The U.S. Air Force is studying options for a hypersonic demonstrator, including potentially a return to rocket-based combined-cycle concepts similar to the X-43B project that was canceled in the 2000s.
Credit: NASA
To fully exploit the military utility of hypersonic speed in roles beyond high-speed weapons, the U.S. Air Force is stepping up its decades-long quest to develop a combined-cycle air-breathing...
https://aviationweek.com/defense-space/aircraft-propulsion/us-air-force-studies-rocket-based-hypersonic-flying-testbed-plan