A Chinese hypersonic test flight involving a high speed missile launch points to a major breakthrough, but Beijing's capacity to deploy the advanced technology in combat is still doubtful, experts said.

The American defense establishment has been rattled by the discovery that a Chinese hypersonic glider around-the-earth test flight in July culminated in the firing of a missile in mid-flight at more than five times the speed of sound over the South China Sea, media reports said at the weekend.

Top powers the United States, Russia and China have all been experimenting with so-called hypersonic glide vehicles -- defined as reaching speeds of at least Mach 5 -- but up to now none had displayed comparable mastery of a mid-flight missile launch.

Weapons traveling at hypersonic speed would enable an attacking military to overcome defense installations through sheer speed and unparalleled maneuverability, and allow a country under assault to pick off incoming missiles more easily.

"The Chinese appear to have mastered the thermic and aerodynamic shock effects linked to hypersonic speed," said Joseph Henrotin, defence strategy researcher and chief editor of DSI, a French military review.

This, he told AFP, required "huge computing capacity".

US defense officials were caught off-guard by the Chinese display, the Financial Times reported, citing people familiar with the intelligence.

Details of Beijing's test are still sketchy, with analysts wondering whether the missile hit or missed its target, or whether there even was a target.

'Great leap forward'

Either way, the demonstration showed that China has made surprising advances in a technology that many experts had placed much further in the future.

"The recent tests constitute a great leap forward for China in terms of technology," said Niklas Swanstrom, China expert and director of the Institute for Security and Development in Stockholm.

But, he told AFP, "even if they have the technology, it is much less clear if they have the ability to deploy them and to make effective use of them in combat operations".

And, as important as superfast weaponry may become in the future, any edge China may have gained over the US in that area is nowhere near changing the overall military balance.

"We still have to realize that the US is far ahead of China in terms of overall military technology," Swanstrom said.

China makes no secret of having developed at least one aerodynamic wind tunnel capable of conducting tests for hypersonic weapons and equipment.

The state-owned Aviation Industry Corp of China (AVIC) confirmed this month that a Mach 8 wind tunnel called FL-64 had been completed and now had "testing capability", including "weapon separation and delivery".

Meanwhile Chinese scientists are building the JF-22 wind tunnel which can simulate flight at 30 times the speed of sound, state broadcaster CCTV reported in August.

Chinese Academy of Sciences researcher Jiang Zonglin told CCTV the tunnel could be used to develop aircraft that could "reach any place on earth within one or two hours".

'Playing up the Chinese threat'

The advances in China's spacecraft development make the reports of the missile launch "credible", said James Char, an expert on the Chinese military at Singapore's Nanyang Technological University.

But it was also possible that US defense officials were exaggerating the real danger from the missile display in a bid to secure more money for their own weaponry.

"The US military leadership has been playing up the Chinese military threat in recent years, so this may well be another example of its officials trying to seek a bigger defense budget going forward," he said.

He noted that the US administration had requested a bigger budgetary increase for Space Force next year, 13.1 percent, than for any of the other four branches of the military.

The US is developing its own hypersonic glider under the ARRW program, but that system's first real-life test failed in April.

Russia meanwhile recently launched a hypersonic missile, called Zircon, from a submarine and deployed a hypersonic, nuclear-capable ballistic system in 2019, called Avangard.