 In World War II, the large-scale, relentless bombing operations of American Air Forces gave the world convincing proof of the destructive power of our aircraft. But even while we were showering devastation upon the enemy, our huge bomber fleets were on their way to becoming obsolete. In 1944, a year before the war ended, a new and mighty weapon was in the most crucial phase of its development. This weapon, the atomic bomb, became a reality. A great new force had come into being, one that brought World War II to an abrupt halt, one that was destined to change the whole character of warfare in the future. Much remained to be learned, however, about this newest and most deadly of weapons, so a long and elaborate series of tests was planned and undertaken by the armed services of the United States, in close cooperation, first with Manhattan District, and later, after 1947, with the Atomic Energy Commission. In 1946, Bikini et al. in the Marshall Islands was the scene of the first of these tests. This was Operation Crossroads. These islands in the Pacific, Bikini, Quajolain, and Anuitok, were chosen because no populated areas would be put in danger and because there was an ideal place in which to assemble the 93 naval vessels that were to form the target. When we arrived at the islands, we saw signs of the heavy fighting that took place here. Little Japanese cemeteries reminded us of those terrific battles. Coming into Anuitok Island, in the weeks preceding the bomb drop, were many C-54s, bringing men, supplies, and technical equipment. Operation Crossroads was to be a scientific experiment on a vast scale, both in the quantities of material and in the number of personnel. Many thousands of us, from all the armed services and civilian experts, were needed at the islands for the tests. Our air arm had the responsibility not only for logistics, but also for furnishing men and aircraft for the bomb drop, for gathering weather data along, for air rescue. For air photography of every phase of the operation and for operating cloud sampling drones. Quajolain was the base for our Crossroads B-29s. We needed them in many ways. Every one of them had an important assignment and all were going to be aloft at H-hour Unable Day. Another chapter in the long and honorable history of the B-29. It was another B-29, the outlaw that brought General Curtis LeMay to the islands. He was then Deputy Chief of Air Staff for Research and Development. General LeMay is greeted by Brigadier General Roger Ramey, Commander of the Army Air Force's Task Group, under Major General William E. Kepner, Deputy Commander for Aviation for the Whole Operation. Major Woodrow piece one-cut aircraft commander of Dave's Dream, the B-29 that is going to drop the test bomb, holds a final inspection of his crew just before takeoff. Dave's Dream takes off on an historic mission to drop the first atomic bomb directed against naval vessels. Aboard USS Mount McKinley, 14 miles from the target area, Vice Admiral William Blandy in charge of the entire operation as Commander of Task Force One and his staff are waiting for H-hour, the big moment when the bomb will fall. Dave's Dream aloft and ready. Major Swancut is at the controls, all set as his men are, for the bomb run when he gets the word. Major Harold E. Wood, the Bombardier, ready to bring to a climax many months of preparation by a great many people. With Dave's Dream airborne, it's time for the B-17 drones to take off. They will be sent through the cloud mass after the detonation to pick up samples for radioactivity tests. At first the drones are under control from the ground. Soon the mother ships will take over. Operation Crossroads combined all the features of a full-scale military operation and the conditions of a laboratory experiment of imposing proportions. The ground control pilot now turns the drones over to the mother aircraft and there she is. More of the B-17 drones are moved toward the target area. The paper pilot in the nose of the mother aircraft can see on his TV scope right into the cockpit of the drone. When he moves the control stick in the mother ship, the controls in the drone respond. Two C-54s and 8 B-29s are aloft as photographic planes. The big blast is going to be well recorded. Converging on the target, which consists of battleships, cruisers, carriers, destroyers, submarines, merchant men and landing craft. Nearly time now for the bomb drop. A naval craft miles away, a wise precaution. HR is here. This is the first controlled and fully observed test of an atomic weapon dropped on a military target. The bombs dropped on Japan had ended the war, but we still lacked scientific information on blast pressure, heat, light and radioactivity. About 8 minutes after the detonation of the Able Day bomb, the B-17s begin their run through the dangerous mushroom cloud. This is the sort of testing possible only under controlled conditions and after elaborate preparations. The drones are a complete success. After their runs through the atomic cloud, they return to base controlled by mother planes from a distance up to 8 miles. Although the bomb drop was not a bullseye, five ships were sunk, one of them a cruiser, and there was heavy damage to many others. We had plenty of evidence that an A-bomb could effectively attack naval formations. Able Day was to be followed by Baker Day when a submarine blast sank other ships of the target fleet. Operation Crossroads proved again that nuclear weapons had vitally changed the character of warfare. The B-17 drones return still under control of the mother aircraft. The ground control pilot takes over. The landings couldn't be better even if pilots were aboard the aircraft. The radiological crew generally takes over the task of removing the contamination filters. These samples will reveal the exact gamma ray and neutron measurements within the atomic cloud. The filters are placed in lead shipping containers to be sent stateside to Los Alamos and other scientific laboratories for analysis and study. Any aircraft that had been in or near an atomic cloud will carry away some contamination. A washing down method was developed which makes the cloud sampling aircraft safe and ready for service within 24 hours. Work went forward to convert these barren islands into a fully equipped military installation with barracks, mess halls, observation posts, runways, a chapel, recreation facilities and maintenance shops. Because before long, there were to be other A-bomb tests here. Operation Sandstone in 1948 and Operation Greenhouse in 1951. Also from 1951 on, for those of us who worked on the new A-bomb testing range in Nevada, another important program was in progress. We decided to find out what the effect of atomic bombs on grounded aircraft would be. So a number of airplanes, some of them obsolete, others of the latest types were set up in the target area at various angles to the blast point. Test buildings were targets too, some of them of sturdy construction. Abort a C-54, a group of flight surgeon volunteers are about to test their visual reaction to the actual flare of an atomic blast because it is important to learn the effect of terrifically brilliant atomic light on the eyes of aircraft crews. That none of the flight surgeons suffered any permanent eye damage. It was increased our knowledge of the new and fearsome weapon. And even while these tests continued, with improved and more powerful A-bombs, a new development of vast importance was in progress. In January 1950, it was revealed that President Truman had directed the Atomic Energy Commission to continue its work on a weapon of even more overwhelming destructive force, the thermonuclear or hydrogen bomb. It happened that after years of intensified effort by our scientists, the most terrible of all the weapons that man has ever built, the H-bomb, was detonated at Anuitok. The time never comes when we must use it. But if that time does come, the men, the machines and the know-how will all be a part of the readiness of the United States Air Force.