The name of the first satellite in orbit was Sputnik 1. It was launched by the Soviet Union on October 4, 1957, and orbited the Earth for 29 months before burning up in the Earth's atmosphere on January 4, 1958. Sputnik 1 weighed 83.6 kilograms (184.3 pounds) and was about the size of a basketball. It carried a radio transmitter that sent out short radio pulses, which were detected by radio receivers around the world. The launch of Sputnik 1 marked the beginning of the space age and sparked the U.S.-Soviet space race.