High-Speed Fusion-Based Combined Cycle Transport Vehicle Design Project

This paper presents Hypersonic Experimental Nuclear Aircraft (HyENA), a groundbreaking fusion-based hypersonic transport aircraft concept developed for the University of Maryland’s 2025 Aerospace Engineering senior capstone. HyENA is a Mach 5, 38-passenger aircraft partially powered by a compact fusion reactor. The vehicle integrates a gas turbine airbreathing propulsion cycle with a compact deuterium–tritium fusion reactor to create a dual-mode propulsion system. With a range of nearly 10,000 nautical miles at 100,000 feet altitude, it dramatically reduces intercontinental flight times. Key technical challenges in propulsion, aerodynamics, thermal protection, and structural analysis were addressed. Thrust from takeoff through hypersonic cruise is generated by a low-bypass turbofan and a fusion-augmented afterburner/ramjet. The airframe features highly swept double-delta surfaces and an advanced thermal protection system that insulates the vehicle from extreme thermal loads. The heat blocked by the thermal protection system enables a cold structure, which utilizes robust titanium alloys to withstand loading. The aircraft operates with a fuel fraction under 20% for the trans-Pacific missions studied, exceptionally low for a transoceanic route. Although significant technological hurdles remain, this study provides a path toward feasible future hypersonic commercial travel. This project was performed under the guidance of Kevin G. Bowcutt and Christoph Brehm.