HermeusIn Development
A multi-mission reusable hypersonic uncrewed aerial system (UAS) designed for defense and national security missions including ISR and strike in contested environments. Powered by the Chimera II TBCC engine.
Latest update Sep 18, 2026
01
Darkhorse remains the defense product Hermeus is building toward as Quarterhorse expands the validated flight envelope and Chimera II matures around the Pratt & Whitney F100 core. The company aircraft page now dates Mk 3 (Chimera II mode transition) to 2028 and Mk 4 (sustained ramjet TBCC) to 2029 ahead of Darkhorse.
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03
Announced next steps from Hermeus that mention Darkhorse.
2026-2027
The May 2026 $159M DIU contract modification - taking the program ceiling to $219M - commits Hermeus to a series of intensive 2026-2027 flight tests with the USAF and USN proving uncrewed Quarterhorse can hold high-Mach speeds while carrying and releasing payloads, the technical foundation for a Darkhorse-class operational system. Hermeus cleared the first concrete step in late July 2026, when Quarterhorse Mk 2.1's fifth flight completed an unmanned stores-separation test under DIU's HyCAT program, safely releasing an external payload; the campaign continues toward higher-Mach payload releases through 2027.
2028-2029
Hermeus's aircraft roadmap now dates a multipurpose high-Mach Mission Plane and a Chimera II-powered Mk 3 (in-flight turbine-to-ramjet transition) to 2028, with a Mk 4 hypersonic TBCC demonstrator in 2029 and Darkhorse as the reusable operational UAS beyond that.
04
Hypersonic aircraft developer Hermeus appointed Zach Shore as chief executive officer effective June 1, with founding CEO AJ Piplica transitioning to executive chairman. The leadership change comes as Hermeus advances its uncrewed Quarterhorse Mk 2.1 - billed as the world's first privately developed unmanned supersonic jet, which has flown to Mach 1.21 - and develops the larger Darkhorse, for which it has accepted its first Pratt & Whitney F100 engine to integrate into its Chimera II turbine-based combined cycle propulsion system. The company has won a $159 million Defense Department contract exploring military applications of its high-speed technology.
Hermeus said its Quarterhorse Mk 2.1 test aircraft hit Mach 1.21 (~930 mph) on its third flight from Spaceport America over the White Sands Missile Range, making it the first privately-developed unmanned aircraft to break the sound barrier and, by Hermeus's claim, the fastest unmanned jet flying today. The milestone came 364 days after Hermeus's Mk 1 maiden flight and roughly three months after Mk 2.1's first flight, validating the iterative build cadence behind the company's path to its Mach 5 Darkhorse military UAS.
05
An iterative program of unmanned, remotely piloted test aircraft designed to unlock high-speed flight one step at a time. Hermeus's aircraft page now lists Mk 0 through Mk 4 plus a 2028 Mission Plane, each purpose-built to validate a specific technical challenge and feed the next build.
A planned Mach 5 commercial hypersonic airliner that would carry approximately 20 passengers at 90,000+ feet altitude, cutting transatlantic flight times from 7 hours to 90 minutes. Represents Hermeus's long-term commercial vision.
06
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