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BSAT-3a
BSAT-3a, is a geostationary communications satellite operated by Broadcasting Satellite System Corporation (B-SAT) which was designed and manufactured by Lockheed Martin on the A2100 platform. It is stationed on the 110,0° East orbital slot with its companion BSAT-3b and BSAT-3c from where they provide redundant high definition direct television broadcasting across Japan. History On 27 April 2005, Lockheed Martin announced that it had been granted by B-SAT an authorisation to proceed to the construction of its first third generation broadcasting satellite, BSAT-3a. On 18 May 2005, both companies announced the signature of the definitive contract for the satellite. It would be based on the A2100 platform, sport eight 130 watts Ku-band transponders (plus 4 spares), have a design life of 13 years and have a 1.8 kW power generation capability. It was expected launch in the second quarter of 2007 to be co-located at the 110.0° East orbital position. On 15 June 2005, Arian ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-definition Television
High-definition television (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the generation following standard-definition television (SDTV), often abbreviated to HDTV or HD-TV. It is the current de facto standard video format used in most broadcasts: terrestrial broadcast television, cable television, satellite television and Blu-ray Discs. Formats HDTV may be transmitted in various formats: * 720p (1280 horizontal pixels × 720 lines): 921,600 pixels * 1080i (1920×1080) interlaced scan: 1,036,800 pixels (~1.04 MP). * 1080p (1920×1080) progressive scan: 2,073,600 pixels (~2.07 MP). ** Some countries also use a non-standard CEA resolution, such as 1440×1080i: 777,600 pixels (~0.78 MP) per field or 1,555,200 pixels (~1.56 MP) per frame When transmitted at two megapixels per frame, HDTV provides about five times ... [...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 n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airbus
Airbus SE (; ; ; ) is a European multinational aerospace corporation. Airbus designs, manufactures and sells civil and military aerospace products worldwide and manufactures aircraft throughout the world. The company has three divisions: '' Commercial Aircraft (Airbus S.A.S.)'', '' Defence and Space'', and '' Helicopters'', the third being the largest in its industry in terms of revenues and turbine helicopter deliveries. As of 2019, Airbus is the world's largest airliner manufacturer. The company's main civil aeroplane business is conducted through the French company Airbus S.A.S., based in Blagnac, a suburb of Toulouse, with production and manufacturing facilities mostly in the European Union and the United Kingdom but also in China, the United States and Canada. Final assembly production is based in Toulouse, France; Hamburg, Germany; Seville, Spain; Tianjin, China; Mobile, United States; and Montreal, Canada. The company produces and markets the first commercially ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spaceway-3
Spaceway-3 is a communications satellite which was launched in August 2007. The third satellite in the Spaceway series, it includes a Ka-band communications payload. It is used by Hughes Network Systems to provide broadband Internet Protocol network service. History In March 2007, shortly after the failure of a Sea Launch rocket launch in January 2007, Hughes Network Systems switched launch of Spaceway-3 from a Zenit-3SL rocket to an Ariane 5 launch vehicle. Launch Spaceway-3 was launched 14 August 2007 on an Ariane 5 launch vehicle with BSAT-3a. It lifted off at 23:44 UTC from ELA-3 of the Centre Spatial Guyanais. Five hours and 46 minutes later, signals from the spacecraft were successfully received at a ground station in Hartebeesthoek, South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ariane 5
Ariane 5 is a European heavy-lift space launch vehicle developed and operated by Arianespace for the European Space Agency (ESA). It is launched from the Centre Spatial Guyanais (CSG) in French Guiana. It has been used to deliver payloads into geostationary transfer orbit (GTO) or low Earth orbit (LEO). The launch vehicle had a streak of 82 consecutive successful launches between 9 April 2003 and 12 December 2017. Since 2014, Ariane 6, a direct successor system, is in development. The system was designed as an expendable launch system by the '' Centre national d'études spatiales'' (CNES), the French government's space agency, in cooperation with various European partners. Despite not being a direct derivative of its predecessor launch vehicle program, it is classified as part of the Ariane rocket family. ArianeGroup is the prime contractor for the manufacturing of the vehicles, leading a multi-country consortium of other European contractors. Ariane 5 was originally inten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JCSAT-11
JCSAT-11, was a geostationary communications satellite ordered by JSAT Corporation (now SKY Perfect JSAT Group) which was designed and manufactured by Lockheed Martin on the A2100 platform. The satellite was designated to be used as an on-orbit, but was lost on launch failure. Satellite description The spacecraft was designed and manufactured by Lockheed Martin on the A2100AX satellite bus. It had a launch mass of and a 15-year design life. A near copy of JCSAT-3A, it was to be used as an on orbit spare. As most satellites based on the A2100 platform, it uses a LEROS-1C LAE for orbit raising. Its solar panels span when fully deployed and, with its antennas in fully extended configuration it is wide. Its payload is composed of eighteen 27 MHz and twelve 36 MHz Ku band plus twelve C band transponders, for a total bandwidth of 1,350 MHz. Its high-power amplifiers had an output power of 127 Watts on Ku band and 48 Watts on C band. History On Octo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Watt (1736–1819), an 18th-century Scottish inventor, mechanical engineer, and chemist who improved the Newcomen engine with his own steam engine in 1776. Watt's invention was fundamental for the Industrial Revolution. Overview When an object's velocity is held constant at one metre per second against a constant opposing force of one newton, the rate at which work is done is one watt. : \mathrm In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the volt-ampere (the latter unit, however, is used for a different quantity from the real power of an electrical cir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traveling-wave Tube
A traveling-wave tube (TWT, pronounced "twit") or traveling-wave tube amplifier (TWTA, pronounced "tweeta") is a specialized vacuum tube that is used in electronics to amplify radio frequency (RF) signals in the microwave range. The TWT belongs to a category of "linear beam" tubes, such as the klystron, in which the radio wave is amplified by absorbing power from a beam of electrons as it passes down the tube. Although there are various types of TWT, two major categories are: *''Helix TWT'' - in which the radio waves interact with the electron beam while traveling down a wire helix which surrounds the beam. These have wide bandwidth, but output power is limited to a few hundred watts. *''Coupled cavity TWT'' - in which the radio wave interacts with the beam in a series of cavity resonators through which the beam passes. These function as narrowband power amplifiers. A major advantage of the TWT over some other microwave tubes is its ability to amplify a wide range of frequencies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Maneuver
In spaceflight, an orbital maneuver (otherwise known as a burn) is the use of propulsion systems to change the orbit of a spacecraft. For spacecraft far from Earth (for example those in orbits around the Sun) an orbital maneuver is called a ''deep-space maneuver (DSM)''. The rest of the flight, especially in a transfer orbit, is called ''coasting''. General Rocket equation The Tsiolkovsky rocket equation, or ideal rocket equation is an equation that is useful for considering vehicles that follow the basic principle of a rocket: where a device that can apply acceleration to itself (a thrust) by expelling part of its mass with high speed and moving due to the conservation of momentum. Specifically, it is a mathematical equation that relates the delta-v (the maximum change of speed of the rocket if no other external forces act) with the effective exhaust velocity and the initial and final mass of a rocket (or other reaction engine.) For any such maneuver (or journey invo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LEROS
Leros ( el, Λέρος) is a Greek island and municipality in the Dodecanese in the southern Aegean Sea. It lies (171 nautical miles) from Athens's port of Piraeus, from which it can be reached by an 9-hour ferry ride or by a 45-minute flight from Athens, and about 20 miles to Turkey. Leros is part of the Kalymnos regional unit. The island has been also called in it, Lero. This island has population of 7,988 Geography The municipality has an area of . The municipality includes the populated offshore island of Farmakonisi (pop. 10), as well as several uninhabited islets, including Levitha and Kinaros, and had a 2011 census population of 7,917, although this figure swells to over 15,000 during the summer peak. The island has a coastline of . It is known for its imposing medieval castle of the Knights of Saint John possibly built on a Byzantine fortress. Nearby islands are Patmos, Lipsi, Kalymnos, and the small islands of Agia Kyriaki and Farmakos. In ancient times ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
