Changes

==Etymology==

==Etymology==

Middle French, from [[Latin]] satellit-, satelles attendant

Middle French, from [[Latin]] satellit-, satelles attendant

*Date: circa [http://www.wikipedia.org/wiki/16th_Century 1548]

*Date: circa [https://www.wikipedia.org/wiki/16th_Century 1548]

==Definitions==

==Definitions==

*1 : a hired [[agent]] or obsequious follower : minion, sycophant

*1 : a hired [[agent]] or obsequious follower : minion, sycophant

In the [[context]] of spaceflight, a '''satellite''' is an object which has been placed into [[orbit]] by human endeavor. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the [[Moon]].

In the [[context]] of spaceflight, a '''satellite''' is an object which has been placed into [[orbit]] by human endeavor. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the [[Moon]].

The first artificial satellite, [http://en.wikipedia.org/wiki/Sputnik_1 Sputnik 1], was launched by the Soviet Union in 1957. By 2010 thousands of satellites have been launched into orbit around the [[Earth]]. These originate from more than 50 countries and have used the satellite launching capabilities of ten nations. A few hundred satellites are currently operational, whereas thousands of unused satellites and satellite fragments orbit the Earth as [http://en.wikipedia.org/wiki/Space_debris space debris]. A few [http://en.wikipedia.org/wiki/Space_probe space probes] have been placed into orbit around other bodies and become artificial satellites to the Moon, Venus, Mars, Jupiter and Saturn.

The first artificial satellite, [https://en.wikipedia.org/wiki/Sputnik_1 Sputnik 1], was launched by the Soviet Union in 1957. By 2010 thousands of satellites have been launched into orbit around the [[Earth]]. These originate from more than 50 countries and have used the satellite launching capabilities of ten nations. A few hundred satellites are currently operational, whereas thousands of unused satellites and satellite fragments orbit the Earth as [https://en.wikipedia.org/wiki/Space_debris space debris]. A few [https://en.wikipedia.org/wiki/Space_probe space probes] have been placed into orbit around other bodies and become artificial satellites to the Moon, Venus, Mars, Jupiter and Saturn.

Satellites are used for a large [[number]] of [[purposes]]. Common [[types]] include military (spy) and civilian Earth [[observation]] satellites, [[communication]] satellites, [[navigation]] satellites, weather satellites, and [[research]] satellites. [http://en.wikipedia.org/wiki/Space_station ]Space stations and human spacecraft in orbit are also satellites. Satellite orbits vary greatly, depending on the purpose of the satellite, and are classified in a number of ways. Well-known (overlapping) classes include [http://en.wikipedia.org/wiki/Low_Earth_orbit low Earth orbit], [http://en.wikipedia.org/wiki/Polar_orbit polar orbit], and [http://en.wikipedia.org/wiki/Geostationary_orbit geostationary orbit].

Satellites are used for a large [[number]] of [[purposes]]. Common [[types]] include military (spy) and civilian Earth [[observation]] satellites, [[communication]] satellites, [[navigation]] satellites, weather satellites, and [[research]] satellites. [https://en.wikipedia.org/wiki/Space_station ]Space stations and human spacecraft in orbit are also satellites. Satellite orbits vary greatly, depending on the purpose of the satellite, and are classified in a number of ways. Well-known (overlapping) classes include [https://en.wikipedia.org/wiki/Low_Earth_orbit low Earth orbit], [https://en.wikipedia.org/wiki/Polar_orbit polar orbit], and [https://en.wikipedia.org/wiki/Geostationary_orbit geostationary orbit].

Satellites are usually semi-independent computer controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control and orbit control.[http://en.wikipedia.org/wiki/Sattelite]

Satellites are usually semi-independent computer controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control and orbit control.[https://en.wikipedia.org/wiki/Sattelite]

[[Category: Physics]]

[[Category: Physics]]

[[Category: Astronomy]]

[[Category: Astronomy]]