European Space Agency reveals 3 key space missions threatened by Trump's NASA budget cuts

The European Space Agency (ESA) has revealed that three of the 19 missions it is planning or operating in collaboration with NASA are at risk as a result of President Trump's proposed budget cuts, which could slash finances available to the U.S space agency by 24%.

During a press conference held on Thursday (June 12), ESA Director of Science Carole Mundell revealed that the space-based gravitational wave observatory LISA, the Venus orbiter EnVision, and the largest X-ray observatory ever planned, NewAthena, could be threatened if the proposed NASA budget cuts in Trump's FY26 budget go ahead.

ESA thinks that at this initial stage, the impact can be mitigated on the other 16 missions in collaboration with NASA, but the remaining three missions may require a rethink if they happen at all. "We're looking at three potential missions that, should the budget proposal come to pass as written, would require recovery actions. That's LISA, EnVision, the NewAthena," Mundell said.

ESA Director General Josef Aschbacher added: "This is an ongoing negotiation in the United States. It is not for us as ESA to comment on these negotiations or to interfere, but we are impacted in quite a number of domains that are, at least at the moment, proposed for cancellations or reductions.

"This will require that some of the activities may be frozen. No decisions or cancellations have yet been made because the decisions on the side of the U.S. are not yet finalized. We need to wait for the final decisions from the U.S."

Mundell continued by underlining how deeply ESA values the collaboration between Europe and NASA, but added that Europe does have or could acquire the technical capabilities to reduce to reproduce missing elements.

"That's something that we're now working through," she added.

The number of missions that could be threatened if ESA is forced to repurpose funds extends beyond the three missions mentioned above.

Though the Nov. 16, 2025 launch of the sea-level rise monitoring Sentinel-6B spacecraft will go ahead as planned, its sibling mission, Sentinel-6C, could also be impacted by the proposed budget cuts if they are passed successfully.

"It was my proposal when I was director of Earth observation, to rename a satellite Sentinel-6 Michael Freilich [after former director of the Earth Science Division in the Science Mission Directorate at NASA Headquarters from 2006 to 2019]," Aschbacher added. "It would be a pity if Sentinel-6C were not funded or supported, as it is a successor of the mission Michael Freilich, which is still in space. We offered our satellite to be named after a NASA Administrator as a very visible sign of the of the deepness of the cooperation between NASA and ESA."

Proposed U.S. budget cuts could also impact the planned Mars rover Rosalind Franklin, previously known as the ExoMars rover. That is because the robotic explorer named after the esteemed British chemist was set to feature several components supplied by NASA.

ESA may now seek to develop on its own the technologies for the three main elements of the rover set to be provided by NASA: its launcher, radio isotope heater unit, and aerobraking engine. This will take time and may impact the mission's timeline, which would have seen Rosalind Franklin head to Mars in 2028.

Of course, nothing is yet set in stone, with the U.S. Congress yet to have the final say on how to allocate federal dollars. A final decision on the FY 2026 Discretionary Budget is expected in Fall 2025. Meanwhile, ESA will meet in late November to finalize its own budget. This means that the space agency may have to move ahead with contingency planning and budgeting before the final outcome of proposed U.S. budget cuts is known.

"The timing is expected to be maybe just before decisions are being made, and the fiscal year 26 budget will be known for sure. We need to assess on one side, how much it costs to wait, and how long we can wait," Aschbacher said. "There is a lot of analysis and options that need to be verified and need to be discussed.

"In brief, the main highlight, or the main point, is that we have agreed to make sure that Europe is increasing its resilience and autonomy to make sure that we have the technologies we need in the near future."