Oct. 4, 1957: Sputnik I

The dawn of the Space Age arrived when the Soviet Union launched the first artificial satellite, Sputnik I. It was the size of a basketball, weighed 183 pounds and took 98 minutes to orbit the earth. The following month, the Soviets launched another satellite -- Sputnik II -- with a dog named Laika aboard. The Soviets' technical achievements inspired the U.S. to create NASA a year later.