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Caltech Submillimeter Observatory Decommissioning Update

Last summer, Caltech began the decommissioning of the Caltech Submillimeter Observatory (CSO) on Maunakea. The removal and restoration of the site is expected to be completed during 2023. A review of what has been accomplished so far and a timeline for the remainder of the decommissioning is described below.

"The decommissioning is a multistep process with many variables," said Caltech physics professor and CSO director Sunil Golwala. "Delays in preparatory steps and contracting brought the physical deconstruction close to winter when weather conditions impeded work at the summit. Removal of the telescope, physical deconstruction of the building housing the telescope, and restoration of the site are now anticipated to begin when summit weather conditions allow in spring 2023," said Golwala.

In addition to retaining contractors as previously noted, Caltech has now completed the selection of cultural and invasive species monitors. "All monitors required by the CDUP [Conservation District Use Permit] are under contract now," said Golwala. Caltech has retained AECOM/SWCA as the invasive species monitor (on-site and for vehicles), ASM Affiliates as the archeological monitor, and TayMade Productions LLC as the cultural monitor.

So far, the following decommissioning steps have been completed:

  • A perimeter fence was constructed by Islandwide Fencing at the site in September to delineate the construction zone. This fence allows the public to view site activity without safety risk.
  • Kona Transportation has removed the bulk of Caltech's property inside the observatory, packing it for shipment to Chile (where the telescope is being relocated) or transporting to a local scrapyard for reuse, recycling, or disposal. The telescope remains in the dome, along with a handful of large pieces of equipment and optics.
  • Unitek removed loose lead-based paint and mold-contaminated surfaces in September. Lehua Environmental Inc. provided environmental air monitoring and inspection services during the lead paint removal and mold remediation activities to ensure full containment of these materials. The work was done in accord with the Site Decommissioning Plan (SDP).
  • Oasis Environmental and EnviroServices & Training Center inventoried and removed hazardous materials/waste from the observatory in August and October.
  • Isemoto Contracting has been hired to provide crane services at the summit for telescope removal.
  • Caltech has been in close contact with Hawai‘i Department of Transportation, Hawai‘i County Police Department, and County of Hawai‘i Department of Public Works on road permitting requirements for the transport of the telescope to the Kawaihae Harbor. Okahara and Associates has been brought on to prepare traffic control plans and to assist with permit applications. The transportation plan includes a test run. Due to public notice requirements and allowing for unpredictable weather conditions at the summit, the removal process, including the dummy run, will take place over 3-4 weeks in the spring.

The next steps are as follows:

  • Between now and spring, traffic control plans will be finalized and permits obtained to move the telescope; the public will be informed of planned road closures and restrictions (five individual nighttime closures/restrictions and two individual short daytime closures are anticipated).
  • Once weather conditions are suitable, the crane and other equipment needed for removal of telescope will be mobilized and the removal will commence.

Once the telescope is removed, the project will be turned over to Goodfellow Bros., the general contractor, who will handle the dismantling of the buildings that housed the CSO telescope and the full restoration of the site. M3 will provide deconstruction administration services, while AECOM will provide the independent decommissioning construction monitor (IDCM). Caltech anticipates that decommissioning and restoration will be completed during 2023.

The cost of deconstruction and restoration is expected to be more than $4 million.

The deconstruction process is governed by the CDUP, which was issued by the state's Department of Land and Natural Resources (DLNR) in January 2022. The CDUP sets the terms and conditions that Caltech must follow during the decommissioning. Copies of the CDUP, the Final Environmental Assessment, the SDP, and other planning documents can be found 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:

Whitney Clavin
(626) 395-1944