Ukraine came under some of the heaviest bombardment on Thursday, March 9, when Russia attacked targets across the entire country. Ukrainian defense forces said that Russia had used hypersonic missiles in the attacks.

Officials in Ukraine said at least nine civilians were killed in missile strikes on the capital Kyiv and other places, including the eastern city of Kharkiv and villages in the western Lviv region.

Moscow has used hypersonic missiles before — in the early weeks of the war back in 2022. They are considered a special kind of missile. Here's why.

Are hypersonic missiles invincible weapons?

"Invincible." That's what Russian President Vladimir Putin called hypersonic missiles in 2018 when he unveiled his country's arsenal of the missiles.

It was perhaps a lofty description, designed for propaganda purposes, but there was some element of truth. Hypersonic missiles differ from conventional ballistic weapons in ways that make them harder to catch by missile defense systems. It comes down to speed and altitude.

How fast are hypersonic missiles?

Hypersonic missiles fly five to ten times as fast as the speed of sound. That's known as Mach 5 to Mach 10.There is no fixed speed of sound because it depends on variables, namely the medium and the temperature of the medium through which an object or soundwave moves.

But as a comparison, the Concorde commercial airplane flew at about twice the speed of sound. Concorde was a supersonic aircraft that had a maximum cruising speed of 2,180 km (1,354 miles) per hour, or Mach 2.04. So hypersonic takes those speeds at least three notches higher.

The hypersonic missiles that Russia used in the attacks on Ukraine are known as "Kinzhals," or daggers. They are 8 meters long.

Some experts say this type of missile flies as fast as 6,000 kilometers per hour, which would be around Mach 5. Others say it flies at Mach 9 or even Mach 10.

Either way, it's fast. So fast, in fact, that "the air pressure in front of the weapon forms a plasma cloud as it moves, absorbing radio waves," the weapons experts at US website Military.com explain.

That makes "Kinzhal" and other hypersonic weapons very hard to catch on radar systems, an effect compunded by their low altitude.

Low altitude

Hypersonic missiles fly at a much lower altitude than conventional ballistic missiles.

They follow what is known as a low atmospheric-ballistic trajectory. That means that by the time a radar-based missile defense system clocks them, they are already so close to their target that in many cases it is too late to intercept them.

On top of that, hypersonic missiles can change direction midflight.

What is their range?

The hypersonic missiles used by Russia in Ukraine are launched from aircrafts.

Other hypersonic weapons can be deployed from ships and submarines. And they are capable of carrying nuclear warheads.

The Kinzhal type can hit a target up to 2,000 kilometers away. Other hypersonic missiles have a reach of about 1,000 kilometers.

If hypersonic missiles were stationed in the Russian territory of Kaliningrad, that would put several European capitals within their reach. Kaliningrad is separate from the Russian mainland and borders Poland, Lithuania and the Baltic Sea. The German capital Berlin is less than 600 kilometers away.

But some analysts say that despite the advantages that hypersonic missiles have over conventional ballistic weapons, Russia won't use them indiscriminately. US Air Force General Glen D. VanHerck told a US Senate Armed Services subcommittee in May 2022 that Russia was having "challenges with some of their hypersonic missiles as far as accuracy" was concerned in Ukraine.  

Edited by: Zulfikar Abbany

Editor's note: This article was originally published on March 22, 2022. It was updated on March 10, 2023, with information about Russia's recent wave of missile attacks on cities across Ukraine.