How Satellites Works - History of Satellites Documentary Film

In the context of spaceflight, a satellite is a synthetic object which has actually been purposefully positioned right into orbit. Such things are in some cases called synthetic satellites to differentiate them from all-natural satellites such as the Moon.
The world's very first synthetic satellite, the Sputnik 1, was introduced by the Soviet Union in 1957. Since then, hundreds of satellites have actually been released into orbit around the Earth. Some satellites, especially space terminals, have actually been introduced partially and assembled in orbit. Artificial satellites originate from greater than 40 countries and have actually utilized the satellite launching abilities of ten nations. A couple of hundred satellites are presently functional, whereas thousands of extra satellites and satellite fragments orbit the Earth as area particles. A couple of area probes have actually been placed right into orbit around various other bodies and end up being artificial satellites to the Moon, Mercury, Venus, Mars, Jupiter, Saturn, Vesta, Eros, Ceres, and the Sun.
Typical types include military and civilian Earth monitoring satellites, communications satellites, navigation satellites, weather condition satellites, and research satellites. Satellite orbits vary greatly, depending on the function of the satellite, and are classified in a number of ways.
Regarding 6,600 satellites have actually been launched. Around 500 functional satellites are in low-Earth orbit, 50 are in medium-Earth orbit (at 20,000 km), the remainder are in geostationary orbit (at 36,000 km).
Satellites are moved by rockets to their orbits. Often the launch automobile itself is a rocket taking off from a launch pad on land. In a minority of instances satellites are gone for sea (from a submarine or a mobile maritime system) or aboard an aircraft (see air launch to orbit).