Communications satellite

796:(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 828: 885:(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. 4277: 62: 646: 6195: 5348: 4011: 1050:, 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. 6206: 1542: 31: 5358: 390: 5337: 4267: 1029:

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.

638:. 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 1600:, 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 742:. 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 1296:

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

661:(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 522:. 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. 1912:

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.

768:, 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. 3353: 1458:

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.

819:, 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. 1036:

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.

938:(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. 1895:

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.

949:(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. 1218:, 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 1662:

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.).

1680:. 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, 1608:. 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. 6245: 764:. 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, 665:. The satellite also executed several realtime transmissions before the non-rechargeable batteries failed on 30 December 1958 after eight hours of actual operation. 2525: 2448: 1133:, 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. 2405: 2578:

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.

5452: 3354:"DIRECTV's Spaceway F1 Satellite Launches New Era in High-Definition Programming; Next Generation Satellite Will Initiate Historic Expansion of DIRECTV" 2474: 807:, who did not participate in the Intelsat agreements. The Soviet Union launched its first communications satellite on 23 April 1965 as part of the 3054:

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

3649: 1763:(usually 18 to 24 inches or 45 to 60 cm in diameter). Direct broadcast satellites generally operate in the upper portion of the microwave 1700:, and general commercial telecommunications. FSS satellites are also used to distribute national cable channels to cable television headends. 3970: 3246: 1445:

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.

5509: 5170: 4176: 3654: 3555: 1981: 1965: 1745: 1558: 1305: 1121:, launched on 19 August 1964, and used for communication across the Pacific starting with television coverage of the 658: 411: 366: 4955: 4503: 4305: 4156: 3148: 991: 679:'s satellite applications program launched the first artificial satellite used for passive relay communications in 3107:. INTER-AGENCY SPACE DEBRIS COORDINATION COMMITTEE: Issued by Steering Group and Working Group 4. September 2007. 6235: 5664: 5066: 2962:

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

3210:"TYCHO: Supporting Permanently Crewed Lunar Exploration with High-Speed Optical Communication from Everywhere" 1630:

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.

639: 536: 257: 206: 61: 2639:"United States Aeronautics and Space Activities - first Annual Report to Congress" 1480:(ITU). To facilitate frequency planning, the world is divided into three regions: 1136:

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

2406:"Military Satellite Communications Fundamentals | The Aerospace Corporation" 2189: 2184: 2112: 2072: 1922: 1883: 1867: 1536: 1432: 1388: 1058: 971: 946: 935: 929: 920: 902: 848: 836: 760:, launched on 26 July 1963. Syncom 2 was the first communications satellite in a 500: 305: 160: 3413: 1638:

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

723:(Post Office) to develop satellite communications, it was launched by NASA from 6169: 6156: 6049: 5980: 5970: 5955: 5933: 5923: 5819: 5809: 5758: 5679: 5026: 4898: 4873: 4833: 4803: 4678: 4513: 4466: 4441: 4399: 4253: 4238: 4207: 3669: 3598: 2436:"Extra-terrestrial Relays: Can Rocket Stations Give World-wide Radio Coverage?" 1772: 1760: 1562: 1490:

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

1400: 1141: 872: 852: 724: 581: 541: 492: 456: 300: 3525: 3305: 3228: 906:(LEO), and is about 160 to 2,000 kilometres (99 to 1,243 mi) above Earth. 539:

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

712: 692: 597: 569: 565: 550: 546: 516: 468: 283: 196: 3408:. Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 311–328. 1541: 30: 5238: 5228: 5145: 4970: 4793: 4084: 3883: 3848: 3843: 3833: 3823: 3818: 3746: 3694: 2646:

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".

3380:"India's first 'military' satellite GSAT-7 put into earth's orbit" 2739:

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

1788: 1776: 1764: 1673: 1659: 1384: 1333: 1325: 1321: 1263: 1250:(owns the former RCA Astro Electronics/GE Astro Space business), 1178:

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

1137: 1105: 1011: 704: 603: 488: 2229:

Orbital periods and speeds are calculated using the relations 4π

2008:. India has launched its first Military Communication satellite 974:

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

752:

An immediate antecedent of the geostationary satellites was the

727:

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

5960: 5824: 5263: 5223: 4545: 3944: 3893: 3787: 3736: 3721: 3644: 3634: 2037: 2009: 1871: 1341: 1313: 1309: 995: 793: 765: 757: 746: 680: 5382: 3229:"TYCHO mission to Earth-Moon libration point EML-4 @ IAC 2013" 787: 556: 5248: 5185: 4493: 3929: 3726: 3527:

Beyond The Ionosphere: Fifty Years of Satellite Communication

3057:

Beyond The Ionosphere: Fifty Years of Satellite Communication

2797:

Beyond The Ionosphere: Fifty Years of Satellite Communication

2581:

Beyond The Ionosphere: Fifty Years of Satellite Communication

1748:'s "must-carry" regulations, and for more bandwidth to carry 1719: 1471: 1160: 868: 860: 780: 589: 472: 460: 440: 4039: 2540: 5190: 2585: 2100: 1997: 1989: 1931: 1847: 1816: 1806:

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

1796: 1749: 1408: 1399:

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

1164: 1144:, with the United States following suit with the launch of 1104:

In applications that require many ground antennas, such as

676: 1759:

is a communications satellite that transmits to small DBS

1387:

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

1076: 608:

There are two major classes of communications satellites,

5841: 4233: 2032:

bands. Typically military satellites operate in the UHF,

2013: 1918: 1215: 1211: 1187: 1054: 1438:

Engines used to bring the satellite to its desired orbit

711:

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

3397: 2738: 2610: 2549:"Design of the first artificial satellite of the Earth" 966:

A group of satellites working in concert is known as a

3184: 3008:"NASA Compendium Of Satellite Communications Programs" 2933:"NASA Compendium Of Satellite Communications Programs" 2842:"NASA Compendium Of Satellite Communications Programs" 2698:. The White House. 18 January 1961. pp. 12–13, 26 1956:

connection, or require high availability of services.

699: 2767:"United States Aeronautics and Space Activities 1962" 2693:"United States Aeronautics and Space Activities 1960" 1850:

have also launched experimental satellites carrying K

1616:

connected to the Public Switched Telephone Network .

1340:. In November 1967 Soviet engineers created a unique 982:

systems. The Iridium system has 66 satellites, which

483:

applications. Many communications satellites are in

3170: 2000:

satellites, United Kingdom satellites (for instance

1443:

station keeping tracking and stabilization subsystem

3507: 2772:. The White House. 28 January 1963. pp. 20, 96 1866:owners. Such mobile DBS antennas are also used by 792:In the United States, 1962 saw the creation of the 3328:"Indian GSLV successfully lofts GSAT-14 satellite" 2648:. The White House. 2 February 1959. pp. 13–14 3346: 3201: 2499: 2296:Approximately 8.6 times when the Moon is nearest 2115:). The data rate is typically much lower than in 1779:, DISH Network and Orby TV in the United States, 900:The region below medium orbits is referred to as 6246:Telecommunications-related introductions in 1962 6222: 2400: 2398: 1487:Region 2: North and South America and Greenland 970:. Two such constellations, intended to provide 2095:. It may be based on a secondary payload of a 1226:By 2000, Hughes Space and Communications (now 604:Early active and passive satellite experiments 27:Artificial satellite that relays radio signals 5398: 4306: 4055: 3971:Consultative Committee for Space Data Systems 3549: 3013:. NASA. December 1975. pp. 10-1 to 10-64 2427: 2267:is the gravitational constant, approximately 1378: 412: 3563: 3464:. "Equipment needed for Telemetry of Data". 3406:Observation of the Earth and Its Environment 2466: 2395: 1427:Communication Payload, normally composed of 1065: 683:on 12 August 1960. Echo 1 was an aluminized 510:used for telecommunications links travel by 60: 5321:Global telecommunications regulation bodies 3438:"Satellite Data Telecommunication Handbook" 2938:. NASA. December 1975. pp. 9-1 to 9-56 2847:. NASA. December 1975. pp. 5-1 to 5-16 2571: 1771:. DBS technology is used for DTH-oriented ( 1452:, and batteries that maintain power during 1017: 788:International commercial satellite projects 5405: 5391: 5357: 4313: 4299: 4062: 4048: 3556: 3542: 3462:Intergovernmental Oceanographic Commission 3220: 3000: 2577: 1472:Frequency allocation for satellite systems 1468:can be used to arrive at the exact value. 955: 588:. Sputnik 1 was equipped with an on-board 419: 405: 3997:List of communication satellite companies 3102:"IADC Space Debris Mitigation Guidelines" 3053: 2925: 2834: 2793: 2687: 2685: 2316:, to 9.6 times when the Moon is farthest 2150:List of communication satellite companies 1159:was launched: the experimental satellite 463:. Communications satellites are used for 3494:(Johns Hopkins University Press, 2022); 2957: 2955: 2953: 2789: 2787: 2614:Communications Satellites: Project SCORE 2355: 2279:is the mass of Earth, approximately 5.98 2145:Inter-satellite communications satellite 1795:in the UK, Ireland, and New Zealand and 1540: 1356:, that was based on Molniya satellites. 1075: 914: 826: 644: 555: 487:22,236 miles (35,785 km) above the 29: 5890:Effect of spaceflight on the human body 3992:List of communications satellite firsts 3513:Communications satellites short history 2505: 2382:"Satellites - Communication Satellites" 2155:List of communications satellite firsts 1976:Communications satellites are used for 1921:radio equipment and highly directional 1046:In 1962, the communications satellite, 632:United States Naval Research Laboratory 576:on 4 October 1957. It was developed by 14: 6223: 5912:Psychological and sociological effects 4320: 3874:Shanghai Spacecom Satellite Technology 3403: 3226: 3207: 3124:The Basics of Satellite Communications 3120: 2961: 2759: 2682: 2559:from the original on 26 September 2023 2433: 2111:) or in dedicated satellites (such as 1650:satellites. Examples of these are the 1117:The first geostationary satellite was 893:(MEO) satellites are closer to Earth. 5386: 4294: 4043: 3537: 3360:from the original on 20 December 2023 2950: 2784: 2600:from the original on 29 October 2023. 2528:from the original on 24 November 2023 2472: 2454:from the original on 19 November 2023 1877: 1478:International Telecommunication Union 736:Massachusetts Institute of Technology 5367: 4022: 3078: 1505:Broadcasting satellite service (BSS) 794:Communications Satellite Corporation 2546: 1228:Boeing Satellite Development Center 833:medium altitude orbits around Earth 822: 777:United States Department of Defense 700:More firsts and further experiments 24: 5621:Weather and environment monitoring 3484: 2964:Handbook of Satellite Applications 2742:Communications Satellites: Telstar 2487:from the original on 13 April 2023 2434:Clarke, Arthur C. (October 1945). 2259:is the orbital period in seconds; 2255:is the radius of orbit in metres; 2083:), may use satellites for one-way 2055: 1982:Global Command and Control Systems 1937: 1435:, amplifiers and switching systems 1391:spacecraft and Installations. The 1244:Indian Space Research Organisation 1111: 1040: 572:, which was put into orbit by the 25: 6262: 3655:Automatic Tracking Satellite Dish 3501: 1966:Military communications satellite 1775:) satellite TV services, such as 1559:Public Switched Telephone Network 1515:Radionavigation-satellite service 659:Advanced Research Projects Agency 6204: 6194: 6193: 5366: 5356: 5347: 5346: 5335: 4956:Free-space optical communication 4275: 4265: 4021: 4010: 4009: 2004:), and satellites of the former 1898: 1672:, and the lower portions of the 1520:Meteorological-satellite service 1269: 992:satellite internet constellation 879:Geostationary satellites have a 443:telecommunication signals via a 388: 5665:Space launch market competition 5412: 3454: 3430: 3372: 3320: 3294: 3268: 3239: 3141: 3127:. Intl. Engineering Consortiu. 3114: 3094: 3079:Mann, Reuben (April 26, 2022). 3072: 3047: 3025: 2978: 2903: 2881: 2859: 2812: 2732: 2710: 2660: 2631: 2506:Siddiqi, Asif (November 2007). 2356:Labrador, Virgil (2015-02-19). 2290: 2223: 1859:Global Positioning System (GPS) 1575:submarine communications cables 1525: 1413:Mars Telecommunications Orbiter 634:in 1951 led to a project named 6251:Wireless communication systems 5902:Health threat from cosmic rays 3508:Satellite Industry Association 3227:Hornig, Andreas (2013-10-06). 3208:Hornig, Andreas (2022-05-01). 3149:"Soyuz Flight VS05 Launch Kit" 2604: 2374: 2349: 2135:High-altitude platform station 2012:, its transponders operate in 1972:X Band Satellite Communication 1823:band form for the now-defunct 1359: 831:Clickable image, highlighting 773:Lincoln Experimental Satellite 13: 1: 4069: 2473:Mills, Mike (3 August 1997). 2263:is the orbital speed in m/s; 2211: 1888:Satellite radio offers audio 1692:by schools and universities, 1688:), as well as being used for 1619: 1500:Fixed satellite service (FSS) 1324:and the Russian Far East, in 5342:Telecommunication portal 5123:Telecommunications equipment 4357: 4272:Telecommunication portal 3976:ETSI Satellite Digital Radio 3700:Very-small-aperture terminal 2508:"The Man Behind the Curtain" 2412:. 2010-04-01. Archived from 2342: 2140:History of telecommunication 1530: 1418: 1236:Orbital Sciences Corporation 7: 6018:Self-replicating spacecraft 5854:International Space Station 4859:Alexander Stepanovich Popov 3752:Digital audio radio service 3660:Motor-driven Satellite dish 3414:10.1007/978-3-642-56294-5_4 3356:. SpaceRef. 26 April 2005. 2513:Air & Space/Smithsonian 2122: 1959: 1401:Earth-Moon-Libration points 1300:The first satellite of the 1182:channels such as WTBS (now 1059:broadband internet services 713:Bell Telephone Laboratories 361:List of space organizations 10: 6267: 5532:Space Liability Convention 4563:Telecommunications history 3121:Pelton, Joseph N. (2006). 2130:Commercialization of space 1969: 1963: 1941: 1902: 1881: 1757:direct broadcast satellite 1640:Direct broadcast satellite 1623: 1534: 1379:Beyond geostationary orbit 1363: 1273: 1125:. Shortly after Syncom 3, 1069: 1021: 959: 918: 618:. Passive satellites only 566:artificial Earth satellite 530: 525: 459:at different locations on 439:that relays and amplifies 6231:Communications satellites 6188: 6155: 6108: 6060: 5946: 5895:Space adaptation syndrome 5882: 5787: 5707: 5698: 5586: 5420: 5330: 5272: 5209: 5171:Public Switched Telephone 5131: 5095: 5052: 4993: 4983:telecommunication circuit 4944:Fiber-optic communication 4927: 4689:Francis Blake (telephone) 4636: 4484:Optical telecommunication 4328: 4262: 4226: 4195: 4147:Communications satellites 4134: 4113: 4077: 4005: 3984: 3963: 3912: 3807:Relay satellite companies 3806: 3760: 3708: 3627: 3604:High-throughput satellite 3589:Satellite Internet access 3571: 3276:"Orby TV (United States)" 2384:. Satellites.spacesim.org 2358:"satellite communication" 1944:Satellite Internet access 1870:for DirecTV (supplied by 1066:Geostationary orbit (GEO) 1000:satellite Internet access 857:Van Allen radiation belts 5628:Communications satellite 5082:Orbital angular-momentum 4519:Satellite communications 4358:Communications satellite 3565:Satellite communications 2216: 2165:Reconnaissance satellite 2065:environmental monitoring 1666:Fixed Service Satellites 1510:Mobile-satellite service 1018:Medium Earth orbit (MEO) 636:Communication Moon Relay 497:satellite constellations 433:communications satellite 18:Communication satellites 6132:reusable launch systems 5749:Extravehicular activity 5660:Commercial use of space 5564:Militarisation of space 5537:Registration Convention 5453:Accidents and incidents 4961:Molecular communication 4784:Gardiner Greene Hubbard 4613:Undersea telegraph line 4348:Cable protection system 4142:Cable protection system 3913:Satellite manufacturers 3060:. NASA History Office. 2800:. NASA History Office. 2195:Satellite space segment 1978:military communications 1905:Amateur radio satellite 1854:band beacons recently. 1644:Fixed Service Satellite 1555:long distance telephony 998:, that aims for global 968:satellite constellation 962:Satellite constellation 956:Satellite constellation 873:orbital classifications 853:Moon's orbital distance 817:highly elliptical orbit 754:Hughes Aircraft Company 91:Timeline of spaceflight 6236:Satellite broadcasting 6180:Mission control center 6142:Non-rocket spacelaunch 5576:Billionaire space race 5103:Communication protocol 4889:Charles Sumner Tainter 4704:Walter Houser Brattain 4649:Edwin Howard Armstrong 4457:Information revolution 3304:. ISRO. Archived from 2966:. New York: Springer. 2745:(5th ed.). AIAA. 2617:(5th ed.). AIAA. 2170:Relay (disambiguation) 1996:of the United States, 1980:applications, such as 1934:or similar protocols. 1827:satellite TV service. 1550: 1283:multipath interference 1083: 864: 851:, at one ninth of the 650: 586:Konstantin Tsiolkovsky 584:, building on work by 561: 395:Spaceflight portal 311:Non-rocket spacelaunch 81:History of spaceflight 65: 38: 6030:Spacecraft propulsion 5480:European Space Agency 5077:Polarization-division 4809:Narinder Singh Kapany 4774:Erna Schneider Hoover 4694:Jagadish Chandra Bose 4674:Alexander Graham Bell 4405:online video platform 4282:Telephones portal 2547:Zak, Anatoly (2017). 1970:Further information: 1812:circular polarization 1544: 1254:, Alcatel Space, now 1157:three-axis stabilized 1079: 915:Low Earth orbit (LEO) 830: 648: 559: 547:artificial satellites 449:communication channel 64: 33: 5655:Satellite navigation 4919:Vladimir K. Zworykin 4879:Almon Brown Strowger 4849:Charles Grafton Page 4504:Prepaid mobile phone 4432:Electrical telegraph 4244:Telephone newspapers 3579:Satellite television 3529:(NASA SP-4217, 1997) 3247:"Connected:Maritime" 1864:recreational vehicle 1838:, such as DirecTV's 1626:Satellite television 1405:geosynchronous orbit 1393:Moonlight Initiative 1350:satellite television 1320:stations located in 1123:1964 Summer Olympics 1090:(one revolution per 815:, which describes a 762:geosynchronous orbit 715:, NASA, the British 687:acting as a passive 673:from the satellite. 663:Dwight D. Eisenhower 625:free-space path loss 560:Replica of Sputnik 1 437:artificial satellite 6040:Electric propulsion 5727:Life-support system 5611:Imagery and mapping 5571:Private spaceflight 4869:Johann Philipp Reis 4628:Wireless revolution 4590:The Telephone Cases 4447:Hydraulic telegraph 4167:Mobile phone signal 3964:Trade organizations 3955:Thales Alenia Space 3768:Astra Digital Radio 3761:Broadcast companies 3690:Satellite data unit 3192:"Moonlight Webinar" 3178:"Project Moonlight" 3066:1997bify.book.....B 2972:2017hsa..book.....P 2820:"Project West Ford" 2806:1997bify.book.....B 2594:1997bify.book.....B 2553:RussianSpaceWeb.com 2480:The Washington Post 2205:Traveling-wave tube 2180:Satellite data unit 2099:(as in the case of 2067:equipment (such as 2052:) frequency bands. 1808:linear polarization 1712:Intelsat Americas 5 1694:business television 1577:through the use of 1256:Thales Alenia Space 1232:Space Systems/Loral 1200:The Weather Channel 1081:Geostationary orbit 1072:Geostationary orbit 1057:satellites provide 984:orbital inclination 882:geostationary orbit 845:geostationary orbit 734:, which was led by 721:French National PTT 717:General Post Office 578:Mikhail Tikhonravov 485:geostationary orbit 233:Apollo Lunar Module 6241:Satellites by type 5993:Robotic spacecraft 5919:Space and survival 5774:Space colonization 5670:Space architecture 5522:Outer Space Treaty 5067:Frequency-division 5044:Telephone exchange 4914:Charles Wheatstone 4844:Jun-ichi Nishizawa 4819:Innocenzo Manzetti 4754:Reginald Fessenden 4489:Optical telegraphy 4322:Telecommunications 4157:Free-space optical 3783:Sirius XM Holdings 3674:Parabolic antennas 3522:by David J. Whalen 3518:2015-05-12 at the 2175:Satcom On The Move 2117:satellite Internet 2107:and others in the 1878:Radio broadcasting 1551: 1140:, was launched by 1084: 1024:Medium Earth orbit 890:Medium Earth orbit 865: 740:Lincoln Laboratory 651: 623:attenuated due to 562: 190:Robotic spacecraft 66: 39: 6218: 6217: 6165:Flight controller 5942: 5941: 5700:Human spaceflight 5675:Space exploration 5601:Earth observation 5380: 5379: 5118:Store and forward 5113:Data transmission 5027:Network switching 4978:Transmission line 4824:Guglielmo Marconi 4789:Internet pioneers 4654:Mohamed M. Atalla 4623:Whistled language 4288: 4287: 4121:Answering machine 4037: 4036: 3594:Amateur satellite 3490:Slotten, Hugh R. 3423:978-3-642-62688-3 3332:NASA Space Flight 3308:on 8 January 2014 3134:978-1-931695-48-0 2283:10 kg (1.318 2097:weather satellite 2085:data transmission 1799:in South Africa. 1781:Bell Satellite TV 1698:Videoconferencing 1690:distance learning 1569:telephones to an 1466:network simulator 1152:on 13 April 1974. 895:Orbital altitudes 732:Project West Ford 685:balloon satellite 535:In October 1945, 451:between a source 429: 428: 323:Spaceflight types 267: 266: 224:Crewed spacecraft 216: 215: 131:Earth observation 36:Iridium satellite 16:(Redirected from 6258: 6208: 6197: 6196: 5907:Space psychology 5732:Animals in space 5705: 5704: 5685:Space technology 5527:Rescue Agreement 5407: 5400: 5393: 5384: 5383: 5370: 5369: 5360: 5359: 5350: 5349: 5340: 5339: 5338: 5211:Notable networks 5201:Wireless network 5141:Cellular network 5133:Types of network 5108:Computer network 4995:Network topology 4909:Thomas A. Watson 4764:Oliver Heaviside 4749:Philo Farnsworth 4724:Daniel Davis Jr. 4699:Charles Bourseul 4659:John Logie Baird 4368:Data compression 4363:Computer network 4315: 4308: 4301: 4292: 4291: 4280: 4279: 4278: 4270: 4269: 4268: 4234:Fax transmission 4182:Submarine cables 4064: 4057: 4050: 4041: 4040: 4025: 4024: 4013: 4012: 3940:Northrop Grumman 3619:Carriage dispute 3558: 3551: 3544: 3535: 3534: 3478: 3477: 3475: 3474: 3458: 3452: 3451: 3449: 3448: 3434: 3428: 3427: 3401: 3395: 3394: 3392: 3391: 3376: 3370: 3369: 3367: 3365: 3350: 3344: 3343: 3341: 3339: 3334:. 4 January 2014 3324: 3318: 3317: 3315: 3313: 3298: 3292: 3291: 3289: 3287: 3278:. Archived from 3272: 3266: 3265: 3263: 3262: 3253:. Archived from 3243: 3237: 3236: 3224: 3218: 3217: 3205: 3199: 3198: 3196: 3188: 3182: 3181: 3174: 3168: 3167: 3165: 3163: 3153: 3145: 3139: 3138: 3118: 3112: 3111: 3106: 3098: 3092: 3091: 3089: 3087: 3076: 3070: 3069: 3051: 3045: 3044: 3042: 3040: 3029: 3023: 3022: 3020: 3018: 3012: 3004: 2998: 2997: 2995: 2993: 2982: 2976: 2975: 2959: 2948: 2947: 2945: 2943: 2937: 2929: 2923: 2922: 2920: 2918: 2907: 2901: 2900: 2898: 2896: 2885: 2879: 2878: 2876: 2874: 2863: 2857: 2856: 2854: 2852: 2846: 2838: 2832: 2831: 2829: 2827: 2816: 2810: 2809: 2791: 2782: 2781: 2779: 2777: 2771: 2763: 2757: 2756: 2736: 2730: 2729: 2727: 2725: 2714: 2708: 2707: 2705: 2703: 2697: 2689: 2680: 2679: 2677: 2675: 2664: 2658: 2657: 2655: 2653: 2643: 2635: 2629: 2628: 2608: 2602: 2601: 2588:History Office. 2575: 2569: 2568: 2566: 2564: 2544: 2538: 2537: 2535: 2533: 2503: 2497: 2496: 2494: 2492: 2470: 2464: 2463: 2461: 2459: 2453: 2440: 2431: 2425: 2424: 2422: 2421: 2402: 2393: 2392: 2390: 2389: 2378: 2372: 2371: 2369: 2368: 2353: 2336: 2335: 2333: 2331: 2330: 2327: 2324: 2315: 2313: 2311: 2310: 2307: 2304: 2294: 2288: 2286: 2282: 2274: 2272: 2227: 2073:weather stations 1761:satellite dishes 1586:Ascension Island 1252:Northrop Grumman 1096:equatorial orbit 1088:angular velocity 927: 841:High Earth orbit 823:Satellite orbits 640:Washington, D.C. 537:Arthur C. Clarke 421: 414: 407: 393: 392: 391: 218: 217: 207:Cargo spacecraft 184: 183: 41: 40: 21: 6266: 6265: 6261: 6260: 6259: 6257: 6256: 6255: 6221: 6220: 6219: 6214: 6184: 6151: 6123:Escape velocity 6104: 6056: 6023:Space telescope 5976:Reentry capsule 5938: 5878: 5783: 5754:Overview effect 5737:Bioastronautics 5694: 5582: 5416: 5411: 5381: 5376: 5336: 5334: 5326: 5268: 5205: 5127: 5091: 5048: 4997: 4989: 4930: 4923: 4829:Robert Metcalfe 4684:Tim Berners-Lee 4632: 4452:Information Age 4324: 4319: 4289: 4284: 4276: 4274: 4266: 4264: 4258: 4239:Telephone calls 4222: 4191: 4130: 4109: 4100:Satellite phone 4090:Cable telephony 4073: 4068: 4038: 4033: 4001: 3980: 3959: 3935:Lockheed Martin 3908: 3814:AST SpaceMobile 3802: 3756: 3710:Satellite radio 3704: 3685:Satellite modem 3680:Satellite phone 3665:Multi-satellite 3623: 3609:Relay satellite 3584:Satellite radio 3567: 3562: 3520:Wayback Machine 3504: 3487: 3485:Further reading 3482: 3481: 3472: 3470: 3459: 3455: 3446: 3444: 3442:library.wmo.int 3436: 3435: 3431: 3424: 3402: 3398: 3389: 3387: 3378: 3377: 3373: 3363: 3361: 3352: 3351: 3347: 3337: 3335: 3326: 3325: 3321: 3311: 3309: 3300: 3299: 3295: 3285: 3283: 3282:on 28 July 2020 3274: 3273: 3269: 3260: 3258: 3245: 3244: 3240: 3225: 3221: 3206: 3202: 3194: 3190: 3189: 3185: 3176: 3175: 3171: 3161: 3159: 3151: 3147: 3146: 3142: 3135: 3119: 3115: 3104: 3100: 3099: 3095: 3085: 3083: 3077: 3073: 3052: 3048: 3038: 3036: 3031: 3030: 3026: 3016: 3014: 3010: 3006: 3005: 3001: 2991: 2989: 2984: 2983: 2979: 2960: 2951: 2941: 2939: 2935: 2931: 2930: 2926: 2916: 2914: 2909: 2908: 2904: 2894: 2892: 2887: 2886: 2882: 2872: 2870: 2865: 2864: 2860: 2850: 2848: 2844: 2840: 2839: 2835: 2825: 2823: 2818: 2817: 2813: 2792: 2785: 2775: 2773: 2769: 2765: 2764: 2760: 2753: 2737: 2733: 2723: 2721: 2716: 2715: 2711: 2701: 2699: 2695: 2691: 2690: 2683: 2673: 2671: 2666: 2665: 2661: 2651: 2649: 2641: 2637: 2636: 2632: 2625: 2609: 2605: 2576: 2572: 2562: 2560: 2545: 2541: 2531: 2529: 2504: 2500: 2490: 2488: 2471: 2467: 2457: 2455: 2451: 2438: 2432: 2428: 2419: 2417: 2404: 2403: 2396: 2387: 2385: 2380: 2379: 2375: 2366: 2364: 2354: 2350: 2345: 2340: 2339: 2328: 2325: 2323:405,696 km 2322: 2321: 2319: 2317: 2308: 2305: 2303:363,104 km 2302: 2301: 2299: 2297: 2295: 2291: 2284: 2280: 2270: 2268: 2228: 2224: 2219: 2214: 2209: 2200:Space pollution 2190:Satellite modem 2185:Satellite delay 2125: 2058: 2056:Data collection 2049: 2044:(also known as 2036:(also known as 2029: 1974: 1968: 1962: 1946: 1940: 1938:Internet access 1907: 1901: 1886: 1884:Satellite radio 1880: 1868:JetBlue Airways 1853: 1842:satellite, and 1835: 1822: 1805: 1768: 1725: 1709: 1677: 1628: 1622: 1563:telephone calls 1539: 1537:Satellite phone 1533: 1528: 1474: 1421: 1381: 1368: 1362: 1344:of national TV 1278: 1272: 1248:Lockheed Martin 1114: 1112:Examples of GEO 1074: 1068: 1043: 1041:Examples of MEO 1026: 1020: 972:satellite phone 964: 958: 947:signal strength 936:low Earth orbit 932: 930:Low Earth orbit 925: 923: 921:Low Earth orbit 917: 903:low Earth orbit 849:graveyard orbit 825: 790: 702: 606: 533: 528: 501:low Earth orbit 447:; it creates a 425: 389: 387: 382: 381: 362: 354: 353: 324: 316: 315: 306:Escape velocity 301:launch vehicles 279: 269: 268: 263: 262: 226: 212: 211: 192: 181: 171: 170: 121: 111: 110: 76: 28: 23: 22: 15: 12: 11: 5: 6264: 6254: 6253: 6248: 6243: 6238: 6233: 6216: 6215: 6213: 6212: 6201: 6189: 6186: 6185: 6183: 6182: 6177: 6172: 6170:Ground station 6167: 6161: 6159: 6157:Ground segment 6153: 6152: 6150: 6149: 6144: 6139: 6134: 6125: 6120: 6114: 6112: 6106: 6105: 6103: 6102: 6097: 6092: 6090:Interplanetary 6087: 6086: 6085: 6083:Geosynchronous 6080: 6070: 6064: 6062: 6058: 6057: 6055: 6054: 6053: 6052: 6050:Gravity assist 6047: 6042: 6037: 6027: 6026: 6025: 6020: 6015: 6010: 6005: 6000: 5990: 5985: 5984: 5983: 5981:Service module 5978: 5973: 5971:Orbital module 5963: 5958: 5956:Launch vehicle 5952: 5950: 5944: 5943: 5940: 5939: 5937: 5936: 5934:Space sexology 5931: 5926: 5924:Space medicine 5921: 5916: 5915: 5914: 5904: 5899: 5898: 5897: 5886: 5884: 5880: 5879: 5877: 5876: 5871: 5866: 5861: 5856: 5851: 5850: 5849: 5839: 5834: 5833: 5832: 5827: 5817: 5812: 5807: 5802: 5797: 5791: 5789: 5785: 5784: 5782: 5781: 5776: 5771: 5766: 5761: 5759:Weightlessness 5756: 5751: 5746: 5745: 5744: 5739: 5734: 5724: 5723: 5722: 5711: 5709: 5702: 5696: 5695: 5693: 5692: 5687: 5682: 5680:Space research 5677: 5672: 5667: 5662: 5657: 5652: 5651: 5650: 5645: 5640: 5635: 5625: 5624: 5623: 5618: 5616:Reconnaissance 5613: 5608: 5598: 5592: 5590: 5584: 5583: 5581: 5580: 5579: 5578: 5568: 5567: 5566: 5561: 5556: 5546: 5545: 5544: 5539: 5534: 5529: 5524: 5514: 5513: 5512: 5507: 5502: 5497: 5492: 5487: 5485:European Union 5482: 5477: 5472: 5462: 5457: 5456: 5455: 5450: 5445: 5440: 5430: 5424: 5422: 5418: 5417: 5410: 5409: 5402: 5395: 5387: 5378: 5377: 5375: 5374: 5364: 5354: 5344: 5331: 5328: 5327: 5325: 5324: 5317: 5312: 5307: 5302: 5297: 5296: 5295: 5290: 5282: 5276: 5274: 5270: 5269: 5267: 5266: 5261: 5256: 5251: 5246: 5241: 5236: 5231: 5226: 5221: 5215: 5213: 5207: 5206: 5204: 5203: 5198: 5193: 5188: 5183: 5178: 5173: 5168: 5163: 5158: 5153: 5148: 5143: 5137: 5135: 5129: 5128: 5126: 5125: 5120: 5115: 5110: 5105: 5099: 5097: 5093: 5092: 5090: 5089: 5084: 5079: 5074: 5069: 5064: 5062:Space-division 5058: 5056: 5050: 5049: 5047: 5046: 5041: 5040: 5039: 5034: 5024: 5023: 5022: 5012: 5007: 5001: 4999: 4991: 4990: 4988: 4987: 4986: 4985: 4975: 4974: 4973: 4963: 4958: 4953: 4952: 4951: 4941: 4935: 4933: 4925: 4924: 4922: 4921: 4916: 4911: 4906: 4901: 4899:Camille Tissot 4896: 4891: 4886: 4881: 4876: 4874:Claude Shannon 4871: 4866: 4864:Tivadar Puskás 4861: 4856: 4851: 4846: 4841: 4836: 4834:Antonio Meucci 4831: 4826: 4821: 4816: 4811: 4806: 4804:Charles K. Kao 4801: 4796: 4791: 4786: 4781: 4779:Harold Hopkins 4776: 4771: 4766: 4761: 4756: 4751: 4746: 4741: 4736: 4731: 4726: 4721: 4716: 4711: 4706: 4701: 4696: 4691: 4686: 4681: 4679:Emile Berliner 4676: 4671: 4666: 4661: 4656: 4651: 4646: 4640: 4638: 4634: 4633: 4631: 4630: 4625: 4620: 4618:Videotelephony 4615: 4610: 4609: 4608: 4603: 4593: 4586: 4581: 4575: 4570: 4565: 4560: 4555: 4554: 4553: 4548: 4543: 4533: 4532: 4531: 4521: 4516: 4514:Radiotelephone 4511: 4506: 4501: 4496: 4491: 4486: 4481: 4480: 4479: 4469: 4464: 4459: 4454: 4449: 4444: 4439: 4434: 4429: 4424: 4419: 4418: 4417: 4412: 4407: 4402: 4400:Internet video 4392: 4391: 4390: 4385: 4380: 4375: 4365: 4360: 4355: 4350: 4345: 4340: 4334: 4332: 4326: 4325: 4318: 4317: 4310: 4303: 4295: 4286: 4285: 4263: 4260: 4259: 4257: 4256: 4251: 4246: 4241: 4236: 4230: 4228: 4224: 4223: 4221: 4220: 4215: 4210: 4208:Misdialed call 4205: 4199: 4197: 4193: 4192: 4190: 4189: 4184: 4179: 4174: 4169: 4164: 4159: 4154: 4149: 4144: 4138: 4136: 4132: 4131: 4129: 4128: 4123: 4117: 4115: 4111: 4110: 4108: 4107: 4102: 4097: 4092: 4087: 4081: 4079: 4075: 4074: 4067: 4066: 4059: 4052: 4044: 4035: 4034: 4032: 4031: 4019: 4006: 4003: 4002: 4000: 3999: 3994: 3988: 3986: 3982: 3981: 3979: 3978: 3973: 3967: 3965: 3961: 3960: 3958: 3957: 3952: 3947: 3942: 3937: 3932: 3927: 3922: 3916: 3914: 3910: 3909: 3907: 3906: 3901: 3896: 3891: 3886: 3881: 3876: 3871: 3866: 3861: 3856: 3851: 3846: 3841: 3836: 3831: 3826: 3821: 3816: 3810: 3808: 3804: 3803: 3801: 3800: 3795: 3790: 3785: 3780: 3775: 3770: 3764: 3762: 3758: 3757: 3755: 3754: 3749: 3744: 3739: 3734: 3729: 3724: 3718: 3716: 3706: 3705: 3703: 3702: 3697: 3692: 3687: 3682: 3677: 3670:Satellite dish 3667: 3662: 3657: 3652: 3647: 3642: 3637: 3631: 3629: 3625: 3624: 3622: 3621: 3616: 3611: 3606: 3601: 3599:Ground station 3596: 3591: 3586: 3581: 3575: 3573: 3569: 3568: 3561: 3560: 3553: 3546: 3538: 3532: 3531: 3523: 3510: 3503: 3502:External links 3500: 3499: 3498: 3486: 3483: 3480: 3479: 3453: 3429: 3422: 3396: 3371: 3345: 3319: 3293: 3267: 3238: 3219: 3200: 3183: 3169: 3158:. June 1, 2013 3140: 3133: 3113: 3093: 3071: 3046: 3024: 2999: 2977: 2949: 2924: 2902: 2880: 2858: 2833: 2811: 2783: 2758: 2752:978-1884989193 2751: 2731: 2709: 2681: 2659: 2630: 2624:978-1884989193 2623: 2603: 2570: 2539: 2498: 2465: 2444:Wireless World 2426: 2394: 2373: 2362:Britannica.com 2347: 2346: 2344: 2341: 2338: 2337: 2329:42,164 km 2309:42,164 km 2289: 2221: 2220: 2218: 2215: 2213: 2210: 2208: 2207: 2202: 2197: 2192: 2187: 2182: 2177: 2172: 2167: 2162: 2157: 2152: 2147: 2142: 2137: 2132: 2126: 2124: 2121: 2057: 2054: 2047: 2027: 1964:Main article: 1961: 1958: 1942:Main article: 1939: 1936: 1903:Main article: 1900: 1897: 1882:Main article: 1879: 1876: 1851: 1833: 1820: 1803: 1773:Direct-To-Home 1766: 1723: 1707: 1675: 1636:geosynchronous 1624:Main article: 1621: 1618: 1535:Main article: 1532: 1529: 1527: 1524: 1523: 1522: 1517: 1512: 1507: 1502: 1492: 1491: 1488: 1485: 1473: 1470: 1461: 1460: 1456: 1446: 1439: 1436: 1420: 1417: 1380: 1377: 1364:Main article: 1361: 1358: 1312:from a Moscow 1274:Main article: 1271: 1268: 1224: 1223: 1168: 1153: 1142:Telesat Canada 1134: 1113: 1110: 1070:Main article: 1067: 1064: 1063: 1062: 1051: 1042: 1039: 1022:Main article: 1019: 1016: 960:Main article: 957: 954: 924: 919:Main article: 916: 913: 908: 907: 898: 886: 871:, while other 839:to the lowest 824: 821: 789: 786: 725:Cape Canaveral 701: 698: 605: 602: 582:Sergey Korolev 542:Wireless World 532: 529: 527: 524: 493:satellite dish 427: 426: 424: 423: 416: 409: 401: 398: 397: 384: 383: 380: 379: 374: 369: 367:Space agencies 363: 360: 359: 356: 355: 352: 351: 346: 341: 339:Interplanetary 336: 331: 325: 322: 321: 318: 317: 314: 313: 308: 303: 291: 286: 280: 275: 274: 271: 270: 265: 264: 261: 260: 255: 250: 248:Space stations 245: 240: 238:Space capsules 235: 230: 227: 222: 221: 214: 213: 210: 209: 204: 199: 193: 188: 187: 182: 177: 176: 173: 172: 169: 168: 163: 158: 153: 148: 143: 138: 133: 128: 126:Communications 122: 117: 116: 113: 112: 109: 108: 103: 101:Lunar missions 98: 93: 88: 83: 77: 72: 71: 68: 67: 57: 56: 50: 49: 34:Replica of an 26: 9: 6: 4: 3: 2: 6263: 6252: 6249: 6247: 6244: 6242: 6239: 6237: 6234: 6232: 6229: 6228: 6226: 6211: 6207: 6202: 6200: 6191: 6190: 6187: 6181: 6178: 6176: 6173: 6171: 6168: 6166: 6163: 6162: 6160: 6158: 6154: 6148: 6145: 6143: 6140: 6138: 6135: 6133: 6129: 6126: 6124: 6121: 6119: 6118:Direct ascent 6116: 6115: 6113: 6111: 6107: 6101: 6100:Intergalactic 6098: 6096: 6093: 6091: 6088: 6084: 6081: 6079: 6076: 6075: 6074: 6071: 6069: 6066: 6065: 6063: 6059: 6051: 6048: 6046: 6043: 6041: 6038: 6036: 6035:Rocket engine 6033: 6032: 6031: 6028: 6024: 6021: 6019: 6016: 6014: 6011: 6009: 6006: 6004: 6001: 5999: 5996: 5995: 5994: 5991: 5989: 5986: 5982: 5979: 5977: 5974: 5972: 5969: 5968: 5967: 5966:Space capsule 5964: 5962: 5959: 5957: 5954: 5953: 5951: 5949: 5945: 5935: 5932: 5930: 5929:Space nursing 5927: 5925: 5922: 5920: 5917: 5913: 5910: 5909: 5908: 5905: 5903: 5900: 5896: 5893: 5892: 5891: 5888: 5887: 5885: 5883:Health issues 5881: 5875: 5872: 5870: 5867: 5865: 5862: 5860: 5857: 5855: 5852: 5848: 5845: 5844: 5843: 5840: 5838: 5837:Space Shuttle 5835: 5831: 5828: 5826: 5823: 5822: 5821: 5818: 5816: 5813: 5811: 5808: 5806: 5803: 5801: 5798: 5796: 5793: 5792: 5790: 5786: 5780: 5777: 5775: 5772: 5770: 5769:Space tourism 5767: 5765: 5762: 5760: 5757: 5755: 5752: 5750: 5747: 5743: 5740: 5738: 5735: 5733: 5730: 5729: 5728: 5725: 5721: 5718: 5717: 5716: 5713: 5712: 5710: 5706: 5703: 5701: 5697: 5691: 5690:Space weather 5688: 5686: 5683: 5681: 5678: 5676: 5673: 5671: 5668: 5666: 5663: 5661: 5658: 5656: 5653: 5649: 5646: 5644: 5641: 5639: 5636: 5634: 5631: 5630: 5629: 5626: 5622: 5619: 5617: 5614: 5612: 5609: 5607: 5604: 5603: 5602: 5599: 5597: 5594: 5593: 5591: 5589: 5585: 5577: 5574: 5573: 5572: 5569: 5565: 5562: 5560: 5557: 5555: 5554:Space command 5552: 5551: 5550: 5549:Space warfare 5547: 5543: 5540: 5538: 5535: 5533: 5530: 5528: 5525: 5523: 5520: 5519: 5518: 5515: 5511: 5510:United States 5508: 5506: 5503: 5501: 5498: 5496: 5493: 5491: 5488: 5486: 5483: 5481: 5478: 5476: 5473: 5471: 5468: 5467: 5466: 5463: 5461: 5458: 5454: 5451: 5449: 5446: 5444: 5441: 5439: 5436: 5435: 5434: 5431: 5429: 5428:Astrodynamics 5426: 5425: 5423: 5419: 5415: 5408: 5403: 5401: 5396: 5394: 5389: 5388: 5385: 5373: 5365: 5363: 5355: 5353: 5345: 5343: 5333: 5332: 5329: 5322: 5318: 5316: 5313: 5311: 5308: 5306: 5303: 5301: 5298: 5294: 5291: 5289: 5286: 5285: 5283: 5281: 5278: 5277: 5275: 5271: 5265: 5262: 5260: 5257: 5255: 5252: 5250: 5247: 5245: 5242: 5240: 5237: 5235: 5232: 5230: 5227: 5225: 5222: 5220: 5217: 5216: 5214: 5212: 5208: 5202: 5199: 5197: 5194: 5192: 5189: 5187: 5184: 5182: 5179: 5177: 5174: 5172: 5169: 5167: 5164: 5162: 5159: 5157: 5154: 5152: 5149: 5147: 5144: 5142: 5139: 5138: 5136: 5134: 5130: 5124: 5121: 5119: 5116: 5114: 5111: 5109: 5106: 5104: 5101: 5100: 5098: 5094: 5088: 5087:Code-division 5085: 5083: 5080: 5078: 5075: 5073: 5072:Time-division 5070: 5068: 5065: 5063: 5060: 5059: 5057: 5055: 5051: 5045: 5042: 5038: 5035: 5033: 5030: 5029: 5028: 5025: 5021: 5018: 5017: 5016: 5013: 5011: 5008: 5006: 5003: 5002: 5000: 4998:and switching 4996: 4992: 4984: 4981: 4980: 4979: 4976: 4972: 4969: 4968: 4967: 4964: 4962: 4959: 4957: 4954: 4950: 4949:optical fiber 4947: 4946: 4945: 4942: 4940: 4939:Coaxial cable 4937: 4936: 4934: 4932: 4926: 4920: 4917: 4915: 4912: 4910: 4907: 4905: 4902: 4900: 4897: 4895: 4892: 4890: 4887: 4885: 4882: 4880: 4877: 4875: 4872: 4870: 4867: 4865: 4862: 4860: 4857: 4855: 4854:Radia Perlman 4852: 4850: 4847: 4845: 4842: 4840: 4837: 4835: 4832: 4830: 4827: 4825: 4822: 4820: 4817: 4815: 4812: 4810: 4807: 4805: 4802: 4800: 4797: 4795: 4792: 4790: 4787: 4785: 4782: 4780: 4777: 4775: 4772: 4770: 4767: 4765: 4762: 4760: 4757: 4755: 4752: 4750: 4747: 4745: 4744:Lee de Forest 4742: 4740: 4739:Thomas Edison 4737: 4735: 4732: 4730: 4729:Donald Davies 4727: 4725: 4722: 4720: 4717: 4715: 4714:Claude Chappe 4712: 4710: 4707: 4705: 4702: 4700: 4697: 4695: 4692: 4690: 4687: 4685: 4682: 4680: 4677: 4675: 4672: 4670: 4667: 4665: 4662: 4660: 4657: 4655: 4652: 4650: 4647: 4645: 4642: 4641: 4639: 4635: 4629: 4626: 4624: 4621: 4619: 4616: 4614: 4611: 4607: 4604: 4602: 4599: 4598: 4597: 4594: 4592: 4591: 4587: 4585: 4582: 4579: 4576: 4574: 4571: 4569: 4566: 4564: 4561: 4559: 4558:Smoke signals 4556: 4552: 4549: 4547: 4544: 4542: 4539: 4538: 4537: 4536:Semiconductor 4534: 4530: 4527: 4526: 4525: 4522: 4520: 4517: 4515: 4512: 4510: 4507: 4505: 4502: 4500: 4497: 4495: 4492: 4490: 4487: 4485: 4482: 4478: 4475: 4474: 4473: 4470: 4468: 4465: 4463: 4460: 4458: 4455: 4453: 4450: 4448: 4445: 4443: 4440: 4438: 4435: 4433: 4430: 4428: 4425: 4423: 4420: 4416: 4413: 4411: 4408: 4406: 4403: 4401: 4398: 4397: 4396: 4395:Digital media 4393: 4389: 4386: 4384: 4381: 4379: 4376: 4374: 4371: 4370: 4369: 4366: 4364: 4361: 4359: 4356: 4354: 4351: 4349: 4346: 4344: 4341: 4339: 4336: 4335: 4333: 4331: 4327: 4323: 4316: 4311: 4309: 4304: 4302: 4297: 4296: 4293: 4283: 4273: 4261: 4255: 4252: 4250: 4247: 4245: 4242: 4240: 4237: 4235: 4232: 4231: 4229: 4225: 4219: 4216: 4214: 4213:Nuisance call 4211: 4209: 4206: 4204: 4201: 4200: 4198: 4194: 4188: 4185: 4183: 4180: 4178: 4175: 4173: 4170: 4168: 4165: 4163: 4160: 4158: 4155: 4153: 4152:Fibre-optical 4150: 4148: 4145: 4143: 4140: 4139: 4137: 4133: 4127: 4124: 4122: 4119: 4118: 4116: 4112: 4106: 4103: 4101: 4098: 4096: 4093: 4091: 4088: 4086: 4083: 4082: 4080: 4076: 4072: 4065: 4060: 4058: 4053: 4051: 4046: 4045: 4042: 4030: 4029: 4020: 4018: 4017: 4008: 4007: 4004: 3998: 3995: 3993: 3990: 3989: 3987: 3983: 3977: 3974: 3972: 3969: 3968: 3966: 3962: 3956: 3953: 3951: 3948: 3946: 3943: 3941: 3938: 3936: 3933: 3931: 3928: 3926: 3923: 3921: 3918: 3917: 3915: 3911: 3905: 3902: 3900: 3897: 3895: 3892: 3890: 3887: 3885: 3882: 3880: 3877: 3875: 3872: 3870: 3867: 3865: 3862: 3860: 3857: 3855: 3852: 3850: 3847: 3845: 3842: 3840: 3837: 3835: 3832: 3830: 3827: 3825: 3822: 3820: 3817: 3815: 3812: 3811: 3809: 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