While strategic defense against airborne attack is a product of the 20^th century, the concept can be found as early as the Enlightenment. In 1783, the Montgolfer brothers staged a demonstration of their balloon near Paris, France. The military significance of this demonstration was noted by a Prussian Lieutenant named J.C.G. Hayne who wrote that aerial warfare might make it possible for fleets of balloons to bombard fortifications and cities without impediment.

The military use of balloons spread very slowly, however. These early balloons were expensive, unreliable, could not be effectively maneuvered. Moreover, such balloons were capable of carrying only a very tiny payload. By the mid-19^th century balloons were used primarily for limited observation of troops in the field. On August 31, 1861, Thaddeus Low deployed a balloon on behalf of Federal forces in northern Virginia. This balloon was fired on by gunners of a Louisiana artillery unit. An important military principle was demonstrated by this event: you need not hit the enemy - intimidation was an equally effective defense. While unable to strike the balloon, the gunners were none-the-less able to intimidate its occupants and the balloon was quickly lowered.

Later in the 20^th century, the development of cheaper, lighter engines allowed for the development of powered balloons. Count Zeppelin built a fleet of dirigibles for the Imperial German forces. This fleet was deployed over London during World War I in an attempt to demolish the city. Attempts to thwart the dirigible threat included defensive measures such as anti-aircraft guns and offensive measures such as raiding German dirigible bases. Britain’s defensive and counter offensive measures effectively destroyed the German dirigible fleet.

Air defense became important again by the 1930s when it became clear in Europe that fascist countries were preparing for yet another war. Britain felt the necessity of developing large bombers capable of deterring a war with fascist countries while at the same time recognizing the need to defend against the attach of enemy bombers. By 1937, the United States Navy recognized the need to develop the ability to detect incoming bombers and offered Bell Laboratories a contract to research radar. When the United States entered World War II radar played an important part in United States defensive tactics. A comprehensive air defense apparatus was set up that included radar installations spotted along the east and west coasts of the United States. These radars were linked together by simple communications nets. Existing anti-aircraft guns were converted to fire control by radar.

It was also during World War II that the United States military began to experiment with rockets and Missiles. While anti-aircraft guns had been reasonably effective against air attacks on London, it was evident to the United States Army officials that the speeds and rates of maneuver of jet-propelled aircraft would quickly surpass the capabilities of ground fired shells. In 1944, Jake Schaefer, an ordinance officer in the United States Army formerly employed by Bell Laboratories, advocated the development of a surface-to-air missile. Schaefer’s ideas were presented in a paper he wrote for the Army in which he conceptualized a command guidance system composed of radar that would track the defending missile from it’s point of launch. The computer would calculate the place of impact and command the missile by radio to intercept the target. The Army called the system anti-aircraft Guided Missile (AAGM) until Colonel Trichel, director of advanced research for the Army, renamed the project NIKE for the Greek goddess of victory.

Air Defense of the United States in 1950 consisted of radar-directed 90mm and 120mm anti-aircraft guns placed in cities during World War II under the control of the National Guard. These guns were deployed around and in major cities and ports of the United States. New York and Washington had four battalions; Chicago had three battalions; Philadelphia, Detroit and San Francisco had Two; Boston, Baltimore, Pittsburgh, and Los Angeles had One. While little was done to actively provide strategic defense for the United States from 1945 to 1950, the invasion in 1950 of South Korea by North Korea with the aid of Soviet tanks and artillery spurred new concern for anti-aircraft research. In addition to the Korean War, the ability of the Soviet Union to attack the Continental United States over the North Pole or over the seas against either coast coupled with their demonstrated testing of the hydrogen bomb in 1949 spurred the United States Army to establish a nationwide defense system to protect against Soviet intercontinental ballistic missiles. The adversarial relationship between the Soviet Union and the United States became known as the Cold War and spurred the development and deployment of the NIKE system.

Beginning in 1953, NIKE was deployed first on the East and West Coast and then in the interior of the United States. More than 4000 missiles were installed. Many went into old anti-aircraft gun sites, however, the 25 mile range of the NIKE missiles allowed the batteries to be placed further from the potential targets. This allowed more time to shoot at the incoming bombers. America’s suburbs became sites of the NIKE Ajax, the first technological advance in the conversion of the United States air defense from artillery to guided missiles. Due to the extensive nature of the NIKE Ajax, the next generation missile, the Hercules, was designed to fit into the existing system. A bigger, more powerful missile with a longer range, the Hercules system was capable of being fitted with nuclear as well as conventional warheads. The Hercules system was first deployed in 1959 and by 1960, most Ajax missiles had been replaced by Hercules. Development of yet another NIKE missile system, the Zeus, began in 1958. Equipped with a more efficient radar system than either the Ajax or Hercules, the Zeus was never activated; however, many of the systems developed in its research were used in later anti-tactical ballistic missile systems. After 1960, technology developed relating to ballistic-missile defense (BDM) made the NIKE system obsolete, although it was not entirely decommissioned until 1974.