At the peak of Apollo program spending in 1966, Dreier says, NASA accounted for roughly 4.4% of the federal budget — 6.6% of discretionary spending — more than the Manhattan Project that developed the first atomic bomb.

https://www.cbsnews.com/news/apollo-11-moon-landing-how-much...

as a percentage of the yearly federal budget, it's not that extreme.

I believe the DoD budget (entirely non-NASA) is presently running around 700 billion a year.

some very quick searching tells me the total federal budget is something like 3500 billion a year. 4.4% of that would be 154bn a year.