NASA supergeeks have top secret program. Released a paper on the principles of it in 2020. Chinese colleagues politely point out a fundamental flaw in the design on the program and how it would led to failures at hypersonic speeds. Basically, the heat causes chemical changes NASA didn't account for. China flags ‘fatal flaw’ in NASA’s hypersonic aerodynamics software (msn.com) Led by Professor Liu Jun, the paper explains that when an aircraft’s speed exceeds Mach 5, intense friction with the air generates sizzling temperatures that can ionize air molecules and spark chemical reactions. If not modeled accurately, this could impact the effective development of working hypersonic vehicles. ........... If true, this could explain why America’s hypersonic program seems to lag behind on the international stage. For example, on April 3, North Korea announced the successful test of a land-based hypersonic gliding missile called Mars 16B. Meanwhile, the US Army’s Long-Range Hypersonic Weapon (LRHW) failed consecutively in 2021 and 2022, resulting in the scrapping or postponement of the subsequent three planned launches. The U.S. Congressional Budget Office has reported that “the fundamental remaining challenge involves managing the extreme heat that hypersonic missiles are exposed to by traveling at high speeds in the atmosphere for most of their flight.”
There are some interesting points in there, but I’m not sure anyone who worries about our hypersonic program understands the main thing: our enemies need hypersonics, and we don’t. The only — well, the most useful — thing we get out of our admittedly underfunded program is data about how to defeat these weapon systems. Air defense is not my wheelhouse (except for how to avoid it), but I have had it strongly implied to me that Russia (and perhaps China) has already lost whatever temporary tactical advantage hypersonics would have given them initially in a clash with U.S. forces.
