There were a two key reasons that Kennedy decided to challenge the Soviets in the space race and declare this major new goal. The first was that he felt the need maintain the positive image that the United States had acquired as a leading global power. (5) He feared that other countries would doubt the capabilities of the United States if they were to lose this space competition to the Soviets.
A second reason was the aforementioned fear of Soviet missile capabilities. Jerome Wiesner, chairman of Kennedy's Science Advisory Committee, warned the president of the "potential military dangers and disadvantages to the West" if the United States didn't counter the Soviets in the space race. This warning implied a global—not just nationwide—fear the Soviet's lead in space was paired with a growth of missile weapons. (6)