Activists who have opposed the planned Thirty Meter Telescope atop Maunakea for over a decade want project backers to know that their resistance has not dimmed.

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Activists who have opposed the planned Thirty Meter Telescope atop Maunakea for over a decade want project backers to know that their resistance has not dimmed.

Leaders of the local movement against TMT on Monday sent a seven-page letter to project organizers warning them that continuing efforts to build the telescope on the Hawaii island mountaintop would be met with more opposition.

“Any attempt to construct the Thirty Meter Telescope on Maunakea in Hawaii would be an extremely poor decision and bad investment,” the letter said. “The project would face sustained and significant opposition, creating serious programmatic, financial, legal, and reputational risks.”

The letter, framed as a notice to “cease and desist” pursuit of building TMT on Maunakea, also referenced a change.org petition that at one point Tuesday had 500,527 signatures. The global online petition opposing TMT on Maunakea was started by a group called Maunakea Education and Awareness in 2019, and in its first week or so had attracted roughly 152,000 signatures.

Monday’s letter was sent under the umbrella of Pu‘uhonua o Pu‘uhuluhulu, the name of a resistance camp formed in 2019 around an access road to the mountaintop where several thousand protesters gathered and 38 were arrested for blocking construction vehicles from delivering equipment needed to start building the observatory.

The protest at the time ended in a standoff, and both sides retreated.

Since then, a consortium of science institutions doing business as TMT International Observatory has been exploring a potential alternate site for TMT in Spain’s Canary Islands, but has not ruled out trying to develop the project on Hawaii’s tallest mountain, which many Native Hawaiians view as a sacred place that would be further desecrated by another observatory.

In October, Gov. Josh Green pledged in a letter to consortium leaders to help establish a procedure to permit construction of TMT on a Maunakea site that had been previously developed for observatory use, instead of an undisturbed area as originally planned.

Green said he and officials in his administration would work with the state Maunakea Stewardship and Oversight Authority and the University of Hawaii to establish a clear and transparent procedure for obtaining necessary permits associated with a decommissioned telescope site.

The governor’s letter followed a presentation to the authority’s board in Hilo in September by TMT project manager Fengchuan Liu, who told board members that the entity trying to develop the roughly $3 billion telescope will consider redevelopment of a former telescope site, including where the Caltech Submillimeter Observatory had been until 2024.

Caltech is one of the partners trying to develop TMT, along with the University of California and science institutions from Canada, Japan and India. The developers also have sought major funding from the National Science Foundation for TMT, parts of which are still in a design phase.

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At the authority’s April board meeting, an update was slated to be given by Liu on the status and feasibility of developing TMT on a decommissioned Maunakea observatory site. Neither minutes nor a video of the meeting were available Tuesday on the authority’s website.

TMT International Observatory, based in California, did not respond to requests for comment on the opposition letter Tuesday. The organization on its website said that the decision about whether to move ahead with TMT on Maunakea, its preferred site selected in 2009, “ultimately rests with the Hawaii and Native Hawaiian communities.”

Copies of the cease and desist notice were sent to the authority and to the University of Hawaii.

UH said in a statement that it is transitioning from a steward to a tenant on Maunakea as directed under a 2022 state law that established the board-led authority to assume complete management of a long-­established astronomy precinct on the mountain from UH, and to establish a framework for astronomy-related development there, following a five-year transition period.

“The university is no longer involved in any future plans on the Mauna,” UH said. “The University of Hawaii continues to believe that the Thirty Meter Telescope has the potential to bring meaningful educational, scientific and inspirational benefits to Hawaii and to advance world-class astronomy from Maunakea. At the same time, we recognize that the future of TMT and astronomy largely rests with the community and the Maunakea Stewardship and Oversight Authority. We remain hopeful that a respectful path forward can be found.”

A representative of the authority, which is attached to the state Department of Land and Natural Resources, could not be reached for comment Tuesday to respond to the opposition letter. DLNR said it is aware of the document and is reviewing it, but did not have any additional comment Tuesday.

TMT, described as astronomy’s “next generation” observatory, was initially slated for construction on Maunakea in 2015 but was halted that year initially by protesters who blocked construction vehicles.

A further setback due to a legal challenge over permitting wasn’t overcome until 2018, but construction was blocked again in 2019 by protesters who occupied the summit access road for eight months.

Monday’s letter said any narrative that support for TMT is rising among Hawaiians is grossly inaccurate, and that “every attempt to advance construction has faced galvanized and sustained resistance from thousands of Maunakea protectors, with no indication that future efforts would proceed differently.”

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