The Law of Parsimony says that, if US Naval Research Laboratory has found "discovery of an experimental configuration and flow conditions" enabling greater than Mach 3 atmospheric flight, then other countries' military research programs have also considered, or invented, the same ( as opposed to E.T. visitations ).
I noted, with some curiosity, this briefing the other day: https://physicsworld.com/a/frozen-detonation-could-enable-hypersonic-flight/
The Law of Parsimony says that, if US Naval Research Laboratory has found "discovery of an experimental configuration and flow conditions" enabling greater than Mach 3 atmospheric flight, then other countries' military research programs have also considered, or invented, the same ( as opposed to E.T. visitations ).