The W49 was an American thermonuclear warhead, used on the Thor, Atlas, Jupiter, and Titan I ballistic missile systems. W49 warheads were manufactured starting in 1958 and were in service until 1965, with a few warheads being retained until 1975.
The W49 warhead
The PGM-17A Thor was the first operative ballistic missile of the United States Air Force (USAF). It was named after the Norse god of thunder. It was deployed in the United Kingdom between 1959 and September 1963 as an intermediate-range ballistic missile (IRBM) with thermonuclear warheads. Thor was 65 feet (20 m) in height and 8 feet (2.4 m) in diameter.
A Thor intermediate range ballistic missile.
Thor-Able at the Cape Canaveral Space Force Museum, Florida
Thor 101 on a launch pad, January 1957
Missile 151, nicknamed "Tune Up", on December 16, 1958, just prior to its launch from Vandenberg Air Force Base. The successful test was conducted a year after the base was activated.