The U.S.S.R. launched Sputnik I on October 4, 1957. What was the impact of this event? A. It marked the start of the space race between the United States and Soviet Union. B. It marked the start of the arms race between the United States and the Soviet Union. C. It marked the beginning of thawing tensions between the United States and Soviet Union. D. It marked the first time that the Soviet Union had successfully created a nuclear weapon.