Opponents warn Thirty Meter Telescope to stay off Maunakea

Opponents of the Thirty Meter Telescope used a seven-page cease-and-desist letter to put project organizers on notice that any attempt to build the roughly $3 billion observatory on Maunakea will face sustained resistance. The letter warns of serious programmatic, financial, legal and reputational risks, turning a long-running protest into a fresh warning at a moment when the project’s path forward is already unsettled.

The timing matters because the real power over Maunakea is shifting. The Maunakea Stewardship and Oversight Authority, created by Act 255 in 2022, is set to take over summit management from the University of Hawaii. The transfer was first discussed as June 2028 and later pushed to December 2029, placing the authority at the center of any future decision on telescope development, decommissioning or reuse of sites on the mountain. For now, that means the next major gatekeeper is not the university, but the new board that will inherit responsibility for the summit.

The legal backdrop is already heavy. In 2017, Suzanne Case, then chair of the Board of Land and Natural Resources, granted the University of Hawaii at Hilo a conservation district use permit for TMT. Opponents later challenged whether the project met permit conditions and deadlines. In June 2024, the Hawaii Supreme Court ruled the state broke the law when it took control of the Maunakea Access Road and turned it into a state highway before the 2019 protests. A separate 2024 ruling said the designation took almost all property rights from the Department of Hawaiian Home Lands.

TMT’s financial position has also weakened. The National Science Foundation withdrew support in its fiscal year 2026 budget plan, adding uncertainty to the project even as project manager Fengchuan Liu told the board the telescope could still work if it moved to the former Caltech Submillimeter Observatory site, which was fully dismantled in 2024. That alternative would keep construction off the summit while still testing whether a compromise location can survive political and regulatory scrutiny.

Opponents have made clear they see no compromise on the mountain itself. Their movement has been active since at least 2014, and in April 2015, 31 people were arrested after blocking the Maunakea Access Road to keep construction crews away from the summit. By Tuesday, a Change.org petition tied to the dispute had reached 500,527 signatures, showing how far the issue still reaches beyond the Big Island. The cease-and-desist letter does not end the fight, but it sharpens the question now facing Maunakea governance: who can move the project forward, and who has the power to stop it.