Nuking the Moon sounds crazy. Why would anyone want to do that? But when it seemed like the Soviet Union was winning the space race, the United States had to do something to boost morale.
The top secret project was labeled “A Study of Lunar Research Flights,” or "Project A119," and was developed by the U.S. Air Force in the late 1950s. According to physicist Leonard Reiffel, one of the leaders of the project, hitting the moon with an intercontinental ballistic missile would have been relatively easy to accomplish. They planned to hit their target with an accuracy of about two miles. This accuracy would have been particularly important, as the Air Force wanted the resulting explosion to be clearly visible from Earth. As such, it was proposed that the explosion happen on the border of the visible part of the moon, so that the resulting mushroom cloud would be illuminated by the sun. A young Carl Sagan was tasked with modeling how a dust cloud would expand in low gravity.
The project was eventually scrapped, as it was felt that the public would not respond favorably to the U.S. dropping a nuclear bomb on the moon. A119 only came to light in the late 1990s, when Keay Davidson, who was researching his biography of Sagan, discovered that the scientist had disclosed details of the project in his application for the Miller Institute graduate fellowship to Berkeley.