The W25 was a small nuclear warhead that was developed by the Los Alamos Scientific Laboratory for air-defense use.

[1][3] The W25 program began in March 1951, when the Division of Military Application suggested that the use of nuclear weapons to blunt enemy aircraft attacks be examined.

The study was completed in January 1953, which suggested that gun-, rocket- and missile-carried warheads were possible, launched from interceptor and bomber aircraft.

The board specifically recommended the development of nuclear warheads for the RIM-8 Talos, CIM-10 Bomarc and MIM-3 Nike Ajax surface-to-air missiles.

[6] Sandia National Laboratory had been investigating the high-altitude operation of nuclear weapons since 1952 and, in August 1953, concluded that the only major concern was high-voltage breakdown at low pressures.

[6] In October 1953, the air defense warhead programs took an unusual turn in that they avoided the then-trend to highly standardize nuclear and non-nuclear components of weapons.

[12] In March 1955, the assistant secretary for defense authorized the full development of the rocket and its warhead.

[13] The military liaison committee subsequently requested the warhead be in production by the rocket availability date of January 1957.

[14] Concern was expressed at this time over the use of thermal batteries in the weapon, because all the components needed to produce detonation would be present inside the warhead.

Unguided, the rocket would have a range of 3 to 5 miles (4.8 to 8.0 km) and a velocity of 3,000 feet per second (910 m/s) over its launch speed.

[16] The warhead was pressurized to 15 pounds per square inch (100 kPa) at the factory to prevent high-voltage arc over at altitude.

[21] Initially, the rocket was certified for the F-86 Sabre, with later capability with the F-101 Voodoo and F-106 Delta Dart as the aircraft became available.

In July 1956, a preliminary study was concluded stating that, because of the size limitations of the Genie application, a complete redesign would be needed, effectively producing a new warhead.

A study group was convened which reported in November 1956 that, while the plutonium hazard could be reduced to some degree, inside the space limitations given, an all-uranium warhead was not possible without utilizing a gun-type device.

In May 1957, the AEC was directed to examine ways to minimize the plutonium hazard without increasing fissile material requirements.