The California Institute of Technology Submillimeter Observatory
The California Institute of Technology Submillimeter Observatory

The physical removal of the Caltech Submillimeter Observatory (CSO) on Maunakea is scheduled to begin by early May after extensive planning and permitting, according to an April 6 CSO news release. CSO is following the 2010 Decommissioning Sub Plan (PDF) of the Maunakea Comprehensive Management Plan (PDF) for the observatory removal and site restoration.

“Over the winter, we finalized plans and prepared permitting applications to remove the telescope and transport it from the mountain,” said CSO Director Sunil Golwala in the release. “To transport the main mirror of the telescope to the harbor will require several road closures. We are alerting state and county agencies, the University of Hawaiʻi at Hilo Center for Maunakea Stewardship (CMS) and the community at each step.”

CSO is one of two Maunakea observatories expected to be fully decommissioned in 2023. The physical removal of the UH Hilo Hōkū Keʻa observatory is expected to begin in the fall.

“Decommissioning an observatory is a complicated process involving regulatory approvals ensuring environmental stewardship and public safety,” said UH Hilo CMS Executive Director Greg Chun. “The progress being made on the decommissioning of the first two observatories on Maunakea honors a longstanding commitment made by the university. We will complete this important work as we continue to work diligently on the transition to the Maunakea Stewardship and Oversight Authority.”

CSO is coordinating with the Hawaiʻi Department of Transportation, Hawaiʻi County Police Department and County of Hawaiʻi Department of Public Works on road permitting requirements for transporting the telescope’s 34-foot diameter primary reflector to Kawaihae Harbor on the Kona coast.

The entire removal process including a practice run is expected to take about six weeks and will involve publicly announced road closures. Much of the work and major road closures will take place between 10 p.m. and 5 a.m. to minimize public impact. A map of the anticipated transport route can be found here.

“Other telescope parts will be taken down from the summit as weather permits,” said Golwala. “As those parts are smaller, no road closures will be required.”

Once the telescope is removed, the buildings that housed the CSO telescope will be dismantled and the site restored. As required is the sublease for CMS, CSO is paying for the decommissioning, which is expected to exceed $4 million.