Thirty Meter Telescope Gets Green Light to Resume Construction in Hawaii

Thirty Meter Telescope in Hawaii
Artist's illustration of the Thirty Meter Telescope on the volcano Mauna Kea in Hawaii. (Image credit: Courtesy TMT International Observatory)

A $1.4 billion telescope project has finally gotten the go-ahead to resume construction high up on Hawaii's Mauna Kea volcano.

The state's Board of Land and Natural Resources (BLNR) announced Friday (Sept. 29) that it has decided to approve a construction permit for the Thirty Meter Telescope (TMT), which has been in limbo for several years.

TMT broke ground in October 2014, but demonstrations the following spring halted the build. Protesters have cited concerns about the telescope project's cultural and environmental impact; Native Hawaiians regard peaks throughout the island chain as sacred. [Thirty Meter Telescope: Hawaii's Giant Space Eye (Gallery)]

Then, in December 2015, the Hawaii Supreme Court pulled TMT's original construction permit indefinitely, saying the BLNR granted it without properly addressing a petition filed by opposition groups. And in December 2016, a judge with Hawaii's Third Circuit Court ruled that a sublease agreement between TMT and the University of Hawaii was invalid because the BLNR allowed it without holding a "contested case hearing."

As this history suggests, a favorable ruling by the BLNR does not guarantee smooth sailing into the future for TMT. Indeed, opponents of Friday's decision are already planning to appeal it to the Hawaii Supreme Court, Sky & Telescope noted.

If building on Mauna Kea becomes impossible or impractical, the project could relocate to its backup site — the Observatorio del Roque de los Muchachos on La Palma, in the Canary Islands.

TMT will integrate 492 mirror segments into a single light-gathering surface 98 feet (30 meters) wide. When it's operational in the early to mid-2020s, the giant scope will be put to a variety of uses, from detecting and characterizing exoplanets to studying mysterious dark matter and dark energy, project representatives have said.

TMT is one of three ground-based megascopes scheduled to come online in the 2020s. The others — the Giant Magellan Telescope and the European Extremely Large Telescope — are both being built in the Chilean Andes.

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Mike Wall
Senior Space Writer

Michael Wall is a Senior Space Writer with and joined the team in 2010. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.