In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon.
The world's first artificial satellite, the Sputnik 1, was launched by the Soviet Union in 1957. Since then, thousands of satellites have been launched into orbit around the Earth. Some satellites, notably space stations, have been launched in parts and assembled in orbit. Artificial satellites 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, Mercury, Venus, Mars, Jupiter, Saturn, and the Sun.
Satellites are used for a large number of purposes. Common types include military and civilian Earth observation satellites, communications 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.
Read more about Satellite: Space Surveillance Network, Types, Orbit Types, Satellite Subsystems, End of Life, Launch-capable Countries, First Satellites of Countries, Attacks On Satellites, Satellite Services
Other articles related to "satellite, satellites":
... Satellite Internet access Satellite phone Satellite radio Satellite television Satellite navigation ...
... Universal Satellites Automatic Location System (USALS), also known (unofficially) as DiSEqC 1.3, Go X or Go to XX is a satellite dish motor protocol that automatically creates a ... Software on the satellite receiver (or external positioner) calculates the position of all available satellites from an initial location (input by the user), which is the latitude and longitude ... Compared to DiSEqC 1.2, it is not necessary to manually search and store every known satellite position ...
... Satellite Control Processor On 21 May 2005 services were temporarily lost when the Primary Satellite Control Processor failed ... The satellite was switched to use the Backup SCP in order to restore services ... Thereafter the satellite continued to operate from the Backup SCP ...
... Satellite launches Iran's first satellite, the Sinah-1 reconnaissance satellite, built jointly with Russia, is launched from the Plesetsk Cosmodrome in northwestern Russia at 1052 local time (0652 UTC) ...
... Viking was Sweden's first satellite ... It was launched on an Ariane 1 rocket as a piggyback payload together with the French satellite SPOT 1, on February 22, 1986 ... Space was limited underneath the SPOT 1 satellite, and Viking had to be quite sturdy in order to withstand the stress of launch ...
Famous quotes containing the word satellite:
“Books are the best things, well used; abused, among the worst. What is the right use? What is the one end, which all means go to effect? They are for nothing but to inspire. I had better never see a book, than to be warped by its attraction clean out of my own orbit, and made a satellite instead of a system.”
—Ralph Waldo Emerson (1803–1882)