GE Aerospace Advances Hypersonic Propulsion with Dual Engine Demonstrations

Flight tests of solid-fuel ramjet and rotation-detonation technology mark significant milestones in U.S. hypersonic weapons development

GE Aerospace has achieved key milestones in hypersonic propulsion development, successfully demonstrating two advanced engine concepts that could power the next generation of U.S. long-range strike weapons.

The company announced Sept. 22, 2025, that it had conducted flight testing of a Solid Fuel Ramjet (SFRJ) propulsion system aboard the Atmospheric Test Launched Airbreathing System (ATLAS) at Kennedy Space Center, while separately advancing ground testing of its Hypersonic Dual-Mode Ramjet (DMRJ) featuring rotation-detonation combustion technology at the GE Aerospace Research Center in Niskayuna, New York.

Flight Test Campaign

The SFRJ demonstration utilized a modified F-104 Starfighter operated by Starfighters Inc., which carried the ATLAS test article as a fixed captive-carry payload on its port wing. The aircraft achieved supersonic speeds up to Mach 2.2 across three successful flight tests, providing flight-relevant conditions necessary for ramjet ignition and sustainment.

"ATLAS is a test vehicle and we are using that to demonstrate in flight relevant conditions our solid fuel ramjet," said Mark Rettig, vice president and general manager at GE Aerospace's Edison Works Advanced Programs, in an Oct. 1 promotional video. "The F-104 Starfighter can get up to Mach 2.2 and that's a pretty good speed to demonstrate ignition and sustainment of our SFR."

The program received funding from the Department of Defense through Title III of the Defense Production Act to scale air-breathing propulsion technology for extended-range munitions. The F-104 platform was selected specifically for its ability to reach the kinematic conditions where ramjet engines begin producing effective thrust—performance unattainable by other available test aircraft.

Solid-fuel ramjets offer distinct operational advantages over liquid-fueled variants, including reduced weight and continuous, throttleable thrust. This throttling capability enables in-flight maneuvering, complicating intercept calculations for conventional air-defense systems that rely on ballistic trajectory prediction.

Rotation-Detonation Breakthrough

In parallel development, GE's DMRJ program has progressed from initial demonstrations in late 2023 to advanced ground testing in 2024. The engine harnesses rotation-detonation combustion technology within a supersonic flow stream, exploiting powerful detonation shockwaves rather than conventional deflagration to generate thrust.

The company conducted testing of an additively manufactured DMRJ at its Evendale, Ohio, facility beginning in March 2024, recording a three-fold increase in airflow compared to baseline performance. GE characterized the results as a "tremendous success, both from a combustion performance and thermal structure perspective."

The rapid development timeline proved noteworthy: the 3D-printed engine was designed and built in 8.5 months, achieving first ignition within 11 months of program start.

Rotation-detonation engines generate thrust through controlled detonation of fuel-air mixtures rather than conventional combustion. Fuel and oxidizers are introduced through small ports into a circular combustion channel, where traveling detonation shockwaves continuously ignite successive fuel charges in a self-sustaining cycle. This process delivers greater thrust efficiency for equivalent fuel consumption compared to traditional combustion approaches.

Program Applications

According to Aviation Week reporting, GE plans to offer the DMRJ for DARPA's Next-Generation Responsive Strike (NextRS) demonstrator program, as confirmed by Craig Young, executive director of the Edison Works division.

NextRS aims to develop survivable, rapidly deployable long-range strike capabilities with enhanced range, speed and mission flexibility. The program is advancing technologies across multiple domains, including advanced structures and materials, high-speed weapon separation, dual-mode propulsion, power generation, thermal management and high-Mach turbine engines. The initiative seeks to enable penetration of contested environments and precision engagement of time-sensitive targets.

The GE propulsion systems do not appear destined for current U.S. air-launched hypersonic programs already in flight test or advanced development, suggesting their application to follow-on weapon systems in the expanding DoD hypersonic portfolio.

---

Sources

1. Satam, P. (2025, October). General Electric Demonstrates Ramjet Engines for Hypersonic Missiles - The Aviationist. https://theaviationist.com

2. GE Aerospace. (2025, January 13). Press Release: Hypersonic Dual-Mode Ramjet Development. GE Aerospace.

3. GE Aerospace. (2025, October 1). ATLAS Flight Test Program [Promotional video]. GE Aerospace.

4. Next-Generation Responsive Strike (NextRS) Program Overview. Defense Advanced Research Projects Agency (DARPA).

5. Aviation Week reporting on GE DMRJ and NextRS program (as cited in source document).