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NigComSat-1
NigComSat-1 was a Nigerian communication satellite. The initial contract to build the satellite was signed in 2004. It was launched in China by Nasrda and became the third African geosynchronous communication satellite, when it was launched at 16:01 UTC on 13 May 2007, aboard a Chinese Long March 3B carrier rocket, from the Xichang Satellite Launch Centre in China. The spacecraft was operated by Nigerian Communications Satellite Ltd (NIGCOMSAT). On November 11, 2008, NigComSat-1 failed in orbit after running out of power due to an anomaly in its solar array. Launch The satellite, which is the third Nigerian satellite to be placed into orbit, was launched into a geosynchronous transfer orbit and subsequently it was successfully inserted into a geosynchronous orbit, positioned at 42.5oE. It had a launch mass of 5,150 kg, and had an expected service life of 15 years. Specifications It was based on the Chinese DFH-4 satellite bus, and carries a variety of transponders: *4 C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Space Research And Development Agency
The National Space Research and Development Agency (NASRDA) is the national space agency of Nigeria. It is a parastatal under Federal Ministry of Science and Technology. The agency is based in the Nigerian capital city of Abuja in the Lugbe district and has a ground receiving station, among various other sites. It has had cooperation in space technology with the United Kingdom, China, Ukraine and Russia. The agency has struggled with meeting its financial plans and some of its facilities are rundown. Despite this, the space agency is one of the most advanced space agencies in Africa, boasting of four satellites and very grand ambitions. Nigeria's satellites have been praised for their high-resolution images. NASRDA is host to one of UN-SPIDER's Regional Support Offices (RSO) in Africa. History NASRDA was established on 5 May 1999, after a preparation period since in 1998 by Nigerian president Olusegun Obasanjo and the Nigerian government with a primary objective of establishing a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NIGCOMSAT
Nigerian Communications Satellite (NIGCOMSAT) Limited is a company under the supervision of the Federal Ministry of Communications. Satellites NigComSat-1 NigComSat-1, a Nigerian satellite ordered and built in China in 2004, was Nigeria's second satellite and Africa's first communication satellite. It was launched on 13 May 2007, aboard a Chinese Long March 3B carrier rocket, from the Xichang Satellite Launch Centre in China. The spacecraft was operated by NigComSat and the Nigerian Space Agency, NASRDA. On 11 November 2008, NigComSat-1 failed in orbit after running out of power due to an anomaly in its solar array. It was based on the Chinese DFH-4 satellite bus, and carries a variety of transponders: 4 C band; 14 Ku band; 8 Ka band; and 2 L band. It was designed to provide coverage to many parts of Africa, and the Ka band transponders would also cover Italy. On 10 November 2008 (0900 GMT), the satellite was reportedly switched off for analysis and to avoid a possible col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long March 3B
The Long March 3B (, ''Chang Zheng 3B''), also known as the CZ-3B and LM-3B, is a Chinese orbital launch vehicle. Introduced in 1996, it is launched from Launch Area 2 and 3 at the Xichang Satellite Launch Center in Sichuan. A three-stage rocket with four strap-on liquid rocket boosters, it is currently the second most powerful member of the Long March (rocket family), Long March rocket family after the Long March 5 and the heaviest of the Long March 3 rocket family, and is mainly used to place communications satellites into geosynchronous orbits. An enhanced version, the Long March 3B/E or G2, was introduced in 2007 to increase the rocket's geostationary transfer orbit (GTO) cargo capacity and lift heavier geosynchronous orbit (GEO) communications satellites. The Long March 3B also served as the basis for the medium-capacity Long March 3C, which was first launched in 2008. , the Long March 3B, 3B/E and 3B/G5 have conducted 82 successful launches, plus 2 failures and 2 partial ... [...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] |
Orbit
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a planet, moon, asteroid, or Lagrange point. Normally, orbit refers to a regularly repeating trajectory, although it may also refer to a non-repeating trajectory. To a close approximation, planets and satellites follow elliptic orbits, with the center of mass being orbited at a focal point of the ellipse, as described by Kepler's laws of planetary motion. For most situations, orbital motion is adequately approximated by Newtonian mechanics, which explains gravity as a force obeying an inverse-square law. However, Albert Einstein's general theory of relativity, which accounts for gravity as due to curvature of spacetime, with orbits following geodesics, provides a more accurate calculation and understanding of the exact mechanics of orbi ... [...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] |
Communications In Nigeria
Nigeria is Africa's largest ICT market, accounting for 82% of the continent's telecoms subscribers and 29% of internet usage. Globally, Nigeria ranks 11th in the absolute number of internet users and 7th in the absolute number of mobile phones. Economically, the ICT sector has contributed over 10% to Nigeria's gross national product for over 10 years. Telecommunications in Nigeria include radio, television, fixed and mobile telephones, and the Internet. Radio and television Nigeria's media scene is one of the most vibrant in Africa. Television and radio remain the most important medium of mass communication and information, with Social media rapidly emerging as the next big medium. International broadcasters, including the BBC, are popular."Nigeria Profile" ''BBC News'', 12 September 2013. There are near ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agence France-Presse
Agence France-Presse (AFP) is a French international news agency headquartered in Paris, France. Founded in 1835 as Havas, it is the world's oldest news agency. AFP has regional headquarters in Nicosia, Montevideo, Hong Kong and Washington, D.C., and news bureaus in 151 countries in 201 locations. AFP transmits stories, videos, photos and graphics in French, English, Arabic, Portuguese, Spanish, and German. History Agence France-Presse has its origins in the Agence Havas, founded in 1835 in Paris by Charles-Louis Havas, making it the world's oldest news service. The agency pioneered the collection and dissemination of news as a commodity, and had established itself as a fully global concern by the late 19th century. Two Havas employees, Paul Julius Reuter and Bernhard Wolff, set up their own news agencies in London and Berlin respectively. In 1940, when German forces occupied France during World War II, the news agency was taken over by the authorities and renamed "Office fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L Band
The L band is the Institute of Electrical and Electronics Engineers (IEEE) designation for the range of frequencies in the radio spectrum from 1 to 2 gigahertz (GHz). This is at the top end of the ultra high frequency (UHF) band, at the lower end of the microwave range. Applications Mobile service In Europe, the Electronic Communications Committee (ECC) of the European Conference of Postal and Telecommunications Administrations (CEPT) has harmonized part of the L band (1452–1492 MHz), allowing individual countries to adopt this spectrum for terrestrial mobile/fixed communications networks supplemental downlink (MFCN SDL). By means of carrier aggregation, an LTE-Advanced or UMTS/HSDPA base station could use this spectrum to provide additional bandwidth for communications from the base station to the mobile device; i.e., in the downlink direction. In the Americas, mobile services are operated between the 1.7 GHz to 2.1 GHz range in the PCS and AWS bands. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Band (IEEE)
The C band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 4.0 to 8.0 gigahertz (GHz). However, the U.S. Federal Communications Commission C band proceeding and auction, designated 3.7–4.2 GHz as C band. The C band is used for many satellite communications transmissions, some Wi-Fi devices, some cordless telephones, as well as some Radar and weather radar systems. Use in satellite communication The communications C band was the first frequency band that was allocated for commercial telecommunications via satellites. The same frequencies were already in use for terrestrial microwave radio relay chains. Nearly all C-band communication satellites use the band of frequencies from 3.7 to 4.2 GHz for their downlinks, and the band of frequencies from 5.925 to 6.425 GHz for their uplinks. Note that by using the band from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transponder
In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend word, blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a Transponder (aeronautics), 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 Transponder (satellite communications), 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 Communication channel, channels are called transponders because each is a separate transceiver or repeater. With digital video d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
