Hypersonic Attack Cruise Missile (HACM)

HACM (Hypersonic Attack Cruise Missile) is a US Air Force (USAF) program to develop an operational air-launched hypersonic cruise missile powered by a scramjet (supersonic combustion ramjet) engine. HACM represents the transition from hypersonic research (HIFiRE, SCIFiRE) to an operational weapons system.

Key aspects of HACM:

1. Propulsion: HACM uses a scramjet engine for sustained hypersonic flight. Unlike rocket-powered hypersonic weapons (like boost-glide vehicles), scramjet-powered cruise missiles maintain powered flight throughout their trajectory, providing longer range and maneuverability. The scramjet technology was validated through the HIFiRE and SCIFiRE programs.

2. Launch platform: HACM is designed to be air-launched, primarily from fighter aircraft. The F-15E Strike Eagle and F-15EX are expected to be the primary launch platforms, with potential integration on other aircraft.

3. Speed and range: HACM is designed to fly at Mach 5+ speeds with a range that is classified but expected to be several hundred to over a thousand kilometers. The combination of hypersonic speed and maneuverability makes the missile extremely difficult to intercept.

4. Mission: HACM is designed for time-sensitive strike against heavily defended targets. The missile's speed reduces the target's time to react or relocate, while its maneuverability complicates interception by air defense systems.

5. Woomera testing: HACM-related testing has been conducted at the Woomera Range Complex in South Australia, leveraging the established US-Australia hypersonic test infrastructure. The vast airspace and established test range at Woomera provide ideal conditions for hypersonic weapons testing.

6. Industrial team:

• Raytheon Technologies — prime contractor for HACM
• Northrop Grumman — scramjet engine (based on GDE-1/GDE-2 technology)
• Boeing — vehicle integration and testing support

7. Relationship to ARRW: HACM is distinct from the AGM-183A Air-launched Rapid Response Weapon (ARRW), which was a boost-glide hypersonic weapon. ARRW was cancelled in 2023, making HACM the primary USAF air-launched hypersonic weapon program. The two programs represented different technical approaches: ARRW used a rocket booster to accelerate a glide vehicle, while HACM uses scramjet propulsion for sustained cruise.

8. SCIFiRE connection: HACM directly builds on the SCIFiRE (Southern Cross Integrated Flight Research Experiment) program, which developed and tested scramjet technology at Woomera. The SCIFiRE program, in turn, built on the HIFiRE program. This 15+ year research lineage has produced the scramjet technology foundation for HACM.

9. AUKUS connection: HACM connects to the AUKUS Pillar 2 hypersonic cooperation framework. The US-Australia hypersonic collaboration that produced HACM's technology foundation is being expanded under AUKUS to include the UK. The UK's HTCDF and Project Bowline programs may benefit from the SCIFiRE/HACM technology base.

HACM represents the operationalization of decades of hypersonic research. If successful, it will provide the USAF with a critical capability for penetrating advanced air defenses and engaging time-sensitive targets. The missile's scramjet propulsion, validated through the US-Australia collaboration, represents a significant advancement in hypersonic weapons technology.