1958 US–UK Mutual Defence Agreement as an atomic spy, caused the proposal to be dropped. The June 1951 defection of Donald Maclean, who had served as a British member of the Combined Policy Committee from January 1947 to August 1948, reinforced the Americans' distrust of British security arrangements. The first British atomic bomb was successfully tested in Operation Hurricane on 3 October 1952, but although it was more advanced than the American bombs of 1946, Britain was still several years behind in nuclear weapons technology. The United States conducted Ivy Mike, the first nuclear test of a true thermonuclear device (also known as a hydrogen
Redstone Test Stand in tests to study the effects of nuclear detonations in the upper atmosphere, Operation Hardtack I. After being static-fired at the Interim Stand in January 1958, two missiles were shipped to the Pacific Test Range. In July and August, the missiles became the first missiles ever to detonate atomic warheads. In 1958, Redstone development ended and Chrysler began mass production for deployment. Only a few of these missiles were tested at the Interim Test Stand because the propulsion system had become so reliable. As the space race continued, the civilian space agency, NASA started on October 1, 1958 but the