4 ms·

I wonder what kind of hardware debugging could be used to find the source of the leak. Could they spacewalk to the exterior of the tunnel and then emit some kin

I wonder what kind of hardware debugging could be used to find the source of the leak. Could they spacewalk to the exterior of the tunnel and then emit some kind of detectible but inert gas from the interior to see where it appears outside? I suppose even if you found the leak there would still be some challenges in sealing it, especially if it's a growing leak like the data suggests. Would be a good experience for future space station maintenance though.

cabirum 2y ago
"tunnel that connects a larger module to a docking port" - reads like stress-induced metal fatigue, where it leaks a bit from every seam. It may not be a nice round hole somewhere.
- rbanffy 2y ago
  And being a docking module, I'd guess it'd be near the docking port structure (although all Russian modules are connected via docking ports, rather than berthing ones).
- potato3732842 2y ago
  Or just not an ideal design and the welded ring at the end is where it comes to a head because that's where the part connects to the next one. All aluminum stuff is gonna suffer fatigue problems eventually.
bobmcnamara 2y ago
For cars I've used a smoke generator (cigarette) and waved it around until the smoke is sucked into the vacuum leak. I'm sure NASA has something nicer.
- deleted 2y ago
  [deleted]
- jandrese 2y ago
  It is currently a very slow leak. That said a cloud of smoke shouldn't dissipate much at all in zero g so it might work.
  - bobmcnamara 2y ago
    Probably so, I think that it's about 50 cubic feet per day, set up a time lapse camera and watch where it goes.
dotnet00 2y ago
I feel like there must be something being lost in communication. Since this is a docking port connector, they ought to be able to block it off on one side with some sort of temporary airtight seal and measure the direction the air within flows in to gradually narrow down where the leak is. I get the impression that maybe NASA is avoiding openly discussing the cause of the leak to be nice to roscosmos (because despite all the geopolitical conflict, they're still trying to keep the station running as is for a few more years).
- rbanffy 2y ago
  They are just closing the hatch to the faulty module. Considering the leak is very small and that it'd be a huge hassle to detect it (with little that could be done to fix the structural problem - while you can stop the leak with bubble-gum, but can't redo the weld in space)
toomuchtodo 2y ago
https://www.nasa.gov/nexis/robotic-external-leak-locator/ https://www.nasa.gov/nexis/robotic-external-leak-locator/ https://ntrs.nasa.gov/api/citations/20070022572/downloads/20070022572.pdf https://ntrs.nasa.gov/api/citations/20070022572/downloads/20...
rbanffy 2y ago
> some challenges in sealing it It's a 1 atm difference, so even adhesive tape stuck on the inside would do the trick. Unfortunately, I don't think there is much unexposed hull on the inside and I bet the crack is behind some equipment that isn't trivial to remove (or else it'd have been found years ago by some annoyed astronaut in their off-time). Detecting from the outside is also complicated, as you'd need to release (and reattach) the thermal blankets to see the actual surface of the module. Closing the hatch and stopping the use of that docking port seems to be the smart thing to do. Worst case scenario, repressurise, dock the Progress, unload, load it with trash, and close the hatch. I also don't think anyone is considering using this module to boost the station's altitude - I would't put any additional stresses on it anyway.
- schiffern 2y ago
  True, but also sealing the leak is only putting a bandaid over the problem. The hull is still going to fail eventually. A better fix would be (believe it or not) drilling holes in it, then sealing it over. This "stop drilling" prevents the crack from growing any larger. https://old.reddit.com/r/engineering/comments/6bdugb/how_does_stop_drilling_arrest_metal_crack/ https://old.reddit.com/r/engineering/comments/6bdugb/how_doe...
molticrystal 2y ago
Maybe several pieces of flat paper or thin foam and see what walls and joints it likes to stick too. Repeated often enough it might show some suspicious spots.
- rtkwe 2y ago
  The station has so many fans for cooling equipment and circulation to keep the air fresh I doubt that'd show results fast enough that the station could be kept half shut down for. Anything that's air cooled up there requires circulation remember because convection requires gravity for density to drive movement.
- zikduruqe 2y ago
  They could send up a few cartons of cigarettes to detect the cracks. /s https://www.upi.com/Archives/1988/05/27/The-recently-imposed-smoking-ban-on-many-commercial-flights/6624580708800/ https://www.upi.com/Archives/1988/05/27/The-recently-imposed...
  - hashishen 2y ago
    How do you just pulled this up on a whim is crazy to me
    - zikduruqe 2y ago
      And just think... at some point in your future, you will be reading a forum, social media or message board, and someone will pose a question about detecting small air leaks. You will remember this, and amaze them. themoreyouknow.gif
jjk166 2y ago
For something like this an ultrasonic leak detector would likely be ideal. Much like wind blowing through an open window, as air flows through the leak it makes noise which is totally inaudible to the human ear but detectable by sensitive electronics. The closer you get to the leak, the louder it is.

cabirum 2y ago

"tunnel that connects a larger module to a docking port" - reads like stress-induced metal fatigue, where it leaks a bit from every seam. It may not be a nice round hole somewhere.

rbanffy 2y ago
And being a docking module, I'd guess it'd be near the docking port structure (although all Russian modules are connected via docking ports, rather than berthing ones).
potato3732842 2y ago
Or just not an ideal design and the welded ring at the end is where it comes to a head because that's where the part connects to the next one. All aluminum stuff is gonna suffer fatigue problems eventually.

bobmcnamara 2y ago

For cars I've used a smoke generator (cigarette) and waved it around until the smoke is sucked into the vacuum leak. I'm sure NASA has something nicer.

deleted 2y ago
[deleted]
jandrese 2y ago
It is currently a very slow leak. That said a cloud of smoke shouldn't dissipate much at all in zero g so it might work.
- bobmcnamara 2y ago
  Probably so, I think that it's about 50 cubic feet per day, set up a time lapse camera and watch where it goes.

dotnet00 2y ago

I feel like there must be something being lost in communication. Since this is a docking port connector, they ought to be able to block it off on one side with some sort of temporary airtight seal and measure the direction the air within flows in to gradually narrow down where the leak is. I get the impression that maybe NASA is avoiding openly discussing the cause of the leak to be nice to roscosmos (because despite all the geopolitical conflict, they're still trying to keep the station running as is for a few more years).

rbanffy 2y ago
They are just closing the hatch to the faulty module. Considering the leak is very small and that it'd be a huge hassle to detect it (with little that could be done to fix the structural problem - while you can stop the leak with bubble-gum, but can't redo the weld in space)

toomuchtodo 2y ago

https://www.nasa.gov/nexis/robotic-external-leak-locator/ https://www.nasa.gov/nexis/robotic-external-leak-locator/ https://ntrs.nasa.gov/api/citations/20070022572/downloads/20070022572.pdf https://ntrs.nasa.gov/api/citations/20070022572/downloads/20...

rbanffy 2y ago

> some challenges in sealing it It's a 1 atm difference, so even adhesive tape stuck on the inside would do the trick. Unfortunately, I don't think there is much unexposed hull on the inside and I bet the crack is behind some equipment that isn't trivial to remove (or else it'd have been found years ago by some annoyed astronaut in their off-time). Detecting from the outside is also complicated, as you'd need to release (and reattach) the thermal blankets to see the actual surface of the module. Closing the hatch and stopping the use of that docking port seems to be the smart thing to do. Worst case scenario, repressurise, dock the Progress, unload, load it with trash, and close the hatch. I also don't think anyone is considering using this module to boost the station's altitude - I would't put any additional stresses on it anyway.

schiffern 2y ago
True, but also sealing the leak is only putting a bandaid over the problem. The hull is still going to fail eventually. A better fix would be (believe it or not) drilling holes in it, then sealing it over. This "stop drilling" prevents the crack from growing any larger. https://old.reddit.com/r/engineering/comments/6bdugb/how_does_stop_drilling_arrest_metal_crack/ https://old.reddit.com/r/engineering/comments/6bdugb/how_doe...

molticrystal 2y ago

Maybe several pieces of flat paper or thin foam and see what walls and joints it likes to stick too. Repeated often enough it might show some suspicious spots.

rtkwe 2y ago
The station has so many fans for cooling equipment and circulation to keep the air fresh I doubt that'd show results fast enough that the station could be kept half shut down for. Anything that's air cooled up there requires circulation remember because convection requires gravity for density to drive movement.
zikduruqe 2y ago
They could send up a few cartons of cigarettes to detect the cracks. /s https://www.upi.com/Archives/1988/05/27/The-recently-imposed-smoking-ban-on-many-commercial-flights/6624580708800/ https://www.upi.com/Archives/1988/05/27/The-recently-imposed...
- hashishen 2y ago
  How do you just pulled this up on a whim is crazy to me
  - zikduruqe 2y ago
    And just think... at some point in your future, you will be reading a forum, social media or message board, and someone will pose a question about detecting small air leaks. You will remember this, and amaze them. themoreyouknow.gif

jjk166 2y ago

For something like this an ultrasonic leak detector would likely be ideal. Much like wind blowing through an open window, as air flows through the leak it makes noise which is totally inaudible to the human ear but detectable by sensitive electronics. The closer you get to the leak, the louder it is.