CSO telescope could be gone by 2022

  • The Caltech Submillimeter Observatory is shown in 2015 on the summit of Maunakea. (Tribune-Herald file photo)

The Caltech Submillimeter Observatory could completely be removed from the summit of Maunakea as early as the end of next year.

Caltech representatives presented their decommissioning plans for the observatory at a Tuesday meeting of the University of Hawaii’s Maunakea Management Board.


The submillimeter observatory is the first of five summit telescopes slated to be decommissioned in exchange for the planned construction of the Thirty Meter Telescope. CSO operations in 2015, and had at one point been scheduled to be fully demolished by 2018.

Jim Hayes, president of Honolulu consultancy firm Planning Solutions Inc., said the observatory is now on schedule to be removed by the end of 2022, assuming all goes smoothly with the upcoming permitting process.

Hayes and CSO Director Sunil Golwala submitted a 600-page decommissioning plan to the Maunakea Management Board describing every aspect of the decommissioning process. Hayes said the process, estimated to cost a little over $4 million, will include a full restoration of the site, obliterating any trace that the observatory was ever there.

“We understand the important role that the CSO plays as the first observatory to undertake decommissioning, and our work will serve as not just an example, but really a template for the future decommissionings,” Golwala said. “We think the plan will lay the groundwork for a demonstration that an observatory can be decommissioned and completely removed and the site can be fully restored with no permanent physical or biological impact.”

Hayes said the actual decommissioning process itself will take an estimated 141 working days, and will involve dismantling the 43-ton telescope and its 60-foot dome, as well as the breaking apart the concrete foundation on which the whole edifice rests. Local fill material will be used to fill in the site and a nearby cesspool.

The only non-natural part of the site that will not be removed will be underground power and communication lines that are shared by the other summit observatories, Hayes said.

In order to prevent lasting environmental impacts at the site, Hayes said the decommissioning process will involve measures to minimize vehicle traffic to the area and preventing spills and disturbances to the surrounding environment. The project also will be supervised by a decommissioning manager and archaeological, cultural and invasive species monitors.

CSO will continue to monitor the site for three years after the process is complete to determine the efficacy of the restoration.

The Maunakea Management Board voted unanimously Tuesday to approve the decommissioning plan, and Hayes explained that Caltech hopes to have a draft environmental assessment and conservation district use application to present to the board by May. The assessment and application should be available for public review around August or September, Hayes said, and the application should go before the Board of Land and Natural Resources around December of this year.

If all goes well, Hayes said, deconstruction work could begin by spring or summer of next year.

Of course, there could still be hiccups. OMKM board member Doug Simons, who is executive director of the Canada-France-Hawaii Telescope, pointed out that submitting the use application also will open the way for people to file a contested case hearing for the project, which could delay the entire enterprise for months or even years.


Hayes said Caltech will shoulder the financial costs of any delays to the project.

Email Michael Brestovansky at

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