A 25 percent reduction in NASA’s budget proposed by the Trump administration is set to curtail spending on several science programmes and redirect human-spaceflight resources toward the Moon. The plan, which still requires congressional approval, would scale back or cancel multiple planetary missions and mothball operating spacecraft. Europe’s long-delayed ExoMars mission is among the most exposed projects. NASA had agreed last year to supply three pieces of hardware that Europe does not yet have in flight-ready form—a heavy-lift launcher, a throttleable descent propulsion system and radio-isotope heater units—to allow ESA’s Rosalind Franklin rover to reach Mars and survive the planet’s frigid nights. Without those U.S. contributions, ESA officials and industry partners warn the rover is unlikely to meet the next launch window in 2028. Missing that slot would push liftoff to 2030 or 2031, forcing costly redesigns because each Earth-Mars alignment demands different entry, descent and landing parameters. ESA member states will review funding options at a ministerial meeting in Bremen this autumn, but agency sources say hundreds of millions of euros would be needed for Europe to develop the missing technologies on its own. The ExoMars programme, first conceived in 2003, has already lost three launch opportunities—initially through NASA’s 2012 withdrawal and later after Russia’s cooperation ended in 2022. A new delay would threaten Europe’s first attempt to drill two metres below the Martian surface for signs of ancient life, a scientific objective proponents describe as still unique despite the rover’s aging hardware.