The US has been testing hypersonic aircraft missiles that could fly at a mile per second.
It has collaborated with Australia to research and pilot weapons able to fly at least five times faster than the speed of sound - anywhere from 3,836mph up to 7,700 mph.
The latest phase of the Hypersonic International Flight Research Experimentation (HiFIRE) programme included at least one successful hypersonic flight at Woomera testing range in South Australia.
The round of experiments concluded on 12 July, confirmed Australian defence minister Marise Payne.
BAE Systems Australia said in a statement that "the successful flight trial [was] the most complex of all HIFiRE flights conducted to date".
The $54m joint initiative involves the US Air Force, Boeing, the Australian Department of Defence’s Defence Science and Technology Group, BAE Systems Australia, and the University of Queensland.
Both Russia and China are building hypersonic glide vehicles, US Air Force General John Hyten recently told a Senate hearing, according to The Washington Examiner.
US Navy Admiral Harry Harris, head of US Pacific Command, told a Congress hearing in May: "I'm concerned about Chinese and Russian hypersonic weapons development, and I expressed those concerns in the right places. What we can do is to develop our own hypersonic weapons and improve our defenses against theirs."
A hypersonic missile could fly 1000 miles in less than 17 minutes. Though many ballistic missiles can fly faster, the typical arc trajectory of such missiles makes them more easily detectable by early warning satellites, according to The Drive. The Pentagon has developed ballistic missile interceptors able to knock such weapons off-course mid-flight, and so mitigate their threat.
But hypersonic weapons are much less easy to track. Prototype designs rely on a booster such as a rocket motor to get the craft up to speed, before a high-speed jet engine takes over. Its smooth and flat flight path is much harder to track than that of a ballistic missile. These prototype crafts may also have the capability to change direction mid-flight, which makes interception much harder.
Developing a hypersonic missile system would enable the US to conduct short-notice or no-notice enemy strikes, the capability for which is a powerful deterrent alone.
The HiFIRE project, which initially included NASA, launched more than eight years ago.