The W-31 warhead was deployed on the Nike-Hercules. Thousands of them were manufactured but very little has been published about them. This time-line has been developed from Chuck Hanson's material as well as other open sources.
Mid 1951 - Boosted, fission concept confirmed by IVY shot during GREENHOUSE series.
June 1952 - Project HEAVENBOUND study by Air Defense Command examines atomic weapons in the air defense role.
April 13, 1954 - AEC tells MLC that boosted air-defense weapons will be developed.
July 1953 - MLC settles on a 30" warhead for the NIKE-B to be operational in early 1957
December 1954 - Army asks AEC to develop the MK7 and a new 30" warhead for the NIKE-B.
January 1955 - DMA authorizes development of new 30" air-defense warhead
March 1955 - The Santa Fe Operations Office issued a scope-of-work covering the design of adaption kits for the XW-7 and the new 30" air-defense warheads.
March 1955 - Sandia and LASL suggest a higher yield air-defense warhead to increase the kill radius of the NIKE-B.
23 March 1955 - Sandia conducts static load test on the XW-31 to determine the structural adequacy of the XW-31 and the Nike case sections. (Report)
April - 1955 - TEAPOT confirms the practicality of small, boosted warheads.
June 1955 - The Assistant Secretary of Defense requests a feasibility study on a high yield air-defense warhead.
Summer 1955 - Test program proposed safety tests on the XW-31.
August 1955 - The XW-31 is deleted from one-point safety tests because the design was still evolving.
August - 1955 - The DMA requests development of the new, high-yield weapon.
Mid September 1955 - Sandia and LASL present the formal design of the XW-31 with a lower yield than the weapon suggested in March.
November 1955 - A Sandia study report recommended that the XW-31 warhead replace the XW-7 warhead on the Air Force’s CROSSBOW missile.
January 1956 - The Department of Defense approves the high-yield program (XW-37) for the NIKE-B.
February 1956 - Both the XW-31 and XW-37 were scheduled to be operational by October, 1958.
Late February 1956 - A proof test of the XW-31 for the NIKE-B was scheduled for the Spring of 1957 at the NTS.
April 1956 - Development engineering begins on the high-yield warhead, XW-37, for the
NIKE-B
27 June 1956 - Sandia presents the ordnance characteristics of the XW-31/37 to the SWDB.
June 1956 - First flight tests of the XW-31 scheduled to begin. (Rescheduled for October)
June 1956 - The XW-31 or XW-37 warhead are proposed for the Air Force’s CROSSBOW anti-radiation missile.
September 1956 - The XW-37 is effectively cancelled when the XW-31 became the XW-31-Y1 and the XW-37 became designated the XW-31-Y2.
October 1956 - First flight tests of the XW-31 to begin after being rescheduled from June, 1956
15 October 1956 - Sandia study on the use of parachute recovery of air-defense warheads to prevent plutonium contamination. (Report)
October 1956 - The proposed ordnance characteristics of the XW-31/NIKE-B were forwarded to the DMA.
November 1956 - The NIKE-B becomes the NIKE-HERCULES
February 1957 - A new version of the XW-31, the XW-31-Y3 is created.
March 1957 - Production engineering begins on the XW-31.
July 1 1957 - Operation PLUMBOB, shot Coulomb A, tests the one-point safety limits of the XW-31
September 6, 1957 - Operation PLUMBOB, shot Coulomb B, tests the one-point safety test of the XW-31
Mid September 1957 - Sandia released the design of the XW-31
May 1958 - The XW-31-Y3 was proof tested during the Holly shot of Operation HARDTACK at the PPG.
June 1958 - The adaption kit for the XW-31/NIKE-HERCULES design released.
June 1958 - First basic NIKE-HERCULES battery deployed.
9 July 1958 - Report of Test Flight No. 7.8-24 XW-7/Nike Hercules Warhead Installation. Beacon failure at 3.8 seconds into flight. (Report)
October 1958 - The W-31 Mod 0 became operationally available.
March 1959 - Sandia proposed incorporation of handling-safety devices in W-31 warheads.
September 1959 - The MLC accepted Sandia’s suggested safety changes.
June 1962 - The design for the W-31 Mod 2 was released.
4 November 1962 - Project Dominic I, Shot Fishbowl, W-31 detonated over Johnston Island.
March 1963 - Production of the W-31 Mod 2 began.
July 1967 - Retirement of the W-31 warheads began
June 1987 - Approximately 75 NIKE-HERCULES equipped with W-31 warheads remain in service in Europe.