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It took 17 seconds to The huge Arecibo radio telescope will collapse. The dust will take much longer to settle.
The structure collapsed on December 1 after cable failures in August and November made the telescope too delicate to repair safely. The US National Science Foundation (NSF), which owns the site, knew the structure could fall at any moment and was evaluating how to do so. telescope dismantling. Now, the agency has gone on to assess what to do with his remains.
“We are in the assessment phase,” Ralph Gaume, director of the NSF Division of Astronomical Sciences, said during a press conference today (December 3).
Related: Losing the Arecibo Observatory creates a hole that cannot be filled
He said the University of Central Florida, which operates the site for the NSF, has hired a cleanup contractor who arrived at the telescope yesterday. “They are beginning to make preliminary plans in the future to provide us with a plan for what the cleanup will be like,” Gaume said. “It’s too early to say exactly what that cleaning will be like.”
The truth is that the collapse itself was brutal. During the press conference, NSF staff shared two videos taken during the collapse of the telescope: one from the observatory control room just beyond the massive dish and another from a drone hovering near the tower that had lost two cables in the last four months.
Arecibo’s troubles began in August, when a support cable connecting the 900-ton science platform to Tower 4 snapped out of its socket. An initial analysis suggested that, with some repairs, the structure would be fine.
But then in November, just as staff were preparing for the repairs to begin, second broken wire. This time it was one of the primary cables and it was also connected to Tower 4, leaving the platform without a third of its support in that corner.
Engineers flocked to assess the structure, using drones to stay a safe distance from the unstable telescope. But they couldn’t find a way to find out for sure how stable the structure was, let alone repair it safely. The second cable had failed under much less stress than it should have been necessary to break it, so the engineers lost confidence in all the other cables as well.
Related: The radio telescope of the Arecibo Observatory in Puerto Rico collapsed
It’s too early to say exactly what that cleaning will look like.
Ralph Gaume, NSF
“We knew at the time it was only a matter of time,” John Abruzzo, Arecibo’s lead engineer for the damage assessment process and managing director of Thornton Tomasetti, said during the news conference. “It was a very dangerous and precarious situation because it could have really happened at any time.”
Then, on November 19, the NSF announced that it would begin the process of dismantling the telescope, but that response was also complicated by the precarious state of the platform. It took the engineers a few weeks to develop a plan to safely demolish the structure.
Turns out they didn’t have that kind of time: collapsed telescope less than two weeks later.
The newly-released drone footage opens up on already broken cables, then shows the failure of additional cables: first slow, then faster, with paint chips flying as individual cables within the thick bundles give way. Once all the cables in that tower break, the triangular metal platform leans down to hit the opposite side of the platter, pulling the tips of the other two support towers as it goes.
During the press conference, officials emphasized their commitment to the telescope during the difficult fall, 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 authorized expenditures to evaluate and stabilize the structure shortly after the August failure on the condition that human safety remained the top priority at the site. Preparations to repair the failure of the first cable were underway when the second cable broke, and personnel were exploring possible stabilizing approaches when the telescope collapsed.
Related: Arecibo is not the first radio telescope to fail unexpectedly. This is what we can learn from the collapse of Green Bank.
“It was a dangerous situation: after the cable failure on November 6, those cables could have failed at any time – you couldn’t predict when it would happen.” Abruzzo said. “It was risky trying to do what we were going to do and frankly the probability of success was actually not that high. It was basically a desperate effort if you could try to preserve it a little bit longer to allow us to do more work.”
Agency officials emphasized that safety remains the top priority in dealing with the aftermath of the collapse.
“Our objetive [going] Advancement has to remain safe, “Gaume said.” We need a full accounting of how stable the site is, particularly those three towers and the remaining structure, along with drawing up a plan to safely remove the remains. ”Gaume did not provide a timeline for that work.
Some limited science at the observatory will resume soon, NSF officials said. The agency has authorized repairs to the facility’s LIDAR instrument and a smaller telescope used for atmospheric science, Gaume said, using money allocated to the facility after Hurricane Maria damaged it in 2017.
But it remains to be seen whether the massive radio telescope will be 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 that involves congressional appropriations and the assessment and needs of the scientific community. So it’s too early for us to comment on replacement.”
Email Meghan Bartels at [email protected] or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.
