Thor missile Site - Caistor

In 1955 the contract from the United States Government for the development of an IRBM (Intermediate Range Ballistic missile) system went to the Douglas Aircraft Corporation, which by prodigious feats of design and engineering delivered the first SM - 75 Thor in October 1956 and despite an inauspicious start in the flight test programme - the first 4 launches ended in failure - the system was declared operational in 1959.