The European Space Agency has begun mitigation efforts for key elements of its LISA mission after a White House budget proposal sought, for the second year running, to eliminate most of NASA’s planned support. One of these mitigation efforts was formalised on 5 May, when ESA awarded a €26.1 million contract to Thales Alenia Space for the development of the mission’s telescopes.
ESA’s Laser Interferometer Space Antenna (LISA) consists of three spacecraft working in tandem to detect gravitational waves from significant events in the Universe, such as when two black holes collide. When ESA adopted the mission in early 2024, NASA was expected to provide several critical LISA subsystems, including laser systems, telescopes, and devices to reduce disturbances from electromagnetic charges.
In May 2025, just months after Donald Trump took office, the White House’s proposed FY2026 NASA budget sought to cut the agency’s science funding by almost 50%, which included eliminating the agency’s support for ESA’s LISA mission. While Congress later rejected the proposal and allocated $80.5 million for the mission, the White House has once again proposed cutting the majority of NASA’s support in its FY2027 budget. The request includes just $2.4 million for Physics of the Cosmos Supporting Research and Technology, which would support technology development efforts for several missions, including LISA.
In June 2025, following ESA’s 334th Council meeting, the agency’s Director of Science said ESA had identified 19 missions that could be affected by the proposed NASA budget cuts. She said the impact on 16 of those missions could be mitigated through “good planning”, while three, LISA, EnVision, and NewAthena, would require specific recovery actions. Although Congress later rejected the proposed cuts, ESA nonetheless moved ahead with recovery actions as uncertainty over NASA’s long-term support remained unresolved.
On 30 September 2025, ESA issued a call for proposals covering the development of LISA’s telescopes. The agency outlined a four-phase development process that would begin with initial testing of a breadboard model, followed by delivery of a qualification model, one flight-ready telescope, and, finally, telescopes for all three spacecraft. Each phase includes decision points, allowing time for NASA to resolve uncertainty around its commitments while still enabling ESA to pursue European replacements. On 5 May 2026, Thales Alenia Space announced that it had been awarded a contract to begin the first phase of LISA telescope development.
In response to questions from European Spaceflight, ESA explained that, while NASA was still involved in the mission, ongoing budget uncertainty had prompted the mitigation actions.
“NASA is still involved in LISA, but budget discussions are ongoing. We have been informed that some projects may be impacted,” explained an ESA spokesperson. “In light of this, ESA has taken the decision, supported by our member states, to initiate risk mitigation actions on LISA. This TAS contract is the result of one of the actions.”
A representative of NASA’s Goddard Space Flight Center, which is responsible for developing LISA’s telescopes, said NASA remains committed to its contributions but did not address the funding issue.
“NASA recognizes the importance of our partnership on the ESA-led LISA mission to both agencies and remains committed to our contributions, as specifically supported by NASA’s FY26 appropriations legislation,” explained the representative. “Under the appropriations, NASA continues to make progress on all of its planned contributions to LISA, which include the telescope and other systems. NASA now has contracts in place with U.S. industry partners to advance those systems. The agency also has recently passed a number of major milestones in the mission, including a successful Key Decision Point and completed tests of prototype hardware.”
The Thales Alenia Space telescope contract is one of several planned mitigation efforts. A tender for a European-developed Charge Management Device (CMD) was announced in November 2025. The call explains that the agency’s executive considers it “prudent to take action now to limit any potential damage to the programme stemming from the unstable situation with NASA.” The CMD initiative is currently under evaluation, suggesting an award is imminent.
Update: This article was updated on 14 May to include the statement from NASA’s Goddard Space Flight Center.
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