The television we watch at home, the weather updates we receive, the knowledge we acquire of other planets in the universe, are all possible due to satellites. Artificial satellites are man-made objects that orbit the Earth. These satellites are launched for specific purposes. A satellite is lifted from the earth’s surface by a rocket and, once placed in orbit, maintains its motion without further rocket propulsion. The first artificial satellite, Sputnik I, was launched on Oct. 4, 1957, by the USSR, which triggered the space race between the Soviet Union and the U.S. The first U.S. satellite, Explorer I, was launched on Jan. 31, 1958. During the first decade of space exploration, satellites were launched from either the United States or USSR. Today, there are more than three dozen launch sites in use or under construction in more than a dozen countries.