Capt. William “Deak” Parsons lowered himself into the bomb bay of the “Enola Gay” in the early morning hours of Aug. 6, 1945. Minutes before, the B-29 Superfortress had departed from the North Field of Tinian Island. Parsons worked by flashlight, inserting a powder charge and detonator into a weapon unlike anything the world had ever seen.
It was a perilous mission. Perhaps no one aboard the heavy bomber understood that more than Parsons, a Naval Academy graduate who had cut his teeth at Dahlgren Naval Proving Ground. Here, in the summer of 1943, the Navy tested a new weapon design — trials that would help shape the atomic bomb Parsons now armed in the skies over the Pacific.
Parsons had first arrived at Dahlgren as a young lieutenant in 1930, where he stayed for less than a year. He returned to the remote post on the Potomac River for a second time in 1939 as Europe — and the world — marched toward war. As Parsons worked out problems about projectiles and battle armor at Dahlgren, he could have no idea the role he would play in developing and delivering the world’s first atomic bomb.
Yet Parsons was, perhaps, a natural fit, someone well-versed in practical and theoretical ordnance—high explosives, guns and fusing. More than that, he was a widely respected naval officer who was also able to earn the esteem of scientists. When Brig. Gen. Leslie Groves, director of the Manhattan Project, announced he was looking for an ordnance expert in the late spring of 1943, Parsons’ name came up immediately. By mid-June of that year, Parsons was relieved of his duties at Dahlgren and, with his family in tow, began the cross-country drive to a secret weapons laboratory in Los Alamos, New Mexico.
‘Spectacular failure’
Parsons did not have to be in this cramped space, face-to-face with a weapon capable of wiping out an entire city. But as Lt. Morris Jeppson, a crew member on the “Enola Gay” who shared space with Parsons inside the bomb bay, would later recall, Parsons “was greatly concerned that B-29s loaded with conventional bombs were crashing at the ends of runways on Tinian during take-off.”
If the plane loaded with the atomic bomb crashed or caught fire on Tinian, an atomic explosion could wipe out half of the island. “On his own, Parsons decided that he would go on the Hiroshima mission and that he would load the gun after the ‘Enola Gay’ was well away from Tinian,” Jeppson said.
That way, if the bomber crashed and burned on takeoff, it would take out only the crew—Parsons included. It was a risk he wanted to take.
Aboard the “Enola Gay,” Parsons was the bomb’s expert. He knew “just about all there was to know about the workings of our bomb, having participated in its development,” said lead pilot Col. Paul Tibbets.
Two years before, the first test of an atomic bomb model occurred at Dahlgren Naval Proving Ground. Dubbed the “Sewer Pipe Bomb,” the prototype consisted of a length of sewer pipe welded between a split 500-pound bomb. In August 1943, the test model arrived at Dahlgren from the Applied Physics Laboratory in Springfield, Maryland, as a routine test item.
But it was anything but ordinary. The sewer pipe design, code-named “Thin Man,” was one of two types of devices initially developed under the Manhattan Project. It used a gun-like design, firing a uranimum-235 slug into a target to trigger a nuclear explosion. The second, codenamed “Fat Man,” used an implosion design in which explosives compressed a plutonium-239 core to set off a reaction.
The drop over Dahlgren was “an ominous and spectacular failure,” said Norman Ramsey, the young scientist who supervised the team designing bomb casings and testing scale models, according to Target Hiroshima. The test scale model fell into a flat spin “the likes of which had rarely been seen before.”
Ramsey was distraught. Parsons, though, was optimistic. He believed, just as his Dahlgren successors still do, that failure is a necessary step toward success. The test drop had provided valuable information. This was a step forward.
Ultimately, the “Thin Man” would prove impractical. The focus shifted to the implosion-type design, “putting Dahlgren out of the Manhattan Project,” wrote the authors of The Sound of Freedom: Naval Weapons Technology at Dahlgren, Virginia, 1918-2006.
Though the testing did not directly contribute to the success of the atomic bomb, Parsons was right. The hands-on findings at Dahlgren acted as a compass, pointing scientists and engineers closer to what they hoped to achieve.
Test run
Scientists at Los Alamos Laboratory thought delivering the bomb would be easy once it was assembled. But Parsons — a military man and ordnance expert — knew they faced enormous hurdles. The weapon would be different than anything that came before it: the size, weight, shape and the way it would be delivered. There was virtually no room for error. A failed bomb could deliver active material to the enemy.
At 5:30 a.m. on July 16, 1945, after months of tests measuring delivery systems, aerodynamics and bomb casing performances, the Manhattan Project moved from theory and prototypes to a proven atomic weapon when it exploded over a barren stretch of desert in southern New Mexico. Three weeks later, Parsons described what he’d seen to crews of seven B-29 bombers from the Army Air Force’s 509th Composite Group on Tinian Island, some 1,500 miles from mainland Japan. He'd watched the Trinity Test, the first-ever detonation of a nuclear weapon, from a B-29. It was the brightest and hottest thing the world had ever seen, he said.
Later that night, four bombers in a row crashed on takeoff from Tinian. Parsons was concerned. The bomber on the nuclear mission would be 15,000 pounds overweight, making the takeoff far riskier. The following morning, Parsons recommended he load the power charges to the gun himself, after the plane took off and was a safe distance from the island.
Parsons had never assembled the powder charges. But he said that he had all day to try it. With the 9,700-pound bomb called “Little Boy” hanging from its hook in the bomb bay of the “Enola Gay”, Parsons crawled inside with an 11-step checklist. Barehanded, the Navy captain repeated the steps over and over again.
Hiroshima
By the time the “Enola Gay” lifted off from Tinian, Parsons knew the checklist by heart. Still, he had Jeppson check off each step as he tackled it. The final assembly of the “Little Boy” was completed within 30 minutes of takeoff. Parsons took note of his hands, covered in dirt and grease and no place to wash them.
Around 5:45 a.m., Iwo Jima appeared through broken clouds. To the east, the sun, a bright red ball, climbed from the ocean. Just as quickly, the island, home to one of the bloodiest battles in the Pacific, was behind them. Tibbets smoked his pipe intensely. With three potential targets identified, he still wasn’t sure precisely where they were headed.
A little after 7 a.m., the skies cleared. It was a perfect day. As the minutes ticked down and the B-29 climbed to its bombing altitude of more than 30,000 feet, a decision was made on the “Enola Gay”: They would go to Hiroshima. It lay before them, some 75 miles in the distance. Parsons, who was now outside the bomb bay, readied his oxygen mask; he would take charge in any emergency that required them to stray from the plan. He and the crew pulled on flak suits.
At 8:47 a.m., Parsons and Jeppson made final circuit tests; at 9:04 a.m., Parsons told the lead pilot that all was in order. He took his position behind the pilot. Five minutes later, Parsons verified the target and authorized the release of the atomic bomb. Then, just after 9:15 a.m., the bomb bay doors opened and “Little Boy”—the bomb Parsons knew virtually everything about — fell from the “Enola Gay”.
Victory
On Aug. 18, 1945, 12 days after Hiroshima and following the delivery of a second atomic bomb—this time on the city of Nagasaki — Capt. David Hedrick, commander of Dahlgren, announced the end of the war in a message:
You men and women, civilian and service personnel of the Naval Proving Ground, may well take pride in your contribution to the defeat of the enemies in Europe and to the surrender of Japan. The Navy is the Nation’s first line of defense, and the weapons of war which have established the Navy’s superiority have been tested and proved by you.
Through your efforts the guns and munitions, and all that go to make up naval ordnance, have been placed on ships and landing crafts with full assurance that they would stand the heat and stress of battle. Your work at the batteries and in the shops of this station, through cold-wintry weather and during the hot summer months, has made this assurance. The importance of the part of the proving ground has had in the war effort has made it a major activity in the Naval establishment of the United States.
Dahlgren had played a key role in helping win the war — a role perhaps far greater than those at the proving ground could yet imagine. Throughout the war years, weapons testing had expanded dramatically, with millions of rounds fired and vast quantities of powder expended. The proving ground tested everything from anti-aircraft artillery and rockets to captured enemy equipment, providing critical insights for combat.
In response to the fierce Japanese resistance at Tarawa in 1943, Dahlgren quickly determined the most effective projectile-fuse combination against fortified positions, work that saved American lives. It also contributed to the development of the Norden Mark XV bombsight and served as the proving site for the revolutionary VT radio proximity fuze, first prototyped in an old coffee can. It would become one of the most devastating weapons of the war.
Dahlgren had been tested under the extreme pressures and challenges of the largest and deadliest conflict in human history — and it had endured.
Editor’s Note: This story was compiled using multiple sources available in the public domain, as well as “Target Hiroshima: Deak Parsons and the Creation of the Atomic Bomb,” “The Sound of Freedom: Naval Weapons Technology at Dahlgren, Virginia, 1918–2006,” and “The Devil Reached Toward the Sky: An Oral History of the Making and Unleashing of the Atomic Bomb.” Every effort has been made to accurately represent the events and contributions of Capt. William “Deak” Parsons and the personnel at Naval Surface Warfare Center Dahlgren Division, drawing on firsthand accounts, historical records and published research to provide a detailed account of this pivotal period in history.