On April 16, JAXA, Waseda University, the University of Tokyo, and Keio University announced that they had successfully conducted Japan’s first ground-based combustion test at Mach 5 for a hypersonic experimental aircraft. The roughly two-meter-long craft was placed inside the ramjet engine testing facility at JAXA’s Kakuda Space Center in Miyagi Prefecture; this setup replicates flight conditions at five times the speed of sound and an altitude of about 25 kilometers — nearly double the typical cruising altitude of today’s commercial airliners. At such speeds, aerodynamic heating raises the temperature of surrounding air to roughly 1,000°C (1,832°F). JAXA reported that the aircraft’s thermal protection system kept interior temperatures close to normal levels throughout the test, ensuring all onboard avionics and control electronics functioned properly. Researchers also recorded surface temperature distribution and exhaust temperature from the hydrogen-fueled ramjet to refine thermal-structure analysis techniques and gather data on possible environmental impacts of future hypersonic propulsion systems.
This test represents a major milestone for the project, which has been under development since 2013; however, it still falls far short of actual flight demonstrations. The next immediate phase involves attaching the experimental aircraft to a sounding rocket and attempting a genuine Mach 5 flight, with the ultimate aim of staging a full-scale demonstration later on. JAXA’s long-term vision calls for launching commercial hypersonic passenger services by the 2040s — an aircraft capable of flying from Tokyo to Los Angeles in roughly two hours instead of the current ten. The agency also anticipates employing the same propulsion and thermal-management technologies to build spaceplanes that can ascend to altitudes nearing 100 kilometers. It should be noted that ramjets lack moving compressor components; however, they cannot function from a stationary state and must first be accelerated to supersonic speeds by another propulsion system prior to ignition.
BGR (Original announcement sources: Waseda University and JAXA, April 16, 2026)