Detonating a thermonuclear weapon on the moon? It sounds like the bizarro scheme of a deranged comic-book villain—not a project initiated inside the U.S. government.
But in 1958, as the Cold War space race was heating up, the U.S. Air Force launched just such an endeavor. Called Project A119, it harnessed the talents of some of America’s top scientists.
How could this happen?
Blame Sputnik, the beach-ball-sized satellite slung into space by the Soviet Union on October 4, 1957, which jolted U.S. officials and citizens alike into a state of high alert. As the two Cold War superpowers duked it out for postwar world dominance—framed by many as a titanic struggle between freedom and tyranny—the prospect of America’s arch enemy gaining any measure of military-industrial advantage seemed chilling indeed.
So the United States needed to reclaim the narrative and prove to the world that it hadn’t lost the space race before it had even begun. Americans needed a reassuring sign that the Communists didn’t have a permanent upper hand—and that Sputnik wouldn’t soon be followed by Soviet nuclear missiles raining down onto U.S. soil.
America needed to show the world it was squarely in the race. And it needed something big—like nuking the moon. Never mind that the project had no practical purpose, no discernible national-security goals and its sole design was to show the world that the U.S.A. could do something ambitiously spectacular.
What could go wrong?
READ MORE: The 5 Deadliest Disasters of the Space Race
To nuke the moon, the government needed the buy-in of top scientists.
In the years directly after World War II, Dr. Leonard Reiffel greatly enjoyed his exciting and rewarding job working alongside physics legend Enrico Fermi at the University of Chicago’s Institute for Nuclear Studies. But in 1949, he was given a chance to manage all of the cutting-edge physics research at another Chicago-based institution, the Armour Research Foundation (ARF—now known as the Illinois Institute of Technology). From that year through 1962, Reiffel and his team pushed physics to its limit, working on projects that studied the global environmental effects of nuclear explosions.
Sometime before May 1958, the U.S. Air Force asked the ARF team to investigate something truly out of the ordinary: the visibility and effects of a hypothetical nuclear explosion on the moon. The Air Force wanted to surprise the Soviets and the world: Hey, look at what we can do. We can blow the hell out of the moon.
Reiffel knew he didn’t have the necessary expertise in-house to do this kind of a study. To supplement his ARF researchers, he brought on Gerard Kuiper, the expert on planetary physics whose name came to define the Kuiper belt, a disk-shaped region beyond Neptune that contains hundreds of thousands of icy bodies and a trillion or more comets. To round out the group, Kuiper suggested Reiffel bring in a young graduate student from the University of Chicago: Carl Sagan.
Yes, that Carl Sagan—who gained fame decades later as an affable TV science guy exceedingly fond of the phrase “billions” which he uttered with regularity on his pop-science show “Cosmos.” Sagan’s job in this project was to do math. Lots of math. It was important that someone like Sagan could accurately model the expansion of the dust cloud that would be caused by a nuclear explosion on the moon. We needed to know how the moon would react so we could know if the explosion could be seen from Earth. After all, putting on a big show was the whole point of the program.
Which brings up two important questions: First: Why would self-respecting scientists agree to a project to detonate a nuclear weapon on the moon? And second: Would this thing work in the first place? What would a nuclear explosion on the moon look like?
To answer the first question, we need to put ourselves in the shoes of American scientists in the late 1950s and early 1960s. This was a time when American science was, for better or for worse, inextricably linked to American Cold War policy. Although the age of Joseph McCarthy’s communist witch hunts had ended, scientists still vividly remembered when atomic bomb developer Robert Oppenheimer was publicly flogged for renouncing his pioneering work and taking a position considered antithetical to U.S. national security—opposing the creation of the hydrogen (thermonuclear) bomb, the A-bomb's exponentially more powerful and destructive successor.
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But it wasn’t just fear that inspired physicists, chemists, biologists, astrophysicists and others to join university laboratories, private industries or government institutions working on aerospace and defense research. Many of these scientists were patriots. Some were WWII refugees who had seen tyranny firsthand—and barely escaped it. They, too, believed in what they were doing. The Cold War was a fight to the death—or at least for the future of the free world. These men and women had a skill set that was integral to national, and potentially global, security.
Still, it seems as if bombing the moon just for the public-relations win would stretch the limits of what even the most patriotic scientists would willingly accept.
Some justified it as a scientific breakthrough.
Whether these were serious considerations, or just ways to justify their actions, many involved in Project A119 cited the potential for real and important scientific discovery that could come out of detonating a nuclear weapon on the surface of the moon. These were exciting times, with the potential to explore new frontiers of science. Carl Sagan, the man who would dedicate his life to searching for evidence of life on other worlds, thought this could be a great way to try and identify the presence of microbes or organic molecules on the moon. (This is when we still thought there might be something up there besides dust.)
Others envisioned experiments centered on lunar chemistry, or the thermal conductivity of the lunar surface. Reiffel’s team also wondered if the nuclear blast would produce enough seismic activity to evaluate the makeup of the moon’s immediate subsurface structure. According to Reiffel, “A central theme, which runs through many of the projected experimental situations, envisions placing of a maximum of three identical instrument packages at arbitrary locations on the visible face of the moon prior to any possible nuclear detonation. These instrument packages would be equipped to make a variety of measurements.”
Would this work? Not all the specific technical details of early American ballistic missile technology are clear (some things are still classified), but during an interview Reiffel gave later in life, he insisted we had the capability to hit a target on the moon with an accuracy of within two miles. That’s pretty good, given that the moon is nearly 240,000 miles from Earth.
So that leaves us with the burning question: How insanely cool would the mushroom cloud on the moon look? Ideally, the bomb would be detonated on the edge (known as the terminator) of the dark side of the Moon, so the sun’s light would silhouette the trademark mushroom cloud from behind. It would be totally rad.
Problem was, that wouldn’t happen.
The optics wouldn’t be as dramatic as they initially hoped.
Mushroom clouds from a nuclear explosion are caused by the movement of dust and debris kicked up in a dense atmosphere. The moon, however, is essentially a vacuum. It has some gases hanging around on its surface, but it really doesn’t have an atmosphere like Earth’s. Without the weight of a dense atmosphere, there would be no resistance to the expansion of the nuclear-produced dust and debris. They would just keep on going and going, instead of curling back to the surface. No big plume, no sound or shock wave, no push-down from the air pressure—and no mushroom cloud. Just a lot of dust.
This doesn’t mean there wouldn’t be a hell of a show. People on earth would see a visible flash from the detonation. And maybe the sun would shine through the dust and debris in such a way as to give the world a pretty view. But it really wouldn’t be the same.
The program was ultimately scrapped—but the final reason is still unclear. All we have is speculation from multiple (knowledgeable) sources. Some say the Air Force canceled the program because of the potential danger to people on earth (in case the mission catastrophically failed the way so many of the early U.S. attempts at spaceflight sadly—and sometimes humorously—did). Others say the scientists were concerned about contaminating the moon with radioactive material, preventing any future mission to land a man on the surface (or even lunar colonization). Or it could be that the mission was scrapped out of a worry that the best-laid P.R. plans of the Air Force would be thwarted when the public saw this as an abhorrent defacement of the moon’s beauty instead of a demonstration of American scientific prowess.
Or maybe we realized landing a man on the moon was possible—and more impressive?
That all said, it’s hard to be fully convinced that the U.S. Air Force, at the height of the Cold War, in the wake of the shocking launch of Sputnik and the fear left in its wake, scrapped A119 because it might mess up the moon a little bit.
Vince Houghton, historian and curator at the International National Spy Museum, is author of Nuking the Moon: And Other Intelligence Schemes and Military Plots Left on the Drawing Board (Penguin Random House). Follow him on Twitter at @intelhistorian.
Watch the full episode of Moon Landing: The Lost Tapes.