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It took 17 seconds for the huge Arecibo Observatory radio telescope to crumble. It will take much longer for the dust to settle.
Puerto Rico’s iconic structure collapsed on December 1 after cable failures in August and November made the telescope too delicate to be safely repaired. The US National Science Foundation (NSF), owner of the site, knew the facility could fall at any time and was considering how to proceed. deactivating the telescope. Now, the agency has moved on to consider what to do with his wreck.
“We are in the evaluation phase,” said Ralph Gaume, director of the NSF’s Division of Astronomical Sciences, during a press conference held today (December 3).
Related: The loss of the Arecibo Observatory creates a hole that cannot be filled
He said the University of Central Florida, which manages the site for NSF, hired a cleaning contractor who arrived at the telescope yesterday. “They are starting to make preliminary plans moving forward to provide us with a plan for what the cleanup will look like,” Gaume said. “It’s too early to say exactly what that cleaning will be like.”
What is certain is that the collapse itself was brutal. During the press conference, NSF personnel shared two videos taken during the collapse of the telescope: one from the control room of the observatory just beyond the huge dish and one from a drone hovering near the tower that had lost two cables in the last four months.
The Arecibo troubles began in August, when a support cable connecting the 900-ton scientific platform to Tower 4 slipped out of its plinth. An initial analysis suggested that, with a few repairs, the structure would do well.
But then in November, just as staff were getting ready for repairs to begin, a the second cable broke. This time it was one of the primary cables and also connected to Tower 4, leaving the platform without a third of its support in that corner.
Engineers swarmed to assess the facility, using drones to stay at a safe distance from the unstable telescope. But they couldn’t find a way to safely understand how stable the structure was, much less to safely repair it. The second cable had failed much less than it should have been necessary to hook it, so the engineers lost faith in all other cables as well.
Related: The radio telescope of the Arecibo Observatory in Puerto Rico has collapsed
It’s too early to say exactly what the cleaning will look like.
– Ralph Gaume, NSF
“At that point we knew it was only a matter of time,” John Abruzzo, chief engineer for the Arecibo damage assessment process and company general manager Thornton Tomasetti, said at the press conference. “It was a very dangerous and precarious situation because it could have really gone at any moment.”
Thus, on November 19, the NSF announced that it would begin the telescope deactivation process, but even that response was complicated by the precarious state of the platform. It took the engineers a few weeks to develop a plan to safely demolish the facility.
They didn’t have that kind of time, it turns out: The the telescope collapsed less than two weeks later.
The newly released drone footage opens on already broken cables, then shows the failure of additional cables: first slow, then faster, with paint splinters flying as the individual wires within the thick bundles give way. Once all the cables in that tower snap, the triangular metal platform lowers to hit the opposite side of the dish, detaching the spikes of the other two support towers as it goes.
During the press conference, officials stressed their commitment to the telescope during the difficult autumn, the terrible precariousness of the telescope after the second cable failure, and their gratitude that no one was injured during the collapse.
The agency had cleared spending on evaluating and stabilizing the facility shortly after the August bankruptcy, provided that human safety remained the top priority at the site. Preparations for repair of the first failed cable were underway when the second cable snapped, and staff were exploring potential stabilization approaches when the telescope collapsed.
Related: Arecibo is not the first radio telescope to fail unexpectedly. Here’s what we can learn from the collapse of the Green Bank.
“It was a dangerous situation: after the cable failure on November 6, those cables could have failed at any moment – it was not possible to predict when that would happen.” Abruzzo said. “It was risky to try and do what we were going to do and, frankly, the probability of success wasn’t really that high. It was basically a last-ditch attempt if you could try to preserve it a little longer to allow us to work harder.”
Agency officials stressed that safety remains the top priority in dealing with the aftermath of the collapse.
“Our aim [going] must remain safe, “Gaume said.” We need a full account of how stable the site is, particularly those three towers and the remaining structure, along with putting together a plan to safely remove the wreck. “Gaume did not provide a timeline for that job.
Some limited science will soon resume at the observatory, NSF officials said. The agency authorized repairs to the facility’s LIDAR instrument and a smaller telescope used for atmospheric science, Gaume said, using the money allocated to the facility after Hurricane Maria damaged it in 2017.
But it remains if the massive radio telescope is replaced an open question.
“Regarding replacement, NSF has a very well-defined process for financing and building large-scale infrastructure, including telescopes,” Gaume said. “It’s a multi-year process involving Congressional appropriations and the evaluation and needs of the scientific community. So it’s very early for us to comment on the replacement.”
Email Meghan Bartels at [email protected] or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.
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