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A geosynchronous satellite is a satellite whose orbital track on the Earth repeats regularly over points on the Earth over time. If such a satellite's orbit lies over the equator and the orbit is circular, it is called a geostationary satellite. The orbits of the satellites are known as the geosynchronous orbit and geostationary orbit. Another type of geosynchronous orbit is the Tundra elliptical orbit. Image File history File links Merge-arrows. ... It has been suggested that this article or section be merged with geostationary orbit. ... Image File history File links Broom_icon. ... For other uses, see Satellite (disambiguation). ... World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ... It has been suggested that this article or section be merged with geostationary orbit. ... Geostationary orbit A geostationary orbit (GEO) is a geosynchronous orbit directly above the Earths equator (0° latitude), with orbital eccentricity of zero. ... Tundra orbit is a class of a highly elliptic orbit with inclination of 63. ...

A geosynchronous network is a communication network based on communication with or through geosynchronous satellites.

Definition

According to Kepler's Third Law, the orbital period of a satellite in a circular orbit increases with increasing altitude. Space stations and shuttles in Low Earth orbit (LEO), typically two or four hundred miles above the Earth's surface make between fifteen and sixteen revolutions per day. The Moon, at an altitude of about 240,000 miles (385,000 km), takes thirty days to make a complete rotation. Between those extremes lies the "magic" altitude of 22,300 miles (35,786 km) at which a satellite's orbital period matches, or is an integral part of, the period at which the Earth rotates: once every sidereal day (23 hours 56 minutes). In that case, the satellite is said to be geosynchronous. Johannes Keplers primary contributions to astronomy/astrophysics were his three laws of planetary motion. ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... Altitude is the elevation of an object from a known level or datum. ... The International Space Station in 2007 A space station is an artificial structure designed for humans to live in outer space. ... NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ... A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ... “Miles” redirects here. ... Look up day in Wiktionary, the free dictionary. ... This article is about Earths moon. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... On a prograde planet like the Earth, the sidereal day is shorter than the solar day. ...

If a geosynchronous satellite's orbit is not exactly aligned with the equator, the orbit is known as an inclined orbit. It will appear (when viewed by someone on the ground) to oscillate daily around a fixed point in the sky. As the angle between the orbit and the equator decreases, the magnitude of this oscillation becomes smaller; when the orbit lies entirely over the equator, the satellite remains stationary relative to the Earth's surface – it is said to be geostationary. World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ... A geostationary orbit occurs when an object (satellite) is placed 37,000 km (22,300 miles) above the Earths equator with the characteristic that, from a fixed observation point on the Earths surface, it appears motionless. ...

Application

There are approximately 300 operational geosynchronous satellites.

Geostationary satellites appear to be fixed over one spot above the equator. Receiving and transmitting antennas on the earth do not need to track such a satellite. These antennas can be fixed in place and are much less expensive than tracking antennas. These satellites have revolutionized global communications, television broadcasting and weather forecasting, and have a number of important defense and intelligence applications. In biology, antenna (plural: antennae) refers to the sensing organs of several arthropods. ... This article is about Earth as a planet. ... Satellite navigation systems allow small electronic devices to determine their location (Longitude, Latitude, and Altitude) in within a few metres using time signals transmitted along a line of sight by radio from satellites. ... The term communications is used in a number of disciplines: Communications, also known as communication studies is the academic discipline which studies communication, generally seen as a mixture between media studies and linguistics. ... Broadcasting is the distribution of audio and video signals (programs) to a number of recipients (listeners or viewers) that belong to a large group. ... Modern weather predictions aid in timely evacuations and potentially save lives and property damage Weather map of Europe, 10 December 1887 Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. ... Pretorian Guards, Roman Soldiers Military has two broad meanings. ... For other uses, see Intelligence (disambiguation). ...

One disadvantage of geostationary satellites is a result of their high altitude: radio signals take approximately 0.25 of a second to reach and return from the satellite, resulting in a small but significant signal delay. This delay increases the difficulty of telephone conversation and reduces the performance of common network protocols such as TCP/IP, but does not present a problem with non-interactive systems such as television broadcasts. There are a number of proprietary satellite data protocols that are designed to proxy TCP/IP connections over long-delay satellite links -- these are marketed as being a partial solution to the poor performance of native TCP over satellite links. TCP presumes that all loss is due to congestion, not errors, and probes link capacity with its "slow-start" algorithm, which only sends packets once it is known that earlier packets have been received. Slow start is very slow over a path using a geostationary satellite. Latency is a time delay between the moment something is initiated, and the moment one of its effects begins. ... For other uses, see Telephone (disambiguation). ... In networking, a communications protocol or network protocol is the specification of a set of rules for a particular type of communication. ... The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet and most commercial networks run. ... Slow-start is part of the congestion control strategy used by TCP, the data transmission protocol used by many Internet applications, such as HTTP and Secure Shell. ... In mathematics, computing, linguistics, and related disciplines, an algorithm is a finite list of well-defined instructions for accomplishing some task that, given an initial state, will terminate in a defined end-state. ... In information technology, a packet is a formatted block of information carried by a computer network. ...

Another disadvantage of geostationary satellites is the incomplete geographical coverage, since ground stations at higher than roughly 60 degrees latitude have difficulty reliably receiving signals at low elevations. Satellite dishes in the Northern Hemisphere would need to be pointed almost directly towards the horizon. The signals would have to pass through the largest amount of atmosphere, and could even be blocked by land topography, vegetation or buildings. In the USSR, a practical solution was developed for this problem with the creation of special Molniya / Orbita inclined path satellite networks with elliptical orbits. Similar elliptical orbits are used for the Sirius Radio satellites. Sky Digital mini-dish Astros mini-dish. Special dish for up to 16 satellite positions (Ku-band) Satellite dish antenna for C-Band Satellite Dishes installed on an apartment complex A satellite dish is a type of parabolic antenna designed with the specific purpose of transmitting signals to and... Northern hemisphere highlighted in yellow. ... Molniya (lightning) was a military communications satellite system used by the Soviet Union. ... Orbita is a Soviet-Russian system of broadcasting and delivering TV-signal via satellites. ... For other uses, see Ellipse (disambiguation). ... Sirius Satellite Radio (NASDAQ: SIRI) is a satellite radio (DARS) service in the United States that provides 65 streams (channels) of music and 55 streams of sports, news and entertainment. ...

History

The concept was first proposed by the science fiction author Arthur C. Clarke in a paper in Wireless World in 1945, based on Herman Potočnik's previous work. Working prior to the advent of solid-state electronics, Clarke envisioned a trio of large, manned space stations arranged in a triangle around the planet. Modern satellites are numerous, unmanned, and often no larger than an automobile. Note that this partial list contains some authors whose works of fantastic fiction would today be called science fiction, even if they predate, or did not work in that genre. ... Wikiquote has a collection of quotations related to: Arthur C. Clarke Sir Arthur Charles Clarke, CBE (born 16 December 1917) is a British science-fiction author and inventor, most famous for his novel 2001: A Space Odyssey, and for collaborating with director Stanley Kubrick on the film of the same... Herman Potočnik (pseudonym Hermann Noordung) (December 22, 1892 - August 27, 1929) was a Slovene rocket engineer and pioneer of cosmonautics (astronautics). ...

The first geosynchronous satellite was Syncom 2, launched on a Delta rocket B booster from Cape Canaveral 26 July 1963. It was used a few months later for the world's first satellite relayed telephone call, between U.S. President John F. Kennedy and Nigerian Prime minister Abubakar Tafawa Balewa. Syncom-type satellite Syncom was a program of three experimental, active geosynchronous communication satellites which was started by NASA in 1961. ... The Delta family of rockets is used in an expendable launch system that has provided space launch capability for the United States since 1960. ... Cape Canaveral from space, August 1991 Cape Canaveral (Cabo Cañaveral in Spanish) is a strip of land in Brevard County, Florida, United States, near the center of that states Atlantic coast. ... is the 207th day of the year (208th in leap years) in the Gregorian calendar. ... Year 1963 (MCMLXIII) was a common year starting on Tuesday (link will display full calendar) of the Gregorian calendar. ... For other uses, see Telephone (disambiguation). ... Motto: (Out Of Many, One) (traditional) In God We Trust (1956 to date) Anthem: The Star-Spangled Banner Capital Washington D.C. Largest city New York City None at federal level (English de facto) Government Federal constitutional republic  - President George Walker Bush (R)  - Vice President Dick Cheney (R) Independence from... John Kennedy and JFK redirect here. ... Sir Abubakar Tafawa Balewa (1912-January 15, 1966) was the first prime minister of an independent Nigeria. ...

The first geostationary communication satellite was Syncom 3, launched on August 19, 1964 with a Delta D launch vehicle from Cape Canaveral. The satellite, in orbit near the International Date Line, was used to telecast the 1964 Summer Olympics in Tokyo to the United States. It was the first television program to cross the Pacific ocean. A geostationary orbit (abbreviated GEO) is a circular orbit in the Earths equatorial plane, any point on which revolves about the Earth in the same direction and with the same period as the Earths rotation. ... Syncom-type satellite Syncom was a program of three experimental, active geosynchronous communication satellites which was started by NASA in 1961. ... is the 231st day of the year (232nd in leap years) in the Gregorian calendar. ... Also Nintendo emulator: 1964 (emulator). ... “Date line” redirects here. ... The 1964 Summer Olympics, officially known as the Games of the XVIII Olympiad, were held in 1964 in Tokyo, Japan. ... For other uses, see Tokyo (disambiguation). ...

See also: Satellite television Satellite television is television delivered by way of communications satellites, as compared to conventional terrestrial television and cable television. ...

External links

• NASA's software for satellite tracking shows clearly the position of satellites in geosynchronous orbit.
• Arthur C. Clarke links & image archive
• Lyngsat list of satellites in geostationary orbit