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Westar (other)
Westar was a fleet of geosynchronous communications satellites operating in the C band which were launched by Western Union from 1974 to 1984. There were seven Westar satellites in all, with five of them launched and operating under the Westar name. Background Westar 1 (launched on April 13, 1974) has the distinction of being the USA's first commercially launched geosynchronous communications satellite, following North America's first geosynchronous communications satellite, Canada's Anik A1 in 1972. Westar 1 was put into orbit at 99° W in the Clarke belt (99° W now being the home of Galaxy 16). Westar 2 was launched shortly afterward on October 10, 1974. Westar 3, the first satellite to use TDMA switched data, was launched on August 10, 1979. Westars 1, 2 and 3 were built by Hughes using the HS 333 platform of spin-scan stabilized satellites. They only had 12 transponders on board, as opposed to later C-band communications satellites having 24, and even contem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geosynchronous
A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital period means that, for an observer on Earth's surface, an object in geosynchronous orbit returns to exactly the same position in the sky after a period of one sidereal day. Over the course of a day, the object's position in the sky may remain still or trace out a path, typically in a figure-8 form, whose precise characteristics depend on the orbit's inclination and eccentricity. A circular geosynchronous orbit has a constant altitude of . A special case of geosynchronous orbit is the geostationary orbit, which is a circular geosynchronous orbit in Earth's equatorial plane with both inclination and eccentricity equal to 0. A satellite in a geostationary orbit remains in the same position in the sky to observers on the surface. Communi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low Earth Orbit
A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never more than about one-third of the radius of Earth. The term ''LEO region'' is also used for the area of space below an altitude of (about one-third of Earth's radius). Objects in orbits that pass through this zone, even if they have an apogee further out or are sub-orbital, are carefully tracked since they present a collision risk to the many LEO satellites. All crewed space stations to date have been within LEO. From 1968 to 1972, the Apollo program's lunar missions sent humans beyond LEO. Since the end of the Apollo program, no human spaceflights have been beyond LEO. Defining characteristics A wide variety of sources define LEO in terms of altitude. The altitude of an object in an elliptic orbit can vary significantly along the orbit. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth Station
A ground station, Earth station, or Earth terminal is a terrestrial radio station designed for extraplanetary telecommunication with spacecraft (constituting part of the ground segment of the spacecraft system), or reception of radio waves from astronomical radio sources. Ground stations may be located either on the surface of the Earth, or in its atmosphere. Earth stations communicate with spacecraft by transmitting and receiving radio waves in the super high frequency (SHF) or extremely high frequency (EHF) bands (e.g. microwaves). When a ground station successfully transmits radio waves to a spacecraft (or vice versa), it establishes a telecommunications link. A principal telecommunications device of the ground station is the parabolic antenna. Ground stations may have either a fixed or itinerant position. Article 1 § III of the International Telecommunication Union (ITU) Radio Regulations describes various types of stationary and mobile ground stations, and their interre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that feasible with the human voice, but with a similar scale of expediency; thus, slow systems (such as postal mail) are excluded from the field. The transmission media in telecommunication have evolved through numerous stages of technology, from beacons and other visual signals (such as smoke signals, semaphore telegraphs, signal flags, and optical heliographs), to electrical cable and electromagnetic radiation, including light. Such transmission paths are often divided into communication channels, which afford the advantages of multiplexing multiple concurrent communication sessions. ''Telecommunication'' is often used in its plural form. Other examples of pre-modern long-distance communication included audio messages, such as coded drumb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lloyd's Of London
Lloyd's of London, generally known simply as Lloyd's, is an insurance and reinsurance market located in London, England. Unlike most of its competitors in the industry, it is not an insurance company; rather, Lloyd's is a corporate body governed by the Lloyd's Act 1871 and subsequent Acts of Parliament. It operates as a partially-mutualised marketplace within which multiple financial backers, grouped in syndicates, come together to pool and spread risk. These underwriters, or "members", are a collection of both corporations and private individuals, the latter being traditionally known as "Names". The business underwritten at Lloyd's is predominantly general insurance and reinsurance, although a small number of syndicates write term life insurance. The market has its roots in marine insurance and was founded by Edward Lloyd at his coffee house on Tower Street in 1688. Today, it has a dedicated building on Lime Street which is Grade I listed. Traditionally business is tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insurance
Insurance is a means of protection from financial loss in which, in exchange for a fee, a party agrees to compensate another party in the event of a certain loss, damage, or injury. It is a form of risk management, primarily used to hedge against the risk of a contingent or uncertain loss. An entity which provides insurance is known as an insurer, insurance company, insurance carrier, or underwriter. A person or entity who buys insurance is known as a policyholder, while a person or entity covered under the policy is called an insured. The insurance transaction involves the policyholder assuming a guaranteed, known, and relatively small loss in the form of a payment to the insurer (a premium) in exchange for the insurer's promise to compensate the insured in the event of a covered loss. The loss may or may not be financial, but it must be reducible to financial terms. Furthermore, it usually involves something in which the insured has an insurable interest established by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Payload (air And Space Craft)
Payload is the object or the entity which is being carried by an aircraft or launch vehicle. Sometimes payload also refers to the carrying capacity of an aircraft or launch vehicle, usually measured in terms of weight. Depending on the nature of the flight or mission, the payload of a vehicle may include cargo, passengers, flight crew, munitions, scientific instruments or experiments, or other equipment. Extra fuel, when optionally carried, is also considered part of the payload. In a commercial context (i.e., an airline or air freight carrier), payload may refer only to revenue-generating cargo or paying passengers. A payload of ordnance carried by a combat aircraft is sometimes alternatively referred to as the aircraft's warload. For a rocket, the payload can be a satellite, space probe, or spacecraft carrying humans, animals, or cargo. For a ballistic missile, the payload is one or more warheads and related systems; their total weight is referred to as the throw-weight. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palapa B2
Palapa is a series of Communications satellites owned by Indosat, an Indonesian telecommunications company (formerly by Perumtel and then by PT Satelit Palapa Indonesia/Satelindo). Starting with the first in July 1976, at which time Indonesia became the first developing country to operate its own domestic satellite system. The estimated cost for the project was US$1 billion. History The first satellite, Palapa-A1 of , was launched on 8 July 1976 at 23:31 UTC from Kennedy Space Center by a Delta 2914 launch vehicle, or at 06:31 Indonesian Time on 9 July 1976. Palapa-A2 was launched on 10 March 1977. The name "Palapa" was bestowed by then Indonesian President Suharto, after the Palapa oath sworn by Gajah Mada, the Prime Minister of Majapahit Kingdom, in 1334. According to the Pararaton (Book of Kings), Gajah Mada swore that he would not taste any ''palapa'' (historians suggest it refers to spice or a kind of flavouring), as long as he had not succeeded in unifying N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long March 3
The Long March 3 (), also known as the Changzheng 3, CZ-3 and LM-3, was a Chinese orbital carrier rocket design. They were all launched from Launch Area 3 at the Xichang Satellite Launch Center. It was a three-stage rocket, and was mostly used to place DFH-2-class communications satellites into geosynchronous transfer orbits. It was complemented and later replaced by the more powerful Long March 3A The Long March 3A (), also known as the Chang Zheng 3A, CZ-3A and LM-3A, is a Chinese orbital carrier rocket design. It is a 3-stage rocket, and is usually used to place communications satellites and Beidou navigation satellites into geosynchron ..., which has an improved third stage. List of launches Launch failures Dong Fang Hong 2 launch failure On January 29, 1984, a LM-3 rocket failed during launch. The third stage failed 4 s after restart for GTO insertion of the satellite, due to incorrect mixture ratio in the engine gas generator, which caused high temperatures a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AsiaSat 1
AsiaSat 1 was a Hong Kong communications satellite, which was owned, and was operated, by the Hong Kong based Asia Satellite Telecommunications Company. It was positioned in geostationary orbit at a longitude of 100.5° East. It spent its operational life at 100.5° East, from where it was used to provide fixed satellite services, including broadcasting, audio and data transmission, to Asia and the Pacific Ocean. Satellite description AsiaSat 1 was built by Hughes Space and Communications. It is based on the HS-376 satellite bus. At launch, it had a mass of , and a design life of thirteen years. It carries twenty four C-band transponders. Launch The launch of AsiaSat 1 was contracted to the China Great Wall Industry Corporation (CGWIC), and used a Long March 3 launch vehicle. The launch was conducted from Xichang Launch Area 3 (LA-3) at the Xichang Satellite Launch Centre at 13:30:02 UTC on 7 April 1990. Westar 6 Westar 6 was launched from the space shuttle in Februa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hong Kong
Hong Kong ( (US) or (UK); , ), officially the Hong Kong Special Administrative Region of the People's Republic of China ( abbr. Hong Kong SAR or HKSAR), is a city and special administrative region of China on the eastern Pearl River Delta in South China. With 7.5 million residents of various nationalities in a territory, Hong Kong is one of the most densely populated places in the world. Hong Kong is also a major global financial centre and one of the most developed cities in the world. Hong Kong was established as a colony of the British Empire after the Qing Empire ceded Hong Kong Island from Xin'an County at the end of the First Opium War in 1841 then again in 1842.. The colony expanded to the Kowloon Peninsula in 1860 after the Second Opium War and was further extended when Britain obtained a 99-year lease of the New Territories in 1898... British Hong Kong was occupied by Imperial Japan from 1941 to 1945 during World War II; British administration resume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AsiaSat
Asia Satellite Telecommunications Holdings Limited, known by its brand name AsiaSat, is a commercial operator of communication spacecraft. AsiaSat, based in Hong Kong, is incorporated in Bermuda. AsiaSat is jointly owned by Chinese state-owned CITIC Limited and private equity fund The Carlyle Group L.P. indirectly. It had a market capitalization of HK$2 billion on 30 November 2018. It was a red chip company of the stock exchange. On 23 August 2019, the take private proposal scheme was approved by AsiaSat's public shareholders, followed by the approval of the Bermuda Court on 3 September 2019, whereupon the Company became a private wholly owned subsidiary of Bowenvale Limited, a joint venture of CITIC and Carlyle. The listing of the company's shares was withdrawn from the Stock Exchange of Hong Kong on 5 September 2019. History In September 2017, AsiaSat 9, AsiaSat's latest satellite built by Space Systems/Loral was successfully launched and replaced AsiaSat 4 at 122° East. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
