ABSTRACT
A man-made object placed in orbit round the Earth or some other celestial body. The first artificial Earth satellite was Sputnik 1, launched by the then Soviet Union, on 4 October 1957. Spherical in shape, and with a mass of 84 kg, it entered an orbit with a perigee altitude of 229 km, an apogee altitude of 947 km and a period of 96 min
