The Process

/The Process


The TMT International Observatory LLC (TIO), a non-profit organization, was established in May 2014 to carry out the construction and operation of the TMT Project. The Members of TIO are Caltech, UC, the National Institutes of Natural Sciences of Japan, the National Astronomical Observatories of the Chinese Academy of Sciences, the Department of Science and Technology of India, and the National Research Council (Canada); the Association of Universities for Research in Astronomy (AURA) is a TIO Associate. Major funding has been provided by the Gordon & Betty Moore Foundation. This project is a remarkable demonstration of international collaboration and will transform the way we think about the universe and our place in it.

It began with a dream: To build a revolutionary 30-meter telescope to study the beginnings of the universe in the most optimal place in our Northern Hemisphere. After an extensive site testing campaign, Maunakea in Hawaii emerged as the preferred site. Located above approximately 40 percent of Earth’s atmosphere, Maunakea has a climate that is particularly stable, dry, and cold; all of which are important characteristics for capturing the sharpest images and producing the best science. In addition, the atmosphere over Maunakea offers exceptional conditions for astronomical measurements with adaptive optics, which will be equipped on TMT.

Maunakea is also of cultural, historical and environmental significance to many Native Hawaiians and others in Hawaii. Located 500 feet below the summit, TMT’s site was chosen because of its lack of archaeological, cultural or biological impact. It was also selected in response to concerns from Native Hawaiians that there be no more development on the summit of Maunakea and its puu (peaks), as these cultural areas need to be protected. TMT is already minimizing its impact on this special place. Environmental considerations include use of a special reflective aluminum-like coating to reduce the visibility of the structure as well as a commitment to leave zero waste.

Community outreach and engagement are part of the core mission of TMT. Past community outreach efforts have included pandemic relief and a focus on education. For example, TMT launched The Hawaii Island New Knowledge (THINK) Fund in 2014 to better prepare Hawaii Island students for careers in STEM. TMT also initiated a Workforce Pipeline Program, funding summer internships, STEM camps, Robotics, community events and other programs to help Hawaii Island students achieve success at becoming lifelong learners. Future efforts will continue to build on the most successful programs of the past and evolve with the changing educational, social and economic environment on Hawaii Island.

The journey to build the Thirty Meter Telescope in Hawaii has been challenging at times. While the project has meticulously followed the detailed planning and permitting process laid out by the State of Hawaii, TMT’s renewed focus is an effort to connect more meaningfully with the Hawaii community.


Download a PDF of the TMT Timeline here.

JUNE 1, 2003

Founding of TMT Observatory Corporation by the Association of Canadian Universities for Research in Astronomy (ACURA), the University of California (UC), and the California Institute of Technology (Caltech).

APRIL 1, 2005

Creation of the TMT Project Office

JANUARY 1, 2008

The National Optical Astronomy Observatory of Japan (NAOJ) joins TMT

MARCH 1, 2009

Completion of Design Development Phase (DDP)

APRIL 1, 2009

State of Hawaii Land Board Approves Comprehensive Management Plan for Maunakea

JULY 1, 2009

TMT Board of Directors Selects Maunakea as Preferred Site

NOVEMBER 17, 2009

The National Astronomical Observatories of the Chinese (NOAC) Academy of Sciences and the Indian Institute of Astrophysics (IIA) join TMT as observers

MAY 1, 2010

Maunakea Management Board Approves TMT Project

Completion of the Environment Impact Statement in Hawaii

JUNE 1 , 2010

University of Hawaii Board of Regents Approves TMT Project


Maunakea Management Board Approves Conservation District Use Permit Application

FEBRUARY 1, 2011

TMT granted its Conservation District Use Permit (CDUP)

APRIL 1, 2012

State of Hawaii Board of Land and Natural Resources issues CDUP (4/12)

APRIL 1, 2013

TMT obtains building permit

MAY 1, 2014

The Kahu Ku Mauna Council, made up of local Native Hawaiian cultural practitioners, and the University of Hawaii Board of Regents approve the University of Hawaii granting a sublease to TMT to build on Maunakea

MAY 6, 2014

Formation of TMT International Observatory LLC (TIO)

OCTOBER 7, 2014

Ground blessing ceremony for the TMT site.

DECEMBER 2, 2014

India formally joins TMT as a member of the TMT International Observatory

MARCH 1, 2015

The Hawaii State Department of Land and Natural Resources issues TMT a Notice to Proceed

MAY 5, 2015

Temporary stand-down issued by Governor of Hawaii

DECEMBER 2, 2105

Hawaii Supreme Court invalidates the Conservation District Use Permit

On December 2, 2015, the Hawaii Supreme Court invalidated the Conservation District Use Permit issued by the Board of Land and Natural Resources (BLNR) to the University of Hawaii – Hilo to build TMT on Maunakea.

MAY 1, 2016

Alternate site study begins

OCTOBER 20, 2016

New contested case hearing begins in Hawaii

DECEMBER 15, 2016

Sublease vacated by Third Circuit Court

JULY 26, 2016

State Hearings Officer and former Judge Riki May Amano releases a 305-page report recommending that a Conservation District Use Permit (CDUP) be issued.

SEPTEMBER 28, 2017

The State Land Board announces its decision to approve the Conservation District User Permit (CDUP) for TMT to be built on Maunakea.

OCTOBER 30, 2018

Hawaii Supreme Court Affirms TMT Permit

The Hawaii Supreme Court, by majority decision, today issued its opinion affirming the Board of Land and Natural Resources’ decision to issue a Conservation District Use Permit (CDUP) for construction of the Thirty Meter Telescope (TMT) on Maunakea.

JUNE 6, 2019

Enclosure Pre-ship review

JUNE 20, 2019

Notice to proceed issued by Hawaii Department of Land and Natural Resources

JULY 10, 2019

Gov. David Ige and the Thirty Meter Telescope International Observatory (TIO) announces that construction of the Thirty Meter Telescope (TMT) will begin the week of July 15, 2019.

JULY 15, 2019

Efforts to restart construction stalls

DECEMBER 19, 2019

Gov. David Ige announces that the state will reduce its law enforcement personnel on Maunakea.


TMT, along with its other partners in the US-Extremely Large Telescope Program presents their technical readiness to the Astro2020 survey panel.

JUNE 2021

Project Manager Fengchuan Liu relocates to Hilo, Hawaii