On this day in 1957 the Soviet Sputnik 1 was launched. It was the first artificial Earth satellite. Although it was not equipped with sensors, it allowed scientists to study the atmosphere by tracking and studying its orbit. It transmitted radio signals for 21 days until its batteries died and burned up in January of 1958 as it reentered the Earth’s atmosphere. The launch of Sputnik pushed the United States to accelerate their own space exploration efforts and triggered the Space Race.