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Reason 1: because they were afraid of it failing catastrophically just like what happened this morning. One person was on site (director of telescope operations

Reason 1: because they were afraid of it failing catastrophically just like what happened this morning. One person was on site (director of telescope operations Angel), but imagine what would have happened if a work crew was up in the structure working on cables during such a failure. Reason 2: They are not going to build a new one. NSF has tried to get rid of AO for a long time now.

dheera 6y ago
Re: Reason 1 Well sure, but a hypothetical new structure is also going to require cables, just hopefully a more reliable construction. So why not keep the dish for now, and consider rebuilding the cables in a more modern fashion, and with redundant cables?
- petschge 6y ago
  The cables were (originally) redundant. There are actually replacement cables on the way from Germany right now. But after the one main cable failed earlier this year they noticed that all cables are MUCH weaker than previously thought. So there was (even before the collapse) no way of replacing the existing cables with the replacements. And yes that probably implies that they should have swapped out all cables years ago. But they didn't have the funding.
  - dheera 6y ago
    > no way of replacing 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.
    - kaikai 6y ago
      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.
      - dheera 6y ago
        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.
        bigbubba 6y ago
        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.
      - Twisell 6y ago
        Also this video can help realize the amazing scale of this thing: https://youtube.com/watch?feature=emb_title&v=QZAWqk-wrzc https://youtube.com/watch?feature=emb_title&v=QZAWqk-wrzc 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)
    - paledot 6y ago
      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.
      - dredmorbius 6y ago
        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.
      - deleted 6y ago
        [deleted]
      - dheera 6y ago
        Why would there workers in the towers? 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.
        vkou 6y ago
        Your assumption is off by a few decades. 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.
    - kzrdude 6y ago
      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.
      - maigret 6y ago
        Interesting, I read 300 tons (which is already a lot!)
    - throwanem 6y ago
      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.
    - URSpider94 6y ago
      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.
    - JohnBooty 6y ago
      Basically I'm not understanding how it is impossible to replace something but it is evidently possible to build that something. Ah, you are fortunate. I see you've never worked on a large software project with lots of technical debt. =)
acqq 6y ago
I'd like to know more about why "NSF has tried to get rid of AO for a long time now." Anybody knows something interesting and specific? What I was able to find was the Washington Post 2007 article, where it's mentioned that: "states with major observatories, such as New Mexico and West Virginia, have senators famous for their power over purse strings, some of whom are already gearing up to fight proposed cuts. By contrast, Puerto Rico, a commonwealth of the United States, has no senators. And its representative in the House" "does not have a vote." and "The cash crunch stems from a "senior review" completed last November at NSF." and ""The ambitions of the astronomy community for new things was far outstripping the capacity of the federal budget to cover them," said Wayne van Citters, NSF's astronomy division director, who organized the independent review" https://www.washingtonpost.com/wp-dyn/content/article/2007/09/08/AR2007090801654.html https://www.washingtonpost.com/wp-dyn/content/article/2007/0...

dheera 6y ago

Re: Reason 1 Well sure, but a hypothetical new structure is also going to require cables, just hopefully a more reliable construction. So why not keep the dish for now, and consider rebuilding the cables in a more modern fashion, and with redundant cables?

petschge 6y ago
The cables were (originally) redundant. There are actually replacement cables on the way from Germany right now. But after the one main cable failed earlier this year they noticed that all cables are MUCH weaker than previously thought. So there was (even before the collapse) no way of replacing the existing cables with the replacements. And yes that probably implies that they should have swapped out all cables years ago. But they didn't have the funding.
- dheera 6y ago
  > no way of replacing 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.
  - kaikai 6y ago
    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.
    - dheera 6y ago
      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.
      - bigbubba 6y ago
        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.
    - Twisell 6y ago
      Also this video can help realize the amazing scale of this thing: https://youtube.com/watch?feature=emb_title&v=QZAWqk-wrzc https://youtube.com/watch?feature=emb_title&v=QZAWqk-wrzc 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)
  - paledot 6y ago
    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.
    - dredmorbius 6y ago
      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.
    - deleted 6y ago
      [deleted]
    - dheera 6y ago
      Why would there workers in the towers? 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.
      - vkou 6y ago
        Your assumption is off by a few decades. 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.
  - kzrdude 6y ago
    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.
    - maigret 6y ago
      Interesting, I read 300 tons (which is already a lot!)
  - throwanem 6y ago
    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.
  - URSpider94 6y ago
    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.
  - JohnBooty 6y ago
    Basically I'm not understanding how it is impossible to replace something but it is evidently possible to build that something. Ah, you are fortunate. I see you've never worked on a large software project with lots of technical debt. =)

acqq 6y ago

I'd like to know more about why "NSF has tried to get rid of AO for a long time now." Anybody knows something interesting and specific? What I was able to find was the Washington Post 2007 article, where it's mentioned that: "states with major observatories, such as New Mexico and West Virginia, have senators famous for their power over purse strings, some of whom are already gearing up to fight proposed cuts. By contrast, Puerto Rico, a commonwealth of the United States, has no senators. And its representative in the House" "does not have a vote." and "The cash crunch stems from a "senior review" completed last November at NSF." and ""The ambitions of the astronomy community for new things was far outstripping the capacity of the federal budget to cover them," said Wayne van Citters, NSF's astronomy division director, who organized the independent review" https://www.washingtonpost.com/wp-dyn/content/article/2007/09/08/AR2007090801654.html https://www.washingtonpost.com/wp-dyn/content/article/2007/0...