The first artificial satellite launched into space was Sputnik 1. It was launched by the Soviet Union on October 4, 1957. Sputnik 1 was a significant milestone in the Space Age; it measured about 58 centimeters in diameter and weighed 83.6 kilograms. Its successful launch marked the beginning of space exploration and the space race between the United States and the Soviet Union. Sputnik transmitted radio signals that could be received on Earth, providing valuable data about the ionosphere and demonstrating the feasibility of sending objects into orbit.