Hermeus has completed the first flight of its Quarterhorse Mk 2.1 unmanned aircraft at Spaceport America in New Mexico, beginning a flight test campaign that aims to reach supersonic speeds.
The vehicle is the company’s largest and fastest to date, comparable in size to an F-16 and powered by a Pratt & Whitney F100 engine. It is nearly three times larger and four times heavier than its predecessor, the Mk 1, making it one of the largest unmanned aircraft ever built, according to Hermeus.
Iterative development
The February 27 flight was conducted remotely from Hermeus’ ground-based flight deck over White Sands Missile Range airspace. The test validated aircraft systems, handling qualities and operational procedures ahead of planned supersonic test flights.
The flight marked the Atlanta-based company’s second successful first flight in less than a year, following the Mk 1’s maiden flight in May 2025. That earlier campaign validated Hermeus’ rapid, iterative development approach, in which multiple prototypes are designed, built and flown in quick succession.
“We’re building and flying aircraft on timelines that match the urgency of the world we’re in,” said AJ Piplica, CEO and founder of Hermeus. “Today’s flight kicks off a critical flight test campaign that will ultimately get us to supersonic speeds, bringing the United States closer to having the high-speed capability it needs now, not decades from now.”
Prototype flight testing
The company, which works with the US Department of War to develop high-speed and hypersonic capabilities, uses flight data from each prototype to refine designs, reduce risk and accelerate progress. Hermeus said the approach compresses timelines that traditionally span decades into a single development cycle.
The current Mk 2 phase of the Quarterhorse program is a multi-aircraft series focused on achieving and expanding the supersonic flight envelope. Mk 2.1 is the first of several planned vehicles, with the next iteration, Mk 2.2, expected to become the fastest unmanned aircraft in the world.
Subsequent phases will push toward the company’s end goal of unlocking sustained ramjet-powered hypersonic flight within the current decade. Ramjets use high-speed airflow to initiate fuel mixing and thrust, and are typically used in vehicles that operate at or above Mach 2.
Hermeus began operations at Spaceport America in December 2025, selecting the facility for its extensive test infrastructure. The federally licensed complex in southern New Mexico sits on 18,000 acres and offers 6,000 square miles of restricted airspace adjacent to the US Army White Sands Missile Range.
“Hermeus wanted to move fast, and we were able to move fast with them, allowing them to build up a site suitable for this kind of unique operation,” said Scott McLaughlin, executive director of the New Mexico Spaceport Authority.
