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Failure analysis of the Arecibo 305 meter telescope collapse
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- magicalhippo 2y agoIn the summary they state: All the reported experimental zinc electroplasticity (EP) data were developed at current densities orders of magnitude higher than those possibly present in the Arecibo Telescope but measured in laboratory experimental periods that were orders of magnitude shorter than the telescope's socket zinc service. There are no reported experimental data concerning low-current, long-term EP, which the committee has lumped together under the term "LEP", affecting zinc's creep mechanisms over decades. The timing and patterns of the Arecibo Telescope's socket failures make the LEP hypothesis the only one that the committee could find that could potentially explain the failure patterns observed. Accelerated aging is, as far as I know, pretty much standard in the industry. Nobody can wait 20 years to find out if a certain material is good enough or not. However, the real failure seems to be the lack of urgency when they signs started to show up: Upon reflection, the unusually large and progressive cable pullouts of key structural cables that could be seen during visual inspection several months and years before the M4N failure should have raised the highest alarm level, requiring urgent action. The lack of documented concern from the contracted engineers about the inconsequentiality of the cable pullouts or the safety factors between Hurricane Maria in 2017 and the failure is alarming.
- nick3443 2y agoSounds like it was a blind spot for the engineers due to the normally bulletproof service history of zinc spelter cable terminations in structures.
- potato3732842 2y ago>normally bulletproof service history of zinc spelter cable terminations in structures. They're relatively new, they're relatively expensive (which saves them from being used in the worst of the applications) and like most things inherent to steel cable and whatnot they tend to get employed in situations where safety factors are generous. Don't count your chickens before they hatch.
- nick3443 2y agoI am not an expert, I read this in the report: The long-term zinc creep failure of the Arecibo Telescope sockets and the subsequent cable pullout has never been documented elsewhere despite a century of zinc-filled cable spelter sockets use. 17 The type, size, length, and fittings of the cables used in the Arecibo Telescope (whether the original cables constructed in the 1960s or the auxiliary cables installed in the 1990s) were catalog-selected items, not at all unusual, with decades of proven performance. Exten-sive structural modeling of the Arecibo Telescope, independently confirmed by laser cable sag surveys, validated that under all static and cyclic loading conditions, the cable loads barely exceed half the nominal cable strength. While PLC can occur at stresses well below yield, such a creep failure has never been reported in spelter socket zinc.
- hinkley 2y agoI think we might need to send some microbiologists to do their own forensics. You have a mechanical failure that can’t be seen in the labs and isn’t reproducible at other sites. Suggests something environmental. Like when natural fiber army gear starts dissolving in the jungles of Vietnam. Could be direct action, or a side effect of a chemical in plant or animal detritus. Like pigeon poop on car paint.
- madaxe_again 2y agoThe paper posits that it’s due to low frequency electromagnetic induction in the tethers from the observatory operations, which is a pretty unique environmental factor.
- deskr 2y ago> The lack of documented concern from the contracted engineers about the inconsequentiality of the cable pullouts or the safety factors between Hurricane Maria in 2017 and the failure is alarming. This is crazy. Basically cables were pulling out for months and years and no one raised the alarm? In many industries that could be a criminal or career ending malpractice. Are the "contracted engineers" liable?
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- magicalhippo 2y agoIn chapter 5 they go into how the ownership was transferred to the University of Central Florida (UCF) at the start of 2018, after the hurricanes in 2017. It seems unlikely that UCF had adequate time and resources to review and understand the Arecibo Telescope's original 1963 design, the 1974 upgrade, the structural inspection and maintenance records produced for nearly 50 years, [...] and the key factors, such as the wire breaks and cable pullout of the sockets and their significance on the strength and integrity of the structure. The measured cable pullout may have appeared "normal" to [the UCF staff] and was not on their radar as signs of structural distress. The lack of concern may be because a small cable pullout was present from the beginning, and no one in authority had previously raised an alarm But yeah, seems weird no-one of the contractors tried to raise an alarm.
- hinkley 2y agoI bet there’s a r/MaliciousCompliance in Spanish out there somewhere about how UCF cancelled existing maintenance contracts and hired new companies to keep an eye on the equipment, and did it so rudely that the old company didn’t hand over important warnings like this. Discontinuity could explain problems like this readily.
- renewiltord 2y ago[flagged]
- mkesper 2y agoAnd further: The reliance by the consultants (before and after the first cable failure in 2020) on a perceived allowable pullout of one-sixth of the cable diameter, which should only be seen at loading at 80 percent of ultimate cable strength, does not align with the AASHTO M 277 standard guidance. The committee, therefore, disagrees with the suggestion made in the Thornton Tomasetti, Inc. (TT) 2022 report, Arecibo Telescope Collapse: Forensic Investigation,13 to use the D/6 limit as a threshold for slip monitoring.
- Iolaum 2y agoI would be curious if there are any accounts/reports of people working there - especially engineers - that could verify the claims of no alarm being raised when the first structural failures started showing up. It is often the case that people on the ground report such things but when "reports" are written for the higher ups, facts get "massaged" according to expectations.
- 77pt77 2y agoBearers of bad news get shot. Everyone working in large corporations knows this.
- lazystar 2y agobeing a bearer of bad news is a sign that you are not disagreeing and committing.
- photon_rancher 2y agoI was on the suspended section about a year before collapse - everyone could tell it was about to fail. Visible stress in rusty beams, old cables, and failing concrete. I think it just came down to underfunding at the end of the day - there was no money available to ask for even if the alarms were louder. And for most applications it was obsoleted by the larger new telescope in china, so there was no large push to turn that ship around from the wider scientific community.
- thimkerbell 2y ago[flagged]
- magicalhippo 2y agoI think absolutely not, for several reasons. First off, the report mentions this failure of the zinc filled sockets never been reported elsewhere before. Secondly, even if it had, the report mentions that written documentation of inspections and so on was spotty and inconsistent. That said, if the failure mode had been published before, and inspections and maintenance was written down in a consistent and detailed manner, then perhaps an LLM-based tool could have linked the two. I'm thinking of a RAG-like search thing that compared inspection reports with published documents. Alternatively just assisting a human in finding relevant published reports.
- _yb2s 2y agoAs a sailor that uses similar fittings in sailboat rigging… the idea of not treating a cable pullout from a terminal as an emergency is absurd. If that happened on a sailboat rig I’d assume it had a remaining strength of zero and will fall in seconds or less- and take the most rapid possible action to keep the structure from coming down by deloading the shroud and rigging an emergency replacement.
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- nonfamous 2y agoFrom the summary: >>> The only hypothesis the committee could develop that provides a plausible but unprovable answer to all these questions and the observed socket failure pattern is that the socket zinc creep was unexpectedly accelerated in the Arecibo Telescope's uniquely powerful electromagnetic radiation environment. The Arecibo Telescope cables were suspended across the beam of "the most powerful radio transmitter on Earth." The other investigations failed to note several failure patterns and provided no plausible explanation for most of them. To answer these questions with empirical evidence instead of only the inferences that can be made from the existing data, a more comprehensive and widespread forensic analysis of "good" and "bad" socket workmanship and the low-current, long-term effect on zinc creep is required.
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- shagie 2y ago(There was a comment that I was replying to about the realization that this was a transmitter and not just a receiver that was deleted ...) It was both. The Arecibo message was transmitted from there - https://en.wikipedia.org/wiki/Arecibo_message https://en.wikipedia.org/wiki/Arecibo_message > The entire message consisted of 1,679 binary digits, approximately 210 bytes, transmitted at a frequency of 2,380 MHz and modulated by shifting the frequency by 10 Hz, with a power of 450 kW. There's also the field of radar astronomy (not radio astronomy) https://en.wikipedia.org/wiki/Radar_astronomy https://en.wikipedia.org/wiki/Radar_astronomy where you bounce of a signal off of an object in the solar system (such as an asteroid) > Radar provides the ability to study the shape, size and spin state of asteroids and comets from the ground. Radar imaging has produced images with up to 7.5-meter resolution. With sufficient data, the size, shape, spin and radar albedo of the target asteroids can be extracted. > ... > In August 2020 the Arecibo Observatory (Arecibo Planetary Radar) suffered a structural cable failure, leading to the collapse of the main telescope in December of that year. > There is one remaining radar astronomy facility in regular use, the Goldstone Solar System Radar.
- Syonyk 2y agoFortunately, more novel research comes out of "Huh, that's weird... why did that happen?" than out of things behaving as expected. Though this one does seem rather baffling.
- Wololooo 2y agoEven if I am not a radio astronomer, this instrument was unique in nature and still in use for very specific observations and until the very end of its operation was able to deliver data. It is disheartening to learn that it was indeed due to gross maintenance negligence (as assumed originally by many) that the final fatal failure occurred, when potentially the structure could have been salvaged.
- axus 2y agoMy uninformed recollection from when the warning signs were raised, is there was not even budget to perform emergency maintenance, and they were resigned to the inevitable collapse.
- jdhwosnhw 2y agoI worked and did research atobservatory for my PhD - you are exactly correct. It was well known to the scientists and onsite engineers that a collapse was imminent, for years. Ironically, prior to the collapse the agency responsible for funding performed a study to see would need to do to stop supplying money to the observatory, and found that due to environmental impact, it would actually be more expensive to stop funding. After that study we all suspected that the agency was just waiting for decay or a natural disaster to do the dirty work for them
- WillPostForFood 2y agoThat's not what the report says. There was ~$14 million allocated for repairs in 2-18 after Hurricane Maria, but the cable sockets weren't identified as needing repairs until the first one failed. The problem wasn't the money, it was the failure to identify the problem. See page 28/29.
- ionwake 2y ago[flagged]
- KPGv2 2y ago> in developing country Arecibo is located in the United States. Unless Puerto Rico declared independence recently, that is. Snide remarks about Texas aside, would you say SpaceX is located in a developing country? Because you'd be hard-pressed to argue that Arecibo was located in a less developed place than SpaceX's South Texas facility. This is Arecibo: https://i.ytimg.com/vi/Dd6pCS1IBN4/hq720.jpg?sqp=-oaymwEhCK4FEIIDSFryq4qpAxMIARUAAAAAGAElAADIQj0AgKJD&rs=AOn4CLBA-Q1VXGlO1bAE0XOdfC1OQ_ni6w https://i.ytimg.com/vi/Dd6pCS1IBN4/hq720.jpg?sqp=-oaymwEhCK4... This is the nearest town to SpaceX's facility: https://archleague.org/wp-content/uploads/2021/03/AMRT_TX00_01_Downtown_1300x975.jpg https://archleague.org/wp-content/uploads/2021/03/AMRT_TX00_...
- stavros 2y agoIsn't that what the GP said?
- dark-star 2y agoBy some metrics, the US is considered a developing country. For example the U.N. places it at rank 46, below such countries as Romania, Cuba, Bulgaria, Albania: https://dashboards.sdgindex.org/rankings https://dashboards.sdgindex.org/rankings Edit: you US people can downvote me as much as you want, that won't change the facts :-D
- rootusrootus 2y agoI can find some ranking metric that your country will be low on the list, I guarantee it. On the other hand, what metric can I find that puts it at #1? There are a few of those that work for the US.
- dark-star 2y agosure, if you're looking for "any" ranking... but this is not some random dude's "top 100 countries to visit" or something. It's the U.N.'s official list of developed countries. That puts some credibility to it, and it is definitely relevant in this topic since people were discussing whether the US counted as developed country or not. That is certainly more credible than finding "some list where [my] country is low on". I'm sure they are out there but I don't think you can find any list by the UN or any other credible world-wide organization. Please, feel free to prove me wrong! Oh, and what list(s) did you have in mind where the US is #1? I can't think of many (at least not positive ones)
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- alexnewman 2y agoPuerto Rican here. Everything on our island is like that. Preventive maintence is ignored and our insurance companies go bankrupt every big hurricane
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- wileydragonfly 2y agoEverything in the Caribbean is like that if you want to be honest.
- rovr138 2y ago> if you want to be honest. They might only know about Puerto Rico thus limiting themselves to just that.
- BobaFloutist 2y agoIf we ever make you a state proper hopefully that will offer an opportunity for that to change.
- dylan604 2y agoBecause insurance payouts in Florida are so spectacular? Please, don't lead them along with false hope! /s
- ordu 2y agoAren't you afraid that US insurance companies will go bankrupt?
- rovr138 2y agoIf a corporation can't provide a service, they should limit themselves and not provide it, or go for bankruptcy after making bad decisions.
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- bell-cot 2y agoThe NSF's 2022 report on the collapse: https://www.nsf.gov/news/special_reports/arecibo/Arecibo-Telescope-Collapse-Forensic-Investigation-508c.pdf https://www.nsf.gov/news/special_reports/arecibo/Arecibo-Tel...
- pantulis 2y agoWhat an imposing document: the details are overwhelmingly detailed, it really does justice to the marvel of engineering that the Telescope was.
- sideshowb 2y agoAnalysis of recorded audio contains the phrase "for England, James?"
- fijiaarone 2y agoFinally a cogent post. Kids these days.
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- ctippett 2y agoPractical Engineering on YouTube has an episode covering the collapse of this structure[1]. It's very good and worth a watch. [1] https://youtu.be/3oBCtTv6yOw https://youtu.be/3oBCtTv6yOw
- jschrf 2y agoPerhaps it was a response to the Arecibo message, and the response was "quiet, they'll hear you".
- loa_in_ 2y agoOr what we found is the Vogon and their poetry induces beaurocracy issues on the receiving side
- dudeinjapan 2y agoFor England, James?
- nmc 2y agoDirect PDF download: https://nap.nationalacademies.org/cart/download.cgi?record_id=26982 https://nap.nationalacademies.org/cart/download.cgi?record_i...
- zinekeller 2y agoAh, no, like most journals (although NAP is not stricly a journal, PNAS is), there isn't a direct PDF link (OP: try to click that on a clean browser and you'll be disappointed).
- kazinator 2y agoPages and pages of name-dropping fluff before any substance. That is telling.