| Following World War II, the US Naval Research Laboratory (NRL) was left with a great deal of missile and rocket related expertise. As the lab returned to a research, rather than weapons development, role, it found that the available sounding rockets, such as the Wac Corporal, lacked the guidance control it needed to conduct upper atmospheric science.
Thus the Viking was born, designed to build in from the start many of the guidance and other advanced technologies found in the German V-2 missile. The final design was in the end superior to the V-2's in several respects, and incorporated a number of technologies that would prove their worth during the space race of the 1960's.
Unlike the V-2, or it's descendant, the Redstone, the Viking used a gimballed rocket engine rather than sticking vanes into the exhaust to steer the rocket. Another important design element for later generations of rockets was making the propellant tanks part of the rocket fuselage, rather than creating a seperate airframe to house the tanks.
The Viking program also introduced the notion of testing each rocket by static firing it on the ground before attempting a launch. This type of rigourous ground testing was to prove to be a critical factor in the success of the Apollo project's Saturn V and Saturn 1B boosters.
The first Viking was launched on May 3, 1949. Various problems plagued the early flights, but soon both the rocket and its scientific payloads were performing well. A Model II was introduced with an increased diameter, allowing larger fuel tanks, and higher altitudes.
After 12 flights, the project was cancelled, with the last flight occuring on May 24, 1954, reaching an altitude of 158 miles. However, the Viking was not forgotten, and would go on to form the the first stage of the NRL's ill-fated Vanguard rocket.
The Model I Viking had a height of 48.6 feet and a diameter of 32 inches. The Model II was 41.4 feet high and had a diameter of 45 inches. | 
