The Northrop Grumman XRQ-73 SHEPARD is an experimental hybrid-electric Group 3 unmanned aerial vehicle (UAV) developed for the Defense Advanced Research Projects Agency (DARPA). As the centerpiece of the Series Hybrid Electric Propulsion AiRcraft Demonstration (SHEPARD) program, the aircraft is designed to validate a series hybrid-electric architecture intended to increase fuel efficiency, reduce emissions, and significantly lower the acoustic signature of military aircraft. This focus on "extra-quiet" propulsion makes the XRQ-73 a critical asset for future Intelligence, Surveillance, and Reconnaissance (ISR) platforms requiring high levels of covertness.
Designed and built by Northrop Grumman Aeronautics Systems in collaboration with its subsidiary, Scaled Composites, the XRQ-73 utilizes a tailless flying-wing configuration. This aerodynamic layout is chosen to optimize efficiency and maintain low radar and acoustic signatures. The aircraft is a "missionized" evolution of the earlier, more secretive XRQ-72A Great Horned Owl (GHO) program, scaling up the hybrid-electric architecture matured under the GHO project to create a more operational demonstrator.
The propulsion system is a series hybrid-electric setup where a gas turbine generates electricity to power the propulsors, rather than driving them mechanically. While specific engine models are not public, the program involved several key suppliers: Brayton Energy provided the gas-turbine power systems, and EaglePicher Technologies supplied energy storage and battery systems. Other contributing partners included PC Krause & Associates and Cornerstone Research Group. The resulting aircraft has an approximate weight of 1,250 lb (approximately 570 kg), placing it within the DoD's Group 3 UAS classification, which typically encompasses aircraft with maximum weights up to 1,320 lb.
The XRQ-73 first flew on April 14, 2026, at Edwards Air Force Base in California. The flight was conducted remotely by Scaled Composites test pilot Dr. Mike McLean. As an experimental X-plane, the XRQ-73 is a single demonstrator vehicle rather than a serial production aircraft. While it has not participated in combat operations, it serves as a pathfinder for next-generation uncrewed systems, proving that hybrid-electric powertrains can be integrated into tactical ISR platforms to enhance endurance and survivability.