platform. Its payload was supplied by Alcatel Alenia Space. The Badr-4-payload consists of 28 active channels in Ku band (16 in BSS and 12 in FSS). Payload power is about 6 kW. The satellite has two 2.5 m deployable antennas and one 1.35 m top floor antenna. Due to success of the satellite, Arabsat let another agreement for an upgraded version of Badr-4 communication satellite: in June 2006, Arabsat gave the contract to EADS Astrium for construction of Badr-6, a high-power broadcast satellite to cover the Middle East and Africa. Badr-6 was launched by an Ariane 5 on 7 July 2008. Description This satellite carries 32 transponders In telecommunications, a transp ... [...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 communications sate ... [...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 sat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Satellites In Geostationary Orbit
Communication (from la, communicare, meaning "to share" or "to be in relation with") is usually defined as the transmission of information. The term may also refer to the message communicated through such transmissions or the field of inquiry studying them. There are many disagreements about its precise definition. John Peters argues that the difficulty of defining communication emerges from the fact that communication is both a universal phenomenon and a specific discipline of institutional academic study. One definitional strategy involves limiting what can be included in the category of communication (for example, requiring a "conscious intent" to persuade). By this logic, one possible definition of communication is the act of developing meaning among entities or groups through the use of sufficiently mutually understood signs, symbols, and semiotic conventions. An important distinction is between verbal communication, which happens through the use of a language, and non ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurostar (spacecraft)
Eurostar is a satellite bus made by Airbus Defence and Space (formerly Astrium, and before 1994, British Aerospace, and Matra Marconi Space (the former Marconi Space having been merged with Matra's former "Matra Espace" division) which has been used for a series of spacecraft providing telecommunications services in geosynchronous orbit (GEO). More than 70 Eurostar satellites have been ordered to date, of which more than 55 have been successfully launched since October 1990 and have proven highly reliable in operational service. In December 2013, the Eurostar satellites accumulated 500 years of successful operations in orbit. The Eurostar spacecraft series is designed for a variety of telecommunications needs including fixed services and broadcast, mobile services, broadband and secured communications. Development Eurostar was designed in the mid 1980s jointly by Matra Marconi Space and BAe (now integrated within Airbus Defence and Space) to Inmarsat specifications, for a market whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transponders
In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a flight transponder is an automated transceiver in an aircraft that emits a coded identifying signal in response to an interrogating received signal. In a communications satellite, a satellite transponder receives signals over a range of uplink frequencies, usually from a satellite ground station; the transponder amplifies them, and re-transmits them on a different set of downlink frequencies to receivers on Earth, often without changing the content of the received signal or signals. Satellite/broadcast communications A communications satellite’s channels are called transponders because each is a separate transceiver or repeater. With digital video data compression and multiplexing, several video and audio channels may travel through a single trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fixed Satellite Service
Fixed-satellite service (short: FSS | also: fixed-satellite radiocommunication service) is – according to ''article 1.21'' of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as ''A radiocommunication service between earth stations at given positions, when one or more satellites are used; the given position may be a specified fixed point or any fixed point within specified areas; in some cases this service includes satellite-to-satellite links, which may also be operated in the inter-satellite service; the fixed-satellite service may also include feeder links for other space radiocommunication services.'' Classification This ''radiocommunication service'' is classified in accordance with ''ITU Radio Regulations'' (article 1) as follows: Fixed service (article 1.20) * (article 1.21) *Inter-satellite service (article 1.22) *Earth exploration-satellite service (article 1.51) ** Meteorological-satellite service (article 1.52) ; Frequency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct-broadcast Satellite
Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna commonly referred to as a satellite dish and a low-noise block downconverter. A satellite receiver then decodes the desired television program for viewing on a television set. Receivers can be external set-top boxes, or a built-in television tuner. Satellite television provides a wide range of channels and services. It is usually the only television available in many remote geographic areas without terrestrial television or cable television service. Modern systems signals are relayed from a communications satellite on the X band (8–12 GHz) or Ku band (12–18 GHz) frequencies requiring only a small dish less than a meter in diameter. The first satellite TV systems were an obsolete type now known as television receive-only. These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arabsat
The Arab Satellite Communications Organization (often abbreviated as Arabsat) is a communications satellite operator in the Arab World, headquartered in the city of Riyadh, Saudi Arabia. Arabsat was created to deliver satellite-based, public and private telecommunications services to the Arab States, in accordance with International Standards. With 21 member countries, the organization plays a vital role of enhancing communications in the Arab World. The Arabsat satellites are a series of geostationary communications satellites launched from 1985 through 2019. Some of the later satellites in the series remain operational in orbit, while others have been retired and are derelict. History The foundation of Arab Satellite Communications Organization (Arabsat) dates from the late 1960s. In 1967, information ministers of Arab states developed a series of principles in relation to a satellite network, to create an integration of social and cultural activities among the Arab League co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geocentric Orbit
A geocentric 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. Spacecraft with a perigee belo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arab Satellite Communications Organization
The Arab Satellite Communications Organization (often abbreviated as Arabsat) is a communications satellite operator in the Arab World, headquartered in the city of Riyadh, Saudi Arabia. Arabsat was created to deliver satellite-based, public and private telecommunications services to the Arab States, in accordance with International Standards. With 21 member countries, the organization plays a vital role of enhancing communications in the Arab World. The Arabsat satellites are a series of geostationary communications satellites launched from 1985 through 2019. Some of the later satellites in the series remain operational in orbit, while others have been retired and are derelict. History The foundation of Arab Satellite Communications Organization (Arabsat) dates from the late 1960s. In 1967, information ministers of Arab states developed a series of principles in relation to a satellite network, to create an integration of social and cultural activities among the Arab League ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Launch Services
International Launch Services, Inc. (ILS) is a joint venture with exclusive rights to the worldwide sale of commercial Angara and Proton rocket launch services. Proton launches take place at the Baikonur Cosmodrome in Kazakhstan while Angara is launched from the Plesetsk and Vostochny Cosmodrome in Russia. Ownership ILS was formed in 1995 as a private spaceflight partnership between Lockheed Martin (LM), Khrunichev and Energia. ILS initially co-marketed non-military launches on both the American Atlas and the Russian Proton expendable launch vehicles. With the Atlas V launch of the SES Astra 1KR satellite on 20 April 2006, ILS had made 100 launches, 97 of which were successful. In September 2006, Lockheed-Martin announced its intention to sell its ownership interests in Lockheed Khrunichev Energia International, Inc. (LKEI) and International Launch Services, Inc. (ILS) to Space Transport Inc. Space Transport Inc. was formed specifically for this transaction by Mario Lemme, who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baikonur Cosmodrome Site 200
Site 200 at the Baikonur Cosmodrome is a launch site used by Proton rockets. It consists of two launch pads, areas 39 and 40. Area 39 is currently (as of 2021) used for Proton-M launches, including commercial flights conducted by International Launch Services. Area 40 is currently (as of 2021) inactive, as it was slated to be rebuilt as a launch site for the Angara rocket. Although the project was relocated to Site 250, Area 40 was not put back into service. A number of planetary probes have been launched from Site 200. Venera 14, Venera 15, Vega 1, Fobos 1, the failed Mars-96, and ExoMars were launched from area 39. Venera 13, Venera 16, Vega 2, Fobos 2 were launched from Area 40. Area 39 was also the launch site for the core of the Mir space station, along with both Kvant modules, and the Kristall module. Salyut 7 and Granat The International Astrophysical Observatory "GRANAT" (usually known as Granat; russian: Гранат, lit. ''pomegranate''), was a Soviet (later Russi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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