NASA's budget peaked in 1964–66 when it consumed roughly 4% of all federal spending. The agency was building up to the first Moon landing and the Apollo program was a top national priority, consuming more than half of NASA's budget and driving NASA's workforce to more than 34,000 employees and 375,000 contractors from industry and academia.
US GDP in 1965 was $743.7 billion[0].
NASA's budget peaked in 1964–66 when it consumed roughly 4% of all federal spending. The agency was building up to the first Moon landing and the Apollo program was a top national priority, consuming more than half of NASA's budget and driving NASA's workforce to more than 34,000 employees and 375,000 contractors from industry and academia.
$5 billion is 0.67% of $743.7 billion.
[0] https://countryeconomy.com/gdp/usa?year=1965
[1] https://en.wikipedia.org/wiki/Budget_of_NASA