PROJECT ORTHRUS
Combined-Cycle Hypersonic Propulsion
Mach 0
Mach 6.7+
1
2
3
4
5
6
Executive Summary
Orthrus is a high efficiency combined cycle engine for hypersonic applications, developed by Horizon Apogee.
Core Technology — ORTHRUS
- Single-piece, combined-cycle, air-breathing propulsion system
- Additive manufactured using advanced ultra-high temperature materials
- Achieves concurrent dual-mode operation eliminating transition instability
- Kerosene-based fuel simplifying logistics overhead
Eclipse Trajectory Simulator
Target Intercepted
92.0 s
—
200 km range
Trajectory
Mach
Thrust (kN)
Altitude (km)
Capabilities
Mach 6.7+
Maximum Operating Speed
45%
Mass Savings vs. Conventional
~1,200s
Combined-Cycle Avg Isp (+20% vs. conventional)
Readiness
04
2026
TRL 4
Achieved
Subscale hot-fire testing complete — May 31, 2026
06
2026
TRL 6
Full size hot-fire test in analog conditions — End of 2026
09
2028
TRL 9
End Goal
Validate production-ready engine — End of 2028
