As Major General Leslie Groves, chief of the wartime Manhattan Project, surveyed the world scene in 1946, he found little that gave him comfort. Two former enemies, Germany and Japan, lay in ruins, the latters surrender due in no small part to the atomic bombs whose development Groves had guided. In the place of its former enemies, however, a fearsome new challenge had arisen, one the United States lacked the military means to counter. Despite a destructively rapid military demobilization that daily weakened the U.S. armed forces, many Americans did not share Groves concerns. They unwittingly believed that their nations sole possession of the atomic bomb would suffice to deter or respond effectively to any Soviet attack on its vital interests.
With good reason, the general feared the Soviet leaders intentions. The war in East Asia had ended with Soviet territorial gains at the expense of both China and Japan. Stalins Red Army had delayed its promised withdrawal from Iran, and he pressed the Turks to allow Soviet forces to occupy bases along the Straits connecting the Black Sea to the eastern Mediterranean. By March the Soviet dictators resistance to a Europe of truly independent and democratic states had badly frayed the Big Threes wartime alliance, prompting Winston Churchill to charge Stalin with erecting an "Iron Curtain" between the new Soviet empire and the free states to its west.
Only days before Churchills March 1946 observation, George Kennan, the American chargé in Moscow, had warned Secretary of State James Byrnes that Stalin was "committed fanatically to the belief that there can be no permanent modus vivendi" with the United States. A few days later Kennan predicted that the Soviet dictator would not rest until he had disrupted Americas "internal harmony," destroyed its "traditional way of life," and overthrown its governments "international authority." "Nothing short of complete [American] disarmament," he advised Byrnes, "would even dent" Stalins mistrust.2
Even as Stalin expanded his empire and sought to enhance its military capacity, the United States demobilized its armed forces with such rapidity as virtually to destroy their effectiveness. Within five months of Japans surrender the navy lost more than half its wartime manpower, the army cut its strength from eight million to half that number, and the army air forces eliminated half their two hundred combat groups. As a result, the army cut up aircraft for scrap and the navy mothballed ships. Though further losses of equipment and personnel continued apace throughout 1946, they do not tell the whole story. Defense expert Samuel Huntington found that the "decline in the military effectiveness of the armed forces far exceeded the decline in their personnel strengths." When poorly trained draftees replaced seasoned veterans and experienced technicians, military units "disintegrated to little more than large groups of individual replacements."3
Despite the Wests conventional weakness vis-à-vis the Red Army in Europe, Americas defense leaders doubted that the Soviet Union wanted war in the near future. Speaking for the Joint Chiefs of Staff in April 1947, General Dwight Eisenhower predicted that the "Russians would not initiate war, short of stupidity or blunder, short of five years. In the interval they would continue to export their one commodity, the composite of chaos, anarchy and confusion." By skimping on defense in order to finance Western Europes economic recovery, Secretary of Defense James Forrestal recognized that the United States was taking "a calculated risk." To cover that bet, he noted in his diary, the nation must rely upon its sea power, productive capacity, and exclusive possession of the atomic bomb.4 Better than the defense secretary, Groves knew the inadequacies of the atomic deterrent on which Forrestal relied should Stalin consider initiating a war or simply blunder into one by pushing the United States too far. In 1946 the U.S. atomic stockpile included fewer than a dozen of the highly enriched uranium and plutonium cores needed for an atomic bomb, and Groves was struggling to preserve those elements of the Manhattan Project essential to producing more of the two radioactive elements. For a time it also seemed that technical difficulties would force at least partial closure of the Hanford reactor, source of the bombs plutonium cores and polonium initiators. When Truman learned the true state of the stockpile the next year, one of those present recalled that the president "looked grim and gray, the lines of his face visibly deepened." Not only did the armed forces lack the components to make the estimated four hundred atomic bombs needed to defeat the Soviet Union, it lacked teams to assemble the few that it had. Without a devastating atomic response to a Red Army assault on Europe, the nations military planners estimated that Soviet forces could reach the Rhine within a day and quickly occupy all of Europe save Britain and Scandinavia.5
Convinced that the United States must not only retain but also strengthen its atomic deterrent, Groves cut through the dangerous uncertainty of the immediate postwar period in an effort to restore the armed forces capacity to employ atomic weapons. A year before the president learned the full extent of American weakness, and while the Congress still debated and the United Nations discussed the future of atomic energy, the general pushed ahead without waiting for official policy to emerge.
Recognizing those steps as insufficient, Bradbury wrote Groves in August 1946 identifying as the nations most significant atomic weakness its lack of "an organization capable of assembling an atomic weapon on short notice." In an emergency, Bradbury advised the general, the bombs various parts could be "produced in a shorter time than an assembly crew could be collected and trained." Some months before Bradbury reached that conclusion, Groves had already initiated establishment of such an organization at Sandia Base, not far from Albuquerque, New Mexico, and the Los Alamos atomic laboratory. The army had acquired the base, a former civilian airfield, during the war. There, it trained aircraft mechanics until converting the site to a convalescent center. At wars end it became the graveyard for several thousand planes being cut up for scrap. To verify the progress of his plans for the new assembly organization, Groves sent an officer on his staff, Colonel Gilbert M. Dorland, to Sandia in July 1946. When Dorland reported back that all was not well, Groves listened carefully to the thirty-three-year-old colonels recommendations and, in Engineer fashion, told him: "Well, go do it."7
That simple order sent to Sandia an officer with a masters degree in civil engineering and an outstanding war record building airfields in North Africa and Italy. John Ord, a Signal Corps lieutenant colonel with a doctorate in science and chosen for his wartime direction of a radar school, joined Dorland in August. The first of his sixty young officers with baccalaureate degrees in engineering had also arrived when Dorland activated the 2761st Engineer Battalion (Special) on the 19th of the month. Incredibly perhaps, none of those young men had studied "atomic energy at West Point or wherever they came from . No one knew anything about it." He nevertheless later described them as "hot-shot officers, the best the Army had [and] the greatest single collection of abilities in one small unit that has existed in the history of the United States Army." They would need to be; on them rested responsibility for making "absolutely certain that in case of war, or even the threat of war, the Defense Department would have at its instant disposal teams ready and trained to assemble atomic weapons."8
Accomplishing that mission required Dorlands officers to learn how to store, inspect, and maintain the bombs components and develop techniques for assembling them quickly, in large numbers, and under wartime conditions. A war with the Soviet Union would not end, as with Japan, after dropping two atomic bombs three days apart. Because the design of the early bombs precluded assembling them in advance of a crisis, an effective atomic deterrent required formation of a few dozen assembly teams. Dorland consequently looked to Ord to establish a school that would train the additional officers and enlisted men assigned to Sandia Base in the next few years. Due to the B-29s limited rangeit could not fly from the contiguous United States to targets in the Soviet Union and returneach bomb assembly team must also prepare to work at undetermined and therefore unprepared overseas bases. For their location, early arrival, and Groves later characterization of their accomplishments as pioneering, Dorlands first group of officers adopted the name Sandia Pioneers.
Given the complexity of the early Fat Man atomic bombthe type tested at Trinity, used against Nagasaki, and thereafter Americas principal atomic weaponmany of the atomic scientists believed that military personnel could not possibly assemble one. The Pioneers must prove them wrong. Setting aside the atomic scientists very evident bias, there were good reasons to doubt that young officerslet alone enlisted mencould master what scientist Richard Bice called a "Rube Goldberg affair that took an assembly team of scientific experts a weeks worth of effort to assemble." "To put it bluntly," Bradbury explained, "we had lousy bombs." Major General Alfred M. Gruenther, then director of the armed services joint staff, put it equally bluntly during a 1947 orientation visit to Sandia. After viewing the Fat Man, he demanded of his host, "When are you going to show us the real thing? Surely this laboratory monstrosity is not the only type of atomic bomb we have in stockpile?"9
Weighing more than ten thousand pounds, five feet in diameter, and over ten feet long, simply handling an assembled Fat Man atomic bomb posed a challenge. First however, the officers must construct one from its hundreds of often heavy, dangerous, and toxic parts, many of which required careful pre-assembly testing to verify their serviceability.
The explosive heart of the bomb and much of its weight consisted of a series of concentric spheres. At their center lay a walnut-sized polonium-beryllium initiator that when crushed would release a cloud of neutrons to initiate a burst of chain reactions in the two hemispheres of radioactive plutonium surrounding the initiator. At normal temperature and pressure, those hemispheres remained sub-critical, giving off some heat as their plutonium atoms slowly decayed but incapable of initiating an atomic detonation. The plutonium sphere and its initiator sat, like a pit in a peach, within a tamper of natural uranium. If powerfully compressed by the uranium tamper, the plutonium sphere would crush the initiator, become supercritical, and explode with a force equal to thousands of tons of TNT. The remaining two hollow spheres, consisting of sixty-four shaped charges made from conventional high explosive, provided that compression. Surrounded finally by a thin metal shell, the entire assembly exploded when the bombs firing mechanism sent an electrical charge to detonators placed in contact, through holes in the metal shell, with the outer thirty-two high-explosive blocks.10
The firing mechanisma collection of wet-cell batteries and devices to step up their voltage so as to charge a capacitor bankfit within one of two cones bolted to the explosive spheres metal shell. The Fat Mans fusing system, made up of clock timers, barometers, and radar altimeters, fit within the other cone. That system would determine the point at which the firing systems electrical charge would flow from the capacitor bank to the detonators. The sphere and its two cones fit inside an armored ballistic envelope containing devices with which to monitor the bombs internal components, arm them for use, and when released from a B-29, activate the bombs fusing system.
The Fat Man had a number of features that complicated and slowed its assembly and made it impossible to build well in advance of its use. The fusing systems batteries, similar to those used in prewar automotive equipment, required twenty-four hours to reach full charge. After three days, they must be recharged, which required removal of the bombs ballistic envelope. After a subsequent charge, the batteries needed replacement.
To ensure that the outer thirty-two blocks of the bombs explosive sphere detonated at exactly the same instant, the assembly team must carefully check the impedance of the cables connecting the detonators to the firing system. That required use of a Bowden camera, a complicated device developed to measure the speed of light and another example of the scientists wartime use of what was available rather than develop components and text equipment exclusively for the Fat Man.
The bombs radar altimeters, designed to measure the horizontal distance between a fighter plane and an enemy aircraft approaching from its rear, provide another instance of that practice. The assembly team had to reset the radar altimeters to measure the Fat Mans vertical height of burst and, before installing them in the fusing system, take them on dizzying roller coaster flights in a small plane to ensure they all activated at the proper altitude. To enhance reliability, both the fusing and firing systems contained a great deal of redundancytwo sets of batteries, two clock timers, four barometers, and four radar altimeters.
Inserting the bombs radioactive core also posed problems. Were it placed at the heart of the explosive sphere during assembly, the heat released by the gradual sub-critical decay of its plutonium would in a few hours so warm the surrounding uranium tamper as to cause the inner layer of explosive blocks to soften. The wartime atomic scientists had therefore developed means to insert the radioactive core late in the assembly process. It would occur just before attachment of the ballistic envelope and loading the bomb into a B-29. Reversed, that procedure permitted the assembly team to extract the core for disarming the bomb or to permit the high-explosive blocks to cool before core reinsertion at a later time. To accomplish insertion and removal, the scientists had included a trap door in the explosive spheres outer metal skin. Using a suction device, the assembly team could remove through that opening a shaped charge from both the outer and inner high-explosive spheres and gain access to the uranium tamper, which contained a cylindrical hole through which the plutonium core and its polonium-beryllium initiator could be inserted or withdrawn.
Nor was radioactive heating the only thing that prevented advanced assembly of the Fat Mans explosive heart. The polonium-beryllium initiator at the center of the core had an atomic half life of about four months, which meant that the core must be periodically disassembled to determine the initiators ability, when crushed, to supply the requisite number of neutrons to initiate an efficient detonation of the plutonium.
To prepare his men to accomplish the work previously done by the scientistsand to do it more quickly and at unprepared sitesDorland arranged for his officers to receive a general orientation on the bomb and its operation. Periodic lectures by some of the nations leading atomic physicists and weeklong orientations at Los Alamos to observe the work of its researchers supplemented the initial sessions.
Dorland had no intention, however, of making each officer a physicist and expert on all aspects of the bomb. To reduce the amount of training needed and also to speed the entire assembly process, he divided it into three separate tasks. Specialization in one of three tasks would reduce the extent of each officers needed training, and to save time they could perform the three tasks simultaneously rather than serially.
Those officers placed on the nuclear team, initially sent to work with the scientists at Los Alamos, would learn how to maintain the bombs radioactive cores and prepare to insert them (or a stainless steel dummy during training exercises) into a partially assembled bomb. Following a short course in electronic fundamentals, the officers of the electrical team learned how to test and assemble the bombs batteries, detonator cables, radar, and related components of the Fat Mans firing and fusing cones. After studying the theory of explosives, the members of the mechanical team learned assembly of the bombs explosive sphere and the attachment of the two cones and the bombs protective ballistic envelope.
Constant repetition of their assembly tasks quickly produced expertise, and Dorland soon formed his Pioneers into a prototype assembly team charged with fabrication of a complete bomb. Though the teams first complete assembly went very slowly, experience soon enabled it to pick up the pace. Innovations helped as well. The Pioneers pre-tested bomb components in the storage area and built in advance those of the bombs major sub-assemblies that might be safely stored. Soon assembly time fell from days, as at Tinian for the bombs used against Japan, to hours. By the end of 1946, the Pioneers had also assembled and loaded their first Fat Man on a B-29. The moment had come to do what had never before been attempted, assemble a bomb on short notice at a simulated overseas base lacking a suitable assembly facility.
Safe assembly required that such a facility be static free and electronically grounded, lest a stray spark detonate one of the bombs sixty-four high explosive blocks. To operate its test equipment, the facility must have a dependable power supply, and the close tolerances of the bombs critical parts required that the structure be climate controlled. In addition to mechanical and electrical work areas, the nuclear team would need an appropriate space in which to store and test the bombs highly toxic plutonium core and its initiator. Finally, the facility must be capable of movement by air. The Kansas City Area Engineer met the challenge by designing a 20 x 100 "Butler" building assembled from air-portable 5 x 7 panels of a honeycomb material enclosed within a wooden frame and covered with aluminum.
While Dorlands prototype team equipped that assembly building and, with air force support, ran tests of its loading and use, he sent some of his Pioneers on recruiting trips to various army technical centers. They returned with the names of technically qualified noncommissioned officer volunteers who were soon ordered to Sandia for assembly training by the Pioneers. By November 1947, following extensive coordination with the air force, all was ready for a major field exercise, Operation AJAX.
Between 15 and 25 November 1947, the assembly team that Dorland formed pulled the components of six Fat Man atomic bombs from bunkers in the ordnance area of Kirtland Air Force Base, located adjacent to Sandia. The team partially assembled the six bombs before loading them, the portable assembly building, and all needed men and equipment aboard B-29s and cargo aircraft from the 1st Air Transit Unit. By a long circuitous route meant to simulate the exhausting flight to an overseas base, the Pioneers made the trip to Wendover Field in nearby Utah. There, other members of the team completed assembly and testing of the bombs before turning them over to the 509th Bombardment Group, descendent of the organization that had dropped the bombs on Hiroshima and Nagasaki.
The groups B-29s took the bombs on simulated strike missions before returning five of them to Sandia Base for disassembly and storage. To verify the Fat Mans proper assembly, the 509th air dropped the sixth bomb at the naval testing station at Inyokern, California. Though the Fat Man lacked a fissionable core, the puff of white smoke indicating detonation of the bombs high-explosive sphere at the proper altitude demonstrated that, in Dorlands words, "wed done our job." The armed forces were "back in business," and the Sandia Pioneers had taken the first major step in building the nations atomic deterrent.11
Many similar operations testing new techniques, better equipment, and recently trained personnel would follow beginning monthly in mid-1948. Prior to that, the demonstrated skill of the Pioneers resulted in their being called upon to assist the other services atomic programs. In many small but significant ways the Pioneers, who became part of the Armed Forces Special Weapons Project (AFSWP) in January 1947, also supported the work of the Atomic Energy Commission (AEC), along with AFSWP a successor of Groves Manhattan Project.
The dawn of the atomic age found the navy without aircraft capable of delivering the Fat Man and no carriers equipped to store, test, and assemble it. To ready three of his carriers, the chief of naval operations sought Dorlands help. In late 1947 several of the Pioneers and technicians from Sandia Bases Z-Division, the former Ordnance Division of the Los Alamos atomic laboratory and still part of the AEC, made the first of several visits to Norfolk to advise on the carriers conversion, inspect the resulting modifications, and participate in sea trials of shipboard Fat Man assembly. Playing catch up, the navy also sent men to Sandia to learn bomb assembly and the duties of the weaponeer, the member of an air crew who armed the Fat Man in flight and monitored its operability en route to its target. In November 1948 a navy team trained at Sandia successfully assembled a Fat Man onboard one of the carriers. The navys assembly crew would be ready when the carriers received their first AJ-1 atomic-capable aircraft.
While still part of the army, the air force received its first assistance from Dorlands unit. Several of his Pioneers served as B-29 weaponeers during the early field operations, and they later began training the air forces own weaponeers and bomb commanders. In late 1948 the Pioneers completed the training and certification of the air forces first two atomic bomb assembly teams. With that underway, General Curtis LeMay began looking ahead to the construction of permanent assembly facilities at each Strategic Air Command (SAC) base. When his own engineers estimated the cost of each structure at $100,000, a budget-busting figure, LeMay learned from one of Dorlands officers how SAC could do the job for a tenth that amount.
By that time, the officer, Captain Phil Barnes, had already become deeply involved in a project initiated by General Carl Spaatz and Air Chief Marshall Sir Arthur Tedder, chiefs of the American and British air forces. Fearful of Soviet intentions, the two men had informally agreed in July 1946 that "just in case" the United States should equip several Royal Air Force (RAF) bases to "support atomic operations." Without reference to president or prime minister, observed historian Simon Duke, Britain prepared to become "host to a group of bombers with a nuclear role.".12
To implement the agreement, Groves promptly dispatched two Manhattan Project officers to England, and one of them, Colonel Alexander Stevens, donned civilian clothes to remain in England and oversee construction of the necessary assembly and bomb-loading facilities. With the project nearing completion, Drew Person brought it to a sudden halt with an October 10, 1946, column falsely claiming that the United States had sent a stockpile of atomic bombs to Britain. Fearful of the reaction of the British press and public should they discover what was, in fact, underway, Tedder suspended construction.13
Back home, in what the New York Times called the "largest news conference" since V-J Day, President Truman sought to "end speculation" by stating "categorically and with blunt finality that Great Britain did not have any atomic bombs." Three days later, his press secretary had to revisit the issue, assuring mistrustful reporters "on the authority of the president" that Trumans denial included "incomplete bombs with or without detonators." He could hardly tell the reporters that the United States had too few bombs for one stockpile, let alone two. Pearson nevertheless refused to drop the matter. Later in the month he claimed that "the decision to send a small quantity of A-bombs to England was so closely guarded that it was known only to about six top men"and one Washington Post columnist.14
The Czech crisis of February 1948 and subsequent Berlin Blockade revived Stevens project that summer, this time based upon a Tedder-Eisenhower understanding. Barnes, who received his orders in August, got his two-month construction project underway in October. Before years end, the selected RAF bases possessed the simpler assembly facilities required by the Sandia Pioneers method for delivering bombs to the overseas bases from which B-29s might carry them to targets deep within the Soviet Union. Unaware of the activities of Stevens and Barnes, in mid-September Truman directed Forrestal to "sound out" the British on the construction of "nuclear support facilities" in England. Unaware of how the task had been accomplished, both president and prime minister soon knew of their armed forces new capability.15
Though relations between the highest levels of AFSWP and the AEC had not been good since the bruising 1946 public and congressional debate leading to the creation of both agencies, the Sandia Pioneers had always worked well with the AECs Z-Division at Sandia. When Operation AJAX revealed that many of the bomb components stored under AEC supervision at Kirtland were not serviceable without time consuming repair, the AFSWP field commander at Sandia sent Pioneers Bev Snow, Kermit Lindell, and Cy Brown to work within Z-Division. Their inspections ensured that components received from the manufacturer as well as those returned to storage following exercises met military standards. When the AEC began sending components to the newly constructed national storage sites to which it would soon disperse the nations atomic stockpile, its inspectors used the standards developed by the Snows team.16
Before the AEC took formal custody of all atomic weapons in early 1947, Groves had initiated design and construction of the first three national storage sites. They would both disperse the American atomic stockpile and better protect it against attack than the crude facilities at Los Alamos and Kirtland Field. To assist the two members of the AECs Z-Division charged with laying out and equipping the sites bomb handling facilities, Dorland assigned Pioneer Tom Hagler. With the groups work completed, to include the specifications for electric forklifts suitable for work underground, Hagler carried the plans to the Kansas City Area Engineer, whose office would oversee construction. To verify the suitability of the work, in late 1948 the Pioneers conducted field exercises at the new facilities.17
Though AEC chief David Lilienthal continued to deny the militarys ability to do technical work related to the bomb itself, the Pioneers nuclear specialists helped AEC scientists inspect and maintain the bombs fissionable cores stored at Los Alamos and Sandia. In December 1948 Dorland also lent Z-Division two officers assigned to him fresh from graduate work in aeronautical engineering. For the AEC, Wilfred Dondanville performed wind tunnel tests that improved the ballistic performance of later Fat Man models, and Bob Pearce discovered an error in the design of the Fat Man IV electrical system, which, if left uncorrected, would have prevented detonation of the atomic bomb about to become SACs principal weapon. Though AEC headquarters would not acknowledge such contributions, its field manager at Sandia stated that members of Dorlands battalion had greatly assisted his agencys work.18
Operation SANDSTONE, the Eniwetok Atoll test of three new Fat Man designs in early 1948, represented the Pioneers most extensive contribution to the AEC. Eager to "place the Army at the core of the countrys nuclear program," including allowing his Pioneers to observe the detonation of live bombs, and aware that the AEC desperately needed technicians with security clearances, Groves arranged for Dorlands battalion to support the tests. Before leaving for Eniwetok, Pioneer Frank Camm selected and assigned those who would assist. Some Pioneers helped AEC scientists gather needed equipment and arrange for its shipment. Others escorted the test cores and bomb components to port and prepared to assemble the modified devices after arrival at Eniwetok. At the atoll, Pioneer officers and enlisted men helped AEC and contract scientists set up the apparatus and conduct the experiments that would measure each devices overall yield and its blast, heat, and radiation effects. In keeping with their special expertise, teams of Dorlands men also assembled the three test devices, whose detonation pointed the way to increased yields despite use of reduced amounts of fissionable material. Their effectiveness and predicted yield verified, the new and more efficient cores would permit a considerable increase in the size of the U.S. atomic stockpile.19
When the Pioneers returned to Sandia in late spring 1948, they undertook to form new assembly teamsrepresenting all three servicesfrom the officers and enlisted men being graduated by Ords school. Once Dorland had certified them in assembly, he put his old and new teams through a series of monthly exercises. They tested various methods of providing bombs to the navy and air force and use of improved air-portable assembly facilities, including one built into one of the air forces giant C-97 cargo planes. By January 1949, Dorlands unit, now the 8460th Special Weapons Group, had seven fully qualified teams and was well on its way to creating fourteen more by mid-1950. With more efficient fissionable cores permitting an increase in the number of bombs, the United States had begun to acquire the weapons needed to support its war plans and achieve a rudimentary atomic deterrent to a Soviet invasion of Western Europe.
Even as that occurred, the Pioneers realized that improved versions of the bomb would soon eliminate the need for a large number of teams capable of handcrafting an atomic weapon. As AEC historian Richard Hewlett observed, in the period after Operation SANDSTONE "the day of tailor-made bombs was fading fast," soon to be replaced with the "mass production of components and assembly-line techniques." The "militarized" bombs on the drawing boards would be smaller and lighter, industrially produced and assembled, and capable of long storage and arming in flight. While the AECs atomic scientists designed that future, the Sandia Pioneers served in the vanguard of atomic deterrence, providing Americas weakened armed forces a means to respond to and thereby deter a Soviet attack on Western Europe. In the words of Leslie Groves, their "imagination and foresight" had enabled Dorlands officers to play "a major pioneering role in an entirely new and extraordinarily difficult" aspect of modern warfare. In so doing they had laid the foundations of atomic deterrence in what Pioneer Keith Eiler described as "a radically new era in the history of military technology and warfare."20
This article is based upon research for "Vanguard of American Atomic Deterrence: The Sandia Pioneers, 1946-1949" by the author and Paul H. Carew. Praeger will publish the book this fall. The articles description of the bomb derives from open-source unclassified materials.
July 21, 2002