Mach 15? NASA’s 1st Hypersonic Jet Concept That Never Flew But Is Still Relevant Today

Hypersonic flight is no longer science fiction. In recent years, interest in aircraft capable of exceeding Mach 5 has surged, driven by strategic competition, defense challenges, and NASA’s pursuit of next-generation propulsion. But decades before hypersonics entered today’s headlines, NASA had already drafted an aircraft so ambitious it bordered on surreal: a Mach 15 scramjet-powered jetthat never left the drawing board, yet still shapes modern hypersonic research. This guide explores NASA’s forgotten X-43 Hyper X concept, how it fits within the agency’s ambitious hypersonic roadmap, and why ideas like it remain relevant as the US Air Force and global aerospace…