Ukraine says it shot down Russian Kinzhal missiles. What is the hypersonic weapon?

Ukraine is claiming to have achieved a rare feat in warfare: the shooting down of sophisticated Russian hypersonic Kinzhal missiles.

The Russian air force fired six Kh-47M2 Kinzhals at targets in Kyiv, Ukraine's capital, early Tuesday, a weapon it has used sparingly since the early months of its invasion of its neighbour in February 2022.

Ukraine has not said if the U.S.-supplied Patriot missiles were used to thwart some or all of the attempted strikes, but it happened 10 days after the military said it brought down another Kinzhal, over Kyiv, using a Patriot missile defence system. The Pentagon also credited the Patriot system for thwarting the strike on May 6.

If a Patriot missile was able to intercept a Kinzhal, it's a significant development in air defence, according to experts.

Here's a look at what makes the Kinzhal different from other missiles Russia is using against Ukraine and why the ability to blow it out of the sky, before it strikes, is a big deal.

The Kinzhal, which means "dagger" in Russian, is an air-launched ballistic missile.

When Russian President Vladimir Putin unveiled the weapons in 2018, he said they could penetrate both existing and future missile defence systems.

The Kinzhal is the cousin of the 9K720 Iskander-M — a short-range, ground-launched ballistic missile that Russia has used somewhat frequently throughout the war.

It's referred to as a hypersonic missile, meaning it travels at least five times faster than the speed of sound. Russia claims the Kinzhal can reach Mach 10 — that's 10 times the speed of sound, or 12,350 km/h — within a range of 2,000 kilometres.

Russia uses a modified MiG-31 fighter jet to launch the eight-metre-long missile from the air, something that helps boost its speed, said Sidharth Kaushal, a research fellow at the Royal United Services Institute, a defence and security think-tank in London.

But he called Russia's hypersonic description a "bit of conscious misdirection."

"It does fly at hypersonic speeds, but typically what we would mean when we use the term is something that's highly manoeuvrable at hypersonic speed," he said.

Tom Karako, a senior fellow and director of the Missile Defence Project at the Center for Strategic and International Studies (CSIS) in Washington, D.C., agrees that Russia's claims of the Kinzhal's hypersonic manoeuvrability may be exaggerated compared to that of weapons typically referred to as hypersonic, such as a cruise or a boost glide missile.

"[It] may or may not have been at hypersonic speeds, but it's nevertheless a sophisticated and challenging intercept problem," he said.