The arming and safety plugs removed from the first atomic bomb that was dropped on Hiroshima have sold for £76,000 ($99,343).
The green safety plug and red arming plug were pulled out of ‘Little Boy’, the 4.4-tonne weapon, before it was unleashed to such devastating effect on August 6, 1945.
The bombing killed over 140,000 people, bringing forward the end of World War Two with the Japanese surrender.
The three-inch plugs, which were made of metal and wood, were kept as a souvenir of the mission by Lieutenant Morris Jeppson, the weapons test officer on the B29 bomber ‘Enola Gay’.
The safety plug prevented the bomb going off during transport and flight while the arming plug enabled the weapon to be detonated by radar once it was dropped over the target.
Lieutenant Jeppson later recounted: ‘Before this time, bombs dropped from aircraft detonated by striking the ground.
‘Atomic bombs with 30,000 times the explosive power had to be detonated in the air at heights proportional to the size of the explosion.
‘Scientists recognised that an atomic explosion from a bomb dropped from low altitude would destroy the B-29 (Enola Gay).
‘Therefore the plane should fly at a high altitude. As a result, the bomb designers faced several new problems.
‘The first was how to detonate the bombs at 1,500 ft above the ground while it is falling at 1,000 ft per second. The answer had to be by radar directed between bomb and ground to electronically detect height.
‘Secondly, to make sure that the bomb could not detonate too soon after leaving the plane, timing clocks isolated the firing voltage from the bomb detonator.
‘Thirdly, the concern that radars in the bomb, if turned on too soon, might pick up radiations from Japanese radar to cause premature firing too high above ground.’
The items sparked a bidding war when they were sold with auction house Bonhams New York.
They were consigned by descendants of Dr Edward Doll, a friend and colleague of Lt Jeppson who was gifted the plugs by him.
A Bonhams New York spokesperson said: ‘The auction featured a green safety plug and a red arming plug from ‘Little Boy’, the first atomic bomb dropped on Japan.
‘The plugs, roughly the shape of a car cigarette lighter, had distinct functions which were integral to the mission.
‘They were saved by Jeppson as souvenirs of it.’
After the war, the Enola Gay returned to the US where it was operated from Roswell Army Air Field in New Mexico.
It was subsequently transferred to the Smithsomian Institution’s storage facility at Suitland, Maryland, in 1961.
About 80,000 people, around 30 per cent of the population of Hiroshima at the time, were killed by the blast and resultant firestorm, with tens of thousands more perishing from the effects of the radiation in the months that followed.