Months of devastating Russian air attacks suggest Moscow has succeeded in altering its missiles to evade Ukraine’s air defences, according to Ukrainian and western officials. Bombardments that targeted Ukrainian drone makers this summer were a prominent example of Russia improving its ballistic missiles to better defeat US Patriot batteries, current and former Ukrainian and western officials told the Financial Times. Russia was likely to have modified its Iskander-M mobile system, which launches missiles with an estimated range of up to 500km, as well as Kinzhal air-launched ballistic missiles, which can fly up to 480km, they added. The missiles now follow a typical trajectory before diverting and plunging into a steep terminal dive or executing manoeuvres that “confuse and avoid” Patriot interceptors.

It is a “game-changer for Russia”, said one former Ukrainian official. With Kyiv also contending with slower deliveries of air defence interceptors from the US, the missile campaign has destroyed key military facilities and critical infrastructure ahead of winter. Ukraine’s ballistic missile interception rate improved over the summer, reaching 37 per cent in August, but it plummeted to 6 per cent in September, despite fewer launches, according to public Ukrainian air force data compiled by the London-based Centre for Information Resilience and analysed by the Financial Times.

Yeah, I highly doubt the rate was ever 37% this year. “according to public Ukrainian air force data” sure dude, the famously reliable and truthful official Ukrainian government information!

Ukraine’s air force on Wednesday reported all four Iskander-M missiles fired overnight had eluded the country’s defences and hit their targets. At least four drone-making plants in and around Kyiv were badly damaged by missiles this summer, said current and former Ukrainian officials. This included a strike on August 28 on a facility producing Turkish Bayraktar drones, according to public posts by local officials. Two missiles launched in that attack appeared to have targeted the offices of a company designing and producing components for drone systems, said two officials briefed on the incident. The Russian projectiles eluded Ukrainian air defences and also damaged the offices of the EU delegation and British Council, which were located nearby.

The Patriot interceptors are the only ones in Kyiv’s arsenal capable of shooting down Russian ballistic missiles. Moscow’s cruise missiles can be taken down with less sophisticated air defences, but the updates have made it harder to do so, according to the officials. A western official briefed on Patriot performance data said the first indication of an upgrade to the Russian missiles was a marked drop in interception rates. They said a “pattern” had emerged in which incoming missiles behaved differently in their “terminal phase”, veering from their previously established engagement settings. The official’s assessment is supported by a report compiled by the US Defense Intelligence Agency’s special inspector general that covers the period of April 1 to June 30. The report said Ukraine’s armed forces had “struggled to consistently use Patriot air defence systems to protect against Moscow’s ballistic missiles because of recent Russian tactical improvements, including enhancements that enable their missiles to change trajectory and perform manoeuvres rather than flying in a traditional ballistic trajectory”. It cited a Russian attack on June 28 that included seven ballistic missiles, of which Ukraine shot down only one, and a barrage on July 9 — at the time the largest air assault since the start of the war — that included 13 missiles, of which the Kyiv downed or suppressed 7.

Ukraine shared Patriot engagement data with the Pentagon and the air defence system’s US manufacturers, said the western and Ukrainian officials. Virginia-based Raytheon makes the Patriot system, while Maryland-based Lockheed Martin produces the system’s interceptor missiles. The data is used to make updates needed to keep pace with Russia’s adjustments, but one official said those improvements often lagged behind Moscow’s evolving tactics. Sergiy Kyslytsya, Ukraine’s first deputy foreign minister, told the FT “the Russians continue to significantly upgrade their Iskander and other missiles’ technology”. He stressed the need for Kyiv’s partners to choke off flows of western-made components to Russia, including via China. Ukraine’s defence ministry and air force did not respond to requests for comment. Analysts said software adjustments were likely to be the reason behind the Russian missiles’ increased effectiveness. Fabian Hoffmann, a missile researcher at the University of Oslo, said manufacturers routinely mined interception data to improve performance. Russia, he said, appeared to be doing this. The Iskander-M “can manoeuvre quite aggressively in the terminal stage”, he noted. Rather than costly hardware changes, tweaks to guidance systems could instruct a missile to execute a quick manoeuvre just before hitting the target and then dive steeply, complicating the Patriot’s tracking and engagement ability. “A steeper terminal trajectory, that’s something you can programme in the missile,” Hoffman said.

Ukraine and Russia were “playing an adaptability game” when it came to their weapons technology, he said. But there was also a cat-and-mouse game being played in trying to destroy each other’s weapons systems. Kinzhal missiles are launched from Moscow’s strategic bombers or fighter jets out of reach of Ukraine’s air defences. Russia’s mobile Iskander missile launchers were also difficult for Kyiv to take out, Hoffmann said. Ukraine’s Patriot air defence systems, which consist of a radar, control station and launchers that are transported on trucks or trailers, are also mobile. Some of them have been targeted and damaged after months of sustained Russian attacks, meaning the country’s layered air-defence architecture has thinned. Specialist personnel trained on the Patriot systems are also a target, among them Lieutenant Colonel Denys Sakun, chief engineer of an anti-aircraft missile unit in Kyiv’s 96th Brigade. He had helped set up systems credited with what Kyiv said was the world’s first downing of a Russian Kh-47M Kinzhal missile. Sakun was killed in December while attempting to save Patriot equipment during a fire after a Russian strike in the Kyiv region, according to public accounts. Patriots were previously protected by other systems such as Europe’s Iris-T and medium-range batteries. Now, with some of those assets damaged or redeployed, “the Patriots have to cover themselves” while engaging incoming Russian missile threats in some cases, said one person familiar with the matter.

Ukraine does not disclose information about the number of Patriot batteries it has and where they are deployed, but at least six are known to have been delivered, with components of at least an additional three delivered in recent weeks by Germany and Norway. President Volodymyr Zelenskyy has pleaded with Ukraine’s western partners to provide his country with more, offering to purchase up to 10 complete systems. With winter approaching, Zelenskyy has warned Moscow is reverting to its familiar strategy of striking Ukraine’s power grid to plunge the country into darkness and sap morale. But Russia’s evolving missile technology makes this year’s threat more acute. “Unfortunately, this has already become a traditional Russian tactic,” he said. “Russia is once again trying to hit Ukraine with a blackout this year.”