Mk 1: The first flyable version of Quarterhorse, Mk 1, is set for flight tests later in 2024. These tests will focus on high-speed takeoffs and landings

Mk 2: Scheduled for 2025, Mk 2 will be powered by a Pratt and Whitney F100 engine, enabling supersonic flight. This version will serve as a precursor to the full hypersonic capabilities planned for future iterations

Mk 3: Expected to be developed by 2026, Mk 3 will incorporate Hermeus' Chimera II propulsion system, which includes a modified F100 engine. This version aims to achieve speeds faster than Mach 3.3, supporting Defense Department testing.