PGM-17 Thor

SM-75/PGM-17A Thor
A Thor intermediate range ballistic missile.
Type	Intermediate-range ballistic missile
Place of origin	United States
Service history
Used by	United States Air Force (testing) Royal Air Force (operational deployment)
Production history
Designed	1957
Manufacturer	Douglas Aircraft Company
Produced	1959–1960
No. built	About 225; peak deployment was 60
Variants	Delta rockets Thor rocket family
Specifications
Mass	49,590 kilograms (109,330 lb) at start.
Length	19.76 metres (64 ft 10 in).
Diameter	2.4 metres (8 ft).
Propellant	kerosene and liquid oxygen
Operational range	2,820 kilometres (1,750 mi)
Flight altitude	630 kilometres (390 mi).

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.

The first generation of Thor missiles were rushed into service, and design mistakes resulted in a 24% launch failure rate. The competing Jupiter missile saw more use, but both were quickly eclipsed by the Air Force's long range ICBM program, which could be fired from US soil. By 1959, with the Atlas rocket well on its way to operational status, both Thor and Jupiter programs became obsolete as delivery vehicles, yet continued to be built and deployed until 1963 for political reasons and to maintain aerospace industry employment.

The missile's lasting legacy continued as the Thor and later Delta families of space launch vehicles used boosters derived from the initial Thor missile, and continued on into the 21st century.