The U.S. and Australia Conducted a Secretive Hypersonic Missile Test
The United States and Australia conducted a joint missile test earlier this month of a hypersonic missile capable of traveling faster than six thousand miles an hour. The test of the HiFiRE vehicle paves the way for a new generation of hypersonic weapons that can strike enemies with a minimum of reaction time.
The test, first reported by Flightglobal, was conducted jointly by Australia's Defence Science and Technology Group and the U.S. Air Force Research Lab at the Woomera Test Range in Australia. According to the site, the tests involved the HiFiRE scramjet vehicle. Here's a very short video of the launch:
Australia's News.com later linked the test to an unexplained fireball that was seen that night over much of the southern Australian outback.
The HiFiRE program has been ongoing since 2009, when the first test involving the scramjet engine took place. Previous tests have involved HiFiRE being lofted upward on an Orion sounding rocket with an S-30 rocket as a first stage.
A scramjet engine burns a combination of fuel and oxygen from the atmosphere in the engine's combustion chamber. Like its cousin the ramjet, a scramjet sucks in air but the difference is the scramjet lowers the air to subsonic speeds, allowing for greater engine efficiency and hypersonic speeds. Unlike conventional missiles and airplanes, scramjet -equipped vehicles need a carrier vehicle, like an Orion rocket, to boost them to high speeds where the scramjet can take over.
Past HiFiRE experiments have been brief forays into hypersonic travel. A 2012 test involving NASA took HiFiRE from Mach 6 to Mach 8, where it flew for twelve seconds. The test also failed to keep incoming oxygen at subsonic speeds, indicating the program still needed some work. At the time, NASA claimed it was the second of a planned 10 flights. News.com.au claims there have been at least three previous tests prior to this month's test, with a mockup of the configuration for test #5 published in an undated paper on the NASA web site.
The last mention of HiFiRE on the NASA web site is five years old. A statement by the Australian Minister for Defence fails to mention NASA, so the space agency may have exited the program and it may now be entirely in U.S. Air Force hands.
The Australian/American HiFiRE effort comes as the Russians and Chinese are developing their own hypersonic missiles. Like HiFiRE, China's DF-ZF piggybacks on the back of a missile to reach speeds between Mach 5 to Mach 10 and has been tested seven times, the latest in April 2016. Russia's Yu-71 system tags along on a RS-18 intercontinental ballistic missile, flies at Mach 10 and was tested in October 2016.
