Bell Telephone Laboratories were tasked with evaluating future air defense problems in the 1960 to 1970 time frame, which led to the Nike Zeus proposal.

[4] The assistant secretary of defense was anxious to establish an early anti-ballistic missile capability and requested that the Atomic Energy Commission (AEC - now the Department of Energy) work with the army on a feasibility study of suitable nuclear warheads for Nike Zeus.

It was believed that these values could not be adequately defined for another two years as tests of target vulnerability and the practical limits of warhead hardening needed to be performed.

This included the requirement to perform many flight tests to establish reentry vehicle (RV) vulnerability.

[6] Concurrently, interest in the proposed Pershing missile had increased and in January 1958, a meeting was held to discuss a nuclear warhead for the system.

[7] The division of military application (DMA) expressed concern in February 1958 about the number of weapons programs that Livermore were working on with planned operational availabilities in the 1960 to 1962 time frame.

In June 1958, the DMA then suggested that a single warhead be developed for Nike Zeus, Minuteman, Pershing and Hopi (a short lived air-to-surface missile proposal).

Tests of missile components against the effects of nuclear explosions were conducted in the shot Cactus (5 May 1958, 18 kilotonnes of TNT (75 TJ)).

[11] In August 1958, Sandia were asked if a warhead meeting all four system requirements could be furnished with an operational availability date of late 1961.

This application required extreme miniaturization of components due to space limitations inside Nike Zeus and a parallel design using explosively actuated devices was initiated.

[14] In October 1958, Los Alamos and Sandia wrote to the Albuquerque Operations Office stating that a warhead for all four systems was possible.

[21] In July 1962, Sandia concluded a study on incorporating a permissive action link (PAL) system into the warhead for Pershing use.

[22][23] Due to the need to divert firing sets for the approaching test series, production of the W50-1 was delayed until March 1963.

The boosting gas bottle was mounted outside the pressure cover to enable replacement without breaking the warhead seal.

[34] The W50 lacked enhanced detonation safety systems and insensitive high explosives, and featured a Category A PAL for use control.

There is no substitute warhead available in this weight class.After launch, an inertial fuze received power from the Pershing second stage.

If the missile was on course and if the second stage separation occurred within 300 milliseconds of engine cutoff, the ignition circuit on a set of thermal batteries was enabled.

The thermal battery was fired just prior to reentry, and when a deceleration of 0.5 g (4.9 m/s2) was sensed, the fuze was enabled and warhead arming functions took place.