That seems a very odd thing for a physicist to say, given that of course a mushroom cloud wouldn't form in a vacuum. Perhaps Dr. Reiffel was not at his best on the day of the interview?
- ICBMs can't reach the moon, or even anything remotely close to it
- Mushroom clouds don't form in a vacuum.
- The fact that some Air Force officer thought it would be a neat idea (if any of this is factual) does not in any way imply that it was even remotely considered by anyone with the authority to make such a decision, any more than seeing a person who works at the Apple store drinking a coke implies that Apple Inc is buying the entire CocaCola corporation.