Until now, Ukraine's air defenses say they have largely succeeded in destroying a substantial number of the Russian rockets being fired into the country's civilian centers. On Thursday, the Kremlin threw in a new wrinkle.
In an early morning attack on targets across the country, Russian forces apparently added several hypersonic missiles, known as Kinzhals — or "Daggers" in Russian — to the lethal mix. Ukrainian forces say their defensive capabilities are not up to the task of taking out a Kinzhal.
Six Kinzhals were included in Thursday's attack, according to Ukrainian defense forces. Although Russia has used these weapons before, in the opening weeks of the conflict, Yuriy Ignat, an air force spokesman, told Ukrainian TV that the enemy had never fired so many of them in a single attack. Ignat said only 34 of the 81 total incoming Russia missiles were shot down.
Hypersonics pose a serious challenge to air defenses
Hypersonic missiles such as the Kinzhal are a fairly new breed of weapon that combine superior speed with the ability to maneuver to evade being shot down. Not only are they difficult to detect, but they make radical and unpredictable course changes as they get close to a target.
The Kinzhal, unveiled by Russian President Vladimir Putin five years ago, can accelerate to Mach 4 — four times the speed of sound — and may be capable of speeds of up to Mach 10, with a range to about 1,250 miles. The missile is also believed to be nuclear-capable.
An even more sophisticated weapon, Russia's Avangard hypersonic glide vehicle, can fly at speeds as high as Mach 27, according to the Kremlin. Another hypersonic, the Zircon anti-ship missile, has also reportedly been developed, but there are no reports of the Zircon or Avangard being used in combat.
There's debate over how much of a game changer they are
The Kinzhal "is launched from an aircraft and has a shorter range than Avangard," according to James Acton, co-director of the nuclear policy program at the Carnegie Endowment for International Peace.
But last year, after the first reported use of the Kinzhal in Ukraine, Acton downplayed the significance of the weapons as a "game changer" in the conflict.
"I don't know how much of an advantage Russia is getting from using hypersonic missiles," he told the BBC.
That is a sentiment largely echoed by U.S. Northern Command chief Air Force Gen. Glen VanHerck. Last May, VanHerck told a Senate Armed Services strategic forces subcommittee that Russia was having "challenges with some of their hypersonic missiles as far as accuracy" in Ukraine.
However, Victor Cha, who served on the National Security Council during the George W. Bush administration, told NPR last year that hypersonics could pose a real challenge — even to U.S. missile defense systems. At the time, Cha was referring to hypersonic missiles being developed by North Korea. U.S. missile defense systems are "good," he said, but they are mostly "geared towards stopping a handful of fairly primitive missiles from North Korea." Those systems dwarf the type of defenses that Ukraine is using in the fight against Russia.
"[T]hey would need to be improved to be able to handle more sophisticated sorts of missiles," Cha said.
The Pentagon, too, has expressed some urgency on the subject. Last year, Dee Dee Martinez, comptroller of the U.S. Missile Defense Agency, said hypersonic missiles "pose a new challenge to our missile defense systems."
"The development and deployment of missile defense systems to counter these advanced threats presents unique, but surmountable challenges, which require further development and technology investments," she said.