CSO on Maunakea

Caltech Submillimeter Observatory Decommissioning Updates

News Release from MaunaKeaAndTMT.org

California Institute of Technology’s (Caltech) draft Site Decommissioning Plan (SDP) to remove the Caltech Submillimeter Observatory (CSO) and restore the site was unanimously approved by the Maunakea Management Board (MKMB) on March 2, 2021.

MKMB is a board of community volunteers that advises the University of Hawai‘i’s Office of Maunakea Management, which oversees the Maunakea Science Reserve.

CSO is one of the first two observatories on the mountain to undertake the decommissioning process, along with the University of Hawai‘i Hoku‘kea telescope. CSO is the first to submit its SDP for review.

Caltech’s next planning steps are the Draft Environmental Assessment (EA), which is currently under review, and the Conservation District Use Application (CDUA).

The EA and CDUA will go to MKMB and the public for comment. Then, with the Site Decommissioning Plan (SDP) attached, they will be submitted the state Department of Land and Natural Resources. If all goes smoothly, Caltech anticipates DLNR will hold a hearing, with public comment period, later this year. Caltech will also host three public workshops toward the end of 2021. Caltech hopes to have its plans approved by early 2022, which would enable the physical deconstruction and restoration to begin by summer 2022.

CSO's 10.4-meter radio telescope went online in 1987 for research by astronomers at Caltech and other institutions, including more than 200 students. Operations at the observatory ended in 2015.

“It was Caltech’s privilege to operate CSO on Maunakea and an honor to continue our relationship with the mauna and its people through this decommissioning effort and Caltech’s participation in other astronomy projects,” Caltech physics professor and CSO Director Sunil Golwala said.

For additional information please visit www.cso.caltech.edu.