The basic premise of SAC’s airborne alert was hard to refute: planes that were already in the air wouldn’t be destroyed by missiles that hit bases on the ground. Keeping a portion of the bomber fleet airborne at all times would allow the United States to retaliate after a surprise attack. During an airborne alert, American bombers would take off and fly within striking distance of the Soviet Union. If the planes failed to receive a “Go” code, they’d turn around at a prearranged spot, circle for hours, and then return to their bases. The plan erred on the side of safety — a breakdown in communications between SAC headquarters and one of the bombers would end its mission without any bombs being dropped. The mission would “fail safe,” an engineering term for components designed to break without causing harm. The fail-safe measures of an airborne alert could reduce the effectiveness of SAC’s nuclear retaliation, once America was at war: bombers that didn’t receive a Go code would circle and then return home, leaving their targets untouched. But the alternative — an airborne alert in which crews were ordered to fly to the Soviet Union and bomb it, unless they received some sort of “Don’t Go” code from headquarters — could easily start a war by mistake. That sort of mission was bound, at some point, to “fail deadly.”
“Day and night, I have a certain percentage of my command in the air,” General Power told the press, the week after the second Sputnik launch. “These planes are bombed up and they don’t carry bows and arrows.” The message to the Soviet Union was unmistakable: SAC’s ability to retaliate wouldn’t be diminished by intercontinental ballistic missiles. But Power was bluffing. The airborne alert existed only on paper, and the United States didn’t keep bombers in the air, day and night, ready to strike. Carrying nuclear weapons over populated areas was still considered too dangerous. Designers at the weapons labs had been surprised to hear about SAC’s ground alert. Aside from the occasional training exercise, the Atomic Energy Commission had always assumed that hydrogen bombs and atomic bombs would be safely locked away in igloos until the nation was at war. The idea of parking bombers near runways, loaded with nuclear weapons and fuel, had been proposed by LeMay, backed by the Joint Chiefs, and approved by President Eisenhower without input from Los Alamos or Sandia.
An airborne alert would be much riskier. The safety questions about the new sealed-pit weapons hadn’t been resolved. And if older weapons were used during an airborne alert, their nuclear cores would have to be placed, before takeoff, into an “in-flight insertion” mechanism. It held the core about a foot outside the sphere of explosives, while the plane was en route to the target — and then pushed the core all the way inside the sphere, using a motor-driven screw, when the bomb was about to be dropped. The contraption made the weapon safer to transport, but not much. Once the core was placed into this mechanism, according to a Sandia report, “nuclear safety is not ‘absolute,’ it is nonexistent.” The odds of a nuclear detonation during a crash or a fire would be about one in seven.
Weapon safety became an ongoing point of contention between the Strategic Air Command and the Atomic Energy Commission. General Power not only wanted to start an airborne alert as soon as possible, he also wanted SAC’s ground-alert bombers to take off and land with fully assembled weapons during drills. When the AEC suggested that dummy weapons could be used instead, the Air Force came up with a series of arguments for why that would be “operationally unsuitable.” During an emergency, having dummy weapons onboard would “degrade the reaction time to an unacceptable degree,” SAC’s director of operations argued. They’d hurt “crew morale and motivation,” and they were hard to obtain. The typical air base had only seven dummy weapons, SAC claimed, a scarcity that made it necessary to train with real ones. Although the Atomic Energy Commission no longer retained physical possession of the hydrogen bombs stored at SAC bases, it still had legal custody. The AEC refused to allow any fully assembled bombs to be flown on SAC bombers. That prohibition applied to sealed-pit weapons and to older weapons with their cores attached. Crews were permitted, however, to train with fully assembled bombs and to load them onto planes — so long as the planes never left the ground.