Hermeus unveils Ramjet-X for low-cost high-Mach flight testing

Hermeus has unveiled Ramjet-X, an expendable ramjet-powered vehicle designed to lower the costs associated with high-Mach airbreathing flight testing. To overcome the limitation that ramjets require significant initial speed to operate, the vehicle will be air-launched from the company’s Quarterhorse uncrewed aircraft.

Once released at approximately Mach 3, Ramjet-X is expected to climb to roughly 100,000 feet and cruise near Mach 4 for several minutes. This method replaces the need for expensive expendable rocket boosters, as the Quarterhorse carrier can return for subsequent missions.

Hermeus plans to offer this capability as ‘high-Mach Flight Test as a Service,’ allowing customers to integrate sensors, communications, autonomy software, and propulsion technologies for testing in sustained high-speed conditions. Engine testing is currently underway at the HEAT facility in Jacksonville, Florida, while high-temperature structure development continues in El Segundo, California. Integrated vehicle testing is scheduled for 2027.