On 6 August 1945, six miles high, the B-29 Enola Gay cruised toward the Japanese city of Hiroshima at 285 miles per hour. Short seconds after a designated checkpoint appeared in the plane’s bomb sight, the Enola Gay released its terrible, five- ton cargo: “Little Boy,” the first atomic bomb ever used as a wartime weapon.
Moments later, as the plane went into a sharp, breakaway turn, a bright purple flash penetrated the crew’s protective goggles. A heavy blow jolted the plane upward. Someone yelled, “Flak!” He was promptly corrected. Captain William S. (“Deak”) Parsons, U.S. Navy, the weaponeer in ultimate command of the mission, called out, “No, no. That’s not flak. That’s it—the shock. We’re in the clear now.”
As a black and boiling mushroom cloud climbed above the devastated city, the Enola Gay’s copilot Bob Lewis noted that “Captain Parsons—calm, quiet, and knowing more about the bomb than any of us—seemed to be as amazed as we were.”
Whatever the quiet Navy captain’s emotions were on that memorable August day more than 46 years ago, it was not amazing that he was so intimately involved in the delivery of the most devastating bomb ever devised. Unlike previous wars, World War II was won with technology and weapons not available before hostilities began. And few men meant as much to the most important scientific-military programs of that time as Deak Parsons. He made significant contributions toward the development of radar, the proximity fuze, and the atomic bomb-three of the most vital elements of Allied victory. By war’s end, he was the foremost nuclear authority in the Navy. He was also, according to Vice Admiral Frederick Ashworth, “the premier ordnance expert of the modem Navy.” Almost as soon as he was graduated from the U.S. Naval Academy in 1922, Deak Parsons began to demonstrate exceptional skill in applying science to the solution of ordnance and gunnery problems. In time, he would work with leading men of science and establish himself as a scientist in his own right, as well as an officer.
When his superiors recommended him for engineering- duty-only, however, he objected. He was a line officer and a sailor! Periodic sea duty, he felt, would keep him in touch with the real problems and needs of the fleet. His wishes were respected and, except for World War II—when national priorities ruled—his technical assignments ashore were interspersed with sea duty.
Radar
In May 1933, Parsons received orders not likely to please many line officers: He was sent to the Naval Research Laboratory (NRL) in Washington, D.C., where he was to serve as liaison officer between the laboratory and the Bureau of Ordnance. Soon after his arrival, Parsons became concerned with the minimal support being given a project he believed had immense potential—research on practical applications for high-frequency radio waves.
Ten years earlier, Hoyt Taylor and Leo Young, two of the first scientists of the newly established NRL, provided evidence that radio waves might be used to detect ships. But the lab’s parent organization, the Bureau of Engineering, refused direct support. The notion of using radio waves for anything but sending messages ran counter to tradition. NRL had to use bootleg funds to keep the investigation alive. Even when later evidence showed that aircraft, too, could be detected by radio waves, the Bureau’s position did not change. When Parsons reported to NRL, U.S. work on the device that was to become known as radar existed only in the part-time efforts of Young and two other engineers.
Less than a month after his arrival, Parsons tried a new tack. He wrote a letter (for the director's signature) informing the Bureau of Ordnance of “radio research which has possible application in fire control work and airplane detection.” He reported detection of airplanes more than 20 miles away and at altitudes above 8,000 feet. “An outlay of $5,000 a year would permit hiring additional personnel whose services would be devoted exclusively to this project.”
Five thousand dollars then would have been worth years in catch-up time later. But no funds were approved. Detecting airplanes was not Ordnance’s business any more than it was Engineering’s. Parsons later wrote, “It really pained me when I looked over the [deficient] electronic gear in our ships in the Pacific in early 1943 ... to think how much two years of fleet experience with radar before 1941 could have saved us in lives, planes, ships and battles lost during the initial phases of the Pacific war.”
If detection was not the business of the Bureau of Ordnance, fire control surely was. Upon learning that ultra-high frequency waves could track shells in flight. Parsons suggested a new application. Dr. Ross Gunn, a senior scientist, later recalled, “He jumped right in with the idea of using radars for gun laying.” But this was an idea ahead of its time. Radar for gun laying had to wait until the British developed the magnetron for generating high-power microwave energy.
Although Parsons failed to obtain Bureau of Ordnance support, his missionary zeal carried the message of radar's revolutionary potential to fellow ordnance officers. As a retired rear admiral. F. I. Entwistle, who served at the Antiaircraft Fire Control Desk, gave Parsons credit for the Navy's having operational, albeit primitive, radars by the start of World War II.
Parsons’ influence on NRL scientists went beyond his rank and years. His enthusiasm testified that their radio- echo research had practical importance. He pursued this goal. Dr. Gunn stated, “as a boy’s dream, that is, with great fervor and lack of discouragement. That was one of his strengths. He helped push the people on.”
In December 1934, Dr. Robert M. Page, a newcomer to NRL, demonstrated the use of radio frequency pulses for detecting airplanes, thus moving the focus of research from continuous waves to pulses. Page’s invention of the duplexer, which allowed the use of a common antenna for both transmission and reception, opened the way for shipboard systems by reducing the need for space.
The Navy installed 20 pulsed-radar systems, mainly on battleships and cruisers, before the United States entered World War II. After the war, the Chief of Naval Operations acknowledged that the early radars contributed to the victories in the Coral Sea, at Midway, and at Guadalcanal.
For Parsons, the lesson of radar lay not in what the Navy accomplished but in what it could have accomplished. He carried that knowledge with him into other scientific programs.
Smart Fuzes
In the early months of World War II, Hitler’s bombers flew with alarming ease through English antiaircraft fire. Better ways of shooting down bombers became a high priority for U.S. scientists mobilized in 1940 under Vannevar Bush.
Bush asked Merle Tuve of the Carnegie Institution to seek a solution. Tuve’s group of scientists first attempted the development of an optical fuze for the bizarre mission of bombers bombing bombers. It proved impractical. Yet Parsons, who was then head of a broad test program of guns, armor, turrets, and gun directors of the Naval Proving Grounds at Dahlgren, Virginia, still was interested when Tuve offered his next wild idea: a gun projectile fuze that could “hear.”
This new fuze required a radio transmitter and a receiver that would fit into the projectile’s nose cone—a space no larger than a one-pint milk carton. The device had to be mass producible at reasonable cost, safe to store and transport, and rugged enough to withstand rough handling in combat. Despite its glass vacuum tubes and intricate circuitry, it had to withstand acceleration forces of 20,000 Gs when fired from a gun and centrifugal forces of 500 rotations per second during flight.
Despite a tumultuous flight, the transmitter had to be capable of sending out radio signals. When the receiver picked up reflections of the signals from the target aircraft, it would have to determine when the target was within range. At that precise moment, the fuze would detonate the projectile.
Parsons listened as Tuve described the difficulties. He measured those difficulties against the tremendous potential payoff of a workable gun fuze. Existing “time- clock” fuzes nearly always burst too soon or too late; the only hope for a hit was by massive firings. Parsons agreed to tests and became an advocate for what became a Navy program unprecedented in size, secrecy, and military- scientific collaboration. As experimental officer, Parsons made the proving ground facilities available for a massive test program, and his fleet and ordnance experience added practicality to the scientific effort.
There still were skeptics in the Bureau of Ordnance, particularly Captain G.L. Schuyler, who ridiculed the fuze as “the world’s most complicated form of self-destroying ammunition.” But it did not take the scientists long to make a model that worked under laboratory conditions. Although similar fuzes sometimes functioned on one test and not another, Parsons recommended—and the Bureau approved—that when the fuzes functioned at least 50% of the time, mass production would start. That goal was reached in January 1942, and the project shifted from research to production.
At this point, the Navy took over program management and Vannevar Bush was asked to retain technical direction. He agreed, “provided they would attach one damned good officer to my office for liaison.” Parsons fit the description and thus moved into his second role in the proximity program. As Bush’s special assistant, he joined Tuve, Lawrence Hafstad, and D. Luke Hopkins in what has been described as “one of the ablest and smoothest working teams which ever sought to translate new scientific ideas into mass-produced devices for combat use.”
By the summer of 1942, production fuzes were scoring 70%. Parsons arranged for tests on the USS Cleveland (CL-55), using 5-inch shells with live warheads and production fuzes against drone aircraft. The results were spectacular. Vice Admiral George Hussey later described the action, “One drone, one shot, no drone; second drone, one shot, no drone; third drone, one shot, exercise completed, no more drones available.”
The smart fuze was ready for battle—and Parsons was ready to take it there. To assist him, three scientists were given on-the-spot commissions so they could be in uniform to help introduce the fuzes to the fleet.
Levering Smith, who served in a cruiser task force in the South Pacific, recalled, "Parsons came to see if he could get these things battle-tested. . . . We weren’t really anxious to go looking for trouble. But he came out there, saying, ‘Come, let’s go; let’s go get into a fight.’”
Parsons—with fuzes—was assigned to the cruiser most likely to see action, the USS Helena (CL-50). On 5 January 1943, four Aichi dive bombers broke formation and attacked the task force. One streaked by the Helena. There were two rounds fired and then the firing abruptly stopped. The first victim of the proximity fuze plunged into the sea in flames. Hundreds more would follow.
The smart fuze was revolutionary in design and effectiveness. Of equal importance, it was on time. It was ready early enough to counter Japanese kamikaze attacks. It was ready as an adjunct to radar in countering Hitler’s secret weapon, the V-l “buzz bomb.” And it was ready for massive land use by December 1943, when the Nazis launched the counteroffensive that came to be known as the Battle of the Bulge. No individual contributed more in these battles against time than Deak Parsons.
Atomic Bomb
Upon his return from the Helena. Parsons hoped for his own command at sea. Instead, he received instructions to report to an Army general in Washington.
Brigadier General Leslie Groves and the scientists working for him under the cover name Manhattan Engineering District were developing a nuclear weapon—a bomb that could win the war. They believed the Germans were doing the same; the United States had to have it first.
General Groves was confident that U.S. scientists could achieve nuclear fission, but he doubted they could solve the practical problem of making a bomb that was operationally reliable and deliverable. He needed a savvy ordnance officer who could “attract and hold the respect of the scientists.” In brief, he wanted Deak Parsons.
In June 1943, Captain Parsons returned to his home state of New Mexico and reported to the highly secret Project Y at Los Alamos. The project’s director, Dr. Robert Oppenheimer, named Parsons head of the Ordnance Division. The other three divisions were headed by civilians, eminent scientists all. In September 1944, Parsons also became Oppenheimer’s Deputy Technical Director.
Oppenheimer and Parsons were an odd combination— the one theoretical, cryptic, and social; the other practical, direct, and modest. Yet they developed a deep mutual respect and, in time, close friendship. Some of the other scientists accepted a military officer in their midst less readily. Their initial skepticism broke down, however, as they came to know Parsons as a man who could talk their language, a man who practiced what he preached: “A person can accomplish anything if he does not care who gets the credit.”
Parsons’ role in Project Y covered two types of atomic bombs. The first, the gun-type, was developed exclusively within his division. The result was “Little Boy,” the uranium bomb eventually used at Hiroshima. Although “Little Boy” looked like an ordinary bomb, inside it was a gun with a Uranium-235 projectile aimed at a target of more U-235. Firing the projectile would bring two sub- critical quantities of fissionable material together to form a critical mass, causing nuclear fission. Parsons' knowledge of guns, powder requirements, and proving ground procedures were essential in the development of this gun- type bomb.
The other bomb used plutonium as its fissionable material. A series of precisely shaped explosive charges would be detonated around a near-critical quantity of plutonium, causing shock waves to squeeze the plutonium into a critical state—a process called implosion. The result was “Fat Man,” the bomb dropped on Nagasaki and the prototype for later atomic weapons.
Although Parsons’ division conducted the early studies of implosion, he originally opposed enlarging that effort. He changed his position after tests revealed that plutonium could not be used with the gun method because of predetonation problems.
In July 1944, Oppenheimer reorganized Project Y, and. in the process, cleared the way for Parsons to concentrate on making both bombs combat-deliverable. One problem was the difficulty in incorporating the large sphere required for implosion into an aerodynamically stable shape. Parsons solved this problem by adding a box tail with baffles to provide a parachute effect.
The bombs also had to be protected against bullets from attacking aircraft. Parsons had a steel company make special armor plating in accordance with his design specifications. He worked with his own group in the design of fuzes for detonation at predetermined altitudes above the targets.
Parsons saw to it that every item and every procedure related to bomb delivery was tested. Some scientists believed he overdid it; they objected, saying he treated the revolutionary weapon too much like standard ordnance. But Oppenheimer appreciated Parsons’ thoroughness. He wrote General Groves:
“It is impossible to overestimate the value which Captain Parsons has been to the project. ... He has been almost alone in this project to appreciate the actual military and engineering problems which we should encounter. He has been almost alone in insisting on facing these problems at a date early enough so that we might arrive at their solution. ... He has steadfastly insisted that the project remain focused on its military directives, and by doing so has provided a necessary counterpart to the exploratory enthusiasm of his scientific associates.”
With Germany’s defeat in May 1945, the original reason for the bomb was gone. Now, the Truman administration—and Groves and Parsons as well—had a new cause: to end the war with Japan without the necessity of invading the Japanese mainland. That invasion would involve one-and-a-half million troops, with anticipated U.S. casualties in the tens of thousands.
In the rush to deploy the new weapon. Groves appointed Parsons Officer in Charge of the Los Alamos Overseas Technical Group. He also named him weaponeer for the first bombing mission. This position called for a senior officer familiar with all aspects of the bomb “to render final judgment in the event that an emergency requires deviation from the tactical plan.”
Parsons remained in New Mexico long enough to observe the July 1945 “Trinity” test, the explosion of the first nuclear bomb. In the meantime, reconnoitering by Commander Frederick L. Ashworth of Parsons’ Overseas Group resulted in the selection of Tinian as the base from which Air Force B-29 bombers would deliver the bombs. Parsons joined Ashworth in Tinian and took command of his overseas team of 37 persons—a strange mix of Navy officers. Army officers, civilian scientists in Army uniform, and bona-fide Army enlisted personnel. This bomb-assembly and delivery team worked in close cooperation with the Army Air Force’s 509th Composite Group, which by then had completed extensive training in B-29 bombers carrying simulated atomic bombs.
On 5 August 1945, Parsons watched the cautious hoisting of “Little Boy” into the bomb bay of the Enola Gay. Concerned over an alarming number of B-29 crashes during takeoffs from Tinian, Parsons called Brigadier General Thomas Farrell aside and warned, “If that happens tomorrow morning, we could get a nuclear explosion and blow up half the island.” Despite Groves’ instructions to the contrary. Parsons believed he should make the final assembly in flight.
“Have you ever done it?” Farrell asked.
“No,” answered Parsons, “but I’ve got all day and night to learn.”
Farrell agreed. When he returned that evening, Farrell saw Parsons’ blackened hands were bleeding from handling finely tooled parts within the bomb. “For God’s sake, man,” he said, “let me loan you a pair of pigskin gloves.”
“I wouldn’t dare,” Parsons responded. “I’ve got to feel the touch.”
Thus, Tinian was safeguarded as Colonel Paul Tibbets nursed the overloaded Enola Gay off the very end of the airstrip at 0245 on 6 August. After Tibbets reached cruising altitude, Parsons and the Electronics Test Officer, Lieutenant Morris Jeppson, entered the bomb bay.
Standing on a narrow catwalk across the bomb bay doors, Parsons began unscrewing plates to reach his work inside “Little Boy.” Jeppson held a flashlight and handed the captain tools and parts as needed. In strict accordance with an 11-point checklist prepared the previous day. Parsons inserted the gunpowder and detonator behind the fissionable “bullet” of U-235.
After 25 minutes, he withdrew his nicked, graphite- blackened hands. “Okay, that’ll do it,” he said. Parsons and Jeppson returned to their electronic monitoring panels in the crew compartment. At 0630 Japan time. Parsons nodded to Jeppson. The lieutenant returned to the bomb bay, where he pulled the green safety plug from the bomb and replaced it with a red plug. The bomb was now completely armed.
Parsons stood behind Tibbets as the Enola Gay approached the primary target of Hiroshima. Two other B- 29s followed for instrument and photographic coverage. With the aiming point in sight, Tibbets asked Parsons to confirm the target. Parsons did so, thereby acknowledging that everything was proceeding according to plan. There was no reason for Parsons to exert ultimate command and alter the mission; his thoroughness in planning, testing, re-testing, and arming the bomb had paid off.
After the mission. Parsons reported seeing “a great black cloud of boiling dust and churning debris 1,000 feet off the ground, and above it smoke climbed like a mushroom to 20,000 feet. A few fires were visible around the edges of the smoke, but we could see nothing of the city except the dock area, where buildings were falling down.” What he had witnessed at the Trinity test was confirmed: The world was forever changed.
On 9 August, the implosion bomb, with Commander Ashworth as weaponeer, was dropped on Nagasaki. The combined effect of the two bombs—and the real threat of more on the way—led the Japanese to seek surrender five days later.
Postwar
By accepting the Manhattan District assignment. Parsons sacrificed his opportunity for a wartime sea command. Without command time, he foresaw a bleak future in the Navy. But at Tinian he was promoted to commodore, and, soon after, he received the two stars of a rear admiral.
When he returned once more from the Pacific, Parsons found his scientific expertise in great demand. He , was soon dividing his time among three groups: the Military Liaison Committee to the Atomic Energy Commission, the Weapon Systems Evaluation Group, and the i Atomic Defense Division in the Office of Chief of Naval Operations.
The latter assignment led to his role as technical deputy to the commander of Operations Crossroads. Under the code name “Wet Nurse,” Parsons served as a key link between military commanders and civilian scientists testing the effects of two atomic bombs—one an air burst, the other underwater—on 70 surplus naval vessels anchored in Bikini lagoon.
In 1951, Parsons’ desire for a sea command was finally fulfilled; he became Commander, Cruiser Division Six, in the Atlantic and Mediterranean. His future looked bright. In March 1952, he became Deputy Chief of the Bureau of Ordnance. In this position, he promoted postwar research and development programs and used his influence I to build Navy laboratories on a foundation of military-scientific cooperation. He cleared the way for many innovative ordnance developments, in particular, the Sidewinder guided missile.
Parsons’ rapport with scientists and his reputation within the Navy led many a senior officer to say, “Let’s see if Deak can help with our problem." No one objected to his taking on additional burdens. The only limitation was his own physical capacity.
Too soon, that capacity was exhausted. The evening Parsons learned that Robert Oppenheimer’s special security clearance was to be canceled, he became, as his wife recalled, “terribly upset, just terribly upset.” Dropping his usual calmness, he exclaimed, “This is the biggest mistake that the United States could make!”
Later that evening, Deak Parsons suffered a pain in the chest. The next morning, 5 December 1953, at Bethesda Naval Hospital, he died during an electrocardiogram. In his 52nd year, the premier ordnance expert of the modern Navy was gone; the nation lost its most brilliant military-scientific mind. Fortunately, Deak Parsons’ legacy lives on in the excellence of the ordnance, technology, and research institutions of today’s Navy.