During the second set of atomic tests, called Operation Sandstone, in April of 1948, the drones were again used in a job deemed too dangerous for airmen. During an eighteen-kiloton atomic blast called Zebra, however, a manned aircraft accidentally flew through a mushroom cloud, and after this, the Air Force made the decision that because the pilot and crew inside the aircraft had “suffered no ill effects,” pilots should be flying atomic-sampling missions, not drones. Whether or not pilots were exposed to lethal amounts of radiation during the Zebra bomb or hundreds of other atomic tests has never been accurately determined. The majority of the records regarding how much radiation pilots were exposed to in these early years and who died of radiation-related diseases have allegedly been destroyed or lost. But when the Air Force pilot accidentally flew through the Zebra bomb’s mushroom cloud, the incident “commenced a chain of events that resulted in manned samplers.”
“Manned samplers were simply more efficient,” wrote officer Colonel Paul H. Fackler in a 1963 classified historical review of atomic cloud sampling made for the Air Force systems command, declassified in 1986. As the official radiation safety officer assigned to Operation Sandstone, Fackler held sway. Fackler’s colleague Colonel Cody also argued in favor of man over drone. Cody said the drone samples were obtained haphazardly by “potluck.” A human pilot would be able to maneuver around a cloud during penetration so that the “most likely parts of the cloud could be sampled.” It was a case of dangerous semantics; most likely was a euphemism for “most radioactive.” For future tests, Air Force officials decided to pursue both manned and unmanned atomic-sampling wings.
Both kinds of aircraft would be needed for an ultrasecret test that was pending in the Pacific in 1951. Operation Greenhouse would involve a new kind of nuclear weapon that was being hailed as the “Super bomb.” It was a thermonuclear weapon, or hydrogen bomb, the core of which would explode with the same energy found at the center of the sun. Los Alamos scientists explained to weapons planners that the destructive power of this new kind of science, called nuclear fusion, was entirely unknown. Fusion involves exploding a nuclear bomb inside a nuclear bomb, and privately the scientists expressed fear that the entire world’s atmosphere could catch on fire during this process. Scientists became deeply divided over the issue and whether or not to go forward. The push to create the Super was spearheaded by the indomitable Dr. Edward Teller and cosigned by weapons planners with the Department of Defense. The opposition to the Super was spearheaded by Robert Oppenheimer, the father of the atomic bomb and now Teller’s rival. Oppenheimer, who felt that developing a weapon capable of ending civilization was immoral, would lose his security clearance over his opposition to the Super bomb. According to Al O’Donnell, the EG&G weapons test engineer who wired many of Dr. Teller’s Super bombs in the Marshall Islands, what happened to Oppenheimer sent a strong message to everyone involved: “If you want to keep your job, don’t oppose decisions” on moral grounds. In the end, the weapons planners won, and the world’s first thermonuclear bomb moved forward as planned.
Drones were needed to take blast and gust measurements inside the thermonuclear clouds, and to take samples of radioactive debris inside. During the Greenhouse test series, which did not wind up setting the world on fire, the first drone in went out of control and crashed into the sea before it ever reached the stem of the mushroom cloud. Two other drone missions were aborted after not responding to controls, and a fourth sustained such heavy damage in the shock wave, it lost control and crash-landed on a deserted island called Bogallua, where it caught fire and exploded. When the test series was over, the Air Force ultimately concluded that the unmanned samplers were unreliable. “Following Operation Greenhouse, the Air Force and the Atomic Energy Commission looked more favorably upon manned samplers,” wrote a Defense Nuclear Agency historian in 1963. “Greenhouse became the last atomic test series during which drone aircraft were used for this purpose.” So when it came time to detonate the world’s first full-scale thermonuclear device—an unimaginably monstrous 10.4 megaton bomb code-named Mike—in the next test series, called Operation Ivy in the fall of 1952, it was decided that six human pilots, all volunteers, would fly straight into the center of the radioactive stem and mushroom cloud. Another group of pilots was assigned to fly along the outer edges of the predicted fallout zones. That group included Hervey Stockman, who, four years later, would become the first CIA pilot to fly over the Soviet Union in a U-2.