Facing uncertainties about the Thirty Meter Telescope’s future atop Hawaii’s tallest mountain, its board has decided to search for an alternative site in case it can’t build here in the next couple of years.

What’s more, Ed Stone, TMT executive director, said in an interview Wednesday that the $1.4 billion project will need assurances from the state that it can obtain a permit for unhindered construction on Mauna Kea no later than September 2017 — or it will take its next-generation telescope to another mountain.

Obtaining a permit by September 2017 will allow the TMT International Observatory Board to gather enough funding to launch construction in the spring of 2018, he said.

“We have to move on,” said Stone, a physics professor at the California Institute of Technology. “Hopefully, moving on can be done here. But time will tell whether that’s possible.”

TMT officials are now awaiting an outline for a new permitting process and projected timetable from the state after the Hawaii Supreme Court invalidated the project’s permit in December.

The state’s highest court ordered a new contested case hearing after ruling that the state Board of Land and Natural Resources violated the state Constitution by holding the hearing only after the project’s conservation district use permit was approved.

State officials have said they can’t provide a new construction timetable until the case is sent to the BLNR. The case is currently in the possession of Circuit Judge Greg K. Nakamura but is expected to move next week.

The state, meanwhile, is in the process of hiring a hearing officer for an anticipated new contested case.

Stone, meeting with the Honolulu Star-Advertiser Editorial Board on Wednesday, said the announcement about the alternative site search and timeline isn’t meant to apply pressure to the state but rather to let the public know where TMT stands.

“We have to have a plan. This is not a game. We’re not gaming it. We really need a place to build a telescope,” Stone said.

Part of the motivation, he said, is the desire to be the first to make the kind of important discoveries that only a cutting-edge telescope of this size and power can make.

The project has been billed as the most powerful optical telescope in the world, capable of seeing the origins of the universe more than 13 billion light years away.

“Science is about learning new things and it’s easiest to do when you are there first with a new instrument,” he said.

There are at least two other planned “extremely large telescopes” with which the TMT is in competition for these discoveries.

“In science, timing is important,” he said. “Having a new instrument is very important to being at the forefront of research. And we feel we’ve got to move on. Building a telescope 10 years from now is a totally different science return than building it now.”

Stone said the search for a “Plan B” will take the better part of a year and will consider both access and quality as a place to conduct high-level astronomy.

He said mountains in both the Northern and Southern hemispheres will be considered, including Cerro Armazones, the mountain in Chile’s Atacama Desert that was announced as the TMT’s runner-up location in 2009.

“There are lots of good mountains in Chile. We don’t know if they are available or not … ,” he said, but “I’m confident we can find a place. More than one, actually.”

Stone said the telescope, with more than $170 million already invested, can be easily relocated with its current design.

The TMT partnership of the University of California and Caltech plus the national research organizations of Japan, India, China and Canada still prefers Mauna Kea, he said, describing the 13,796-foot mountain as a “noticeably better” place for astronomy than any other location previously evaluated.

“It’s the best site in the Northern Hemisphere,” he said.

Stone said the TMT board appreciates the “firm support” of Gov. David Ige and others in the state. He also acknowledged that while state officials can provide assurances, they can’t make guarantees as some events and processes are out of their control.

“That’s why we need to have a Plan B in place,” he said. “It took us five years on the first go-round (contested case hearing). We do not have another five years. It has to be. There is no time to go back to square zero.

“The question is: Is there a way to do it? Is there a way to do this that will actually pass the test of the Supreme Court? Is there a way that will allow us to work on the mountain even though there is a suit, because there is surely going to be another appeal. And can we start, nevertheless?” he said.

Project foes have promised to oppose and appeal the telescope at every step. In addition, they have vowed to block construction crews, as they did successfully on three occasions last year, if the TMT wins approvals once again.

Asked if TMT is willing to make more concessions to the telescope’s opponents, Stone responded: “It’s not clear that some of them want concessions.”

Stone said the project has already offered more than any other telescope on the mountain. That includes: $1 million a year to underwrite a fund for students of science, technology, engineering and math; a $1 million investment in an initiative supporting low-income and first-generation college students; and a commitment to a lease rent of $1 million annually, with 80 percent going to mountain stewardship by the Office of Maunakea Management and 20 percent to the Office of Hawaiian Affairs.

The loss of TMT would also have dramatic and long-term repercussions on the state’s astronomy industry and the University of Hawaii’s Institute for Astronomy, he predicted.

“It’s important for Hawaii. It’s important for the U.S.,” he declared.

In the meantime, delays are driving up the cost of construction, adding 3 percent or 4 percent per year, he said.

“We really need to start building this telescope or forget it,” he said. “And none of us, having spent that amount of money, want to just walk away and forget it.”