The Vanguard rocket was intended to be the first launch vehicle the United States would use to place a satellite into orbit. Instead, the Sputnik crisis caused by the surprise launch of Sputnik 1 led the U.S., after the failure of Vanguard TV-3, to quickly orbit the Explorer 1 satellite using a Juno I rocket, making Vanguard 1 the second successful U.S. orbital launch. Vanguard rockets were used by Project Vanguard from 1957 to 1959. Of the eleven Vanguard rockets which the project attempted to launch, three successfully placed satellites into orbit. Vanguard rockets were an important part of the Space Race between the United States and the Soviet Union. Overview In 1955, the United States announced plans to put a scientific satellite in orbit for the International Geophysical Year (IGY) in 1957–1958. The goal was to track the satellite as it performed experiments. At that time, there were three candidates for the launch vehicle: The Air Force's SM-65 Atlas, a derivative of the Army Ballistic Missile Agency's SSM-A-14 Redstone, and a Navy proposal for a three-stage rocket based on the RTV-N-12a Viking sounding rocket. The RAND Corporation, Air Force and CIA had long pursued the idea of a reconnaissance satellite. Such a program was under way, Weapon System 117L, which was top secret compartmented. One problem with reconnaissance was the question of legality: Was there "freedom of space" or did a nation's airspace end when space is entered? The National Security Council backed the IGY satellite because it would make good cover for WS117L and set a precedent of freedom of space peaceful civilian satellite. At the same time the NSC stressed that the IGY satellite must not interfere with military programs. The Army's Redstone-based proposal would likely be the first one ready for a satellite launch. Its connection with German-born scientist Wernher von Braun, however, was a public-relations risk. In any case, the Atlas and Redstone ballistic missiles were top-priority military projects, which were not to be hindered by pursuing a secondary space launch mission. Milton Rosen's Vanguard was a project at the Naval Research Laboratory (NRL), which was regarded more as a scientific than a military organization. Rosen and Richard Porter (IGY satellite chief and head of the American Rocket Society) both lobbied for the Vanguard and against using the Atlas or von Braun's rockets. They emphasized the non-military goals of the satellite program. Besides the public-relations