After 14 years of planning, Caltech is finally gearing up to remove its telescope from the Mauna Kea summit in the next couple of months, the first of five observatories earmarked for decommissioning to make way for the landmark Thirty Meter Telescope.

A second Mauna Kea telescope, the University of Hawaii’s Hoku Kea telescope, is expected to get the green light for removal by the state Board of Land and Natural Resources at its meeting Friday.

The physical removal of the Caltech Submillimeter Observatory, or CSO, will take place over a six-week window in late spring, the Pasadena, Calif., institution announced last week.

The $4 million-plus removal project will involve dismantling the structure, hauling its parts down the 13,803-foot mountain and restoring the site to its natural state.

Caltech is one of the partners planning to build the $2.65 billion TMT, along with the University of California and science institutions from China, India, Canada and Japan. The removal of five telescopes from the Mauna Kea summit is a condition of the TMT’s conservation district use permit.

However, the controversial telescope remains on hold while the National Science Foundation conducts environmental studies and weighs the possibility of investing hundreds of millions of dollars in the project.

When the CSO removal project begins, a big part of the job will be transporting the telescope’s 34-foot diameter primary mirror to Kawaihae Harbor. To move the oversize load down the mountain and across the island, the contractor will have to temporarily close several roads in an operation that will take several days, officials said.

Specific dates for the effort have yet to be chosen, in order to allow flexibility with the weather.

Included in the six-week window is a practice run with a dummy mirror, which is being planned to verify procedures and identify potential issues. The removal of the real mirror will take place approximately one week after the practice run.

“Other telescope parts will be taken down from the summit as weather permits,” Caltech physics professor and CSO Director Sunil Golwala said. “As those parts are smaller, no road closures will be required.”

So far, contractor Kona Transportation has removed the bulk of Caltech’s property inside the observatory, packing it up either for shipment to Chile, where the telescope is being relocated, or for transport 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, officials said.

Once the telescope is removed, general contractor Goodfellow Bros. will begin dismantling the buildings that housed the CSO telescope and will undertake a full restoration of the site. Caltech officials said they anticipate that decommissioning and restoration will be completed before the end of the year.

The latest University of Hawaii Mauna Kea Master Plan calls for a maximum of nine observatories to remain atop Hawaii’s tallest mountain by the time the Mauna Kea Science Reserve lease expires in 2033. There are currently 13 telescopes, with four to be decommissioned and, if the TMT is built, a fifth would be taken out of operation.

According to a UH Board of Regents resolution, a determination would be made on the decommissioning of the remaining three observatory sites by Dec. 30, 2025.

How that plan ultimately plays out remains uncertain under the new Maunakea Stewardship Oversight Authority, approved last year by the state Legislature and signed into law by former Gov. David Ige. The authority will take full control of the astronomy precinct from the university following a five-year transition period.

While the CSO was originally earmarked as one of the Mauna Kea telescopes to be removed in exchange for the TMT, plans for its decommissioning were first announced in 2009. At that time, the plan was to begin dismantling the observatory in 2016 and aim for returning the site to its natural state by 2018.

Caltech originally said it was decommissioning the observatory because of construction of the next-­generation radio telescope the Cornell Caltech Atacama Telescope. That project, since renamed the Fred Young Submillimeter Telescope, remains under construction in Chile, although it is reportedly nearing completion.

When it achieved first light 36 years ago, the CSO was one of the world’s premier observatories for astronomical research and instrument development at submillimeter wavelengths.

The observatory was closed in 2015 following 30 years of “groundbreaking achievements” and numerous discoveries, according to Caltech. Hundreds of students used the facility, including more than 100 working on doctoral research projects. UH was one of the telescope’s partners.

Observations at the 10.4-meter radio telescope, which is protected by a 60-foot dome, led to the detection of heavy water on comets, which helped to determine the composition of comets, Caltech said. It also led to the observation of “dusty” planets, which optical telescopes often have trouble seeing.

Under the proposal to decommission and remove the Hoku Kea, University of Hawaii at Hilo’s teaching telescope, two buildings and associated infrastructure would be removed and the site restored as close as possible to its original state. UH Hilo and the Center for Maunakea Stewardship’s application for a conservation district use permit for the project is on the BLNR’s Friday agenda.

The Hoku Kea site was built by the U.S. Air Force in 1970 and was one of the first observatories on the mountain before it was handed over to UH Hilo.

In its day, the Air Force’s 24-inch telescope conducted pioneering observations of objects in the solar system, including asteroids and the outer planets. In 1995, the small telescope was given to UH Hilo, where faculty and students used it to collect data for more than a dozen published research projects since 1995, according to the university.

The Air Force telescope was removed in 2008 and the facility was outfitted with a larger dome and mirror in 2010 and named the Hoku Kea telescope.

UH now plans to install a new state-of-the-art, 0.7-­meter teaching telescope in a small structure at the Hale Pohaku midlevel facility on Mauna Kea.

In 2015, UH identified a third Mauna Kea telescope to be decommissioned if TMT becomes a reality: the UKIRT Observatory, formerly known as the United Kingdom Infrared Telescope.