Britains Nuclear Deterrent Development – Part 11

Part of the Britain's Nuclear Deterrent Development series

William Penney, the man in charge of Britain’s bomb design, William Cook, his deputy, and the scientists at the Atomic Weapons Research Establishment (AWRE) at Aldermaston in Berkshire did not have full knowledge on how to build a hydrogen bomb. The team produced three megaton-range designs that would require testing. Orange Herald was a large boosted fission weapon, Green Bamboo was an interim thermonuclear design and Green Granite was a true thermonuclear weapon. Operation Grapple was planned to test these weapons and further develop the designs.  

Operation Grapple was a huge operation, with approximately 20,000 British service personnel being deployed to Christmas Island in the Pacific Ocean, alongside New Zealand and Fijian forces. Overall, nine nuclear explosions would take place between 15 May 1957 and 23 September 1958.   

KN434. Royal Air Force Douglas C-47B Dakota C.4 
Prestwick 1950s. Scanned from my father’s original negative. © Jim Cain 

The Douglas C47 Dakota is one of the most successful military transport aircraft designs in history. The aircraft was widely used by the Allies during World War Two, but most RAF Dakotas had been retired or sold by 1950. This ‘Christmas Island Newspaper’, shared with us by Mike Tolson who is a long-time supporter of Vulcan XH558, describes the long-retired Dakota being brought back into service in late 1956 and the task that ‘Christmas Airways’ played in overcoming the logistical challenges of Operation Grapple. 

The first three tests of Operation Grapple were during May and June 1957. The tests were to airdrop and detonate bombs over Malden Island. This was Britain’s second airdrop of a nuclear bomb and the first of a thermonuclear weapon. 

The United States had attempted their first thermonuclear airdrop just a year before, on 21 May 1956, during their Operation Redwing Cherokee test. While the test was primarily to gather data on the effects of high yield air bursts, it would also be a Cold War political demonstration to the Soviet Union of the US capability to deliver hydrogen bombs by air. The bomb was dropped from the B-52 Stratofortress – Barbara Grace.  Navigation error meant the bomb missed the target by 4 miles. The explosive force of the bomb was rated at 3.8 megatons, but because of the error in targeting it negated gathering of the data on the effects of the blast. 

Britain wanted their bomb within 300 yards of the target. Air Commodore Wilfrid Oulton, the task force commander, felt that a good bomber crew could achieve that.   

No. 49 Squadron Badge  

No. 49 Squadron deployed four Vickers Valiant aircraft which were specially-modified to conform to the scientific requirements of the tests and other measures to protect against heat and radiation. The aircraft and crew were XD818, piloted by Wing Commander Kenneth Hubbard, the squadron commander, XD822, piloted by Squadron Leader L. D. (Dave) Roberts, XD823, piloted by Squadron Leader Arthur Steele and XD824, piloted by Squadron Leader Barney Millett. 

XD818, piloted by Hubbard, flew the Grapple 1 mission with XD824 as the observation aircraft. The two aircraft took off from Christmas Island at 09:00 local time on 15 May 1957. At 10:38, the Short Granite bomb was dropped from 45,000 feet off the shore of Malden Island. Hubbard missed the target by 418 yards and the bomb’s yield was estimated at 300 kilotons, which was far below the capability of the device design. 

XD822. Royal Air Force Vickers Valiant B.1 
Prestwick 28 May 1960. Scanned from my father’s original negative. © Jim Cain

On 31 May, Grapple 2 took place. The Orange Herald bomb was dropped by Valiant XD822, while XD823 acted as the observation aircraft. This bomb was dropped at 10:44 local time. XD822’s pilot, Dave Roberts, made the standard 60-degree banked turn to get away after the bomb was released, but the aircraft went into a high-speed stall. The accelerometer failed, but Roberts was able to apply his skills to recover from the stall and use the mechanical accelerometer to complete the manoeuvre. The explosive yield was 720 kilotons. 

The third and final test of the series was Grapple 3. The Purple Granite device was dropped on 19 June, by a Valiant XD823 with XD824 as the observation aircraft. The yield was a very disappointing 200 kilotons of TNT, which was less than the first test for the Short Granite device.  

News coverage at the time reported that Britain had airdropped a hydrogen bomb, but the scientists at Aldermaston had not yet quite mastered the design of thermonuclear weapons to achieve a megaton yield. Pressure was mounting at home and abroad for a ban on nuclear testing. If Britain was going to retain its status as a world power and become the third recognised possessor of thermonuclear weapons, they would need to develop the hydrogen bomb at speed. By late October improved components for the nuclear device were delivered to Christmas Island where the next test would take place – Grapple X.  

It required a major construction effort to improve the facilities on Christmas Island. 26 blast-proof shelters, a control room, tented accommodation and a second runway were all required on the island. Monitoring equipment was set up on Malden Island and Fanning Island and observation posts were re-established on Penrhyn Island and Jarvis Island. 

Grapple X took place on 8 November 1957. At 01:00 on the day, as the final preparations were being made for the single test, Air Commodore Oulton was advised that a Shackleton patrolling the exclusion zone had sighted the SS Effie. To minimise any publicity before this test, the British government had delayed sending out the Notice to Mariners that advises them of important matters affecting navigational safety. The Notice had only been issued three weeks prior, failing to take into account the size of the Pacific Ocean and some of the journey times required by ships. The SS Effie had left its last port of call before the Notice was issued. The Shackleton kept Effie under observation while trying to contact her and the Royal Navy destroyer HMS Cossack, which was supporting the operation, was sent to intercept.  

HMS Cossack. Image from the collections of the Imperial War Museum 

By 06:00 everything was prepared for the test and at 06:15 the Shackleton reported that the SS Effie crew had woken up and the ship had turned about and was now headed out of the exclusion zone. A further report from the Shackleton at 07:25 indicated that Effie was now sailing in company with HMS Cossack. By now the Valiant aircraft had started their engines and took off at 07:35, just as the Cossack reported that Effie had cleared the exclusion area.  

The bomb was dropped from Valiant XD824, piloted by Squadron Leader Barney Millett, at 08:47. The observational aircraft was Valiant XD825. The yield of explosion exceeded expectations. The predicted yield had only been 1 megaton, but the yield was a staggering 1.8 megatons of TNT. This was Britain’s first megaton class hydrogen bomb. 

VTST Volunteer, Cliff Collins, was stationed on Christmas Island in September 1957 for a year. Cliff was aged just 23 at the time. The following film contains footage taken by Cliff with a wind-up Kodak Brownie Cine Camera using Kodak 8mm film stock. 

While Britain had joined the United States and the Soviet Union in becoming the third country to possess thermonuclear weapons, the Soviets had advanced their technological capabilities even further with the launch of the world’s first artificial satellite, Sputnik 1, on 4 October 1957.  

The ‘Sputnik crisis’ caused widespread calls for action and officials in the United States and Britain took the opportunity to mend the relationship between the two nations. 

To be continued… 

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