The enormous Arecibo radio telescope, a destination for astronomers perched in the mountains of Puerto Rico, has collapsed, the National Science Foundation said on Tuesday.
The telescope’s 900-ton receiver platform, which was suspended by cables connected to three towers, fell onto the 1,000-foot antenna dish sometime overnight, the foundation said.
“The platform fell unexpectedly,” said Joshua Chamot, a spokesman for the foundation, which owns the telescope at the Arecibo Observatory. Officials said they were assessing the collapse before releasing more details. They did not specify when the platform had collapsed or why it fell.
“As we move forward, we will be looking for ways to assist the scientific community and maintain our strong relationship with the people of Puerto Rico,” the foundation said on Twitter.
The foundation announced on Nov. 19 that the telescope had to be torn down after an auxiliary cable slipped out of its socket and left a 100-foot gash in the dish below. The observatory is managed by the University of Central Florida.
“The decision comes after N.S.F. evaluated multiple assessments by independent engineering companies that found the telescope structure is in danger of a catastrophic failure and its cables may no longer be capable of carrying the loads they were designed to support,” the foundation said last month.
On Nov. 24, the foundation said engineers had observed more breaks in the wires of the remaining cables attached to one of the towers that held the platform.
The observatory has served as the vanguard of the search for alien civilizations, and astronomers used it to track killer asteroids.
For nearly six decades, the observatory was a renowned resource for radio astronomy and planetary research, and it held enormous cultural significance for Puerto Ricans. Many said they were inspired by the observatory to pursue careers in science and technology.
The telescope beamed signals to and from space, an ability that made it possible to collect undiscovered details about planets in the solar system, said Catherine Neish, an assistant professor of earth sciences at the University of Western Ontario.
One of its early feats, in 1967, the discovery that the planet Mercury rotates in 59 days, not 88 as astronomers had originally thought.
“It was an incredible piece of technology,” Dr. Neish said.
But after years of hurricane damage and financial duress, questions arose about the observatory’s future.
Puerto Rico residents and astronomers had called on the foundation to repair the telescope rather than demolish it.
Before the collapse, nearly 60,000 people signed a petition urging federal agencies to find a way to stabilize the structure.
But Thornton Tomasetti, an engineering firm hired by the University of Central Florida to assess the telescope, said the likelihood of another cable failing was too high to justify repair work.
“Although it saddens us to make this recommendation, we believe the structure should be demolished in a controlled way as soon as pragmatically possible,” the firm said in a letter to the university and the foundation.
On social media, scientists and Puerto Ricans who recalled visiting the observatory mourned the telescope after the collapse
“This is a stunning loss for our science capability,” Justin Kugler, an aerospace engineer, said on Twitter. “The United States needs to create a plan for a successor radio telescope that builds on the heritage of Arecibo and honors the commitment of Puerto Rico over these many years.”
Dr. Neish, the University of Western Ontario professor, said the loss of the telescope is not only devastating, it is also infuriating to scientists who believe the foundation could have done more to save it.
“It was not inevitable,” she said of the collapse. “If they had properly maintained it, it’s likely that wouldn’t have happened.”
“It’s such an undignified end,” she added. “That’s what’s so sad about it.”
Dennis Overbye contributed reporting.