The Nike Ajax was an American guided surface-to-air missile (SAM) developed by Bell Labs for the United States Army.

The world's first operational guided surface-to-air missile,[1] the Nike Ajax was designed to attack conventional bomber aircraft flying at high subsonic speeds and altitudes above 50,000 feet (15 km).

As Hercules developed, the threat moved from bombers to ICBMs, and the LIM-49 Nike Zeus anti-ballistic missile project started to address these.

All of the Nike projects were led by Bell Labs, due to their early work in radar guidance systems during World War II.

Part of the Nike Ajax development program designed a new solid fuel rocket motor used for the missile's booster.

[5] German gunners did better against Allied daylight raids, firing an estimated average of 2,800 shells to down a single Boeing B-17 Flying Fortress.

Aircraft using jet engines roughly double the speed and altitude over piston-powered designs, limiting the number of shells so greatly that the chance of hitting the bomber dropped almost to zero.

As early as 1942, German flak commanders were keenly aware of the problem, and expecting to face jet bombers, they began developing missiles to supplant their guns.

Nevertheless, by the mid-war period, the US Army had reached the same conclusion as their German counterparts: artillery-based anti-aircraft weapons were simply no longer useful.

[8] The introduction of German jet-powered bombers late in 1944 led to a re-evaluation of this policy, and on 26 January 1945 the Army Chief of Ordnance issued a requirement for a new guided missile system.

The request was passed to Bell Labs, then a world leader in radar, radio control, and automated aiming systems (see Hendrik Wade Bode).

[11] At the ranges and speeds being considered, even a supersonic rocket will take enough time to reach the target that the missile needs to lead the bomber in order to properly intercept it.

[12] Early in the program, it was realized that existing radar systems based on the conical scanning method did not supply the performance needed for a high-speed missile.

[1] The first test firing of a static round was carried out at the White Sands Proving Ground on 17 September 1946 and then returned to Douglas in California for study.

A second test series followed in September and October 1947, including several improvements in the design in order to address problems with the booster.

Instead, the project selected a larger booster being developed by the US Navy's Operation Bumblebee, creating a new version known as the Allegheny JATO T39 2.6DS-51,000.

A series of events in the late 1940s led to a re-appraisal of the situation, including the Soviet atomic test in 1949, the communist victory in China, and the Berlin Blockade.

In October 1950, US Secretary of Defense Charles E. Wilson appointed Kaufman Keller to the newly created position of Director of Guided Weapons to speed their development.

[13] A new test series of the proposed production model was carried out starting in October, and on 27 November 1951, Nike successfully intercepted a QB-17 target drone.

Service deliveries began that year, and eventually, a total of 350 launch systems and 13,714 missiles were produced over the production run.

However, while planning the deployment around Chicago, it became clear that Lake Michigan would force sites protecting approach from the east to be located in the city itself.

Moreover, various scenarios demonstrated that having a staggered two-layer layout of the sites would offer much greater protection, which argued for some bases to be located closer to the urban centers.

[1] For range safety reasons, launch sites had to have considerable empty land around them in the event of an accidental warhead or fuel explosion.

[14] As the missile batteries were now protected and accidental explosions would be contained, the safe area was dramatically reduced, and that cut the land requirement down to 40 acres (16 ha).

The first site to build their Nike I system was Fort Meade, who started receiving their missiles in December 1953, replacing their 120 mm M1 guns.

Like the Ajax and Hercules, Zeus could only attack a single target at a time, although by deploying multiple radars it was expected that up to six missiles could be guided at once.

Serious technical problems also arose, including electromagnetic pulse and similar effects that blocked radar, questions about the missile's ability to damage enemy warheads, and above all, rapidly rising costs.

[25] Launch of the missile was accomplished by lighting the solid fuel booster, which provided 59,000 lbf (260 kN) of thrust for three seconds.

Data from the TTR and MTR were sent to the analog tracking computer, which continually calculated the impact point and sent radio commands to the missile to guide it.

[27][28] The Nike batteries were organized in Defense Areas and placed around population centers and strategic locations such as long-range bomber and important military/naval bases, nuclear production facilities and (later) ICBM sites.