How did they build the cables in the first place? Couldn't they just snip the cables with a helicopter or unmanned drone with a flying chopsaw and string new ones as if it was a brand new construction?
Basically I'm not understanding how it is impossible to replace something but it is evidently possible to build that something.
Being unable to fix something you’re able to build isn’t unusual to anyone who has built a large and complicated structure. They had two different engineering firms look at it, and neither of them saw a safe path forward. It’s possible that repairing it was physically possible, but would have put people in harms way while they were, for example, detaching cables on an already unstable structure.
This was basically a whole building suspended into the air. Science or magic? Amazing engineering to be sure (but maybe not built with maintenance and security in mind)
Are there not unmanned solutions to the problem? Drones with flying abrasive chopsaws? Literally strap a Dewalt circular saw onto a big enough drone with the power button taped down? Use a drone to attach a dynamite to the cable? It seems weird to me that the government can figure out how to remotely bomb a town but can't figure out how to remotely do a little snippy snip snip on a cable.
Flying buzzsaws seems unlikely to work, but I don't think snipping the old cables would even be the hard[est] part. Installing new cables would almost certainly require workers to be present on the center platform, and it obviously wasn't safe for anybody to be there.
The dish is nothing but aluminum sheeting with holes in it. The vast majority of the cost and complexity are in the instrument cluster and the towers. There's not much of value left to repair at this point.
As for replacing cables, anyone who has rebuilt a RAID array will tell you that hardware is most likely to fail when it's under stress, like when you have workers in the towers setting the footings for the new ultra-safe cables. It's not just dangerous because they don't know when it'll give way, it's dangerous because messing with it was likely to trigger a collapse like what we just saw.
The location itself, both in terms of terrain and extant infrastructure and personnel also has value. Without the dish to support it, that's also a writeoff.
Still likely not a compelling case for rebuilding, however.
I assumed that in 2020 we have unmanned solutions to taking something down, and then rebuilding would be done with proper engineering as if it were a new radio telescope but the dish is already built for you.
No robot currently exists that can replace even a tiny fraction of the tasks a 16 year old teenager with a hard-hat and steel toed boots can do at a construction site.
Think of a house of cards. Now think of being required to replace a middle layer without disturbing the cards above it. Also, each card weighs forty tons and, on falling, will kill some or all of the people working on the repair job and take out enough structure to make the whole thing a writeoff anyway.
The thing that was hanging suspended above the dish was weighing 900 tons. I don't know how it could be that heavy (it's probably pretty big), but that sounds too heavy for any helicopter or drone to lift - even if it only had to hold 1/100th of the weight of it while the cable was being replaced.
The answer is that they almost certainly built it with almost nothing hanging in the center, and without the dish below it. Once the basic platform was in place, then they hoisted up all of the components to build out the 900 ton platform (actually, that took years and years as equipment was added to upgrade it).
So, in essence, doing a replacement of all of the cables would need to start by essentially disassembling the thing completely and then rebuilding it.
How did they build the cables in the first place? Couldn't they just snip the cables with a helicopter or unmanned drone with a flying chopsaw and string new ones as if it was a brand new construction?
Basically I'm not understanding how it is impossible to replace something but it is evidently possible to build that something.