The interruption of critical satellite connectivity last month has brought home to Ukraine the risks of a more comprehensive reduction in US support.

Since Donald Trump returned to the White House almost two years ago, Volodymyr Zelenskyy and his European allies have been trying to work out how they would get by without the US and how quickly they could be ready.

As officials across Europe try to gauge the potential fallout from Trump’s defeat in the mid-term elections, there is concern in some quarters that a weakened president may become an even more unreliable partner.

Trump’s decision to drop sanctions on Russian diesel as he sought to avert an electoral meltdown and a brief halt to warnings of incoming ballistic missiles underlined for Ukrainians how fragile US support has become. The Russians, meanwhile, are starting to wonder whether they could start to normalize economic ties with the US without even ending the war.

“We understand where this is all going,” Zelenskyy told reporters in the run-up to the US vote. “‘Home Alone’ is the next chapter.”Ukraine produces large amounts of weapons and gets substantial financial backing from Europe so the reduction or even sudden halt of US support wouldn’t lead to immediate collapse. But depending on Europe alone for support would leave Kyiv’s forces, and its civilian population, seriously exposed.

“If the US stopped all aid my sense is that Ukraine could adjust,” Ian Lesser, a fellow at the German Marshall Fund in Brusssels, said. “But the political and strategic signal would be very harmful — and encouraging to Moscow.”While Ukrainian officials were preparing for peace talks with Russia and the US in Abu Dhabi this week, Trump met last Thursday with Russian presidential envoy Kirill Dmitriev at the White House and told reporters that he is expecting a “big agreement” that might involve the whole of Europe.

European allies, on their side, are getting ready to test their ability to secure any potential agreement, with thousands of troops from 11 nations including France and the UK taking part in exercises that will kick off in Poland on Monday.

“The exercise of the Coalition of the Willing will help us prepare in a practical way for potential security guarantees for Ukraine after a ceasefire,” Polish Prime Minister Donald Tusk told reporters in Warsaw Thursday. “The exercise doesn’t mean that there will be a ceasefire anytime soon. We want to be ready.”The Europeans, along with Canada, are also spending billions of dollars on US weapons they ship to Kyiv. But they are a long way from being ready to replace US capabilities in three key areas: air defenses, satellite connectivity and intelligence.

The US-made Patriot interceptors, Ukraine’s most effective protection against ballistic missiles, have been in desperately short supply since Trump launched his war on Iran. The Trump administration’s recent approval of $2.1 billion in missile sales to Ukraine won’t be a quick fix.

“Russia is making ballistic missiles faster than the rest of the world combined is producing the Patriots needed to intercept them,” Serhiy Beskrestnov, an adviser to Zelenskyy on electronic warfare, told reporters in Kyiv last month. “There’s a global shortage.”European stocks of PAC-2 and PAC-3 interceptors for Patriot systems, produced by US firms Raytheon Co. and Lockheed Martin Corp., are at a minimum with national militaries often resistant to hand them over to Ukraine without firm US commitments for fresh supplies, according to people familiar with the matter.

The situation will start looking up in about a year, when Ukraine will receive interceptor missiles commissioned for production in Europe. Kyiv should receive 600 PAC-2 produced in Germany in 2027 and 2028 with a new deal to produce PAC-3 in Poland announced late last month.

Trump’s promise to license production of interceptors in Ukraine hasn’t yet materialized. Neither has a program by Europe’s five biggest defense spenders to develop low cost air defense systems, announced in February.

Zelenskyy’s adviser Beskrestnov called the project tough because of a lot of different nations being involved.

“We can make engines, we can make the missiles, we can make the launch stations,” he said. “But that doesn’t mean it will work in the end because we still have a dependence on components that are made elsewhere.”The intelligence provided by the US to track Russian movements and identify targets is also hard for Europe to match, especially for the real-time early warnings against incoming airstrikes.

In October, Ukraine temporarily stopped receiving advance warnings from the US of incoming ballistic missiles, including five that were aimed at Kyiv. The support was restored after Ukrainian officials appealed to Washington.

SpaceX’s Starlink communication systems remain the backbone of battlefield logistics and midrange strikes for Ukrainian drones.

Their significance was thrown into sharp relief when the speed of service was throttled last month in what the company’s billionaire owner Elon Musk described as a terms of service dispute with Ukraine.

The EU’s answer to Musk’s Starlink system known as Project Bromo is still awaiting anti-trust approval after generating resistance from unions and suppliers.

US military satellites also allow Ukraine to receive advance warning of Russian missile strikes and for targeting. While Europe does have space assets, it doesn’t have the same quantity and scope of satellite capacities to offer to Kyiv.

Ukraine has, since its independence, sent a handful of mini satellites into orbit on foreign launches but has never had a proper space program, and certainly nothing capable of replicating Starlink or even Russia’s Rassvet.