Throughout July and into August, until the first atom bomb was dropped on Japan, the center of dramatic interest, naturally, was Tinian. At the same time, however, our test program at Los Alamos for the second implosion bomb had been going on at an accelerating rate. The main problem was that the company manufacturing certain essential parts for a nonatomic assembly in the Fat Man had been unable to meet delivery schedules. This reduced the number of tests possible on that particular assembly. It also prevented efficient over-all testing, since many tests had to be made twice, once with all components except the missing one and then at a critically late date with a complete assembly minus the nuclear components. In fact, the first live tests of the missing part were conducted only a few days before the actual dropping of the bomb on Nagasaki.
After it had been finally processed and formed into the exact shapes at Los Alamos, the plutonium for the Fat Man was flown to Tinian in a special C-54. Some of the other vital parts for two additional Fat Men were flown out in two B-29’s belonging to the 509th, which had been held at Albuquerque especially for this purpose. In all cases, the plutonium shipments were accompanied by special personnel to guard against accident and special precautions were taken to ensure that if a plane carrying any of the plutonium did crash, we would have a fairly good idea of where it went down.
Like the Little Boy, the first Fat Man was to be used in combat as soon as we had enough fissionable material. Toward the end of July, the bomb was rescheduled to be dropped on August 11, which was an improvement over our previous target date of August 20. By August 7, it had become apparent that we could probably slice off another day from our schedule.
Admiral Purnell and I had often discussed the importance of having the second blow follow the first one quickly, so that the Japanese would not have time to recover their balance. It was Purnell who had first advanced the belief that two bombs would end the war, so I knew that with him and Farrell on the ground at Tinian there would be no unnecessary delay in exploiting our first success.
Good weather was predicted for the ninth, with bad weather to follow for the next five days. This increased the urgency of having the first Fat Man ready still another day earlier. When the decision to do so was reached, the scientific staff made it clear that in their opinion the advancement of the date by two full days, from the eleventh to the ninth, would introduce a considerable measure of uncertainty. I decided, however, that we should take the chance; fortunately all went well with the assembly, and the bomb was loaded and fully checked by the evening of August 8.
Six Pumpkin-carrying planes were assigned various targets in Japan for the eighth, but because of weather only two of them reached their primary targets; three of them reached secondary targets, and one aborted and returned to Tinian. In the field order for the second atomic mission there was nothing to indicate the extraordinary nature of the bomb, although anyone reading it would realize that this was by no means a routine assignment.
There were only two targets designated this time: Kokura, primary; and Nagasaki, secondary. Niigata was not made a third target because of its great distance from the other two cities. To increase the chance of using the primary target, the strike plane, no matter what the weather report, was ordered to pass close enough to it to make certain that visual bombing was not possible before it went on to the secondary target. To avoid any chance that the photo planes would arrive too early, they were required to check in with both Iwo Jima and Tinian before proceeding past Iwo Jima. In case of doubt, due to inadequate information, they were to photograph both targets.
The Kokura arsenal was one of the largest war plants in Japan. It produced many different weapons and pieces of war equipment. It extended over almost two hundred acres and was supported by numerous machine shops, parts factories, electric power plants and the usual utilities.
Nagasaki was one of Japan’s largest shipbuilding and repair centers. It was important also for its production of naval ordnance. It was a major military port. The aiming point was in the city, east of the harbor.
The strike plane and the two observing planes took off shortly before dawn on the ninth. Major Charles W. Sweeney was pilot of the strike ship, Captain Kermit K. Beahan was the bombardier, Commander Ashworth was the weaponeer, and Lieutenant Philip Barnes was the electronics test officer.
It was not possible to “safe” the Fat Man by leaving the assembly incomplete prior to take-off, as had been done in the case of the Little Boy. There was considerable discussion among the technical staff about what would happen if the plane crashed, and possibly caught fire, while it was taking off. They realized that there would be a serious chance that a wide area of Tinian would be contaminated if the plutonium were scattered by a minor explosion; some thought that there was even a risk of a high-order nuclear explosion which could do heavy damage throughout the island’s installations. Of course, we had gone into all this at length during our preliminary planning, and on the basis of my own opinion, as well as that of Oppenheimer and my other senior advisers, that the risk was negligible I had decided that the risk would be taken.
As happens so often, however, there was constant interference by various people in matters that lay outside their spheres of responsibility. Throughout the life of the project, vital decisions were reached only after the most careful consideration and discussion with the men I thought were able to offer the soundest advice. Generally, for this operation, they were Oppenheimer, von Neumann, Penney, Parsons and Ramsey. I had also gone over the problems at considerable length with the various groups of senior men at Los Alamos, and had discussed them thoroughly with Conant and Tolman and with Purnell and Farrell and to a lesser degree with Bush. Yet in spite of this, some of the people on Tinian again raised the question of safety at take-off at the last moment. Their fears reached a senior air officer, who asked for a written statement to the effect that it would be entirely safe for the plane to take off with a fully armed bomb. Parsons and Ramsey signed such a statement promptly though with some trepidation, possibly with the thought that if they were proven wrong they would not be there to answer. Ramsey then advised Oppenheimer at once of the various design changes that must be made to ensure that future bombs would in fact be surely safe.
One very serious problem came up just before take-off, which placed Farrell in the difficult position of having to make a decision of vital importance without the benefit of time for thought or consultation. Despite all the care that had been taken with the planes, the carrying plane was found at the last moment to have a defective fuel pump, so that some eight hundred gallons of gasoline could not be pumped to the engines from a bomb bay tank. This meant that not only would the plane have to take off with a short supply of fuel, but it would have to carry the extra weight of those eight hundred gallons all the way from Tinian to Japan and back. The weather was not good, in fact it was far from satisfactory; but it was good enough in LeMay’s opinion, and in view of the importance of dropping the second bomb as quickly as possible, and the prediction that the weather would worsen, Farrell decided that the flight should not be held up. Just before take-off Purnell said to Sweeney, “Young man, do you know how much that bomb cost?” Sweeney replied, “About $25 million.” Purnell then cautioned, “See that we get our money’s worth.”
Because of the weather, instead of flying in formation, the planes flew separately. To save fuel, they did not fly over Iwo Jima but went directly to the coast of Japan. Their plan was to rendezvous over the island of Yokushima, but this did not work out. The planes were not in sight of each other during their overwater flight and only one of the observation planes arrived at the rendezvous point. The missing plane apparently circled the entire island instead of one end of it, as it was supposed to do according to Sweeney’s plans. Although Sweeney had identified the one plane that did arrive he did not tell Ashworth. Unfortunately, because it did not come close enough, Ashworth was unable to determine whether it was the instrument-carrying plane, which was essential to the full completion of the mission, or the other, which was not. Sweeney’s orders were to proceed after a short delay of fifteen minutes but he kept waiting hopefully beyond the deadline. The result was a delay of over half an hour before they decided to go on to Kokura, anyway.
At Kokura, they found that visual bombing was not possible, although the weather plane had reported that it should be. Whether this unexpected condition was due to the time lag, or to the difference between an observer looking straight down and a bombardier looking at the target on a slant, was never determined.
After making at least three runs over the city and using up about forty-five minutes, they finally headed for the secondary target, Nagasaki. On the way they computed the gasoline supply very carefully. Ashworth confirmed Sweeney’s determination that it would be possible to make only one bombing run over Nagasaki if they were to reach Okinawa, their alternate landing field. If more than one run had to be made they would have to ditch the plane—they hoped near a rescue submarine.
At Nagasaki, there was a thick overcast and conditions at first seemed no better for visual bombing than at Kokura. Considering the poor visibility and the shortage of gasoline, Ashworth and Sweeney decided that despite their positive orders to the contrary, they had no choice but to attempt radar bombing. Almost the entire bombing run was made by radar; then, at the last moment, a hole in the clouds appeared, permitting visual bombing. Beahan, the bombardier, synchronized on a race track in the valley and released the bomb. Instead of being directed at the original aiming point, however, the bomb was aimed at a point a mile and a half away to the north, up the valley of the Urakami River, where it fell between two large Mitsubishi armament plants and effectively destroyed them both as producers of war materials.
On the way to Okinawa warning ditching orders were announced; but the plane made it with almost no gas left. Sweeney reported there wasn’t enough left to taxi in off the runway.
The Nagasaki bomb was dropped from an altitude of 29,000 feet. Because of the configuration of the terrain around ground zero, the crew felt five distinct shock waves.
The missing observation plane, which fortunately was the one without the instruments, saw the smoke column from a point about a hundred miles away and flew over within observing distance after the explosion. Because of the bad weather conditions at the target, we could not get good photo reconnaissance pictures until almost a week later. They showed 44 per cent of the city destroyed. The difference between the results obtained there and at Hiroshima was due to the unfavorable terrain at Nagasaki, where the ridges and valleys limited the area of greatest destruction to 2.3 miles (north-south axis) by 1.9 miles (east-west axis). The United States Strategic Bombing Survey later estimated the casualties at 35,000 killed and 60,000 injured.
While the blast and the resulting fire inflicted heavy destruction on Nagasaki and its population, the damage was not nearly so heavy as it would have been if the correct aiming point had been used. I was considerably relieved when I got the bombing report, which indicated a smaller number of casualties than we had expected, for by that time I was certain that Japan was through and that the war could not continue for more than a few days.
To exploit the psychological effect of the bombs on the Japanese, we had belatedly arranged for leaflets to be dropped on Japan proclaiming the power of our new weapon and warning that further resistance was useless. The first delivery was made on the ninth, the day of the Nagasaki bombing. The following day General Farrell canceled the drops, when the surrender efforts of the Japanese made any further such missions seem ill-advised.
Throughout the week following the Hiroshima strike, we were wrestling with a royal foul-up in the handling of press stories from the Pacific Theater. It will be recalled that Spaatz had been directed not to issue any communiques on our mission. The purpose of this ban and on news stories as well was to avoid lessening the psychological effect of the bomb. Uncertain of how much the Japanese people would learn from their own government, we did not want to weaken the impact of the White House statement. Then, too, there was the chance that an announcement made without full knowledge of the background facts could arouse hope in Japan that other bombs would not follow. Our commanders in the Pacific were not in possession of the facts. Moreover, as far as we knew, there were no newsmen in the theater, besides Laurence at Tinian, who had any background in the atomic field.
We intended to remove the ban as soon as the situation cleared. Before the bombing, we had sent our people definite instructions that would guide them in briefing the overseas commanders on the security problems involved in clearing news stories, when this responsibility was released to the theater.
Frankly, we did not fully anticipate the difficulties that these initial restrictions would cause. The public relations section that had been set up in my office could have handled the expected number of messages. The difficulties arose from three sources: the large number of war correspondents on Guam, the extraordinary number of words each wanted to send, and a completely unforeseen bottleneck in communications, which we should have learned of in advance, but did not. Because the dispatches were still subject to clearance upon arrival in Washington, they could not be sent over the normal press communication channels, but instead had to be sent over a single security channel. This meant that only one message could be sent at a time.
Within twenty-four hours of the White House announcement, the War Department Information Office was under great pressure from all newspapers for relief. The hopelessness of the situation was apparent to everyone involved. It was also clear to me that with the reports already received there was no longer any need to maintain such close control. The restrictions we had imposed were lifted that evening and clearance power passed from Washington to Guam.
Major John F. Moynihan, Farrell’s press assistant, was invaluable, particularly during those hectic early days when our plans for handling press dispatches proved to be so hopelessly inadequate. Had he not been there, we would not have been ready to release the control from Washington to the theater when we did.
After August 11, all information was handled by the theater forces.
Although we had certainly miscalculated in planning our press operations, we were at least well prepared in a different but related respect; and for a long time I gave thanks daily for the Smyth Report. As far back as early 1944, Conant and I had discussed the necessity of having ready some account of the operations of the MED, and of the preparatory work accomplished by the OSRD. It would be a formal record of our activities, particularly scientific and administrative, giving credit where credit was due, and would, we hoped, meet the heavy demands for information that were certain to deluge us, once the bomb proved successful. We also wanted something that would serve as a guide for persons connected with the project in their discussions with outsiders, to help them avoid unwitting breaches of security.
The Military Policy Committee approved, and in April, 1944, we asked Dr. Henry D. Smyth, of Princeton University, to prepare the report. Smyth had been long and closely associated with the project, both with the MED and the OSRD. He had served on the Uranium Committee beginning in the summer of 1941, and had been one of the first to support Ernest Lawrence’s suggestion of the possibility of a large-scale electromagnetic process. In the fall and winter of 1943-44, he acted first as an associate director, and later as a consultant at the Chicago laboratories. In our opinion, he was eminently qualified to carry out this difficult task.
Smyth, who was exempted from all normal compartmental rules that might interfere with his work, visited each of the various elements of the MED, conferring with the key people and collecting data. As the rough drafts of his chapters emerged, he went over them with Conant and me. Each part of his manuscript was cleared with the persons directly responsible for the activities it dealt with. Within a year, twelve of the proposed thirteen chapters had been completed in preliminary draft form. After a thorough review of Smyth’s work, Conant and I agreed that it should be prepared for public release, and set June 30 as the target date for its completion. We asked Tolman to help Smyth put the manuscript into final form for publication.
At the same time Smyth and Tolman, at my request, prepared the rules to be used in determining whether material could or could not be included in the published report. These, after discussion with Conant, were approved, with minor modifications. Under the rules, Tolman was appointed as the principal reviewer of the manuscript, to be assisted by W. S. Schurcliff, who served principally as an editor, and Dr. Paul C. Fine.
Many changes in the original draft became necessary as our security criteria were applied to it. Copies of pertinent sections were given a final review by scientists in the various parts of the project, both for factual content and for security considerations. In order to speed up this process, officer couriers delivered the copies, and generally waited until the review was completed. Each person was asked to give us a written memorandum stating whether the material he had read was acceptable and met with his approval, and to suggest any changes that he thought should be made. We were particularly anxious that everyone be accorded the recognition he deserved. This, we felt, would lessen the chances of future security breaks. The only hitch in our plans occurred at Los Alamos, where Oppenheimer was unable to spare the time required for a thorough review of the section dealing with his laboratory. However, we decided to go ahead with the report as written, which had taken into account comments from Los Alamos on an earlier draft, rather than to hold up publication.
The report was completed on July 28, but not before we had had to fly some fully cleared MED stenographers up to Washington from Oak Ridge. As a part of the final editorial review, Tolman reread every word of the report with extreme care and annotated it by marking all possible material involving security and citing the rule under which each of these particular passages had been allowed.
Finally he and Smyth went over these notes together and prepared a memorandum in which they stated that nothing in the report violated the rules that had been established.
On August 2, when the Smyth Report was ready for submission to the printer, a meeting was held in Mr. Stimson’s office. Present were the Secretary, Harvey Bundy, Conant, Tolman, George Harrison, James Chad wick, Roger Makins (a British Minister in Washington, then handling atomic matters for his government), Colonel Kyle, the Secretary’s aide, and myself. Mr. Stimson opened by saying that he felt the decision on publishing the report could well await the return of the President from overseas; he thought that in the meantime the two statements to be issued by the President and himself would satisfy all demands for information until the President could reach a decision. Conant advised Mr. Stimson to release the report, saying, among other things, that “its publication will help us defend against the inevitable cry for more information about the project.” Faced with this clamor, we would almost certainly have serious breaches in our security. Conant and I both emphasized that the assistance provided by the report to any nation capable of duplicating the bomb would be negligible at best.
After the conference broke up, Chadwick read the report carefully and was quite disturbed by its contents. However, in the course of a meeting with Tolman and me, his fears were laid to rest. Two days later he summed up the situation quite precisely by saying: “I am now convinced that the very special circumstances arising from the nature of the project, and of its organization, demand special treatment, and that a report of this kind may well be necessary in order to maintain security of the really essential facts of the project. To judge how far one must go in meeting the thirst of the general public for information, and the itch of those with knowledge to give it away, so as to preserve security secretly on vital matters is indeed difficult, but so far as I am competent to express an opinion, I find myself broadly in agreement with my United States colleagues.”
Dr. Chadwick went on to recognize that the information divulged in the report would be useful to foreign governments and others interested in atomic energy development, “not because any one item of information is particularly important, but from the illuminating effect of a well-arranged, coherent and well-written presentation on the development of the many aspects of this project.” He continued: “At the same time, I would agree that such assistance to possible competitors is not as much as one might think at first sight; it is indeed more apparent than real.
“I have tried to form an estimate of this assistance as a saving in time to a competitor making a serious attempt to develop the . . . project. I believe that the saving might amount to a few months, say three. It could hardly be more.”
Even before the Hiroshima bombing, a thousand copies of the Smyth Report had been prepared, using the Pentagon’s top secret reproduction facilities. These copies were kept securely locked up in my office.
Soon after the President gave his approval, the report was released for the Sunday morning newspapers of August 12, 1945, and for use by radio broadcasters after 9:00 p.m., EDT, on August 11. The release was made through the Press Branch of the War Department Bureau of Public Relations, and was accompanied by the following statement:
Nothing in this report discloses necessary military secrets as to the manufacture or production of the weapon. It does provide a summary of generally known scientific facts and gives an account of the history of the work and of the role played in the development of different scientific and industrial organizations.
The best interests of the United States require the utmost co-operation by all concerned in keeping secret now and for all time in the future, all scientific and technical information not given in this report or other official releases of information by the War Department.
The following addition should be made to paragraph 12.18 of the Smyth Report: “The War Department now authorizes the further statement that the bomb is detonated in combat at such a height above the ground as to give the maximum blast effect against structures, and to disseminate the radioactive products as a cloud. On account of the height of the explosion, practically all of the radioactive products are carried upward in the ascending column of hot air and dispersed harmlessly over a wide area. Even in the New Mexico test, where the height of explosion was necessarily low, only a very small fraction of the radioactivity was deposited immediately below the bomb.”
As expected, with the publication of the report, objections began to come in from a number of scientists in the project. Smyth examined each one carefully, and where they were justified prepared the appropriate corrections and additions for inclusion in later printings. Any objections that were not met represented nothing more than differences of opinion between individuals. On the whole, and considering the rather difficult conditions under which it was prepared, the Smyth Report was extraordinarily successful in its efforts to distribute credit fairly and accurately. It would have been impossible to have prepared any document for publication covering the work of the Manhattan District that every reader would have found to his liking. But the fact is that all those who had the greatest knowledge of the subject were nearly unanimous in approving its publication as it was finally written. And there can be no question that it excellently served its purpose as an essential source of accurate information, particularly for news-hungry America in the early days after Nagasaki.
Immediately after the Nagasaki drop, I went to see General Marshall about our future operations against Japan. By that time, as I have said, I had become convinced that the war would end just as soon as the Japanese could surrender. In view of the policy that Mr. Stimson had laid down when he deleted Kyoto from the target list, I did not want to provide any basis for later claims that we had wantonly dropped a third bomb when it was obvious that the war was over. Yet our production facilities were operating at such an accelerating rate that the materials for the next bomb would be ready for delivery to the field momentarily. General Marshall agreed completely with my appraisal of the situation and we decided that we should hold up all shipments of fissionable material until the thirteenth. Then if there was no surrender, shipments would be resumed.
When that deadline came, unfortunately, neither the General nor Mr. Stimson was available, being deeply involved in the negotiations for the armistice. However, it seemed to me that under the circumstances it would be a terrible mistake for us to send overseas the ingredients of another atomic bomb.
I discussed the situation with Handy. He said that it was absolutely impossible for me to see the Secretary or the Chief of Staff that day. In that case, I said, I would continue to hold all fissionable materials in the United States and would appreciate it if he would tell Mr. Stimson and General Marshall this at his earliest opportunity. Some days later, General Marshall commented that he was glad I had taken that action.
Throughout the time that the surrender negotiations were going on, our entire organization both at Los Alamos and on Tinian was maintained in a state of complete readiness to prepare additional bombs in case the peace talks should break down. During this period, seven Pumpkin missions were flown against Japan in preparation for further atomic attacks, if they should become necessary.
When peace came, we closed out our activities on Tinian as quickly as possible. The civilian scientists left the island on September 17. Kirkpatrick and Ashworth remained behind to dispose of the project’s property. Anything that might in any way disclose information about the bomb was either to be returned to Los Alamos under tight security guard or taken out to sea and scattered in deep water. This policy was generally observed, although there was the usual slackening off of security immediately after the first bombing, and certain exterior portions of the bombs were seen by outsiders. However, most, if not all, of the recognizable items were parts of the Pumpkin bombs, so this did not constitute a serious breach of any essential security measure.
The aim of the Alberta group had been to assure the successful combat use of an atomic bomb at the earliest possible date after the necessary fissionable material was available. That it was eminently successful was shown by the fact that the first combat bomb was ready for use against the enemy within seventeen days after the Trinity test. These seventeen days were spent largely in accumulating, preparing and shipping the additional active material needed to complete the Little Boy bomb. Actually, Alberta’s procedures proved to be so efficient that it could have had the first atomic bomb ready for the drop on July 31, if the weather had been favorable for its use—within two days of the time the last of the active materials was delivered. The second bomb was used in combat only three days after the first, though it was a completely different model and much more difficult to assemble.
Faced as we were with innumerable uncertainties in our operations against Japan, it had always been comforting to know that the 509th Group was willing and able to perform any task that was humanly capable of achievement. Yet the group had its problems, too. When the war was over, and Tibbets was asked what was the greatest difficulty that the 509th had encountered, he said it was the uncertainty; he never knew from one day to the next whether the plans of the previous day were still in effect. In spite of this, his men went about their work with quiet competence and accomplished their mission in the face of greater unknowns than had ever confronted a military organization.
Only four days after the first bomb was dropped, the Japanese began surrender negotiations. The letdown that had followed the success of the Trinity test became evident on a larger scale throughout the project. With the war ended, or about to end, many of our people began to discuss the future consequences of our work. The thoughts that they expressed were not particularly new, but until then, there had been little time to spend on nonessential conversation. Since 1939 they had been busy. Now they all realized for the first time that atomic energy was a fact and not a theory and they realized, too, that a nuclear war could never be fought on this earth without bringing disaster to all mankind. This had been immediately evident to everyone who witnessed the Trinity test.
When it finally came, V-J Day was a sober and thoughtful occasion for most of us who had labored so hard and so long to help bring it about. We had solved the immediate problem of ending the war, but in so doing we had raised up many unknowns. Our feelings at this time were eloquently summed up by Oppenheimer when, on October 16, 1945, I presented the laboratory with a Certificate of Appreciation from the Secretary of War:
It is with appreciation and gratitude that I accept from you this scroll for the Los Alamos Laboratory, for the men and women whose work and whose hearts have made it. It is our hope that in years to come we may look at this scroll, and all that it signifies, with pride.
Today that pride must be tempered with profound concern. If atomic bombs are to be added as new weapons to the arsenals of the warring world, or to the arsenals of nations preparing for war, then the time will come when mankind will curse the names of Los Alamos and Hiroshima.
The peoples of this world must unite or they will perish. This war that has ravaged so much of the earth has written these words. The atomic bomb has spelled them out for all men to understand. Other men have spoken them, in other times, of other wars, of other weapons. They have not prevailed. They are misled by a false sense of human history who hold that they will not prevail today. It is not for us to believe that. By our works we are committed to a world united, before this common peril, in law, and in humanity.