The advantages of nuclear-powered airplanes mirrored those of nuclear submarines. Nuclear submarines did not need to surface for fuel, and nuclear airplanes would not need to land. A 1945 proposal at the Department of War (now the Department of Defense) promised, “With nuclear propulsion, supersonic flight around the world becomes an immediate possibility.” A secret Atomic Energy Commission memorandum now held in the Eisenhower Presidential Library explained the promise of nuclear flight in a more measured tone. Nuclear energy “should make possible ranges of one or more times around the world with a single loading of the reactor.” The idea of a nuclear-powered bomber became a strategic dream for the military; it could stay aloft for days to cover any number of targets throughout the world, before returning to the United States without refueling.

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The problem of refueling airplanes occupied many Cold War minds. Bombers would strain to reach their targets and strand in enemy territory with too little fuel to return home if they flew on only a single tank. Aerial refueling offered a solution, but a poor one. Planes caught in the act over enemy territory were prone to anti-aircraft fire. Evasive maneuvers would uncouple the two planes, prevent successful refueling, and endanger the mission.

To minimize the need for dangerous refueling, the United States relied on a global network of Air Force bases. Such bases—usually close to the U.S.S.R.—allowed planes to reach their targets and return on a single tank of fuel. Procuring the bases, however, proved expensive and unpopular. At one point, the United States offered $100 million in gold to purchase Greenland from Denmark and gain a new strategic location for bases. In the end, Denmark decided to keep Greenland, but the proposal illustrates the lengths the United States had to go to compensate for its planes’ limited range. A nuclear-powered airplane could avoid all of these issues.

But nuclear power came with its own problems. The reactor would have to be small enough to fit onto an aircraft, which meant it would release far more heat than a standard one. The heat could risk melting the reactor—and the plane along with it, sending a radioactive hunk of liquid metal careening toward Earth.

The problem of shielding pilots from the reactor’s radiation proved even more difficult. What good would a plane be that killed its own pilots?

To protect the crew from radioactivity, the reactor needed thick and heavy layers of shielding. But to take off, the plane needed to be as light as possible. Adequate shielding seemed incompatible with flight.

Still, engineers theorized that the weight saved from needing no fuel might be enough to offset the reactor and its shielding. The United States spent 16 years tinkering with the idea, to no avail. The Soviet Union pursued nuclear aircraft propulsion too, running up against the same problems. By 1958, an infamous article in Aviation Week, mostly made-up, claimed that the Soviets were already testing a functional nuclear airplane. Shortly after, President Dwight Eisenhower counseled calm and denounced the article as contrived. A representative of the Soviet program explained that “if we had flown an atomic-powered aircraft, we would be very proud of the achievement and would let everyone know about it.” Unfortunately for atomic-flight enthusiasts, both countries had little to brag about.