Comment by shadowgovt

It's generally hard to say what's a "front" for what, unless you mean "what can you get someone to grant you research money for when you really expect to parlay the learnings into another topic."

Everything about the rocketry needed to get to orbit started from warfare purposes, for example. And ARPANET was a foray into how to build a disruption-resistant network for military purposes.

Science and knowledge are a bit of a soup.