What Are Artificial Satellites? Explain How They Are Put Into The Orbit?

Satellites are basically are objects that orbit around the earth. They are put into orbit by the help of rockets and are held there by the gravitational pull of the earth. The low flying earth satellites have an acceleration of 9.8 m/s2  towards the centre of the earth. If they do not, they would fly off in a straight line towards the earth. The minimum velocity required to a satellite into orbit is known as critical velocity. The higher the satellite, the slower will the required speed be and the longer it will take to complete one round around the earth. The close orbiting satellites orbit the earth at a height of about 400Km. twenty four such satellites form the famous known Global Positioning System (GPS).

Several geostationary satellites are set-up in orbit at various places. Each one covers 120 of longitude. The earth can be covered by three satellites place in correct positions. These satellites receive their energy for transmissions and receptions from solar panels fitted on them. The largest satellite system is managed by 126 countries and is known as International Telecommunication Satellite Organization (INTELSAT). It operates at microwave frequencies of 4,6,11 and 14 GHz and has a capacity of 30,000 two way telephone circuits and 3 TV channels