An artificial satellite is a man made object placed in orbit around the earth or other celestial body . satellite are used for a variety of reasons . studying the universe , assisting in navigation of ships and aircraft , providing communications, predicting weather etc. the satellite is launched from the surface with the help of rockets . which parks it in particular Earth -orbiting artificial satellite , Sputnik I, was launched in October 1957 ,by the USSR. It was a football-sized globe that transmitted a "beep beep " sound as it orbited the earth, and was the first in series called Sputnik program . Sputnik 1 helped to identify of earth's upper atmospheric layer .
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