The broad-shouldered summit of Mauna Kea holds many meanings for many people: For astronomers, it’s a high-altitude playground of stars, among the best places on Earth to explore the firmament with minimal atmospheric distortion. For environmentalists, it’s a “sky island ecosystem” that hosts rare and altitude-sensitive species, including the wekiu bug found nowhere else in the world. For Hawaiian spiritual practitioners, it is the home of gods, the most holy place on Hawaii’s big island.

As vast as its expanses of ice and lava are, Mauna Kea has not proved sizable enough to accommodate the desires of all three groups. The dormant volcano has become a battleground between astronomers, who have placed 13 telescopes at its summit and now wish to build one more, and Hawaiian cultural and environmental activists who believe the stargazing science has already had too much impact on the 4,205-meter-high mountain.

Two lawsuits are in motion over the California Institute of Technology and the University of California’s proposal to build the Thirty Meter Telescope (TMT); in October activists shut down the project’s groundbreaking in a protest that made headlines worldwide. So far, courts have ruled in favor of the telescope and construction has recently begun. Activists have appealed and say they will continue to protest.

For astronomers, the proposed new telescope represents tremendous promise: With a mirror nearly three times larger than any other on Earth, it could detect signs of life in other solar systems and provide clues to the origins of the universe. But for some Hawaiians, it represents the ongoing desecration of a sacred place. Ancient Hawaiians considered the volcano the umbilical cord connecting the land to the heavens and used the mountain as a site of burials, altars and worship; thousands of shrines and other cultural artifacts have been recorded on the Mauna Kea and many are still tended by Hawaiian families. Fishermen still make offerings at the volcano for a good catch and hunters still fan across its forested skirt in search of prey.

Kealoha Pisciotta, one of a half dozen plaintiffs suing to stop the project, finds herself in the unusual position of having friends on both sides of the debate. She was a telescope systems specialist technician on the James Clark Maxwell radio telescope for 12 years. Meanwhile, she maintained a family shrine near the summit and led a cultural heritage group. “I descend from Polynesian navigators, people who carry the star knowledge, so in the beginning I didn’t see the conflict between telescopes and the mountain,” Pisciotta says. “I only began to see it later when there were problems—people looting antiquities from the mountain, building these bigger telescopes that really affected the landscape, and destroying important landmark features.”

The amount of development at the summit is among the activists’ complaints. As the summit has been carved up by roads and studded with buildings, the awesome beauty of the once-stark landscape has diminished, Pisciotta says. Some of the telescopes can now be seen by 72 percent of the island’s population, according to an environmental impact document. Environmentalists have their own bone to pick with the project, arguing the development has already harmed the habitat of the wekiu bug and other endemic flora and fauna, and limited recreational uses.

Project managers say the new telescope has been carefully designed to avoid these impacts. Although the TMT will loom 18 stories high, making it the largest building on the island, it will be visible only from 15 percent of the island and will touch only 0.08 hectare of the bug’s habitat.

If activists were to succeed in stopping TMT, it wouldn't be the first time: In 2002 a federal court blocked a NASA plan to build a half dozen 1.8-meter telescopes on the mountain because it failed to do a comprehensive environmental assessment; NASA eventually abandoned the project.

Two other U.S. mountaintops have become combat zones between astronomers and activists. In the late 1980s astronomers at the Mount Graham National Observatory in Arizona faced opposition to a new telescope from squirrel-protecting environmentalists and from the San Carlos Apaches, who perform religious ceremonies on the mountain. Astronomers eventually won, but the delays forced them to downsize their project. In the 2000s the Kitt Peak Observatory, built on the tribal reservation of the Tohono O’odham Nation, became the site of another clash. In 2005 the tribe successfully put a stop to a new $13-million telescope complex at the observatory.

When these conflicts arose, says Leandra Swanner, a science sociologist and historian at Arizona State University in Tempe, astronomers “felt blindsided.” They were accustomed to considering themselves the underdogs, continually embattled for funding and support. The astronomy community initially dismissed indigenous claims as spurious, antiquated and antiscience, a perspective that is still prevalent. In a column in The New York Times last October science writer George Johnson likened Hawaiian’s opposition to the telescope to the Catholic Church’s oppression of Galileo, and suggested that the indigenous protesters were pawns of environmentalists who “have learned that a few traditionally dressed natives calling for the return of sacred lands can draw more attention than arguments over endangered species and fragile ecosystems.”

Plantiff Pisciotta bristled at these implications, saying native groups have every right to make claims, and can do so without being antiscience. She noted that plaintiffs have invested tens of thousands of their own dollars into the campaign because it is of deep personal importance to them.

TMT leaders have been more careful than their predecessors and have taken the opposition seriously, by trying to gain public support for their project. TMT spokesperson Sandra Dawson says her team had more than 300 “talk–story sessions”—the Hawaiian pidgin term for dialogue—with community members over the course of several years, including half a dozen well-attended public hearings, and that by their estimates well over half the island’s population supports the project. They collected thousands of pages of testimony and conducted an extensive environmental and cultural impact review that have so far been met with approval from Hawaii’s land board and its courts.

Banana farmer and Hawaii Island Economic Development Board member Richard Ha, who is part Hawaiian, says he was initially ambivalent about the new telescope but now supports it. That support was won when TMT leadership promised $1 million a year to the island’s public schools. But more importantly, he says, project leaders have treated islanders with respect. “The first thing they did right was talk to the community,” he says. “That was a huge deal, because prior to that they would make decisions at a high level and people would just have to deal with it.”

Nevertheless, the project still faces considerable opposition. In October the number of people who showed up to protest at the telescope’s groundbreaking ceremony—protesters estimate around 500—took telescope supporters by surprise, and suggests there may be resilience to the opposition. That momentum may derive in part from a renewed appreciation of Hawaiian heritage as part of a “new Hawaiian renaissance,” as protester Joshua Lanakila Mangauil put it. He says efforts to protect Mauna Kea are one vein of that renaissance. “Hawaiians are learning the laws that were used against us,” he says. “We’re learning the legal game. We’re using it to reclaim our people and our islands and our culture.”

After about 50 protesters lay across the road and later stormed the ceremony the groundbreaking was aborted. Its master of ceremonies concluded, “We do hope we’ll be able to find a common ground and proceed with this in the future.”

But TMT’s Dawson says they later decided not to reschedule the event. “We will have no more ceremonial events,” she says. “We will just move forward.”