It took 17 seconds for the huge radio telescope at the Arecibo Observatory to collapse. It takes much longer for the dust to settle.
The iconic structure collapsed in Puerto Rico on December 1 after cable bugs were too delicate for safe repair due to cable failures in August and November. The U.S. National Science Foundation (NSF), which owns the site, knew the structure could fall off at any time, and evaluated how to proceed. dismantling the binoculars. Now the agency has switched to assessing what to do with its wreckage.
“We are in the evaluation phase,” Ralph Gaume, director of NSF’s Department of Astronomical Sciences, said at a news conference today (December 3).
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He said the University of Central Florida, which operates the NSF site, hired a cleaning contractor who arrived at the binoculars yesterday. “They make preliminary plans going forward to give us the look of the cleaning,” Gaume said. “It’s too early to tell you exactly what the cleaning looks like.”
To be sure, the collapse itself was brutal. At the press conference, NSF staff shared two videos during the telescope crash: one from the observatory’s control room, just behind the huge vessel, and one from a drone floating near the tower that had lost two cables in the past four months.
Arecibo’s troubles began in August, when the power cord connecting the 900-ton science platform to Tower 4 slipped out of its socket. An initial analysis suggested that with some improvements, the structure would be fine.
But then in November, when the staff was getting ready to start repairs, the the second cable popped up. This time it was one of the primary cables and also connected to Tower 4, leaving the platform without one-third of its support in this corner.
Engineers emerged to evaluate the structure, using drones to keep a safe distance from the unstable telescope. But they couldn’t figure out how to safely figure out how stable the structure was, even less safely to fix it. The second cable broke under much less load than would have been needed to secure it, so engineers lost confidence in all the other cables as well.
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“We knew at the time that it was only a matter of time,” said John Abruzzo, Arecibo’s senior engineer for the damage assessment process and managing director of Thornton Tomasetti at the press conference. “It was a very dangerous and precarious situation because he could have gone at any time.”
So on November 19, NSF announced 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 work out a plan for the safe demolition of the structure.
They didn’t have that time, it turns out: It the binoculars collapsed in less than two weeks.
The newly released drone image opens on already snapped cables and then shows the failure of additional cables: first slow and then faster, allowing paint chips to fly as individual wires in thick bundles. As all the cables in the tower snap, the triangular metal platform collapses to touch the other side of the vessel while pulling down the tops of the other two support towers.
At the press conference, officials stressed their commitment to the telescope throughout the heavy fall, the severe uncertainty in the telescope after the second cable failure, and their gratitude that no one was injured in the crash.
Shortly after the August failure, the agency authorized spending to evaluate and stabilize the structure, on the condition that human safety remains paramount on the ground. Preparations for repairing the first cable failure were underway when the second cable crashed, and staff explored possible stabilizing approaches when the telescope crashed.
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“It was a dangerous situation: after the November 6 cable failure, these cables could have failed at any time – he couldn’t predict when that would happen.” said Abruzzo. “It was risky to try to do what we were going to do, and frankly, the probability of success wasn’t really that great. It was basically a last effort if he tried a little further and kept it to allow us to do more work.”
Agency officials stressed that safety remains paramount in dealing with the aftermath of the crash.
“It simply came to our notice then [going] Progress must remain safe, “Gaume said. We need a full account of the stability of the site, in particular by drawing up a plan for the three towers and the remaining structure and the safe removal of the wreckage “is a timetable for that work.
Limited science will soon continue at the observatory, NSF officials said. The agency has authorized the repair of the facility’s LIDAR instrument and a smaller telescope used for atmospheric science, Gaume said, using the money set aside for the facility It was damaged by Hurricane Maria In 2017.
But whether the huge radio telescope is replaced will remain open question.
“In terms of replacement, NSF has a very well-defined process for financing and building large-scale infrastructure, including binoculars,” Gaume said. “It’s a multi-year process that includes congressional appropriations as well as an assessment of the needs and needs of the scientific community. So it’s very early to comment on the replacement.”
Email Meghan Bartels at [email protected] or follow us on Twitter @meghanbartels. follow us on Twitter @Spacedotcom and Facebook.