The SM-75/PGM-17A Thor intermediate range ballistic missile was developed during the early Cold War as an interim nuclear deterrent while the United States Air Force pursued long-range intercontinental ballistic missiles, with a planned range of about 1,500 miles and deployment in Europe. Douglas Aircraft Company received the prime contract on December 27, 1955, after competing bids from Lockheed Corporation and North American Aviation. Britain agreed in June 1958 to base Thor missiles there as Royal Air Force missiles, with the U.S. supplying missiles, spare parts, and training, and the British providing bases, infrastructure, and personnel; sixty missiles were deployed to twenty RAF stations. The Thor on exhibit was built at Douglas's Santa Monica, California, plant in 1958, shipped that year to Britain as one of the sixty assigned to the RAF, returned to Santa Monica in 1963 for refurbishment, and then used in various testing programs before its transfer on March 15, 1994, to the National Museum of Nuclear Science and History. As newer intercontinental ballistic missiles became available, support for Thor ended: on May 1, 1962, the United States announced it would not continue support after October 31, 1964, Britain also moved to end the program, and the last Thor squadrons were inactivated on August 23, 1963.
