The end of the line for the Arecibo radio telescope

[0culus]

Not sure what you're getting at, but Arecibo definitely had military applications in it's early life.

[CatalinaWOW]

I wouldn't be surprised if such occurences become the norm in a few years, quite a lot of the stuff that was build in the 60s and 70s is already starting to fail... Here in germany, nearly 15% of all highway bridges are classified as "dilapidated". And that is certainly not going to get better anytime soon.

It has actually been going on for quite some time.  I work in the basic nuclear science area.  When I got started, there were ion accelerators all over the place.  Now, a whole bunch of them have been shut down, or available only to commercial customers, etc.  So, the old cyclotron at Oak Ridge national lab was shut down, then the Van de Graff there was shut down (highest voltage Van de Graff in the world, 50 MV), the 88" cyclotron at Lawrence Berkeley Labs was made only available to cash customers, right now the superconducting cyclotrons at MSU are being shut down and scrapped.  A bunch of other facilities have also been shut down.  All due to a VASTLY shrinking science budget in the US.

Jon

While I am generally in favor of research spending, and do think there is still good science to be done at a facility like Arecibo was, and could be again, not all facilities need to continue.  While I am sure there are uses for them today, Van de Graff generators and cyclotrons are the doddering old grandparents of the high energy particle accelerators at CERN.  While we can be fond of them it is somewhat like railing against the decommissioning of an old 400 kHz oscilloscope or a seventy five pound signal generator that can hit 950 MHz on a good day.

[msuffidy]

Well they saved some money on the demo. At least it ripped out ALL the cables somehow and no buildings were destroyed. If they are really interested they could just rebuild something like it there as it is an escavated site with maybe reusable towers.

[LaserSteve]

What we just lost was the high power transmit waveguide, two independent transmit feeds, a variable power splitter and part of the
Dish. As well as the astronomy feed horns. The 430 Mhz transmitter is in the building on the hill.
While Arecibo had seven receive feeds, it was also a dual beam radar, both  the Gregorian and the linear array could be used at the same time if desired.

 Arecibo had six auxiliary feedhorns for 430 Mhz receive, More often the VLA / Deep Space networks / other telescopes were used as multiple parallel receive sites , giving the asteroid network the benefits of a phased array and synthetic aperture.  Goldstone has an eight gigahertz transmitter, but is not as available as Arecibo was.

So not only could it transmit, it was a seven pixel imager by itself.

Contrary to popular belief, it could also scan in a limited manor by moving the feeds. and the cables had active tensioning.

In other words, the site was more capable then one might think.

[coppercone2]

I wouldn't be surprised if such occurences become the norm in a few years, quite a lot of the stuff that was build in the 60s and 70s is already starting to fail... Here in germany, nearly 15% of all highway bridges are classified as "dilapidated". And that is certainly not going to get better anytime soon.

it no longer needs to move NATO around in a emergency. Friendly oil relations with russia are sure to prevent an invasion now (probobly part of the reason)

I kinda wonder what the hell will happen if there is WW3 in say 30 years when all the stuff is really falling apart. Whoever has more amphibious vehicles and mobile bridges wins? minor blitzkrieg repeat with whoever has more light vehicles? (if you don't know, nazi tanks only started getting beefy into the middle of the war). You used to be able to discourage that because you could put alot of nasty equipment into the right places at a quick notice. Not sure if they will be able to give the same kind of value to stuff made with the air mobility craze in the modern military (so we can send stuff to the desert). I think it all assumes that no one is going to figure out how to make something heavy scary again (new armor). There does seem to be a sizable amount of people that suggest tanks are not going to be super bypassed by modern equipment as much as we think, so politicians could be making the wrong call based on bad information when it comes to maintaining those sorts of things (from the sounds of it though, it will bring upon a gigantic argument).

[BravoV]

I wouldn't be surprised if such occurences become the norm in a few years, quite a lot of the stuff that was build in the 60s and 70s is already starting to fail... Here in germany, nearly 15% of all highway bridges are classified as "dilapidated". And that is certainly not going to get better anytime soon.

it no longer needs to move NATO around in a emergency. Friendly oil relations with russia are sure to prevent an invasion now (probobly part of the reason)

I kinda wonder what the hell will happen if there is WW3 in say 30 years when all the stuff is really falling apart. Whoever has more amphibious vehicles and mobile bridges wins? minor blitzkrieg repeat with whoever has more light vehicles? (if you don't know, nazi tanks only started getting beefy into the middle of the war). You used to be able to discourage that because you could put alot of nasty equipment into the right places at a quick notice. Not sure if they will be able to give the same kind of value to stuff made with the air mobility craze in the modern military (so we can send stuff to the desert). I think it all assumes that no one is going to figure out how to make something heavy scary again (new armor). There does seem to be a sizable amount of people that suggest tanks are not going to be super bypassed by modern equipment as much as we think, so politicians could be making the wrong call based on bad information when it comes to maintaining those sorts of things (from the sounds of it though, it will bring upon a gigantic argument).

  I thought we're discussing radio astronomy antenna here ? 

Pity you, so much paranoia and hatred, must be like hell living with that kinda thought. 

[magic]

Offtopic being one thing, what's "hateful" about wandering how to fight WW3 on collapsing highways?

[coppercone2]

most old big projects that engineers find cool are basically falling apart because they are said to not benefit the military anymore and most people are super cheap and military applications usually do not allow you to boil a design down to shady levels, so now that the military is left out of things and deemed not important the projects start to suck and maintenance is not had. At least, its a small part of the reason why. In America like 30-40% of the bridges are fucked up (and I shudder to think what the number would be if German engineers that live in Germany and are culturally German would rate the % at given by the quality difference of 'entry grade' German and American products!). Really thrilled to drive to certain places where you can become jam in a cement sandwich because someone does not wanna paint some stuff and replace some bolts. I feel like the people that ignore this and still drive under it every day are some really driven psychopaths (super common for people to show solidarity to people neglecting infrastructure for some reason to show that you are brave and badass. I mention it in the car driving near a suspicious object and you might as well put a fucking barbell in the car and have someone do a 500 pound lift and start gloating about it).

of course its hateful, bridge collapses kill people, like the one in Italy recently. Possibly a similar principle to this telescope, ignore corrosion in load bearing members. Granted the ones in bridges are pretty insidious, I had a granite countertop crack because a metal bar potted in epoxy some how put rust pressure on the granite. You would really need to trust corrosion engineering best practices and forgo your own intuition (as you should) to see that one coming because based on 'common sense' it should not have happened, but if you read about what happens with epoxy and iron, its plainly shown as a regular occurance.

these projects are really interesting if you find 'damn he really squeezed everything he could have out of the companies preferred FEA method! look how he fooled everyone into not making a real life experiment first' interesting and or cool.


BTW I noticed in Poland when I was driving around too many things had a nice heavy coat of rust and dilapidated failing paint on it. All the rusty property fences looked wonderful. Old historical towns with a middle aged feel still had the same rusty moss covered roofs, its like if you plated the renaissance with cheap communism  . Beautiful victorianish house with a black mold, weathered paint and rust covered soviet grain house roof right near the town hall that looks like its from a fairy tale.

[jmelson]

While I am generally in favor of research spending, and do think there is still good science to be done at a facility like Arecibo was, and could be again, not all facilities need to continue.  While I am sure there are uses for them today, Van de Graff generators and cyclotrons are the doddering old grandparents of the high energy particle accelerators at CERN.

Some Van de Graff accelerators are certainly old-school and pretty obsolete.  But, the HHIRF at Oak Ridge was a 50 MV folded Van de Graff, and very sophisticated and about twice the energy of anything else ever built.

Cyclotrons are also old school, but the superconducting cyclotrons at MSU NSCL were very advanced, and I think their larger one (K1200) was the highest energy of any single cycloton in the world.  They were still doing research with them until this month.

MSU is replacing their cyclotrons with a linear accelerator system, but it won't be fully online for a couple years.

Jon

[coppercone2]

those last alot better because its usually in a sealed container of inert gas, at least the vandergaff in the MV range.

[MadTux]

Video on how it collapsed:
https://vid.pr0gramm.com/2020/12/03/36fa6ec3c3b41f57.mp4

[coppercone2]

well that sure is a embarrassing fail, I am not sure you want to let your projects end like that. It really should have been demolished I think. Literary infrastructure that crumbled to pieces on its own. The way it swings to the side like a wrecking ball is so bad.

[MadTux]

Wire snaps:
https://vid.pr0gramm.com/2020/12/03/2ceeb5f0ae90833b.mp4

[tom66]

That drone was lucky to not get taken down by that snapping cable.

Really interesting to see an up close of a structural failure like this.  The cable gives a bit and then total failure and it's all over.

[Sal Ammoniac]

More video of the collapse:

http://players.brightcove.net/679256133001/EkLWnGuil_default/index.html?videoId=6213883083001

[LaserSteve]

If you love RF, this may make you cry.. Tech details toward the end.

https://youtu.be/IqGnnpwEwug

Steve

[Bud]

The aliens must be scratching their heads (or whatever ) why that transmission was suddenly lost.

[Ian.M]

Its deeply suspicious that the main suspension cables were painted white near their anchors to the platform.   Some dumb administrator must have decided to paint the ugly cables which would have been showing signs of surface rust, and once the paint was on them failure was inevitable.

Back when Arecibo was built, there were still plenty of 'greybeards' in the rigging industry who'd served their apprenticeship working on the rigging of large square rig sailing ships, and the maintenance requirements for 'plough steel' static rigging in hostile environments were well known.  However as stainless steel ropes and cables have displaced plough steel ones for most static rigging, this common knowledge has largely been lost.

Its well known that wire rope in dynamic applications requires lubrication.  Its far less well known that contrary to the best practices for stainless wire rigging, its *ESSENTIAL* to lubricate 'plough steel' wire static ropes and cables, preferably with a penetrating lubricant with anti-corrosion properties, to reduce corrosion and prevent the strands fretting against each other as the load varies and the cable stretches.  The paint coating will have trapped water in the core of the cable, and prevented any applied lubricant from penetrating, resulting in rapidly accelerating corrosion of the strands.

[tom66]

Wasn't this a similar issue with the Ponte Morandi collapse?  The cables were encased in concrete because they were 'ugly' which precluded any inspection of them.  The concrete traps moisture and has a corrosive effect itself.

[Ian.M]

Each cable  should have been replaced as soon as there was significant distortion or more than three broken strands in a short length or two at the terminals.
https://www.unionrope.com/Portals/0/Documents/Technical/Crane/when-to-replace.pdf

Its obviously been running with little safety margin for many years and in recent years, allowing personnel access to the platform or under the dish, other than for essential structural maintenance, was criminally negligent.

[RoGeorge]

 

[BravoV]

Its deeply suspicious that the main suspension cables were painted white near their anchors to the platform.   Some dumb administrator must have decided to paint the ugly cables which would have been showing signs of surface rust, and once the paint was on them failure was inevitable.

Yep, just for the look, ... or .. maybe hiding the rust. 

[David Hess]

Maintenance is a rubber band which can be indefinitely stretched a small bit at a time by management and politics.

Why exactly did Physicist Robert Kerr resign as director back in 2015?  The articles I have read imply that after maintenance was deferred, the real condition of the structure was ignored or covered up.

[David Hess]

Its deeply suspicious that the main suspension cables were painted white near their anchors to the platform.   Some dumb administrator must have decided to paint the ugly cables which would have been showing signs of surface rust, and once the paint was on them failure was inevitable.

Yep, just for the look, ... or .. maybe hiding the rust. 

The other photographs I saw looked like the cables had been painted with aluminum or zinc paint however they had broken strands sticking out.

[BravoV]

I guess, the last time they had the money to paint it, to be more "re-presentable" for big screen audiences, was from the James Bond film producer.