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The end of the line for the Arecibo radio telescope

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james_s:
People crazier than I have certainly attempted more dangerous stunts than that, even for no more gain than having accomplished the stunt. I would be more willing to climb up onto that platform to attach some cables than to attempt to climb up Mt Everest for example. Personally I would not want to do either one, but replacing the cables to save this thing from collapse seems far more useful.

How much does the suspended structure weigh? Is it within the realm of what could be lifted straight up by a large heavy lifting helicopter? If so either lift the thing up, cut the cables and then set it aside on the ground, or lift it to take the load off the cables just long enough for a crew to rush out and attach already prepared replacement cables.

Ian.M:
Its two orders of magnitude heavier than any helicopter can handle.  I suspect the next thing that will happen is that a demolition plan will be put forward, probably by dynamiting the ground anchors of the tower restraining cables, and the tower bases to trigger an inwards collapse.

coppercone2:
900 tons, you would need like 60 hinds lol

you would probobly need to build a temporary structure under it, I have my doubts even about cranes. thats why i suggested the 3d printed concrete tower

rdl:
There's still a lot of infrastructure there and the site is obviously ideal for a telescope of that type, why not just rebuild? Maybe the towers can be reused.

TerraHertz:

--- Quote from: David Hess on November 27, 2020, 09:43:20 pm ---The strands were broken from the two recent overload events.

--- End quote ---

Sorry for lack of a link, but somewhere in the various videos I've watched about this recently there was a short sequence of pictures of the cables, taken by drones.

They are a mess. Steel multi-stranded cables, several inches thick, in which there is a lot of internal rusting causing random bulges. The spreading of the strands causes uneven stress on the strands, and together with the corrosion, results in LOTS of broken strands. Many, many places where there are broken strands sticking out like hairs.

So when they say the entire structure could collapse at any time and it's too unsafe to work on, they don't mean the extra weight of workers could make it fall. They really mean it could go at any moment. It has no remaining redundancy, and strengths of the remaining cables are continually reducing due to corrosion and ongoing strand breaks.

The final failure mode would be completely unpredictable, but will likely involve huge cable whipping around, the antenna falling in some random arc, and the support towers falling over dragged by unbalanced cables. No one is going to go anywhere near it. No helicopters, no building an emergency support tower under the antenna, and even walking around under the dish meshwork is a death sport at the moment.

I'd think even controlled demolition by placing cutting charges on all the cables so they can be dropped in one go, would be an extremely dangerous job.

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