Spain has offered to spend up to €400 million ($471 million) to host the Thirty Meter Telescope, an enormous observatory project facing imminent cancellation due to U.S. budget constraints.
If Spain strikes a deal, the TMT would be built on La Palma in the Canary Islands rather than on Mauna Kea, a mountain in Hawaii. In 2016, La Palma became the backup location for the observatory in case the primary site in Hawaii didn’t work out as an option, according to the TMT International Observatory. Now more than ever, it looks like that may be the case. President Donald Trump’s Fiscal Year 2026 budget proposal for the National Science Foundation (NSF), which is funding the TMT’s development, would reduce the agency’s budget by nearly 60%. To make ends meet, the NFS has opted to halt progress on the TMT and instead prioritize development of the Giant Magellan Telescope (GMT) project in Chile.
Now that U.S. investment in the TMT has been thrown into question, Spain is chomping at the bit to take over the project. On July 23, Diana Morant, the Minister of Science, Innovation and Universities in Spain, announced that the Spanish government is willing to pay hundreds of millions of dollars to move construction of the telescope to La Palma.
“Spain wants and can be the home of the future of astronomy and astrophysics,” Morant said, according to a statement translated from Spanish. “We have the capacity and the political will to do so.”
The TMT would bring significant scientific value to Spain. With its nearly 100-foot-wide (30-meter-wide) light-collecting mirror, this optical telescope would be one of the largest in the world. It’s one of three huge ground-based telescopes currently in development, including the GMT and the European Extremely Large Telescope (ELT). Spain already contributes to the ELT—the largest of the three telescopes. Once complete, these huge observatories will allow astronomers to study the cosmos with extremely high resolution.
In response to Morant’s announcement, the TMT International Observatory said there has not been a final decision about the telescope’s future at its primary site in Hawaii. Whether Trump’s budget proposal actually passes will likely be the deciding factor, and there’s reason to believe that it won’t. Congress has shown signs that it would broadly resist NSF budget cuts, according to Inside Higher Ed.
Still, the project faced significant hurdles long before Trump’s second term, largely due to mounting federal pressure on the NSF to cut costs by pursuing one major telescope project instead of two. The TMT has also been mired in controversy due to the fact that its primary construction site is located on a sacred Hawaiian mountain. In 2019, thousands of protestors gathered on the Mauna Kea Access Road to halt construction of the telescope, according to the Honolulu Civil Beat. TMT developers chose this site for its exceptionally dark, light pollution-free skies, making it a premier vantage point from which to observe the cosmos. There are already 13 astronomical observatories seated atop this mountain.
La Palma isn’t as advantageous. The Spanish site sits at a significantly lower altitude than Mauna Kea, which means the telescope would have to peer through more layers of the atmosphere. This would lower the quality of observations, according to Nature News.
If the U.S. moves forward with the proposed NSF budget, that may be a sacrifice worth making. Spain certainly seems to think so. “Faced with the risk of paralyzing this major international scientific project, the Spanish government has decided to act with a redoubled commitment to science and major scientific infrastructures for the benefit of global knowledge,” Morant said.