What does Russia’s launch of an ‘experimental’ weapon at Ukraine mean for allies?

Russian forces on Thursday fired what U.S. officials called an “experimental intermediate-range ballistic missile against Ukraine,” which has characteristics of an inter-continental ballistic missile but did not carry a nuclear warhead. The test has some Russia watchers worried about what that launch might signal. 

In response to the launch, the United States is “providing Ukraine with hundreds of additional [Raytheon-built] Patriot and AMRAAM missiles to strengthen its air defense,” the White House announced Thursday. “Many of these are air defense missiles [that] have been delivered already as a consequence of the president's decisions to divert air defense exports to Ukraine, and deliveries of additional air defense missiles to Ukraine are ongoing.”

Russian officials did not specify the exact type of missile it shot at the Ukrainian city of Dnipro, but Middlebury professor and missile expert Jeff Lewis believes it was “a variant of the long-gestating RS-26 Rubezh IRBM, he wrote on X. His reasons for that are twofold, he wrote: “ (1) Russia hinted that it resumed development of the RS-26 this summer and (2) that's what the Ukrainians predicated a day ago, down to the launch site.”

However, Tom Karako, director of the Missile Defense Project at CSIS, told Defense One that new details suggest it is “probably not” an RS-26, “so it's unclear what it is.”

Footage of the blast indicates that the new weapon probably features a multiple independently targetable reentry vehicle, or MIRV, payload, Karako said, based on the secondary rockets that fired off the original missile. 

“If it is indeed a MIRV, that's going to be a wicked hard problem to hit multiple things, if it's coming in super fast, especially if it's an [intermediate-range ballistic missile] on a lofted trajectory,” he said.

The attack comes as Russian President Vladimir Putin escalated his threats against Western nations for their support of Ukraine, particularly the recent decision by the United States to allow Ukraine to strike targets in Russia using U.S.-supplied ATACMS missiles, and the decision by the U.K. permitting Ukraine to use Storm Shadow missiles, which have a range of 155 miles. Ukraine has already launched both.  

Putin took to Russian television Thursday to boast about the weapon and link the launch directly to the recent decisions by the U.S. and the U.K.  

“The tests were successful,” Putin said, noting they took place “in combat conditions.” Additionally, he said, “Modern air defense systems that exist in the world and anti-missile defenses created by the Americans in Europe can’t intercept such missiles.”

Ukraine has previously intercepted very new hypersonic missiles that Russia had called invincible. 

Regarding the newest missile, Karako said if the multiple warheads “are maneuverable, then that's going to complicate the job of the defender…It would certainly be a hard thing to defend against.” 

But he cautioned against taking the wrong lessons from the Russian display of aggression. 

“I don't think we should fall for it…The response ought to be to not merely give Ukraine the ability to shoot back with ATACMS, but also other things that they need in a broad combined arms effort to, no-kidding, have a winning strategy and put them in a better position to negotiate for a position of strength.”