Demetri Sevastopulo in Washington

November 21, 2021

China’s hypersonic weapon test in July included a technological advance that enabled it to fire a missile as it approached its target travelling at least five times the speed of sound — a capability no country has previously demonstrated.

Pentagon scientists were caught off guard by the advance, which allowed the hypersonic glide vehicle, a manoeuvrable spacecraft that can carry a nuclear warhead, to fire a separate missile mid-flight over the South China Sea, according to people familiar with the intelligence.

Experts at Darpa, the Pentagon’s advanced research agency, remain unsure how China overcame the constraints of physics by firing countermeasures from a vehicle travelling at hypersonic speeds, said the people familiar with details of the demonstration.

Military experts have been poring over data related to the test to understand how China mastered the technology. They are also debating the purpose of the projectile, which was fired by the hypersonic vehicle with no obvious target of its own, before plunging into the water.

Some Pentagon experts believe the projectile was an air-to-air missile. Others think it was a countermeasure to destroy missile defence systems so that they could not shoot down the hypersonic weapon during wartime.

Russia and the US have also pursued hypersonic weapons for years, but experts say the firing of countermeasures is the latest evidence that China’s efforts are significantly more advanced than either the Kremlin or the Pentagon.

The White House declined to comment on the countermeasure, but said it remained concerned about the July 27 test, which was first reported by the Financial Times last month.

“This development is concerning to us as it should be to all who seek peace and stability in the region and beyond,” said a spokesperson for the National Security Council. “This also builds on our concern about many military capabilities that the People’s Republic of China continues to pursue.”

The NSC added that the US would “continue to maintain the capabilities to defend and deter against a range of threats” from China.