While the European Space Agency (ESA) waits to see whether the United States will cut 19 of their joint programmes, experts say the relationship between the two governments will likely not go back to the way it was.
NASA’s 2026 technical budget request, which was released earlier this month, details possible cuts to programmes such as the Laser Interferometer Space Antenna (LISA), a space probe that measures gravitational waves, Envision, ESA’s first mission to Venus to measure its different atmospheres, and NewAthena, the world’s largest X-ray observatory.
The budget also cuts funding to certain components of Moon missions after Artemis III, a mission that would bring humans back to its surface in 2027.
The cancellations are in the name of finding a more “sustainable and cost-effective” lunar exploration strategy. The bill still needs to be approved by Congress, which could likely be in the autumn.
Alberto Rueda Carazo, research fellow with the European Space Policy Institute (ESPI) think tank, said he has never seen any NASA budget like it.
“Whether or not Congress restores the money, the message is clear: Washington’s science commitments can vanish overnight,” he told Euronews Next.
Missions could slip ‘well into the 2030s’
ESA said at a press conference last week that 19 of its research projects might be impacted by the proposed NASA budget cuts.
The ones where mitigation would be needed are the LISA, Envision and NewAthena.
Without NASA contributions to these projects, Carazo said the missions might “slip years,” possibly pushed back “well into the 2030s,” and risk cancellation.
The questions that these three missions address, like the mergers of black holes, hot-plasma physics and the history of Earth-size planets, would “remain unanswered for at least a decade,” he said.
Ludwig Moeller, ESPI’s director, believes that the LISA programme will continue in the future with or without NASA.
“I think the objective of what LISA wants to do is perfectly understood,” he said. “I don’t think we will lose the discovery in the medium term”.
Carazo said it could also affect Europe’s leadership in fundamental astrophysics, the branch of astronomy that studies the physical structure of stars and other celestial bodies.
The hardest hit of the research programmes, according to Carazo, is the ExoMars mission carrying the Rosalind Franklin rover. NASA provides the launch and descent hardware for the craft to fly so the programme cannot continue unless Europe is able to find and build a heavy-lift alternative.
Josef Aschbacher, ESA’s director general, said in a recent press conference that no cuts or cancellations were coming until the US “finalises” its position, but that no matter the decision made by Congress, ESA would be “ready” and “well-prepared” to react.
Europe could lose a “guaranteed” position on the Moon
There are also possible impacts for Europe’s Moon mission aspirations, because if the NASA cuts are approved, Carazo said Europe’s “two principal avenues into the Artemis architecture would disappear”.
The ESA builds European Space Modules (ESMs) that provide electricity and oxygen to Orion, the spacecraft picked by NASA for the Artemis missions to the surface of the Moon. The NASA cuts would mean that the assembly line in Bremen, Germany, would finish the hardware for the flights but would have nothing scheduled after 2028.
That could mean an “early shut down” of the production line and the associated supply chain, Carazo added.
The ESA also contributes three key elements for Gateway, the first international space station to be built around the Moon. Like the ESM parts, the Gateway hardware that’s been built “would have nowhere to go,” and Europe would lose a “guaranteed, sustained presence in cislunar space”.
There are other knock-off effects to consider regarding Europe’s aspirations to study the Moon, he added.
“European astronaut seats after Artemis III would vanish, and key technologies that ESA is counting on for a later lunar-surface architecture—closed-loop life support, high-power solar-electric propulsion—would be delayed, widening the capability gap Europe had hoped to close in the 2030s,” he added.
NASA pull-out ‘completely lawful’
It is quite easy for NASA to get out of deals with the ESA or other partners, even if a contract has been signed, Carazo said.
NASA contracts fall under the US Federal Acquisition Regulation, where the government has a “termination for convenience” clause that lets them cancel any contract they want so long as they pay for costs already incurred.
“If Congress deletes the line item, NASA is legally obliged to stop spending, give ESA formal notice and negotiate a settlement; there is no binding dispute-resolution clause that could force the United States back in,” Carazo said.
“A pull-out would be diplomatically and politically messy but completely lawful”.
The US has done this before by exiting its ExoMars programme obligations in 2012 under the Obama administration, Carazo added. Withdrawing from this project, in particular for a second time, “would cement the perception that US commitments last no longer than a presidential term”.
Europe’s best bet while waiting for the American position to become clear is to offer to absorb a bigger share of the mission and ground costs while also investing in homegrown hardware to supply ESA’s future missions, Carazo added.
Push towards sovereignty
The most immediate consequence of the NASA cuts would be a “permanent dent in Washington’s reputational capital,” Carazo said. A “diversification” of partners to assist with the ESA missions would follow so that “no single foreign veto can stall an ESA flagship [programme] again.”
ESA is looking to broaden relationships with Canada, Japan and India and while no deals are actively being pursued with China, it remains an option that could be explored, Carazo added.
“All of this reshapes the diplomatic map of space science, diluting US soft power,” Carazo said, adding that projects like China’s International Lunar Research Station could start to “woo European participation”.
This is not the first time that Europe has discussed its sovereignty in space, according to Ludwig Moeller, ESPI’s director. In 2023, an expert group released a report that noted Europe has “no independent human launch capacity” and “relies on non-European partners to send humans to space,” according to a press release about the report.
The NASA budget cuts are bringing up this discussion again, Moeller added, along with questions of how much Europe should be investing in security and defence.
“The two points, security, defence and exploration are both on the agenda to an extent that I don’t think in the history of Europe has ever existed,” he said. “This … disruption is unique.”
Part of the sovereignty discussion is how Europe is developing domestic supply chains to build the necessary hardware for NASA-vulnerable missions like the ExoMars, according to Daniel Neuenschwander, ESA’s director of human and robotic exploration in last weeks media briefing.
For example, Neuenschwander said that critical parts for the ExoMars rover, like an americium radioisotope heater unit (RHU) could be built in Europe to sustain future Moon missions.
Yet, Moeller said Europe is not ready to give up on a transatlantic relationship that is built on shared values.
“[Space exploration] really takes a village and the USA is still part of that village… in a different size, maybe in a different shape,” he said. “[But] Space exploration is a decadal task, it’s not a transaction of the day”.