The secret project was dubbed “A Study of Lunar Research Flights,” reported the Associated Press and it was intended to send a message to the Soviet Union. The plan consisted of carrying a nuclear device some 238,000 miles to the moon on a missile that would have detonated on impact.
The U.S. allegedly wanted to blast the moon with a nuclear bomb to display its power to the Soviet Union during the "space race."
The Daily Mail reports that astronomer Carl Sagan’s calculations were used regarding the dust and gas the blast would generate. The website also states that physicist Leonard Reiffel told the Associated Press in an interview in 2000 that a U.S. nuclear flash from Earth might have “intimidated” the Soviets.
The project was eventually scrapped because military officials were worried it would have fallout here on Earth.