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Westar 6
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 c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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, Analemma#Of geosynchronous satellites, typically in a figure-8 form, whose precise characteristics depend on the orbit's Orbital inclination, inclination and Orbital eccentricity, eccentricity. A circular geosynchronous orbit has a constant altitude of . A special case of geosynchronous orbit is the geostationary orbit (often abbreviated ''GEO''), which is a circular geosynchronous orbit in Earth's equatorial plane with both inclination and eccentricity equal to 0. A satelli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Low Earth Orbit
A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, peaking in number at an altitude around , while the farthest in LEO, before medium Earth orbit (MEO), have an altitude of 2,000 km, about one-third of the Earth radius, radius of Earth and near the beginning of the Van Allen radiation belt#Inner belt, inner Van Allen radiation belt. The term ''LEO region'' is 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 spaceflight, sub-orbital, are carefully tracked since they present a collision risk to the many LEO satellites. No human spaceflights other than the lunar missions of the Apollo program (1968-1972) have gone beyond L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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 inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Telecommunications
Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of transmission may be divided into communication channels for multiplexing, allowing for a single medium to transmit several concurrent Session (computer science), communication sessions. Long-distance technologies invented during the 20th and 21st centuries generally use electric power, and include the electrical telegraph, telegraph, telephone, television, and radio. Early telecommunication networks used metal wires as the medium for transmitting signals. These networks were used for telegraphy and telephony for many decades. In the first decade of the 20th century, a revolution in wireless communication began with breakthroughs including those made in radio communications by Guglielmo Marconi, who won the 1909 Nobel Prize in Physics. Othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Lloyd's Of London
Lloyd's of London, generally known simply as Lloyd's, is a 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", include both corporations and private individuals, the latter being traditionally known as "Names". The business underwritten at Lloyd's is predominantly general insurance and reinsurance, with a small amount of term life insurance. The market has its roots in marine insurance and was founded by Edward Lloyd at his coffee-house on Tower Street 1689, making it one of the oldest insurance companies in the world. Today, it has a dedicated building on Lime Street, a Grade I historic landmar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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 protect 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 o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Payload (air And Space Craft)
Payload is the object or the entity that 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. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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). The first satellite was launched 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 (equivalent to $ in ). History The first satellite, Palapa-A1 of , was launched on 8 July 1976 at 23:31 UTC from the 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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 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. ... into geosynchronous transfer orbits. It was complemented and later replaced by the more powerful Long March 3A, 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 temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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 originally launched in February 1984 as Westar 6, but following a booster motor failure it was retrieved and returned to Earth in November of that year by Space Shuttle mission STS-51-A. After being sold to AsiaSat and refurbished, it was relaunched in April 1990, and 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. Westar 6 As Westar 6, the satellite was built by Hughes Space and Communications. It was based on the HS-376 satellite bus. At launch it had a mass of , and a design life of thirteen years. It carried twenty four C-band transponders. After launch from the Space Shuttle as part of mission STS-4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hong Kong
Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the world. Hong Kong was established as a colony of the British Empire after the Qing dynasty ceded Hong Kong Island in 1841–1842 as a consequence of losing the First Opium War. The colony expanded to the Kowloon Peninsula in 1860 and was further extended when the United Kingdom obtained a 99-year lease of the New Territories in 1898. Hong Kong was occupied by Japan from 1941 to 1945 during World War II. The territory was handed over from the United Kingdom to China in 1997. Hong Kong maintains separate governing and economic systems from that of mainland China under the principle of one country, two systems. Originally a sparsely populated area of farming and fishing villages,. the territory is now one of the world's most signific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
AsiaSat
Asia Satellite Telecommunications Company Limited (AsiaSat) is a Hong Kong–based commercial operator of communications satellites founded in 1988. It is a wholly-owned subsidiary of Asia Satellite Telecommunications Holdings Limited (AsiaSat Holdings), which is incorporated in Bermuda. AsiaSat Holdings is jointly owned by Chinese state-owned CITIC Limited and private equity fund The Carlyle Group L.P. indirectly. It had a market capitalisation of HK$2 billion on 30 November 2018. It was a red chip Red chip stocks () are the stocks of mainland China companies incorporated outside mainland China and listed in Hong Kong. It refers to businesses based in mainland China and with (majority) shares controlled either directly or indirectly by a ... company of the stock exchange. On 23 August 2019, the take private proposal scheme was approved by AsiaSat Holdings' public shareholders, followed by the approval of the Bermuda Court on 3 September 2019, whereupon The company bec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
