Noun

Singular satellite

Plural satellites

satellite (plural satellites)

1. An object orbiting a planet or similar celestial body.

   The Moon is a natural satellite of the Earth.

2. Specifically, any man-made apparatus designed to relay telecommunication signals to and from Earth.

   Many telecommunication satellites orbit at 36000km above the equator.

3. (colloquial, uncountable) Satellite TV; reception of television broadcasts via services that utilize man-made satellite technology.

   Do you have satellite at your house?

4. (dated) Anything that follows something else around.
   • 1826, Walter Scott, Woodstock, page 348

     ...he would nevertheless have a better bargain of this tall satellite if they settled the debate betwixt them in the forest... . Betwixt anxiety, therefore, vexation, and anger, Charles faced suddenly round on his pursuer... .

   • 1948, Willard E. Hawkins, The Technique of Fiction: A Basic Course in Story Writing, page 169,

     The unnamed chronicler in his Dupin stories was the first Dr. Watson type of satellite—a narrator who accompanies the detective on his exploits, exclaims over his brilliance... .

5. (noun adjunct) Specifies something which is under the jurisdiction, influence, or domination of another body, such as a satellite state (or country), satellite campus, or satellite office.
6. (noun adjunct) Specifies something utilizing man-made orbital satellite transmission technology; e.g. satellite TV, satellite phone.

Derived terms

• spy satellite
• communications satellite

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, Sputnik 1, was launched by the Soviet Union in 1957. By 2009 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 space debris. A few 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. 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 low Earth orbit, polar orbit, and 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.

History