Caltech Submillimeter Observatory Telescope Removed; Decommissioning Paused until Spring

News Release from Caltech Submillimeter Observatory, December 21, 2023 

Hilo, Hawai‘i – December 21, 2023 – Caltech has taken the Leighton Telescope out of the Caltech Submillimeter Observatory (CSO) dome and removed it from Maunakea for shipment to Chile for re-use. Deconstruction of the dome and restoration of the site will resume after the winter.

“The CSO decommissioning is a complex and multi-phase project,” said Caltech physics professor and CSO Director Sunil Golwala. “We made a lot of progress this summer and fall. In the spring, when weather permits, we will resume decommissioning with the removal of the building that housed the telescope and restoration of the site.”

In the first phase of the decommissioning, the following was accomplished:

• The telescope, including its mount, was taken out of the observatory dome and was removed from Maunakea.
• The cesspool was confirmed to contain no remaining liquid contents.
• Interior demolition began. Two roll-off containers were filled with debris, mainly insulation, drywall, and plywood, and were removed from Maunakea.
• Electrical power to the observatory was cut off and the main circuit breaker was shut off. The electrical transformer feeding the site will be removed by HELCO.
• The site was inspected for rodents, as required by the county building permit.
• Underground utilities, including sewer, water, electrical, communication, and grounding grids, were mapped using ground-penetrating radar so that they can be easily located during the demolition process.
• An Independent Decommissioning Construction Monitor and a Cultural Monitor were present at all appropriate phases.

When decommissioning resumes in the spring, the following will occur:

• Interior demolition will be completed and the observatory dome will be removed.
• The foundation will be removed along with the cesspool, its remaining solid contents, and all underground utilities.
• The ground underneath the foundation and the cesspool will be sampled for chemicals of potential concern.
• The site will be monitored for the appearance of invasive species.
• The land will be restored to the fullest extent consistent with the permits guiding the decommissioning.
• Cultural, construction, and archeological monitors will be present at all appropriate phases.

“Caltech will update the community once decommissioning resumes next year,” said Golwala. “Following the completion of restoration, the site will be monitored for three years, primarily to document repopulation by flora and fauna,” Golwala added.

The cost of deconstruction and site restoration is expected to exceed $4 million and is being funded primarily by the Gordon and Betty Moore Foundation, while the removal of the telescope for reuse is being funded by the Heising-Simons Foundation.

More information on the decommissioning, including related planning documents, permits, and a list of contractors involved in the project, can be found here: here

The CSO came online in 1987 and was used by scientists at Caltech and other institutions, including almost 200 student and postdoctoral researchers, to open a new submillimeter window on the universe. A summary of CSO’s contributions to astronomy and astronomical instrumentation are available here.

About Caltech: Caltech is a world-renowned private science and engineering Institute located in Pasadena, California, that marshals some of the world's brightest minds and most innovative tools to address fundamental scientific questions and pressing societal challenges.

Pictures of the telescope removal can be found here. Video Footage of the Telescope removal can be found here.

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SA: Observatory telescope removed from Mauna Kea