The Japan Aerospace Exploration Agency (JAXA) has completed a Mach 5 ramjet combustion ground test on an experimental hypersonic aircraft, advancing its long-term plan for a hypersonic passenger transport capable of crossing the Pacific in about two hours. The test was conducted at JAXA’s Kakuda Space Center using the agency’s ramjet engine facility, with the experimental vehicle developed in collaboration with three Japanese universities.
According to JAXA, the hypersonic research program focuses on a Mach 5-class hypersonic turbojet concept that would face extreme thermal loads, with inlet outlet temperatures approaching 1,000°C. To address these conditions, engineers are investigating a pre-cooled hypersonic turbojet that uses cryogenic liquid hydrogen fuel to cool incoming high-temperature air to roughly 300°C before it enters the core engine.
The experimental aircraft tested on the ground is intended as a technology demonstrator. In future flight tests, it is expected to be accelerated to Mach 5 by external means, such as a solid rocket motor, to evaluate hypersonic cruise engine performance in realistic flight conditions. The recent ground campaign represents a key technical step in validating ramjet combustion behavior and thermal management approaches for Japan’s emerging hypersonic aircraft program.