The European Space Agency is moving “full steam ahead” with development of a robotic mission to Venus after NASA officials determined they were unlikely to fulfil a commitment to provide a US-built radar instrument for the spacecraft, according to the mission’s project scientist.
The European orbiter, named Envision, will map the Venusian surface at 10 times higher resolution than the last radar mission NASA sent to Venus in the 1990s. The planet is shrouded in thick clouds of sulfuric acid, rendering its mysterious surface unseen by optical cameras in orbit. Radar is the most effective way to penetrate these clouds and reveal the terrain below, and scientists will use Envision to look for signs of active volcanism.
NASA and ESA signed a memorandum of understanding in 2024 outlining their partnership on Envision. NASA agreed to supply a US-made synthetic aperture radar instrument, Envision’s primary means of mapping the surface of Venus, along with tracking and communications support through its Deep Space Network. In exchange, ESA would include US researchers on the mission’s science team. Europe would build the spacecraft and the rest of its science instruments and provide the launch on an Ariane 6 rocket.
Budget Pressures Reshape NASA Partnerships
NASA’s budget for science missions has come under pressure from the Trump administration, which proposed slashing the agency’s science funding by nearly half in fiscal years 2026 and 2027. Congress rejected most of the cuts in 2026, passing a budget with around £1.9 billion for NASA’s planetary science division, well above the White House’s request but roughly £165 million short of the previous year’s funding.
That reprieve saved several key science missions, including one of NASA’s own Venus missions, DAVINCI, designed to send an entry probe into the planet’s crushing atmosphere. However, the shortfall is forcing NASA managers to make difficult decisions. The primary targets for cuts are funding for operating missions, especially those well beyond their original design lives, and support for partnerships on international missions.
International Missions Feel the Impact
Among the most prominent cuts are NASA’s contributions to three European-led science missions. Two are large new space-based observatories, LISA and New Athena. LISA will be the first space mission to measure gravitational waves, ripples in the fabric of spacetime emanating from cataclysmic cosmic events such as mergers of black holes. New Athena will be the largest X-ray telescope ever built, a successor to NASA’s Chandra X-ray Observatory, which remains operational after launching in 1999. Before NASA’s contributions were in doubt, LISA and New Athena were on track for launches in the late 2030s.
The most pressing challenge for ESA is how to fill the void left by NASA in the Envision mission, which was scheduled to launch in 2031. NASA and ESA signed an agreement in early 2024 detailing each partner’s role, and contracts were awarded for construction of the spacecraft and its instruments. NASA had spent more than £39 million on its contributions to the mission as of 2025, when the Trump administration first proposed cancelling it.
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Image: arstechnica.com
