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.
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.
U.S. had plans to nuke the moon CNN Security Clearance - Blogs