Probably it's ongoing in defense research, just usually not much comes of it and it's not published a lot. I did something tangentially like this if you squint

Probably it's ongoing in defense research, just usually not much comes of it and it's not published a lot. I did something tangentially like this if you squint at it the right way, maybe 10-12 years ago, for some defense research grant. It would shock me if they didn't have a dozen other parallel grants going with other companies at the same time, and more since then.