US’ Hermeus supersonic jet breaks sound barrier at Mach 1.21 in high-speed flight test

Hermeus says its uncrewed Quarterhorse Mk 2.1 broke the sound barrier in a third test flight over New Mexico.

The aircraft reached Mach 1.21, a major milestone for the private aerospace company and its Quarterhorse program.

The result supports Hermeus’ rapid-development approach for reusable high-speed aircraft and future hypersonic systems.

Hermeus also announced leadership changes as it continues work on later Quarterhorse variants and related concepts.