Communications satellite

785:(COMSAT) private corporation, which was subject to instruction by the US Government on matters of national policy. Over the next two years, international negotiations led to the Intelsat Agreements, which in turn led to the launch of Intelsat 1, also known as Early Bird, on 6 April 1965, and which was the first commercial communications satellite to be placed in geosynchronous orbit. Subsequent Intelsat launches in the 1960s provided multi-destination service and video, audio, and data service to ships at sea (Intelsat 2 in 1966–67), and the completion of a fully global network with Intelsat 3 in 1969–70. By the 1980s, with significant expansions in commercial satellite capacity, Intelsat was on its way to become part of the competitive private telecommunications industry, and had started to get competition from the likes of 817: 874:(GEO), which is 22,236 miles (35,785 km) from Earth's surface. This orbit has the special characteristic that the apparent position of the satellite in the sky when viewed by a ground observer does not change, the satellite appears to "stand still" in the sky. This is because the satellite's orbital period is the same as the rotation rate of the Earth. The advantage of this orbit is that ground antennas do not have to track the satellite across the sky, they can be fixed to point at the location in the sky the satellite appears. 4266: 51: 635: 6184: 5337: 4000: 1039:, was launched. It was a medium Earth orbit satellite designed to help facilitate high-speed telephone signals. Although it was the first practical way to transmit signals over the horizon, its major drawback was soon realised. Because its orbital period of about 2.5 hours did not match the Earth's rotational period of 24 hours, continuous coverage was impossible. It was apparent that multiple MEOs needed to be used in order to provide continuous coverage. 6195: 1531: 20: 5347: 379: 5326: 4256: 1018:

between 2 and 8 hours. MEO satellites have a larger coverage area than LEO satellites. A MEO satellite's longer duration of visibility and wider footprint means fewer satellites are needed in a MEO network than a LEO network. One disadvantage is that a MEO satellite's distance gives it a longer time delay and weaker signal than a LEO satellite, although these limitations are not as severe as those of a GEO satellite.

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continuous communications capability with these lower orbits requires a larger number of satellites, so that one of these satellites will always be visible in the sky for transmission of communication signals. However, due to their closer distance to the Earth, LEO or MEO satellites can communicate to ground with reduced latency and at lower power than would be required from a geosynchronous orbit.

627:. Military planners had long shown considerable interest in secure and reliable communications lines as a tactical necessity, and the ultimate goal of this project was the creation of the longest communications circuit in human history, with the Moon, Earth's natural satellite, acting as a passive relay. After achieving the first transoceanic communication between 1589:, where no submarine cables are in service, need satellite telephones. There are also regions of some continents and countries where landline telecommunications are rare to non existent, for example large regions of South America, Africa, Canada, China, Russia, and Australia. Satellite communications also provide connection to the edges of 731:. After an initial failure in 1961, a launch on 9 May 1963 dispersed 350 million copper needle dipoles to create a passive reflecting belt. Even though only about half of the dipoles properly separated from each other, the project was able to successfully experiment and communicate using frequencies in the 1285:

The Molniya orbit is designed so that the satellite spends the great majority of its time over the far northern latitudes, during which its ground footprint moves only slightly. Its period is one half day, so that the satellite is available for operation over the targeted region for six to nine hours

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The definitions of FSS and DBS satellites outside of North America, especially in Europe, are a bit more ambiguous. Most satellites used for direct-to-home television in Europe have the same high power output as DBS-class satellites in North America, but use the same linear polarization as FSS-class

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Satellite phone systems can be accomplished by a number of means. On a large scale, often there will be a local telephone system in an isolated area with a link to the telephone system in a main land area. There are also services that will patch a radio signal to a telephone system. In this example,

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In the United States, the National Polar-orbiting Operational Environmental Satellite System (NPOESS) was established in 1994 to consolidate the polar satellite operations of NASA (National Aeronautics and Space Administration) NOAA (National Oceanic and Atmospheric Administration). NPOESS manages a

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Because of their low altitude, these satellites are only visible from within a radius of roughly 1,000 kilometres (620 mi) from the sub-satellite point. In addition, satellites in low Earth orbit change their position relative to the ground position quickly. So even for local applications, many

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As satellites in MEO and LEO orbit the Earth faster, they do not remain visible in the sky to a fixed point on Earth continually like a geostationary satellite, but appear to a ground observer to cross the sky and "set" when they go behind the Earth beyond the visible horizon. Therefore, to provide

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Molniya orbits can be an appealing alternative in such cases. The Molniya orbit is highly inclined, guaranteeing good elevation over selected positions during the northern portion of the orbit. (Elevation is the extent of the satellite's position above the horizon. Thus, a satellite at the horizon

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was launched on 4 October 1960 to explore whether it would be possible to establish a global military communications network by using "delayed repeater" satellites, which receive and store information until commanded to rebroadcast them. After 17 days, a command system failure ended communications

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the signal coming from the source, toward the direction of the receiver. With passive satellites, the reflected signal is not amplified at the satellite, and only a small amount of the transmitted energy actually reaches the receiver. Since the satellite is so far above Earth, the radio signal is

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that worked on two frequencies of 20.005 and 40.002 MHz, or 7 and 15 meters wavelength. The satellite was not placed in orbit to send data from one point on Earth to another, but the radio transmitter was meant to study the properties of radio wave distribution throughout the ionosphere. The

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A medium Earth orbit is a satellite in orbit somewhere between 2,000 and 35,786 kilometres (1,243 and 22,236 mi) above the Earth's surface. MEO satellites are similar to LEO satellites in functionality. MEO satellites are visible for much longer periods of time than LEO satellites, usually

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It is also possible to offer discontinuous coverage using a low-Earth-orbit satellite capable of storing data received while passing over one part of Earth and transmitting it later while passing over another part. This will be the case with the CASCADE system of Canada's

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and so are obstructed by the curve of the Earth. The purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated geographical points. Communications satellites use a wide range of radio and

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or dish antennas. Due to launch costs, most current amateur satellites are launched into fairly low Earth orbits, and are designed to deal with only a limited number of brief contacts at any given time. Some satellites also provide data-forwarding services using the

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These orbits are Sun synchronous, meaning that they cross the equator at the same local time each day. For example, the satellites in the NPOESS (civilian) orbit will cross the equator, going from south to north, at times 1:30 P.M., 5:30 P.M., and 9:30 P.M.

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The bandwidth available from a satellite depends upon the number of transponders provided by the satellite. Each service (TV, Voice, Internet, radio) requires a different amount of bandwidth for transmission. This is typically known as link budgeting and a

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active communications satellite was launched on 11 February 1965 to explore the feasibility of active solid-state X band long-range military communications. A total of nine satellites were launched between 1965 and 1976 as part of this series.

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used by DBS satellites), but this is a minor technical difference that users do not notice. FSS satellite technology was also originally used for DTH satellite TV from the late 1970s to the early 1990s in the United States in the form of

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Geostationary satellites must operate above the equator and therefore appear lower on the horizon as the receiver gets farther from the equator. This will cause problems for extreme northerly latitudes, affecting connectivity and causing

650:(ARPA) and launched on 18 December 1958, which used a tape recorder to carry a stored voice message, as well as to receive, store, and retransmit messages. It was used to send a Christmas greeting to the world from U.S. President 511:. To avoid signal interference, international organizations have regulations for which frequency ranges or "bands" certain organizations are allowed to use. This allocation of bands minimizes the risk of signal interference. 1901:

operators have access to amateur satellites, which have been designed specifically to carry amateur radio traffic. Most such satellites operate as spaceborne repeaters, and are generally accessed by amateurs equipped with

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Within these regions, frequency bands are allocated to various satellite services, although a given service may be allocated different frequency bands in different regions. Some of the services provided by satellites are:

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is an equivalent ESA project that is stated to be compatible and providing navigational services for the lunar surface. Both programmes are satellite constellstions of several satellites in various orbits around the Moon.

757:, launched on 19 July 1964, was the first geostationary communications satellite. Syncom 3 obtained a geosynchronous orbit, without a north–south motion, making it appear from the ground as a stationary object in the sky. 3342: 1447:

Command and Control subsystem, which maintains communications with ground control stations. The ground control Earth stations monitor the satellite performance and control its functionality during various phases of its

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signals. Communication signals were bounced off the satellite from one point on Earth to another. This experiment sought to establish the feasibility of worldwide broadcasts of telephone, radio, and television signals.

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technology as a reference, these antennas automatically re-aim to the satellite no matter where or how the vehicle (on which the antenna is mounted) is situated. These mobile satellite antennas are popular with some

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Thus, for areas close to the North (and South) Pole, a geostationary satellite may appear below the horizon. Therefore, Molniya orbit satellites have been launched, mainly in Russia, to alleviate this problem.

808:, with two high apogees daily over the northern hemisphere. This orbit provides a long dwell time over Russian territory as well as over Canada at higher latitudes than geostationary orbits over the equator. 1025:

Typically the orbit of a medium Earth orbit satellite is about 16,000 kilometres (10,000 mi) above Earth. In various patterns, these satellites make the trip around Earth in anywhere from 2 to 8 hours.

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Like LEOs, these satellites do not maintain a stationary distance from the Earth. This is in contrast to the geostationary orbit, where satellites are always 35,786 kilometres (22,236 mi) from Earth.

927:(LEO) typically is a circular orbit about 160 to 2,000 kilometres (99 to 1,243 mi) above the Earth's surface and, correspondingly, a period (time to revolve around the Earth) of about 90 minutes. 1884:

A satellite radio or subscription radio (SR) is a digital radio signal that is broadcast by a communications satellite, which covers a much wider geographical range than terrestrial radio signals.

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A geostationary orbit is useful for communications because ground antennas can be aimed at the satellite without their having to track the satellite's motion. This is relatively inexpensive.

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almost any type of satellite can be used. Satellite phones connect directly to a constellation of either geostationary or low-Earth-orbit satellites. Calls are then forwarded to a satellite

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number of satellites for various purposes; for example, METSAT for meteorological satellite, EUMETSAT for the European branch of the program, and METOP for meteorological operations.

938:(signal strength falls off as the square of the distance from the source, so the effect is considerable). Thus there is a trade off between the number of satellites and their cost. 1207:, to distribute programming to their local affiliate stations. Satcom 1 was widely used because it had twice the communications capacity of the competing Westar 1 in America (24 1651:

spacecraft in orbit over the European continent. Because of this, the terms FSS and DBS are more so used throughout the North American continent, and are uncommon in Europe.

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To an observer on Earth, a satellite in a gestationary orbit appears motionless, in a fixed position in the sky. This is because it revolves around the Earth at Earth's own

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Allocating frequencies to satellite services is a complicated process which requires international coordination and planning. This is carried out under the auspices of the

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Ward, William W.; Floyd, Franklin W. (1997). "Chapter 8: Thirty Years of Space Communications Research and Development at Lincoln Laboratory". In Butrica, Andrew J (ed.).

1669:. They are normally used for broadcast feeds to and from television networks and local affiliate stations (such as program feeds for network and syndicated programming, 1597:. Other land use for satellite phones are rigs at sea, a backup for hospitals, military, and recreation. Ships at sea, as well as planes, often use satellite phones. 6234: 753:. It revolved around the Earth once per day at constant speed, but because it still had north–south motion, special equipment was needed to track it. Its successor, 654:. The satellite also executed several realtime transmissions before the non-rechargeable batteries failed on 30 December 1958 after eight hours of actual operation. 2514: 2437: 1122:, was launched on 6 April 1965 and placed in orbit at 28° west longitude. It was the first geostationary satellite for telecommunications over the Atlantic Ocean. 2394: 2567:

van Keuren, David K. (1997). "Chapter 2: Moon in Their Eyes: Moon Communication Relay at the Naval Research Laboratory, 1951-1962". In Butrica, Andrew J (ed.).

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Low-Earth-orbiting satellites are less expensive to launch into orbit than geostationary satellites and, due to proximity to the ground, do not require as high

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services in some countries, notably the United States. Mobile services allow listeners to roam a continent, listening to the same audio programming anywhere.

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was the first active, direct relay communications commercial satellite and marked the first transatlantic transmission of television signals. Belonging to

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Operating at lower frequency and lower power than DBS, FSS satellites require a much larger dish for reception (3 to 8 feet (1 to 2.5 m) in diameter for K

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as opposed to the 12 of Westar 1), resulting in lower transponder-usage costs. Satellites in later decades tended to have even higher transponder numbers.

5441: 3343:"DIRECTV's Spaceway F1 Satellite Launches New Era in High-Definition Programming; Next Generation Satellite Will Initiate Historic Expansion of DIRECTV" 2463: 796:, who did not participate in the Intelsat agreements. The Soviet Union launched its first communications satellite on 23 April 1965 as part of the 3043:

Altshuler, José (1997). "Chapter 18: From Shortwave and Scatter to Satellite: Cuba's International Communications". In Butrica, Andrew J (ed.).

3638: 1752:(usually 18 to 24 inches or 45 to 60 cm in diameter). Direct broadcast satellites generally operate in the upper portion of the microwave 1689:, and general commercial telecommunications. FSS satellites are also used to distribute national cable channels to cable television headends. 3959: 3235: 1434:

used to keep the satellite in the right orbit, with its antennas pointed in the right direction, and its power system pointed towards the Sun

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every second revolution. In this way a constellation of three Molniya satellites (plus in-orbit spares) can provide uninterrupted coverage.

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Region A, Low Earth Orbit (or LEO) Region – spherical region that extends from the Earth's surface up to an altitude (Z) of 2,000 km

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using the satellite. Additionally, it was the first satellite used by broadcast television networks in the United States, like

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distribution, the savings in ground equipment can more than outweigh the cost and complexity of placing a satellite into orbit.

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In addition, there are important differences in the onboard and ground equipment needed to support the two types of missions.

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antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Others form

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launch of Sputnik 1 was a major step in the exploration of space and rocket development, and marks the beginning of the

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via broadband data connections. This can be very useful for users who are located in remote areas, and cannot access a

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There are plans and initiatives to bring dedicated communications satellite beyond geostationary orbits. NASA proposed

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of the concept of the communications satellite, and the term 'Clarke Belt' is employed as a description of the orbit.

5498: 5159: 4165: 3643: 3544: 1970: 1954: 1734: 1547: 1294: 1110:, launched on 19 August 1964, and used for communication across the Pacific starting with television coverage of the 647: 400: 355: 4944: 4492: 4294: 4145: 3137: 980: 668:'s satellite applications program launched the first artificial satellite used for passive relay communications in 3096:. INTER-AGENCY SPACE DEBRIS COORDINATION COMMITTEE: Issued by Steering Group and Working Group 4. September 2007. 6224: 5653: 5055: 2951:

Pelton, Joseph N. (2015). "History of Satellite Communications". In Pelton J.; Madry S.; Camacho-Lara S. (eds.).

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in geostationary orbits to relay radio signals. Because of this, Arthur C. Clarke is often quoted as being the

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As television became the main market, its demand for simultaneous delivery of relatively few signals of large

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The first and historically most important application for communication satellites was in intercontinental

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The Atlas-B with SCORE on the launch pad; the rocket (without booster engines) constituted the satellite.

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Some manufacturers have also introduced special antennas for mobile reception of DBS television. Using

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service has also recently used FSS technology as well for their programming packages requiring their

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become successful, because these channels distributed their programming to all of the local cable TV

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After the launches of the Telstar through Westar 1 satellites, RCA Americom (later GE Americom, now

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are also proposed for communication satellites covering the Moon alike communication satellites in

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of 86.4° and inter-satellite links provide service availability over the entire surface of Earth.

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After the 1990s, satellite communication technology has been used as a means to connect to the

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program. This program was also unique at the time for its use of what then became known as the

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antenna, due to Dish Network needing more capacity to carry local television stations per the

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are used to further specify orbital details. MEO and LEO are non-geostationary orbit (NGSO).

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Another passive relay experiment primarily intended for military communications purposes was

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Satellite communications are still used in many applications today. Remote islands such as

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caused some decline in the use of satellites for fixed telephony in the late 20th century.

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Region 1: Europe, Africa, the Middle East, what was formerly the Soviet Union, and Mongolia

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When Intelsat was launched, the United States was the only launch source outside of the

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supporting different missions on surface and other orbits are considered, such as the

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satellites over North America provide a quite large amount of FTA channels on their K

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On 30 May 1974, the first geostationary communications satellite in the world to be

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has zero elevation and a satellite directly overhead has elevation of 90 degrees.)

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in the United States, which, ironically, was then bought by its archrival in 2005.

628: 525: 246: 195: 50: 2628:"United States Aeronautics and Space Activities - first Annual Report to Congress" 1469:(ITU). To facilitate frequency planning, the world is divided into three regions: 1125:

On 9 November 1972, Canada's first geostationary satellite serving the continent,

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In 2013, the first four of a constellation of 20 MEO satellites was launched. The

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Beyond Sputnik and the Space Race: The Origins of Global Satellite Communications

2395:"Military Satellite Communications Fundamentals | The Aerospace Corporation" 2178: 2173: 2101: 2061: 1911: 1872: 1856: 1525: 1421: 1377: 1047: 960: 935: 924: 918: 909: 891: 837: 825: 749:, launched on 26 July 1963. Syncom 2 was the first communications satellite in a 489: 294: 149: 3402: 1627:

comsats. Two satellite types are used for North American television and radio:

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communications satellite. Another system using this store and forward method is

712:(Post Office) to develop satellite communications, it was launched by NASA from 6158: 6145: 6038: 5969: 5959: 5944: 5922: 5912: 5808: 5798: 5747: 5668: 5015: 4887: 4862: 4822: 4792: 4667: 4502: 4455: 4430: 4388: 4242: 4227: 4196: 3658: 3587: 2425:"Extra-terrestrial Relays: Can Rocket Stations Give World-wide Radio Coverage?" 1761: 1749: 1551: 1479:

Region 3: Asia (excluding region 1 areas), Australia, and the southwest Pacific

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published an article titled "Extraterrestrial Relays" in the British magazine

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satellite TV channels are also usually distributed on FSS satellites in the K

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Work that was begun in the field of electrical intelligence gathering at the

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Communications Satellites are usually composed of the following subsystems:

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range from 2,000 to 36,000 kilometres (1,200 to 22,400 mi) above Earth.

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Power subsystem, used to power the Satellite systems, normally composed of

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cover the Earth. Also, dedicated communication satellites in orbits around

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A direct extension of the passive experiments of Project West Ford was the

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The direct successor to SCORE was another ARPA-led project called Courier.

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Manual on sea level measurement and interpretation, volume V: Radar gauges

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satellites are needed if the mission requires uninterrupted connectivity.

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The first satellite purpose-built to actively relay communications was

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to many receivers being a more precise match for the capabilities of

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Communications satellites usually have one of three primary types of

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Published as House Document Number 71, 86th Congress, first Session

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series was launched on 23 April 1965 and was used for experimental

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program, also conducted by the Lincoln Laboratory on behalf of the

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Kramer, Herbert J. (2002). "Data Collection (Messaging) Systems".

3369:"India's first 'military' satellite GSAT-7 put into earth's orbit" 2728:

Martin, Donald; Anderson, Paul; Bartamian, Lucy (March 16, 2007).

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Martin, Donald; Anderson, Paul; Bartamian, Lucy (March 16, 2007).

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Some satellites have been launched that have transponders in the

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for each of the transponders' RF input and output (as opposed to

1777: 1765: 1753: 1662: 1648: 1373: 1322: 1314: 1310: 1252: 1239:(owns the former RCA Astro Electronics/GE Astro Space business), 1167:

in 1975. It was Satcom 1 that was instrumental in helping early

1126: 1094: 1000: 693: 592: 477: 2218:

Orbital periods and speeds are calculated using the relations 4π

1997:. India has launched its first Military Communication satellite 963:

and low-speed data services, primarily to remote areas, are the

741:

An immediate antecedent of the geostationary satellites was the

716:

on 10 July 1962, in the first privately sponsored space launch.

5949: 5813: 5252: 5212: 4534: 3933: 3882: 3776: 3725: 3710: 3633: 3623: 2026: 1998: 1860: 1330: 1302: 1298: 984: 782: 754: 746: 735: 669: 5371: 3218:"TYCHO mission to Earth-Moon libration point EML-4 @ IAC 2013" 776: 545: 5237: 5174: 4482: 3918: 3715: 3516:

Beyond The Ionosphere: Fifty Years of Satellite Communication

3046:

Beyond The Ionosphere: Fifty Years of Satellite Communication

2786:

Beyond The Ionosphere: Fifty Years of Satellite Communication

2570:

Beyond The Ionosphere: Fifty Years of Satellite Communication

1737:'s "must-carry" regulations, and for more bandwidth to carry 1708: 1460: 1149: 857: 849: 769: 578: 461: 449: 429: 4028: 2529: 5179: 2574: 2089: 1986: 1978: 1920: 1836: 1805: 1795:

band, and 12 feet (3.6 m) or larger for C band). They use

1785: 1738: 1397: 1388:

Other orbits are also planned to be used. Positions in the

1153: 1133:, with the United States following suit with the launch of 1093:

In applications that require many ground antennas, such as

665: 1748:

is a communications satellite that transmits to small DBS

1376:

as a data network aiming to provide a „Lunar Internet for

1065: 597:

There are two major classes of communications satellites,

5830: 4222: 2021:

bands. Typically military satellites operate in the UHF,

2002: 1907: 1204: 1200: 1176: 1043: 1427:

Engines used to bring the satellite to its desired orbit

700:

as part of a multi-national agreement between AT&T,

3386: 2727: 2599: 2538:"Design of the first artificial satellite of the Earth" 955:

A group of satellites working in concert is known as a

3173: 2997:"NASA Compendium Of Satellite Communications Programs" 2922:"NASA Compendium Of Satellite Communications Programs" 2831:"NASA Compendium Of Satellite Communications Programs" 2687:. The White House. 18 January 1961. pp. 12–13, 26 1945:

connection, or require high availability of services.

688: 2756:"United States Aeronautics and Space Activities 1962" 2682:"United States Aeronautics and Space Activities 1960" 1839:

have also launched experimental satellites carrying K

1605:

connected to the Public Switched Telephone Network .

1329:. In November 1967 Soviet engineers created a unique 971:

systems. The Iridium system has 66 satellites, which

472:

applications. Many communications satellites are in

3159: 1989:

satellites, United Kingdom satellites (for instance

1432:

station keeping tracking and stabilization subsystem

3496: 2761:. The White House. 28 January 1963. pp. 20, 96 1855:owners. Such mobile DBS antennas are also used by 781:In the United States, 1962 saw the creation of the 3317:"Indian GSLV successfully lofts GSAT-14 satellite" 2637:. The White House. 2 February 1959. pp. 13–14 3335: 3190: 2488: 2285:Approximately 8.6 times when the Moon is nearest 2104:). The data rate is typically much lower than in 1768:, DISH Network and Orby TV in the United States, 889:The region below medium orbits is referred to as 6235:Telecommunications-related introductions in 1962 6211: 2389: 2387: 1476:Region 2: North and South America and Greenland 959:. Two such constellations, intended to provide 2084:. It may be based on a secondary payload of a 1215:By 2000, Hughes Space and Communications (now 593:Early active and passive satellite experiments 16:Artificial satellite that relays radio signals 5387: 4295: 4044: 3960:Consultative Committee for Space Data Systems 3538: 3002:. NASA. December 1975. pp. 10-1 to 10-64 2416: 2256:is the gravitational constant, approximately 1367: 401: 3552: 3453:. "Equipment needed for Telemetry of Data". 3395:Observation of the Earth and Its Environment 2455: 2384: 1416:Communication Payload, normally composed of 1054: 672:on 12 August 1960. Echo 1 was an aluminized 499:used for telecommunications links travel by 49: 5310:Global telecommunications regulation bodies 3427:"Satellite Data Telecommunication Handbook" 2927:. NASA. December 1975. pp. 9-1 to 9-56 2836:. NASA. December 1975. pp. 5-1 to 5-16 2560: 1760:. DBS technology is used for DTH-oriented ( 1441:, and batteries that maintain power during 1006: 777:International commercial satellite projects 5394: 5380: 5346: 4302: 4288: 4051: 4037: 3545: 3531: 3451:Intergovernmental Oceanographic Commission 3209: 2989: 2566: 1461:Frequency allocation for satellite systems 1457:can be used to arrive at the exact value. 944: 577:. Sputnik 1 was equipped with an on-board 408: 394: 3986:List of communication satellite companies 3091:"IADC Space Debris Mitigation Guidelines" 3042: 2914: 2823: 2782: 2676: 2674: 2305:, to 9.6 times when the Moon is farthest 2139:List of communication satellite companies 1148:was launched: the experimental satellite 452:. Communications satellites are used for 3483:(Johns Hopkins University Press, 2022); 2946: 2944: 2942: 2778: 2776: 2603:Communications Satellites: Project SCORE 2344: 2268:is the mass of Earth, approximately 5.98 2134:Inter-satellite communications satellite 1784:in the UK, Ireland, and New Zealand and 1529: 1345:, that was based on Molniya satellites. 1064: 903: 815: 633: 544: 476:22,236 miles (35,785 km) above the 18: 5879:Effect of spaceflight on the human body 3981:List of communications satellite firsts 3502:Communications satellites short history 2494: 2371:"Satellites - Communication Satellites" 2144:List of communications satellite firsts 1965:Communications satellites are used for 1910:radio equipment and highly directional 1035:In 1962, the communications satellite, 621:United States Naval Research Laboratory 565:on 4 October 1957. It was developed by 6212: 5901:Psychological and sociological effects 4309: 3863:Shanghai Spacecom Satellite Technology 3392: 3215: 3196: 3113:The Basics of Satellite Communications 3109: 2950: 2748: 2671: 2548:from the original on 26 September 2023 2422: 2100:) or in dedicated satellites (such as 1639:satellites. Examples of these are the 1106:The first geostationary satellite was 882:(MEO) satellites are closer to Earth. 5375: 4283: 4032: 3526: 3349:from the original on 20 December 2023 2939: 2773: 2589:from the original on 29 October 2023. 2517:from the original on 24 November 2023 2461: 2443:from the original on 19 November 2023 1866: 1467:International Telecommunication Union 725:Massachusetts Institute of Technology 5356: 4011: 3067: 1494:Broadcasting satellite service (BSS) 783:Communications Satellite Corporation 2535: 1217:Boeing Satellite Development Center 822:medium altitude orbits around Earth 811: 766:United States Department of Defense 689:More firsts and further experiments 13: 5610:Weather and environment monitoring 3473: 2953:Handbook of Satellite Applications 2731:Communications Satellites: Telstar 2476:from the original on 13 April 2023 2423:Clarke, Arthur C. (October 1945). 2248:is the orbital period in seconds; 2244:is the radius of orbit in metres; 2072:), may use satellites for one-way 2044: 1971:Global Command and Control Systems 1926: 1424:, amplifiers and switching systems 1380:spacecraft and Installations. The 1233:Indian Space Research Organisation 1100: 1029: 561:, which was put into orbit by the 14: 6251: 3644:Automatic Tracking Satellite Dish 3490: 1955:Military communications satellite 1764:) satellite TV services, such as 1548:Public Switched Telephone Network 1504:Radionavigation-satellite service 648:Advanced Research Projects Agency 6193: 6183: 6182: 5355: 5345: 5336: 5335: 5324: 4945:Free-space optical communication 4264: 4254: 4010: 3999: 3998: 1993:), and satellites of the former 1887: 1661:, and the lower portions of the 1509:Meteorological-satellite service 1258: 981:satellite internet constellation 868:Geostationary satellites have a 432:telecommunication signals via a 377: 5654:Space launch market competition 5401: 3443: 3419: 3361: 3309: 3283: 3257: 3228: 3130: 3116:. Intl. Engineering Consortiu. 3103: 3083: 3068:Mann, Reuben (April 26, 2022). 3061: 3036: 3014: 2967: 2892: 2870: 2848: 2801: 2721: 2699: 2649: 2620: 2495:Siddiqi, Asif (November 2007). 2345:Labrador, Virgil (2015-02-19). 2279: 2212: 1848:Global Positioning System (GPS) 1564:submarine communications cables 1514: 1402:Mars Telecommunications Orbiter 623:in 1951 led to a project named 6240:Wireless communication systems 5891:Health threat from cosmic rays 3497:Satellite Industry Association 3216:Hornig, Andreas (2013-10-06). 3197:Hornig, Andreas (2022-05-01). 3138:"Soyuz Flight VS05 Launch Kit" 2593: 2363: 2338: 2124:High-altitude platform station 2001:, its transponders operate in 1961:X Band Satellite Communication 1812:band form for the now-defunct 1348: 820:Clickable image, highlighting 762:Lincoln Experimental Satellite 1: 4058: 2462:Mills, Mike (3 August 1997). 2252:is the orbital speed in m/s; 2200: 1877:Satellite radio offers audio 1681:by schools and universities, 1677:), as well as being used for 1608: 1489:Fixed satellite service (FSS) 1313:and the Russian Far East, in 5331:Telecommunication portal 5112:Telecommunications equipment 4346: 4261:Telecommunication portal 3965:ETSI Satellite Digital Radio 3689:Very-small-aperture terminal 2497:"The Man Behind the Curtain" 2401:. 2010-04-01. Archived from 2331: 2129:History of telecommunication 1519: 1407: 1225:Orbital Sciences Corporation 7: 6007:Self-replicating spacecraft 5843:International Space Station 4848:Alexander Stepanovich Popov 3741:Digital audio radio service 3649:Motor-driven Satellite dish 3403:10.1007/978-3-642-56294-5_4 3345:. SpaceRef. 26 April 2005. 2502:Air & Space/Smithsonian 2111: 1948: 1390:Earth-Moon-Libration points 1289:The first satellite of the 1171:channels such as WTBS (now 1048:broadband internet services 702:Bell Telephone Laboratories 350:List of space organizations 10: 6256: 5521:Space Liability Convention 4552:Telecommunications history 3110:Pelton, Joseph N. (2006). 2119:Commercialization of space 1958: 1952: 1930: 1891: 1870: 1746:direct broadcast satellite 1629:Direct broadcast satellite 1612: 1523: 1368:Beyond geostationary orbit 1352: 1262: 1114:. Shortly after Syncom 3, 1058: 1010: 948: 907: 607:. Passive satellites only 555:artificial Earth satellite 519: 514: 448:at different locations on 428:that relays and amplifies 6220:Communications satellites 6177: 6144: 6097: 6049: 5935: 5884:Space adaptation syndrome 5871: 5776: 5696: 5687: 5575: 5409: 5319: 5261: 5198: 5160:Public Switched Telephone 5120: 5084: 5041: 4982: 4972:telecommunication circuit 4933:Fiber-optic communication 4916: 4678:Francis Blake (telephone) 4625: 4473:Optical telecommunication 4317: 4251: 4215: 4184: 4136:Communications satellites 4123: 4102: 4066: 3994: 3973: 3952: 3901: 3796:Relay satellite companies 3795: 3749: 3697: 3616: 3593:High-throughput satellite 3578:Satellite Internet access 3560: 3265:"Orby TV (United States)" 2373:. Satellites.spacesim.org 2347:"satellite communication" 1933:Satellite Internet access 1859:for DirecTV (supplied by 1055:Geostationary orbit (GEO) 989:satellite Internet access 846:Van Allen radiation belts 5617:Communications satellite 5071:Orbital angular-momentum 4508:Satellite communications 4347:Communications satellite 3554:Satellite communications 2205: 2154:Reconnaissance satellite 2054:environmental monitoring 1655:Fixed Service Satellites 1499:Mobile-satellite service 1007:Medium Earth orbit (MEO) 625:Communication Moon Relay 486:satellite constellations 422:communications satellite 6121:reusable launch systems 5738:Extravehicular activity 5649:Commercial use of space 5553:Militarisation of space 5526:Registration Convention 5442:Accidents and incidents 4950:Molecular communication 4773:Gardiner Greene Hubbard 4602:Undersea telegraph line 4337:Cable protection system 4131:Cable protection system 3902:Satellite manufacturers 3049:. NASA History Office. 2789:. NASA History Office. 2184:Satellite space segment 1967:military communications 1894:Amateur radio satellite 1843:band beacons recently. 1633:Fixed Service Satellite 1544:long distance telephony 987:, that aims for global 957:satellite constellation 951:Satellite constellation 945:Satellite constellation 862:orbital classifications 842:Moon's orbital distance 806:highly elliptical orbit 743:Hughes Aircraft Company 80:Timeline of spaceflight 6225:Satellite broadcasting 6169:Mission control center 6131:Non-rocket spacelaunch 5565:Billionaire space race 5092:Communication protocol 4878:Charles Sumner Tainter 4693:Walter Houser Brattain 4638:Edwin Howard Armstrong 4446:Information revolution 3293:. ISRO. Archived from 2955:. New York: Springer. 2734:(5th ed.). AIAA. 2606:(5th ed.). AIAA. 2159:Relay (disambiguation) 1985:of the United States, 1969:applications, such as 1923:or similar protocols. 1816:satellite TV service. 1539: 1272:multipath interference 1072: 853: 840:, at one ninth of the 639: 575:Konstantin Tsiolkovsky 573:, building on work by 550: 384:Spaceflight portal 300:Non-rocket spacelaunch 70:History of spaceflight 54: 27: 6019:Spacecraft propulsion 5469:European Space Agency 5066:Polarization-division 4798:Narinder Singh Kapany 4763:Erna Schneider Hoover 4683:Jagadish Chandra Bose 4663:Alexander Graham Bell 4394:online video platform 4271:Telephones portal 2536:Zak, Anatoly (2017). 1959:Further information: 1801:circular polarization 1533: 1243:, Alcatel Space, now 1146:three-axis stabilized 1068: 904:Low Earth orbit (LEO) 819: 637: 548: 536:artificial satellites 438:communication channel 53: 22: 5644:Satellite navigation 4908:Vladimir K. Zworykin 4868:Almon Brown Strowger 4838:Charles Grafton Page 4493:Prepaid mobile phone 4421:Electrical telegraph 4233:Telephone newspapers 3568:Satellite television 3518:(NASA SP-4217, 1997) 3236:"Connected:Maritime" 1853:recreational vehicle 1827:, such as DirecTV's 1615:Satellite television 1394:geosynchronous orbit 1382:Moonlight Initiative 1339:satellite television 1309:stations located in 1112:1964 Summer Olympics 1079:(one revolution per 804:, which describes a 751:geosynchronous orbit 704:, NASA, the British 676:acting as a passive 662:from the satellite. 652:Dwight D. Eisenhower 614:free-space path loss 549:Replica of Sputnik 1 426:artificial satellite 6029:Electric propulsion 5716:Life-support system 5600:Imagery and mapping 5560:Private spaceflight 4858:Johann Philipp Reis 4617:Wireless revolution 4579:The Telephone Cases 4436:Hydraulic telegraph 4156:Mobile phone signal 3953:Trade organizations 3944:Thales Alenia Space 3757:Astra Digital Radio 3750:Broadcast companies 3679:Satellite data unit 3181:"Moonlight Webinar" 3167:"Project Moonlight" 3055:1997bify.book.....B 2961:2017hsa..book.....P 2809:"Project West Ford" 2795:1997bify.book.....B 2583:1997bify.book.....B 2542:RussianSpaceWeb.com 2469:The Washington Post 2194:Traveling-wave tube 2169:Satellite data unit 2088:(as in the case of 2056:equipment (such as 2041:) frequency bands. 1797:linear polarization 1701:Intelsat Americas 5 1683:business television 1566:through the use of 1245:Thales Alenia Space 1221:Space Systems/Loral 1189:The Weather Channel 1070:Geostationary orbit 1061:Geostationary orbit 1046:satellites provide 973:orbital inclination 871:geostationary orbit 834:geostationary orbit 723:, which was led by 710:French National PTT 706:General Post Office 567:Mikhail Tikhonravov 474:geostationary orbit 222:Apollo Lunar Module 6230:Satellites by type 5982:Robotic spacecraft 5908:Space and survival 5763:Space colonization 5659:Space architecture 5511:Outer Space Treaty 5056:Frequency-division 5033:Telephone exchange 4903:Charles Wheatstone 4833:Jun-ichi Nishizawa 4808:Innocenzo Manzetti 4743:Reginald Fessenden 4478:Optical telegraphy 4311:Telecommunications 4146:Free-space optical 3772:Sirius XM Holdings 3663:Parabolic antennas 3511:by David J. Whalen 3507:2015-05-12 at the 2164:Satcom On The Move 2106:satellite Internet 2096:and others in the 1867:Radio broadcasting 1540: 1129:, was launched by 1073: 1013:Medium Earth orbit 879:Medium Earth orbit 854: 729:Lincoln Laboratory 640: 612:attenuated due to 551: 179:Robotic spacecraft 55: 28: 6207: 6206: 6154:Flight controller 5931: 5930: 5689:Human spaceflight 5664:Space exploration 5590:Earth observation 5369: 5368: 5107:Store and forward 5102:Data transmission 5016:Network switching 4967:Transmission line 4813:Guglielmo Marconi 4778:Internet pioneers 4643:Mohamed M. Atalla 4612:Whistled language 4277: 4276: 4110:Answering machine 4026: 4025: 3583:Amateur satellite 3479:Slotten, Hugh R. 3412:978-3-642-62688-3 3321:NASA Space Flight 3297:on 8 January 2014 3123:978-1-931695-48-0 2272:10 kg (1.318 2086:weather satellite 2074:data transmission 1788:in South Africa. 1770:Bell Satellite TV 1687:Videoconferencing 1679:distance learning 1558:telephones to an 1455:network simulator 1141:on 13 April 1974. 884:Orbital altitudes 721:Project West Ford 674:balloon satellite 524:In October 1945, 440:between a source 418: 417: 312:Spaceflight types 256: 255: 213:Crewed spacecraft 205: 204: 120:Earth observation 25:Iridium satellite 6247: 6197: 6186: 6185: 5896:Space psychology 5721:Animals in space 5694: 5693: 5674:Space technology 5516:Rescue Agreement 5396: 5389: 5382: 5373: 5372: 5359: 5358: 5349: 5348: 5339: 5338: 5329: 5328: 5327: 5200:Notable networks 5190:Wireless network 5130:Cellular network 5122:Types of network 5097:Computer network 4984:Network topology 4898:Thomas A. Watson 4753:Oliver Heaviside 4738:Philo Farnsworth 4713:Daniel Davis Jr. 4688:Charles Bourseul 4648:John Logie Baird 4357:Data compression 4352:Computer network 4304: 4297: 4290: 4281: 4280: 4269: 4268: 4267: 4259: 4258: 4257: 4223:Fax transmission 4171:Submarine cables 4053: 4046: 4039: 4030: 4029: 4014: 4013: 4002: 4001: 3929:Northrop Grumman 3608:Carriage dispute 3547: 3540: 3533: 3524: 3523: 3467: 3466: 3464: 3463: 3447: 3441: 3440: 3438: 3437: 3423: 3417: 3416: 3390: 3384: 3383: 3381: 3380: 3365: 3359: 3358: 3356: 3354: 3339: 3333: 3332: 3330: 3328: 3323:. 4 January 2014 3313: 3307: 3306: 3304: 3302: 3287: 3281: 3280: 3278: 3276: 3267:. Archived from 3261: 3255: 3254: 3252: 3251: 3242:. Archived from 3232: 3226: 3225: 3213: 3207: 3206: 3194: 3188: 3187: 3185: 3177: 3171: 3170: 3163: 3157: 3156: 3154: 3152: 3142: 3134: 3128: 3127: 3107: 3101: 3100: 3095: 3087: 3081: 3080: 3078: 3076: 3065: 3059: 3058: 3040: 3034: 3033: 3031: 3029: 3018: 3012: 3011: 3009: 3007: 3001: 2993: 2987: 2986: 2984: 2982: 2971: 2965: 2964: 2948: 2937: 2936: 2934: 2932: 2926: 2918: 2912: 2911: 2909: 2907: 2896: 2890: 2889: 2887: 2885: 2874: 2868: 2867: 2865: 2863: 2852: 2846: 2845: 2843: 2841: 2835: 2827: 2821: 2820: 2818: 2816: 2805: 2799: 2798: 2780: 2771: 2770: 2768: 2766: 2760: 2752: 2746: 2745: 2725: 2719: 2718: 2716: 2714: 2703: 2697: 2696: 2694: 2692: 2686: 2678: 2669: 2668: 2666: 2664: 2653: 2647: 2646: 2644: 2642: 2632: 2624: 2618: 2617: 2597: 2591: 2590: 2577:History Office. 2564: 2558: 2557: 2555: 2553: 2533: 2527: 2526: 2524: 2522: 2492: 2486: 2485: 2483: 2481: 2459: 2453: 2452: 2450: 2448: 2442: 2429: 2420: 2414: 2413: 2411: 2410: 2391: 2382: 2381: 2379: 2378: 2367: 2361: 2360: 2358: 2357: 2342: 2325: 2324: 2322: 2320: 2319: 2316: 2313: 2304: 2302: 2300: 2299: 2296: 2293: 2283: 2277: 2275: 2271: 2263: 2261: 2216: 2062:weather stations 1750:satellite dishes 1575:Ascension Island 1241:Northrop Grumman 1085:equatorial orbit 1077:angular velocity 916: 830:High Earth orbit 812:Satellite orbits 629:Washington, D.C. 526:Arthur C. Clarke 410: 403: 396: 382: 381: 380: 207: 206: 196:Cargo spacecraft 173: 172: 30: 29: 6255: 6254: 6250: 6249: 6248: 6246: 6245: 6244: 6210: 6209: 6208: 6203: 6173: 6140: 6112:Escape velocity 6093: 6045: 6012:Space telescope 5965:Reentry capsule 5927: 5867: 5772: 5743:Overview effect 5726:Bioastronautics 5683: 5571: 5405: 5400: 5370: 5365: 5325: 5323: 5315: 5257: 5194: 5116: 5080: 5037: 4986: 4978: 4919: 4912: 4818:Robert Metcalfe 4673:Tim Berners-Lee 4621: 4441:Information Age 4313: 4308: 4278: 4273: 4265: 4263: 4255: 4253: 4247: 4228:Telephone calls 4211: 4180: 4119: 4098: 4089:Satellite phone 4079:Cable telephony 4062: 4057: 4027: 4022: 3990: 3969: 3948: 3924:Lockheed Martin 3897: 3803:AST SpaceMobile 3791: 3745: 3699:Satellite radio 3693: 3674:Satellite modem 3669:Satellite phone 3654:Multi-satellite 3612: 3598:Relay satellite 3573:Satellite radio 3556: 3551: 3509:Wayback Machine 3493: 3476: 3474:Further reading 3471: 3470: 3461: 3459: 3448: 3444: 3435: 3433: 3431:library.wmo.int 3425: 3424: 3420: 3413: 3391: 3387: 3378: 3376: 3367: 3366: 3362: 3352: 3350: 3341: 3340: 3336: 3326: 3324: 3315: 3314: 3310: 3300: 3298: 3289: 3288: 3284: 3274: 3272: 3271:on 28 July 2020 3263: 3262: 3258: 3249: 3247: 3234: 3233: 3229: 3214: 3210: 3195: 3191: 3183: 3179: 3178: 3174: 3165: 3164: 3160: 3150: 3148: 3140: 3136: 3135: 3131: 3124: 3108: 3104: 3093: 3089: 3088: 3084: 3074: 3072: 3066: 3062: 3041: 3037: 3027: 3025: 3020: 3019: 3015: 3005: 3003: 2999: 2995: 2994: 2990: 2980: 2978: 2973: 2972: 2968: 2949: 2940: 2930: 2928: 2924: 2920: 2919: 2915: 2905: 2903: 2898: 2897: 2893: 2883: 2881: 2876: 2875: 2871: 2861: 2859: 2854: 2853: 2849: 2839: 2837: 2833: 2829: 2828: 2824: 2814: 2812: 2807: 2806: 2802: 2781: 2774: 2764: 2762: 2758: 2754: 2753: 2749: 2742: 2726: 2722: 2712: 2710: 2705: 2704: 2700: 2690: 2688: 2684: 2680: 2679: 2672: 2662: 2660: 2655: 2654: 2650: 2640: 2638: 2630: 2626: 2625: 2621: 2614: 2598: 2594: 2565: 2561: 2551: 2549: 2534: 2530: 2520: 2518: 2493: 2489: 2479: 2477: 2460: 2456: 2446: 2444: 2440: 2427: 2421: 2417: 2408: 2406: 2393: 2392: 2385: 2376: 2374: 2369: 2368: 2364: 2355: 2353: 2343: 2339: 2334: 2329: 2328: 2317: 2314: 2312:405,696 km 2311: 2310: 2308: 2306: 2297: 2294: 2292:363,104 km 2291: 2290: 2288: 2286: 2284: 2280: 2273: 2269: 2259: 2257: 2217: 2213: 2208: 2203: 2198: 2189:Space pollution 2179:Satellite modem 2174:Satellite delay 2114: 2047: 2045:Data collection 2038: 2033:(also known as 2025:(also known as 2018: 1963: 1957: 1951: 1935: 1929: 1927:Internet access 1896: 1890: 1875: 1873:Satellite radio 1869: 1857:JetBlue Airways 1842: 1831:satellite, and 1824: 1811: 1794: 1757: 1714: 1698: 1666: 1617: 1611: 1552:telephone calls 1528: 1526:Satellite phone 1522: 1517: 1463: 1410: 1370: 1357: 1351: 1333:of national TV 1267: 1261: 1237:Lockheed Martin 1103: 1101:Examples of GEO 1063: 1057: 1032: 1030:Examples of MEO 1015: 1009: 961:satellite phone 953: 947: 936:signal strength 925:low Earth orbit 921: 919:Low Earth orbit 914: 912: 910:Low Earth orbit 906: 892:low Earth orbit 838:graveyard orbit 814: 779: 691: 595: 522: 517: 490:low Earth orbit 436:; it creates a 414: 378: 376: 371: 370: 351: 343: 342: 313: 305: 304: 295:Escape velocity 290:launch vehicles 268: 258: 257: 252: 251: 215: 201: 200: 181: 170: 160: 159: 110: 100: 99: 65: 17: 12: 11: 5: 6253: 6243: 6242: 6237: 6232: 6227: 6222: 6205: 6204: 6202: 6201: 6190: 6178: 6175: 6174: 6172: 6171: 6166: 6161: 6159:Ground station 6156: 6150: 6148: 6146:Ground segment 6142: 6141: 6139: 6138: 6133: 6128: 6123: 6114: 6109: 6103: 6101: 6095: 6094: 6092: 6091: 6086: 6081: 6079:Interplanetary 6076: 6075: 6074: 6072:Geosynchronous 6069: 6059: 6053: 6051: 6047: 6046: 6044: 6043: 6042: 6041: 6039:Gravity assist 6036: 6031: 6026: 6016: 6015: 6014: 6009: 6004: 5999: 5994: 5989: 5979: 5974: 5973: 5972: 5970:Service module 5967: 5962: 5960:Orbital module 5952: 5947: 5945:Launch vehicle 5941: 5939: 5933: 5932: 5929: 5928: 5926: 5925: 5923:Space sexology 5920: 5915: 5913:Space medicine 5910: 5905: 5904: 5903: 5893: 5888: 5887: 5886: 5875: 5873: 5869: 5868: 5866: 5865: 5860: 5855: 5850: 5845: 5840: 5839: 5838: 5828: 5823: 5822: 5821: 5816: 5806: 5801: 5796: 5791: 5786: 5780: 5778: 5774: 5773: 5771: 5770: 5765: 5760: 5755: 5750: 5748:Weightlessness 5745: 5740: 5735: 5734: 5733: 5728: 5723: 5713: 5712: 5711: 5700: 5698: 5691: 5685: 5684: 5682: 5681: 5676: 5671: 5669:Space research 5666: 5661: 5656: 5651: 5646: 5641: 5640: 5639: 5634: 5629: 5624: 5614: 5613: 5612: 5607: 5605:Reconnaissance 5602: 5597: 5587: 5581: 5579: 5573: 5572: 5570: 5569: 5568: 5567: 5557: 5556: 5555: 5550: 5545: 5535: 5534: 5533: 5528: 5523: 5518: 5513: 5503: 5502: 5501: 5496: 5491: 5486: 5481: 5476: 5474:European Union 5471: 5466: 5461: 5451: 5446: 5445: 5444: 5439: 5434: 5429: 5419: 5413: 5411: 5407: 5406: 5399: 5398: 5391: 5384: 5376: 5367: 5366: 5364: 5363: 5353: 5343: 5333: 5320: 5317: 5316: 5314: 5313: 5306: 5301: 5296: 5291: 5286: 5285: 5284: 5279: 5271: 5265: 5263: 5259: 5258: 5256: 5255: 5250: 5245: 5240: 5235: 5230: 5225: 5220: 5215: 5210: 5204: 5202: 5196: 5195: 5193: 5192: 5187: 5182: 5177: 5172: 5167: 5162: 5157: 5152: 5147: 5142: 5137: 5132: 5126: 5124: 5118: 5117: 5115: 5114: 5109: 5104: 5099: 5094: 5088: 5086: 5082: 5081: 5079: 5078: 5073: 5068: 5063: 5058: 5053: 5051:Space-division 5047: 5045: 5039: 5038: 5036: 5035: 5030: 5029: 5028: 5023: 5013: 5012: 5011: 5001: 4996: 4990: 4988: 4980: 4979: 4977: 4976: 4975: 4974: 4964: 4963: 4962: 4952: 4947: 4942: 4941: 4940: 4930: 4924: 4922: 4914: 4913: 4911: 4910: 4905: 4900: 4895: 4890: 4888:Camille Tissot 4885: 4880: 4875: 4870: 4865: 4863:Claude Shannon 4860: 4855: 4853:Tivadar Puskás 4850: 4845: 4840: 4835: 4830: 4825: 4823:Antonio Meucci 4820: 4815: 4810: 4805: 4800: 4795: 4793:Charles K. Kao 4790: 4785: 4780: 4775: 4770: 4768:Harold Hopkins 4765: 4760: 4755: 4750: 4745: 4740: 4735: 4730: 4725: 4720: 4715: 4710: 4705: 4700: 4695: 4690: 4685: 4680: 4675: 4670: 4668:Emile Berliner 4665: 4660: 4655: 4650: 4645: 4640: 4635: 4629: 4627: 4623: 4622: 4620: 4619: 4614: 4609: 4607:Videotelephony 4604: 4599: 4598: 4597: 4592: 4582: 4575: 4570: 4564: 4559: 4554: 4549: 4544: 4543: 4542: 4537: 4532: 4522: 4521: 4520: 4510: 4505: 4503:Radiotelephone 4500: 4495: 4490: 4485: 4480: 4475: 4470: 4469: 4468: 4458: 4453: 4448: 4443: 4438: 4433: 4428: 4423: 4418: 4413: 4408: 4407: 4406: 4401: 4396: 4391: 4389:Internet video 4381: 4380: 4379: 4374: 4369: 4364: 4354: 4349: 4344: 4339: 4334: 4329: 4323: 4321: 4315: 4314: 4307: 4306: 4299: 4292: 4284: 4275: 4274: 4252: 4249: 4248: 4246: 4245: 4240: 4235: 4230: 4225: 4219: 4217: 4213: 4212: 4210: 4209: 4204: 4199: 4197:Misdialed call 4194: 4188: 4186: 4182: 4181: 4179: 4178: 4173: 4168: 4163: 4158: 4153: 4148: 4143: 4138: 4133: 4127: 4125: 4121: 4120: 4118: 4117: 4112: 4106: 4104: 4100: 4099: 4097: 4096: 4091: 4086: 4081: 4076: 4070: 4068: 4064: 4063: 4056: 4055: 4048: 4041: 4033: 4024: 4023: 4021: 4020: 4008: 3995: 3992: 3991: 3989: 3988: 3983: 3977: 3975: 3971: 3970: 3968: 3967: 3962: 3956: 3954: 3950: 3949: 3947: 3946: 3941: 3936: 3931: 3926: 3921: 3916: 3911: 3905: 3903: 3899: 3898: 3896: 3895: 3890: 3885: 3880: 3875: 3870: 3865: 3860: 3855: 3850: 3845: 3840: 3835: 3830: 3825: 3820: 3815: 3810: 3805: 3799: 3797: 3793: 3792: 3790: 3789: 3784: 3779: 3774: 3769: 3764: 3759: 3753: 3751: 3747: 3746: 3744: 3743: 3738: 3733: 3728: 3723: 3718: 3713: 3707: 3705: 3695: 3694: 3692: 3691: 3686: 3681: 3676: 3671: 3666: 3659:Satellite dish 3656: 3651: 3646: 3641: 3636: 3631: 3626: 3620: 3618: 3614: 3613: 3611: 3610: 3605: 3600: 3595: 3590: 3588:Ground station 3585: 3580: 3575: 3570: 3564: 3562: 3558: 3557: 3550: 3549: 3542: 3535: 3527: 3521: 3520: 3512: 3499: 3492: 3491:External links 3489: 3488: 3487: 3475: 3472: 3469: 3468: 3442: 3418: 3411: 3385: 3360: 3334: 3308: 3282: 3256: 3227: 3208: 3189: 3172: 3158: 3147:. June 1, 2013 3129: 3122: 3102: 3082: 3060: 3035: 3013: 2988: 2966: 2938: 2913: 2891: 2869: 2847: 2822: 2800: 2772: 2747: 2741:978-1884989193 2740: 2720: 2698: 2670: 2648: 2619: 2613:978-1884989193 2612: 2592: 2559: 2528: 2487: 2454: 2433:Wireless World 2415: 2383: 2362: 2351:Britannica.com 2336: 2335: 2333: 2330: 2327: 2326: 2318:42,164 km 2298:42,164 km 2278: 2210: 2209: 2207: 2204: 2202: 2199: 2197: 2196: 2191: 2186: 2181: 2176: 2171: 2166: 2161: 2156: 2151: 2146: 2141: 2136: 2131: 2126: 2121: 2115: 2113: 2110: 2046: 2043: 2036: 2016: 1953:Main article: 1950: 1947: 1931:Main article: 1928: 1925: 1892:Main article: 1889: 1886: 1871:Main article: 1868: 1865: 1840: 1822: 1809: 1792: 1762:Direct-To-Home 1755: 1712: 1696: 1664: 1625:geosynchronous 1613:Main article: 1610: 1607: 1524:Main article: 1521: 1518: 1516: 1513: 1512: 1511: 1506: 1501: 1496: 1491: 1481: 1480: 1477: 1474: 1462: 1459: 1450: 1449: 1445: 1435: 1428: 1425: 1409: 1406: 1369: 1366: 1353:Main article: 1350: 1347: 1301:from a Moscow 1263:Main article: 1260: 1257: 1213: 1212: 1157: 1142: 1131:Telesat Canada 1123: 1102: 1099: 1059:Main article: 1056: 1053: 1052: 1051: 1040: 1031: 1028: 1011:Main article: 1008: 1005: 949:Main article: 946: 943: 913: 908:Main article: 905: 902: 897: 896: 887: 875: 860:, while other 828:to the lowest 813: 810: 778: 775: 714:Cape Canaveral 690: 687: 594: 591: 571:Sergey Korolev 531:Wireless World 521: 518: 516: 513: 482:satellite dish 416: 415: 413: 412: 405: 398: 390: 387: 386: 373: 372: 369: 368: 363: 358: 356:Space agencies 352: 349: 348: 345: 344: 341: 340: 335: 330: 328:Interplanetary 325: 320: 314: 311: 310: 307: 306: 303: 302: 297: 292: 280: 275: 269: 264: 263: 260: 259: 254: 253: 250: 249: 244: 239: 237:Space stations 234: 229: 227:Space capsules 224: 219: 216: 211: 210: 203: 202: 199: 198: 193: 188: 182: 177: 176: 171: 166: 165: 162: 161: 158: 157: 152: 147: 142: 137: 132: 127: 122: 117: 115:Communications 111: 106: 105: 102: 101: 98: 97: 92: 90:Lunar missions 87: 82: 77: 72: 66: 61: 60: 57: 56: 46: 45: 39: 38: 23:Replica of an 15: 9: 6: 4: 3: 2: 6252: 6241: 6238: 6236: 6233: 6231: 6228: 6226: 6223: 6221: 6218: 6217: 6215: 6200: 6196: 6191: 6189: 6180: 6179: 6176: 6170: 6167: 6165: 6162: 6160: 6157: 6155: 6152: 6151: 6149: 6147: 6143: 6137: 6134: 6132: 6129: 6127: 6124: 6122: 6118: 6115: 6113: 6110: 6108: 6107:Direct ascent 6105: 6104: 6102: 6100: 6096: 6090: 6089:Intergalactic 6087: 6085: 6082: 6080: 6077: 6073: 6070: 6068: 6065: 6064: 6063: 6060: 6058: 6055: 6054: 6052: 6048: 6040: 6037: 6035: 6032: 6030: 6027: 6025: 6024:Rocket engine 6022: 6021: 6020: 6017: 6013: 6010: 6008: 6005: 6003: 6000: 5998: 5995: 5993: 5990: 5988: 5985: 5984: 5983: 5980: 5978: 5975: 5971: 5968: 5966: 5963: 5961: 5958: 5957: 5956: 5955:Space capsule 5953: 5951: 5948: 5946: 5943: 5942: 5940: 5938: 5934: 5924: 5921: 5919: 5918:Space nursing 5916: 5914: 5911: 5909: 5906: 5902: 5899: 5898: 5897: 5894: 5892: 5889: 5885: 5882: 5881: 5880: 5877: 5876: 5874: 5872:Health issues 5870: 5864: 5861: 5859: 5856: 5854: 5851: 5849: 5846: 5844: 5841: 5837: 5834: 5833: 5832: 5829: 5827: 5826:Space Shuttle 5824: 5820: 5817: 5815: 5812: 5811: 5810: 5807: 5805: 5802: 5800: 5797: 5795: 5792: 5790: 5787: 5785: 5782: 5781: 5779: 5775: 5769: 5766: 5764: 5761: 5759: 5758:Space tourism 5756: 5754: 5751: 5749: 5746: 5744: 5741: 5739: 5736: 5732: 5729: 5727: 5724: 5722: 5719: 5718: 5717: 5714: 5710: 5707: 5706: 5705: 5702: 5701: 5699: 5695: 5692: 5690: 5686: 5680: 5679:Space weather 5677: 5675: 5672: 5670: 5667: 5665: 5662: 5660: 5657: 5655: 5652: 5650: 5647: 5645: 5642: 5638: 5635: 5633: 5630: 5628: 5625: 5623: 5620: 5619: 5618: 5615: 5611: 5608: 5606: 5603: 5601: 5598: 5596: 5593: 5592: 5591: 5588: 5586: 5583: 5582: 5580: 5578: 5574: 5566: 5563: 5562: 5561: 5558: 5554: 5551: 5549: 5546: 5544: 5543:Space command 5541: 5540: 5539: 5538:Space warfare 5536: 5532: 5529: 5527: 5524: 5522: 5519: 5517: 5514: 5512: 5509: 5508: 5507: 5504: 5500: 5499:United States 5497: 5495: 5492: 5490: 5487: 5485: 5482: 5480: 5477: 5475: 5472: 5470: 5467: 5465: 5462: 5460: 5457: 5456: 5455: 5452: 5450: 5447: 5443: 5440: 5438: 5435: 5433: 5430: 5428: 5425: 5424: 5423: 5420: 5418: 5417:Astrodynamics 5415: 5414: 5412: 5408: 5404: 5397: 5392: 5390: 5385: 5383: 5378: 5377: 5374: 5362: 5354: 5352: 5344: 5342: 5334: 5332: 5322: 5321: 5318: 5311: 5307: 5305: 5302: 5300: 5297: 5295: 5292: 5290: 5287: 5283: 5280: 5278: 5275: 5274: 5272: 5270: 5267: 5266: 5264: 5260: 5254: 5251: 5249: 5246: 5244: 5241: 5239: 5236: 5234: 5231: 5229: 5226: 5224: 5221: 5219: 5216: 5214: 5211: 5209: 5206: 5205: 5203: 5201: 5197: 5191: 5188: 5186: 5183: 5181: 5178: 5176: 5173: 5171: 5168: 5166: 5163: 5161: 5158: 5156: 5153: 5151: 5148: 5146: 5143: 5141: 5138: 5136: 5133: 5131: 5128: 5127: 5125: 5123: 5119: 5113: 5110: 5108: 5105: 5103: 5100: 5098: 5095: 5093: 5090: 5089: 5087: 5083: 5077: 5076:Code-division 5074: 5072: 5069: 5067: 5064: 5062: 5061:Time-division 5059: 5057: 5054: 5052: 5049: 5048: 5046: 5044: 5040: 5034: 5031: 5027: 5024: 5022: 5019: 5018: 5017: 5014: 5010: 5007: 5006: 5005: 5002: 5000: 4997: 4995: 4992: 4991: 4989: 4987:and switching 4985: 4981: 4973: 4970: 4969: 4968: 4965: 4961: 4958: 4957: 4956: 4953: 4951: 4948: 4946: 4943: 4939: 4938:optical fiber 4936: 4935: 4934: 4931: 4929: 4928:Coaxial cable 4926: 4925: 4923: 4921: 4915: 4909: 4906: 4904: 4901: 4899: 4896: 4894: 4891: 4889: 4886: 4884: 4881: 4879: 4876: 4874: 4871: 4869: 4866: 4864: 4861: 4859: 4856: 4854: 4851: 4849: 4846: 4844: 4843:Radia Perlman 4841: 4839: 4836: 4834: 4831: 4829: 4826: 4824: 4821: 4819: 4816: 4814: 4811: 4809: 4806: 4804: 4801: 4799: 4796: 4794: 4791: 4789: 4786: 4784: 4781: 4779: 4776: 4774: 4771: 4769: 4766: 4764: 4761: 4759: 4756: 4754: 4751: 4749: 4746: 4744: 4741: 4739: 4736: 4734: 4733:Lee de Forest 4731: 4729: 4728:Thomas Edison 4726: 4724: 4721: 4719: 4718:Donald Davies 4716: 4714: 4711: 4709: 4706: 4704: 4703:Claude Chappe 4701: 4699: 4696: 4694: 4691: 4689: 4686: 4684: 4681: 4679: 4676: 4674: 4671: 4669: 4666: 4664: 4661: 4659: 4656: 4654: 4651: 4649: 4646: 4644: 4641: 4639: 4636: 4634: 4631: 4630: 4628: 4624: 4618: 4615: 4613: 4610: 4608: 4605: 4603: 4600: 4596: 4593: 4591: 4588: 4587: 4586: 4583: 4581: 4580: 4576: 4574: 4571: 4568: 4565: 4563: 4560: 4558: 4555: 4553: 4550: 4548: 4547:Smoke signals 4545: 4541: 4538: 4536: 4533: 4531: 4528: 4527: 4526: 4525:Semiconductor 4523: 4519: 4516: 4515: 4514: 4511: 4509: 4506: 4504: 4501: 4499: 4496: 4494: 4491: 4489: 4486: 4484: 4481: 4479: 4476: 4474: 4471: 4467: 4464: 4463: 4462: 4459: 4457: 4454: 4452: 4449: 4447: 4444: 4442: 4439: 4437: 4434: 4432: 4429: 4427: 4424: 4422: 4419: 4417: 4414: 4412: 4409: 4405: 4402: 4400: 4397: 4395: 4392: 4390: 4387: 4386: 4385: 4384:Digital media 4382: 4378: 4375: 4373: 4370: 4368: 4365: 4363: 4360: 4359: 4358: 4355: 4353: 4350: 4348: 4345: 4343: 4340: 4338: 4335: 4333: 4330: 4328: 4325: 4324: 4322: 4320: 4316: 4312: 4305: 4300: 4298: 4293: 4291: 4286: 4285: 4282: 4272: 4262: 4250: 4244: 4241: 4239: 4236: 4234: 4231: 4229: 4226: 4224: 4221: 4220: 4218: 4214: 4208: 4205: 4203: 4202:Nuisance call 4200: 4198: 4195: 4193: 4190: 4189: 4187: 4183: 4177: 4174: 4172: 4169: 4167: 4164: 4162: 4159: 4157: 4154: 4152: 4149: 4147: 4144: 4142: 4141:Fibre-optical 4139: 4137: 4134: 4132: 4129: 4128: 4126: 4122: 4116: 4113: 4111: 4108: 4107: 4105: 4101: 4095: 4092: 4090: 4087: 4085: 4082: 4080: 4077: 4075: 4072: 4071: 4069: 4065: 4061: 4054: 4049: 4047: 4042: 4040: 4035: 4034: 4031: 4019: 4018: 4009: 4007: 4006: 3997: 3996: 3993: 3987: 3984: 3982: 3979: 3978: 3976: 3972: 3966: 3963: 3961: 3958: 3957: 3955: 3951: 3945: 3942: 3940: 3937: 3935: 3932: 3930: 3927: 3925: 3922: 3920: 3917: 3915: 3912: 3910: 3907: 3906: 3904: 3900: 3894: 3891: 3889: 3886: 3884: 3881: 3879: 3876: 3874: 3871: 3869: 3866: 3864: 3861: 3859: 3856: 3854: 3851: 3849: 3846: 3844: 3841: 3839: 3836: 3834: 3831: 3829: 3826: 3824: 3821: 3819: 3816: 3814: 3811: 3809: 3806: 3804: 3801: 3800: 3798: 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