Sputnik, known as the world’s first artificial satellite, was developed by the USSR and sent into space in 1957. It was launched into space from the place located in Kazakhstan. Americans was shocked from this successful launch of Sputnik. It induced Americans to compete the USSR in space field.
The USSR again developed Sputnik II and sent into space just one month after the launching first Sputnik. Then a respond came from United States when they developed Explorer I and successfully sent into space.