American Military History, Volume 2 by Richard W. Stewart

Throughout the period, the United States had keyed its efforts to the strategic bomber; but to be on the safe side, it had also pushed de- velopment of offensive missiles. To that end the Army produced the Ju- piter and the Air Force the Thor, both intermediate-range ballistic mis- siles that could strike targets at a distance of 1,500 miles. The Air Force was also working on Atlas and Titan, intercontinental ballistic missiles (ICBMs) with a reach of 5,000 miles. A jurisdictional dispute between the Army and the Air Force prompted by the roles and missions agree- ment led the Secretary of Defense in 1957 to give the Air Force charge of all land-based ballistic missiles. Although the Army retained control over development and testing of the Jupiter missile, tensions with the Soviet Union soon eased, lessening the sense of urgency that had pro- pelled the program to that point.

The lull lasted only until October 1957, when the Russians launched Sputnik, the first earth satellite. The feat came as a shock to the United States, which lacked the sort of high-thrust rocket the Rus- sians had used. To sustain public morale, the United States boosted several small American satellites into orbit with existing ballistic missile motors. Considerable time would elapse, however, before the nation would produce a rocket engine equal to that of the Russians.