Operation Grapple - Shots 1,2 & 3

 military, nuclear testing area

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Detonated on 15 May 1957 at an altitude of 2,200m/7,200ft over this site, Operation Grapple Shot 1 was the first attempt by the United Kingdom to detonate a thermonuclear bomb. Dropped onto a target marker located on the Southeastern shore of Malden Island by Vickers Valian XD818, the bomb successfully detonated 418 yards off target to the East, however due to errors in the design of the "Short Granite" device the explosive yield of 300kt was well short of design forecasts. Regardless, the detonation was reported by both the Royal Air Force and British Media as a success, and the United Kingdom became the world's third recognized possessor of thermonuclear weapons.

Shot 2 took place on 31 May 1957 and evaluated the "Orange Herald" device design. Air-dropped over the same location as Shot 1 by Vickers Valiant XD822 and successfully detonated at an altitude of 2,400m/7,900ft. Yielding the largest ever explosive force achieved by a single stage device at 720kt, the test was deemed a total success.

Shot 3, the final test to take place at Malden Island, was detonated on 19 June 1957 at an altitude of 2,400m/7,900ft over this location. Comprised of a modified "Short Granite" device used in Shot 1 now called "Purple Granite", the bomb was air-dropped by Vickers Valiant XD823 on target and detonated successfully, but once again failed to produce explosive yields anywhere near the design forecasts.

Following the completion of Shot 3, further tests over Malden Island were planned but the need to save time and expense in the testing process meant that the next series of Operation Grapple tests would take place over Christmas Island.