By Brian Todd and Dugald McConnell
You could easily skip by it in an archive search: a project titled "A Study of Lunar Research Flights." Its nickname is even more low-brow: "Project A-119."
But the reality was much more explosive.
It was a top-secret plan, developed by the U.S. Air Force, to look at the possibility of detonating a nuclear device on the moon.
It was hatched in 1958 - a time when the United States and the Soviet Union were locked in a nuclear arms race that would last decades and drive the two superpowers to the verge of nuclear war. The Soviets had also just launched Sputnik 1, the world's first satellite. The U.S. was falling behind in the space race, and needed a big splash.
"People were worried very much by (first human in space Soviet cosmonaut Yuri) Gagarin and Sputnik and the very great accomplishments of the Soviet Union in those days, and in comparison, the United States was feared to be looking puny. So this was a concept to sort of reassure people that the United States could maintain a mutually-assured deterrence, and therefore avoid any huge conflagration on the Earth," said physicist Leonard Reiffel, who led the project.
Reiffel, now 85, spoke to CNN at his home in Chicago. A 1959 report Reiffel wrote on the project, declassified many years ago, was obtained online by CNN.
According to Reiffel's report, "The motivation for such a detonation is clearly threefold: scientific, military and political."
The military considerations were frightening. The report said a nuclear detonation on the moon could yield information "...concerning the capability of nuclear weapons for space warfare." Reiffel said that in military circles at the time, there was "discussion of the moon as military high ground."
That included talk of having nuclear launch sites on the moon, he said. The thinking, according to Reiffel, was that if the Soviets hit the United States with nuclear weapons first and wiped out the U.S. ability to strike back, the U.S. could launch warheads from the moon.
"These are horrendous concepts," Reiffel said, "and they are hopefully going to remain in the realm of science fiction for the rest of eternity."
The basic plan, Reiffel explained, was for an intercontinental ballistic missile to be launched from an undisclosed location, travel some 240,000 miles to the moon, and detonate on impact. Various news reports since 1958 have said project leaders considered using an atom bomb the same size as "Little Boy," the bomb that was dropped on Hiroshima, Japan, near the end of World War II.
Reiffel, who was cited for that information in those reports, now says he wasn't in on those discussions.
Contrary to some reports, Reiffel told CNN, the device would not have "blown up" the moon. "Absolutely not. It would have been microscopic, so to speak. It would have been, I think, essentially invisible from the Earth, even with a good telescope."
Reiffel had some brilliant minds on his team. One of them was an up-and-coming graduate student named Carl Sagan. Sagan went on to become one of the world's most renowned astronomers, creating the book and popular TV series "Cosmos."
But after working on the moon program, Reiffel said, Sagan violated security when he mentioned the still-classified project on a job application. "He did formally break the classification status of the project", Reiffel said of Sagan, who subsequently died in 1996.
Sagan's widow, Ann Druyan, told CNN she's not sure if Sagan ever broke the classification, but if he did, she said, it wasn't intentional. "I can't imagine he would have done that knowingly," Druyan said.
By 1959, Project A-119 was drawing more concern than excitement.
"We didn't want to clutter up the natural radioactivities of the moon with additional bits of radioactivity from the Earth," Reiffel said. The project was abandoned.
Project planners also weren't sure of the reliability of the weapons, and feared the public backlash in the U.S. would be significant," Reiffel said.
"It disappeared in the files of the Pentagon", he said of the project. "They come up with what I believe was the right answer."
Contacted by CNN, the Air Force would not comment on Project A-119.