Meanwhile, installing a new telescope would cost up to $350 million, money the NSF doesn’t have, Mr Vazquez said, adding it would have to come from U.S. Congress.
“It’s a huge loss,” said Carmen Pantoja, an astronomer and professor at the University of Puerto Rico who used the telescope for her doctorate. “It was a chapter of my life.”
Scientists worldwide had been petitioning US officials and others to reverse the NSF’s decision to close the observatory. The NSF said at the time that it intended to eventually reopen the visitor centre and restore operations at the observatory’s remaining assets, including its two LIDAR facilities used for upper atmospheric and ionospheric research, including analyzing cloud cover and precipitation data. The LIDAR facilities are still operational, along with a 12-metre telescope and a photometer used to study photons in the atmosphere, Mr Vazquez said.
“We are saddened by this situation but thankful that no one was hurt,” NSF Director Sethuraman Panchanathan said in a statement. “When engineers advised NSF that the structure was unstable and presented a danger to work teams and Arecibo staff, we took their warnings seriously.”
The telescope was built in the 1960s with money from the Defence Department amid a push to develop anti-ballistic missile defences. It had endured hurricanes, tropical humidity and a recent string of earthquakes in its 57 years of operation.
The telescope has been used to track asteroids on a path to Earth, conduct research that led to a Nobel Prize and determine if a planet is potentially habitable. It also served as a training ground for graduate students and drew about 90,000 visitors a year.
“I am one of those students who visited it when young and got inspired,” said Abel Mendez, a physics and astrobiology professor at the University of Puerto Rico at Arecibo who has used the telescope for research. “The world without the observatory loses, but Puerto Rico loses even more.”
He last used the telescope on August 6, just days before a socket holding the auxiliary cable that snapped failed in what experts believe could be a manufacturing error. The National Science Foundation, which owns the observatory that is managed by the University of Central Florida, said crews who evaluated the structure after the first incident determined that the remaining cables could handle the additional weight.
But on November 6, another cable broke.
Scientists had used the telescope to study pulsars to detect gravitational waves as well as search for neutral hydrogen, which can reveal how certain cosmic structures are formed. About 250 scientists worldwide had been using the observatory when it closed in August, including Mr Mendez, who was studying stars to detect habitable planets.
“I’m trying to recover,” he said. “I am still very much affected.”