First telescope decommissioning complete on Maunakea on Big Island

A historic milestone has been reached on the summit of Maunakea on the Big Island, as the first observatory on the summit has been completely removed and the site restored.

The decommissioning of the University of Hawaiʻi at Hilo’s Hōkū Keʻa Observatory was completed in May, and the area will be monitored over the next three years to assess species population and diversity.

Once the decommissioning of the Caltech Submillimeter Observatory (CSO) is completed later this year, the University of Hawai‘i will have honored the commitment made to the University of Hawai‘i Board of Regents in 2023 to remove two telescopes before the Maunakea Stewardship and Oversight Authority assumes full management of the summit lands by July 1, 2028.

The University of Hawai‘i at Hilo Center for Maunakea Stewardship (CMS) jointly manages Mauna Kea with the Maunakea Stewardship and Oversight Authority and is overseeing both decommissioning projects.

“Maunakea warrants the highest levels of stewardship, and we remain steadfast in our collaborative efforts to honor and protect the cultural and environmental significance of this ʻāina,” said University of Hawai‘i at Hilo Chancellor Bonnie Irwin. “The removal of Hōkū Keʻa reflects the university’s ongoing pledge to reduce the presence of telescopes on Maunakea.”

The decommissioning work began in April and cost approximately $1 million. The deconstruction of two buildings and the associated infrastructure and site restoration were done in accordance with the decommissioning process required by the Mauna Kea Comprehensive Management Plan.

“The process to remove Hōkū Keʻa and CSO is being done in a way that is pono to this special place as the construction crews received training on Maunakea’s history, cultural significance, environmental and cultural resources, and health and safety,” said CMS Executive Director Greg Chun. “A ceremony was conducted prior to the deconstruction phase and will be conducted again at the projectʻs conclusion and restoration phase.”

Prayers and Native Hawaiian protocol opened and closed each work day. Hawaiʻi Island resident Karl Halemano oversaw both construction and cultural monitoring on site throughout the decommissioning. Morning protocol led by Halemano included E Ala Ē, a chant that welcomes the day.

“We would go up to the site and we would have a pule, oli, mele or just oli and we would start our day so that way we can move forward with a sense of spirituality, the importance of the work we’re doing up there,” Halemano said.

It took six dump trucks and nine trailer loads to remove the debris after the structures were taken down. Fill that had been stored at the summit from when the observatories were first built was used for the site restoration.

CMS received approval for the Conservation District Use Application for the project from the Hawaiʻi Board of Land and Natural Resources in 2023.

A final environmental assessment in June 2022 found that the project would have no significant adverse environmental impacts.

Preparation of the assessment included consultation and outreach with the Native Hawaiian community through the preparation of a cultural impact assessment; meetings with Kahu Kū Mauna (Guardians of the Mountain, a volunteer community-based council); and direct outreach to the Office of Hawaiian Affairs along with other native Hawaiian organizations and stakeholders.

Decommissioning of CSO is scheduled to be completed by fall 2024. The CSO building and telescope have already been removed, and crews are now working to remove the concrete foundations, pavement, underground utilities and cesspool.

Located on the southeastern slope of the summit, the Hōkū Keʻa Observatory served as a cornerstone in training UH astronomy students for decades. It was built by the U.S. Air Force in 1968 and was one of the first observatories on Maunakea before it was given to UH in 1970 and transferred to UH Hilo in 2003.