HACM: first flight test of the US Air Force’s hypersonic cruise missile, held over Australia

The US Air Force, in cooperation with Australia, has carried out the first flight test of the Hypersonic Attack Cruise Missile (HACM), the scramjet-powered hypersonic cruise missile it is developing. The test took place over a test range in Australia and was confirmed on October 6 by an Air Force spokesperson in a statement to Air & Space Forces Magazine. The date of the test was not announced.

According to the spokesperson, the Royal Australian Air Force (RAAF) released a HACM flight test unit over a “designated Australian test range,” gathering data to advance the program. The test is part of the Southern Cross Integrated Flight Research Experiment (SCIFiRE), a cooperative agreement that, the spokesperson said, builds on more than 15 years of partnership between the two countries. The Air Force gave no details on the carrier aircraft, the duration of the flight or the speed reached. RTX, the missile’s prime contractor, referred questions to the Air Force.

What HACM is

The program was formally established in 2022, when the Air Force selected Raytheon (now RTX) for the missile and Northrop Grumman for the scramjet engine. It grew out of the Hypersonic Air-breathing Weapon Concept (HAWC) program of the Defense Advanced Research Projects Agency (DARPA). The missile first accelerates with a conventional rocket booster, which it then discards, after which the scramjet sustains speeds above Mach 5 at high altitude. It is one of two hypersonic weapons the US Air Force is pursuing, together with the larger AGM-183 ARRW.

HACM has slipped by about a year because of design problems, and the Air Force cut the flight tests in the rapid-prototyping phase from seven to five. The Government Accountability Office (GAO) noted in 2024 that the development schedule had no margin. In its fiscal 2027 budget proposal the Air Force is asking for about $1.2 billion to mature the missile and bring it into service. It has also requested a dedicated production line and $404 million for the first operational lot. The plan calls for the missile to begin reaching units in fiscal 2027 and for full-rate production by fiscal 2029.