OTD 15.5 May 15th Traditional Cache

OTD - 15:5 

Perhaps you want a smiley for every day of the year or maybe a birthday smiley. For whatever reason these 12 mini monthly power trails are here to be found. Most are easily located, with an occasional sneaky one in the mix, sat lock can be difficult in some areas.

Here are some facts for this day. You are welcome to log your interesting, quirky or fun fact/s with your log.

On This Day - May 15th 1957

Britain drops its first Hydrogen bomb, near Malden Island in the Pacific Ocean. 

Malden Island is a low, arid, uninhabited island in the central Pacific Ocean, about 39 km² in area. It is located 446 km south of the equator. The nearest inhabited place is Tongareva (Penhryn Island), 450 km to the southwest. The nearest airport is on Kiritimati, 675 km to the northwest.

Britain's thermo-nuclear weapons programme was started in December 1954 to develop the megaton hydrogen bomb. Operation Grapple was the name of the exercise leading to the detonation of the first British hydrogen bomb on 15 May 1957. The very first fusion device was dropped from Vickers Valiant XD818, piloted by Kenneth Hubbard, over Malden Island. The bomb weighed around 4,545 kg. Code-named Green Granite or Short Granite, it was a combination fission-fusion device with a Red Beard primary and a lithium deuteride secondary. The expected yield was around 1 megaton. It was released from a height of almost 13 km and yielded just 300 kilotons. The relatively low yield prompted a redesign of the hydrogen bomb, and to cover up the disappointing yield, a large fission bomb, code-named Orange Herald, was dropped on 31 May 1957. It yielded 700 kilotons and its purpose was to persuade observers that the United Kingdom had an effective thermo-nuclear weapon. Later tests were more successful.