4 ms·

Do these modules undergo pressure tests before launching? I would hope there's some quality control to catch this type of flaw.

rebolek 8y ago
They do, but the hole was filled with glue. Once in space, the glue dried up and depressurizing started. So it was not possible to catch it on ground.
londons_explore 8y ago
I would expect "glue in a hole" to fail as the sun hits the module every 90 mins, and the surface probably heats to 100C and cools to -25C. That kind of heat cycling causes expansion and contraction, causing the boundary between the metal and the glue to weaken then fail. One can test for that in the lab, but it involves heat cycling for a long time to reproduce the same number of cycles the space station could undergo in its multi-decade lifespan.
- pocketstar 8y ago
  only the exterior blankets would have such extreme temperature cycles, the inner aluminum hull would have a much more stable temperature. The diurnal would be much more benign. Still enough for CTE and fatigue to cause a failure.
- INTPenis 8y ago
  Where do you get this glue info? I don't see it in the article. So someone accidentally drilled through an expensive space station module on earth and filled the hole with glue. Wow..
  - unwind 8y ago
    Third paragraph, with a quote directly after it: An unnamed source told RIA Novosti the person responsible for drilling the hole filled it with glue instead of reporting the mistake. "The glue dried and was squeezed out, opening the hole," the source told the media outlet. It's fun that the astronauts did the proper/final fix with epoxy, which to most people is of course also a glue. So perhaps the worker used (or mis-used) the wrong glue to fix this, rather than tried to cover up the mistake? Of course it sounds reasonable that it should have been reported, which didn't happen, so so the working environment seems improvable.
    - deleted 8y ago
      [deleted]
    - Double_a_92 8y ago
      Maybe it was reported and the "proper" fix at that time was to use that glue.
      - Tor3 8y ago
        If it was reported there should be records.
        foxyv 8y ago
        Oh you sweet summer child. /s
    - tim333 8y ago
      Epoxy's probably the best you can do in space but on the ground I imagine it would have been better to weld or replace the part.
      - jandrese 8y ago
        I think "the part" in this case is the entire pressure vessel. You would have to disassemble everything and build a new capsule out of the parts. The thing that gets me is that the glue "squeezed out" of the hole? What did they use? Hot glue? Rubber cement? Once epoxy hardens it might break up but it's not going to squeeze through anything.
    - INTPenis 8y ago
      Ugh ok, wtf. Believe it or not but with JS disabled I get a completely different text that doesn't mention glue.
      - Operyl 8y ago
        Safari, JS disabled, text appears just fine for me.
- moftz 8y ago
  You can do that on Earth if your thermal vacuum chamber is big enough. They will run accelerated hot/cold cycles while under vacuum to simulate something like 30 transitions but if the glue in the hole held out through the entire test, there would be no way to find it. That vehicle had been up there since June so it did pretty well for an unreported patch job.

rebolek 8y ago

They do, but the hole was filled with glue. Once in space, the glue dried up and depressurizing started. So it was not possible to catch it on ground.

londons_explore 8y ago

I would expect "glue in a hole" to fail as the sun hits the module every 90 mins, and the surface probably heats to 100C and cools to -25C. That kind of heat cycling causes expansion and contraction, causing the boundary between the metal and the glue to weaken then fail. One can test for that in the lab, but it involves heat cycling for a long time to reproduce the same number of cycles the space station could undergo in its multi-decade lifespan.

pocketstar 8y ago
only the exterior blankets would have such extreme temperature cycles, the inner aluminum hull would have a much more stable temperature. The diurnal would be much more benign. Still enough for CTE and fatigue to cause a failure.
INTPenis 8y ago
Where do you get this glue info? I don't see it in the article. So someone accidentally drilled through an expensive space station module on earth and filled the hole with glue. Wow..
- unwind 8y ago
  Third paragraph, with a quote directly after it: An unnamed source told RIA Novosti the person responsible for drilling the hole filled it with glue instead of reporting the mistake. "The glue dried and was squeezed out, opening the hole," the source told the media outlet. It's fun that the astronauts did the proper/final fix with epoxy, which to most people is of course also a glue. So perhaps the worker used (or mis-used) the wrong glue to fix this, rather than tried to cover up the mistake? Of course it sounds reasonable that it should have been reported, which didn't happen, so so the working environment seems improvable.
  - deleted 8y ago
    [deleted]
  - Double_a_92 8y ago
    Maybe it was reported and the "proper" fix at that time was to use that glue.
    - Tor3 8y ago
      If it was reported there should be records.
      - foxyv 8y ago
        Oh you sweet summer child. /s
  - tim333 8y ago
    Epoxy's probably the best you can do in space but on the ground I imagine it would have been better to weld or replace the part.
    - jandrese 8y ago
      I think "the part" in this case is the entire pressure vessel. You would have to disassemble everything and build a new capsule out of the parts. The thing that gets me is that the glue "squeezed out" of the hole? What did they use? Hot glue? Rubber cement? Once epoxy hardens it might break up but it's not going to squeeze through anything.
  - INTPenis 8y ago
    Ugh ok, wtf. Believe it or not but with JS disabled I get a completely different text that doesn't mention glue.
    - Operyl 8y ago
      Safari, JS disabled, text appears just fine for me.
moftz 8y ago
You can do that on Earth if your thermal vacuum chamber is big enough. They will run accelerated hot/cold cycles while under vacuum to simulate something like 30 transitions but if the glue in the hole held out through the entire test, there would be no way to find it. That vehicle had been up there since June so it did pretty well for an unreported patch job.