Japan's New Hypersonic Engine Could Make 2-Hour Flights to the US a Reality

Oasis2me/Getty Images At first blush, it sounds like science fiction: supersonic jets able to traverse the vastness of the Pacific Ocean in under two hours. But recent tests by Japan's Aerospace Exploration Agency (JAXA) in conjunction with several Japanese universities have brought that once seemingly impossible vision closer to reality (alongside similar Mach-5 testing in the U.S.).

A team of engineers from JAXA, Waseda University, the University of Tokyo, and Keio University has completed a successful ground combustion trial of a ramjet engine designed for a Mach‑5 hypersonic aircraft, a key step toward a future where flights from Tokyo to Los Angeles could take roughly the same time as a short domestic hop. The test was conducted at JAXA's Kakuda Space Center, simulating flight at five times the speed of sound and focused on validating the aircraft's heat‑shielding, control surfaces, and engine performance under extreme conditions. The results, and aircraft like NASA's "quiet" supersonic X-59, may help redefine how engineers think about high‑altitude, high‑speed passenger and even suborbital travel.

Andrey 69/Shutterstock A ramjet, the technology at the core of the test, is a type of air-breathing jet engine that has no moving parts. The name is derived from the engine's reliance on rapid forward motion to "ram" and compress incoming air before mixing it with fuel and igniting it for thrust. The technology eliminates the need for heavy rotating compressors and allows them to operate at speeds that far exceed the capabilities of conventional turbofans. However, ramjets can't operate from a standstill: to function, they first need to be accelerated to supersonic speeds.