W59

The W59 was an American thermonuclear warhead used on some Minuteman I ICBM missiles from 1962 to 1969, and planned to be used on the cancelled GAM-87 Skybolt air-launched ballistic missile. A British development of the system using a new primary became the WE.177, which was widely deployed as an air-dropped weapon into the 1990s.

History

Minuteman application

Development of the Minuteman I ICBM was authorized in February 1958 and by March, the study of possible warhead for the new ICBM was completed. In April, the XW-56 warhead designed by Lawrence Radiation Laboratory (now Lawrence Livermore National Laboratory) was approved for development. This program required considerable effort and was accompanied by funding issues.

Though the intermediate details and dates remain classified, at some point during or before December 1960, a second Minuteman warhead was authorized with a planned first production date of July 1962 and a full scale production date of December 1962. In March 1961, the XW-59 nomenclature was accepted for this warhead.

Firing set components would be off-the-shelf items repackaged for the special shape required for the role. The warhead would contain no electrical power, with an externally powered rotary chopper provided to charge the weapon's X-unit. An inertial switch would be provided to prevent weapon arming before it experienced its launch environment.