> Once the station reaches the end of its life, NASA intends to transition its activities in low-Earth orbit onto private space stations, and it has funded initial development work by Axiom Space, Northrop Grumman, Blue Origin, and Voyager Space.
One publication I read made a couple of relevant points:
NASA should be careful about privatization and subcontracting, as it replaces NASA top-notch engineers with contract managers and oversight. Most engineers aren't interested in that work, and the skills don't stay sharp.
Also, it said that Gateway, the space station planned to orbit the Moon, is considered the conceptual descendent of ISS.
IMHO NASA should focus on the cutting edge, pushing the frontiers of space and technology. I'm glad they stopped bothering with orbital launch, which they've done for over 60 years - many countries and many private companies can do that now. I'm not sure where ISS falls - LEO is obviously relatively common technology, but habitation in orbit? Space stations orbiting the Moon are the kind of thing where NASA should aim.
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.
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.
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).
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)
"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.
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).
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.
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.
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.
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.
it is planned for decommission. in the interim, they are isolating the impacted module and not planning repair (at least, that's what I got from the article!)
You'll also need to have their agreement before you deorbit the Russian part. There is no way around that marriage (and it'd be better to make it work - space operations shouldn't be run by politicians anyway).
Basically the full workup describes her having a mental breakdown and just making life up there more and more miserable, saying "take me home or I'll escalate" followed by many cycles of not being taken home and escalating. It includes stealing/losing most tools and equipment and "losing them" to the vacuum of space, drilling holes in the space station, and let us diplomatically say... very poor hygiene related to human waste. The astronaut involved basically quit doing any work. Supposedly this ruined the station and basically assured that it be taken offline.
I was an ISS Flight Controller for 6 years and worked in NASA mission planning and the idea that a us astronaut was “losing it in orbit and intentionally drilled a whole” is pretty ridiculous
It’s obvious that the “hole” was some kind of miss by QA on the Russian side on the ground and it’s in Russian media interest currently to spread any unfounded speculation out into the interwebs
Both the Russian Cosmonauts and US Astronauts were eminently professional people hardworking and dependable people and the also ground crews across the world who work night and day operating the station such that no ISS Crewmember should ever deserve to get their names dragged in the mud over this
As a Westerner, the gov blaming things on Russia is like a school kid saying their dog ate their homework... Even if it's true, ts so cliche at this point I just don't believe it
The joys of HN is finding experts in just about anything, so...
Assuming that NASA is correct about this leak being associated with an interior or exterior weld, what can we learn from the rate of growth of the leak? I assume (with no domain knowledge, seeking enlightenment!) that a leak like this is big enough to reflect a fracture in the weld, and not merely air sneaking past a tiny flaw; and I assume its growth means that the fracture itself is growing, under the combination of load (atmospheric pressure on one side) and cycling (thermal, etc). Is a fracture like this likely to continue to grow in a linear-ish domain, or is there a point where propagation goes non-linear assuming the loads stay constant-ish? Is this even a sane question to ask?
Obviously it can't be linear forever, if you assume the crack is along a circumference then eventually there will only be a tiny piece of metal still intact between the two halves, and one would expect it to fail far before then.
These kinds of failures tend to be linear until they are not, and the failure mode is catastrophic. If I were in charge I would have already shut off that module on the risk/benefit analysis of catastrophic loss of the station vs. not being able to evacuate as quickly in a less catastrophic emergency. Maybe they are worried they won't be able to get the hatch open again if they can't equalize the pressure again?
For historical reference, consider Aloha Airlines Flight 243[1].
> Maybe they are worried they won't be able to get the hatch open again if they can't equalize the pressure again?
Well note that they currently keep the hatch to the docking port closed unless they're using it, so that presumably mitigates some of the risk (assuming the leak is confined to that location). Not using the whole Zvezda module itself would be more or less impossible from my understanding.
If they decided to stop using that dock port at all then I think that complicates planning and makes everything overall riskier, so while it wouldn't be a disaster to do there's still risk you have to weigh.
Disclaimer: I don't know how space modules are welded or what forces act on a space module.
Welds fail for multiple reasons - heating too fast, cooling too fast, material defects, human error, equipment issues, oxidation. The best human welder will still have some variance in their weld even if they lay a perfect bead.
Once a weld begins to fail, under normal conditions (vibration, stress, etc), it will slowly get worse, but that can also mean deformation around the weld or even sometimes shearing right next to your weld. The article doesn't mention that the growth has been linear only that it is increasing. I expect that the leak is increasing over time in a non-linear fashion as force is applied to the weak area and metal continues to separate and/or shear. Still, 3.7 pounds of atmosphere a day is a very slow leak (relatively), a few bike tires a day.
> Is a fracture like this likely to continue to grow in a linear-ish domain, or is there a point where propagation goes non-linear assuming the loads stay constant-ish? Is this even a sane question to ask?
It depends on so much that we don't know from the article.
Non-expert, pure speculator here: I cannot help but think of the Titan submersible and its minor flaw in the hull that slowly became more and more of an issue with each dive and pressurization cycle. I wonder if the 'untenable' leak rate that isn't agreed upon is the rate at which an accelerated and catastrophic runaway event occurs?
There was no "minor flaw" in the Titan submersible.
It was a very bad design[1], using substandard material[2] in new and untested ways[3] with poor assembly practices[4]. It was fatally flawed from the start.
1 - Asked about the carbon composite used in Titan’s experimental design, Cameron said, “It’s completely inappropriate for a vessel that sees external pressure.” He went on to say that carbon fiber is very helpful when used for applications subject to internal pressure, like scuba tanks. But, he said, “for something that’s seeing external pressure, all of the advantages of composite material go away and all the disadvantages come into play.”
"Expired" bare carbon fiber might be ok; expired prepreg is likely not ok. And I still can't get my head around the apparent mixing of prepreg and wet winding resins in the same laminates.
That article says Boeing has no record of ever selling oceangate composite material. So either he got it for free (Dumpster diving?) or it came from someone else. Maybe some guy in a parking lot: My boss told me to deliver this stuff to Boeing but they wouldn't take it because its expired, I'll sell it to you cheap.
3 - "Thickness, he says, was estimated using micromechanics, and then verified with finite element analysis (FEA).”. >Wonderful. That sort of maybe can work for tension stresses, but can be highly unreliable for compression loading
4 - https://www.youtube.com/watch?v=4PUTbK5AqY8 :
>For such a critical joint I see some questionable prep work >in the video.
>-Bare hands touching the bond surface.
>-Solvent wiping used instead of caustic degreasers.
>-Poor wiping technique
>-no surface profile/grit blast immediately prior to fixing.
It's important to remember that the pressures involved are very different. The ISS pressure vessels only have to hold 1atm in, and not several atmospheres out.
Equally important is that the ISS is under tensile load (the cylinder is trying to explode), while a submersible is under compressive load (the cylinder is trying to implode).
When I read this I understood _cracking_ in its sense of software piracy aka "hacking."
A mental subprocesses spawned to predict whether the cracking was _of_ the systems on the station—possibly inspired by that movie trailer I saw for the thriller about a new cold war in space after a nuclear war—or _from_ the space station, by bored occupants, either of their own systems or of some system they interact with on the ground.
> Once the station reaches the end of its life, NASA intends to transition its activities in low-Earth orbit onto private space stations, and it has funded initial development work by Axiom Space, Northrop Grumman, Blue Origin, and Voyager Space.
One publication I read made a couple of relevant points:
NASA should be careful about privatization and subcontracting, as it replaces NASA top-notch engineers with contract managers and oversight. Most engineers aren't interested in that work, and the skills don't stay sharp.
Also, it said that Gateway, the space station planned to orbit the Moon, is considered the conceptual descendent of ISS.
Much more here: https://nap.nationalacademies.org/cart/download.cgi?record_i...
IMHO NASA should focus on the cutting edge, pushing the frontiers of space and technology. I'm glad they stopped bothering with orbital launch, which they've done for over 60 years - many countries and many private companies can do that now. I'm not sure where ISS falls - LEO is obviously relatively common technology, but habitation in orbit? Space stations orbiting the Moon are the kind of thing where NASA should aim.
> Most engineers aren't interested in that work
What if you worked for a nasa contractor and you got paid quite a bit more than working for nasa?
Right; that has an impact on NASA's workforce.
Hard to focus on the cutting edge, pushing the frontiers of space and technology with an ever-dwindling budget…
Surely ~$25B/year is enough to push the frontiers of space exploration?
We spend $900bn on “defense” so not really ;)
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.
> 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.
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_doe...
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).
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)
"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.
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.
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).
https://www.nasa.gov/nexis/robotic-external-leak-locator/
https://ntrs.nasa.gov/api/citations/20070022572/downloads/20...
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.
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.
Probably so, I think that it's about 50 cubic feet per day, set up a time lapse camera and watch where it goes.
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.
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.
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.
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...
How do you just pulled this up on a whim is crazy to me
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
It's hard to imagine US/Russian relations improving in the coming years. It might be easier and safer to retire the ISS sooner rather than later.
As a fun juxtaposition to your comment, here is a playlist of videos of them building it: https://www.youtube.com/playlist?list=PLYu7z3I8tdEnjgkBIBgxa...
it is planned for decommission. in the interim, they are isolating the impacted module and not planning repair (at least, that's what I got from the article!)
You'll also need to have their agreement before you deorbit the Russian part. There is no way around that marriage (and it'd be better to make it work - space operations shouldn't be run by politicians anyway).
There are rumors out there in the spacefaring community, wallpapered pretty heavily and media/google censored, regarding the astronaut responsible: https://www.newsweek.com/russia-could-take-legal-action-agai...
Basically the full workup describes her having a mental breakdown and just making life up there more and more miserable, saying "take me home or I'll escalate" followed by many cycles of not being taken home and escalating. It includes stealing/losing most tools and equipment and "losing them" to the vacuum of space, drilling holes in the space station, and let us diplomatically say... very poor hygiene related to human waste. The astronaut involved basically quit doing any work. Supposedly this ruined the station and basically assured that it be taken offline.
Gossip of course rises to the top
I was an ISS Flight Controller for 6 years and worked in NASA mission planning and the idea that a us astronaut was “losing it in orbit and intentionally drilled a whole” is pretty ridiculous
It’s obvious that the “hole” was some kind of miss by QA on the Russian side on the ground and it’s in Russian media interest currently to spread any unfounded speculation out into the interwebs
Both the Russian Cosmonauts and US Astronauts were eminently professional people hardworking and dependable people and the also ground crews across the world who work night and day operating the station such that no ISS Crewmember should ever deserve to get their names dragged in the mud over this
https://www.snopes.com/fact-check/nasa-astronaut-sabotage-is...
As a Westerner, the gov blaming things on Russia is like a school kid saying their dog ate their homework... Even if it's true, ts so cliche at this point I just don't believe it
It's almost as cliche as the Russian gov blaming the west for all their troubles.
The joys of HN is finding experts in just about anything, so...
Assuming that NASA is correct about this leak being associated with an interior or exterior weld, what can we learn from the rate of growth of the leak? I assume (with no domain knowledge, seeking enlightenment!) that a leak like this is big enough to reflect a fracture in the weld, and not merely air sneaking past a tiny flaw; and I assume its growth means that the fracture itself is growing, under the combination of load (atmospheric pressure on one side) and cycling (thermal, etc). Is a fracture like this likely to continue to grow in a linear-ish domain, or is there a point where propagation goes non-linear assuming the loads stay constant-ish? Is this even a sane question to ask?
Obviously it can't be linear forever, if you assume the crack is along a circumference then eventually there will only be a tiny piece of metal still intact between the two halves, and one would expect it to fail far before then.
These kinds of failures tend to be linear until they are not, and the failure mode is catastrophic. If I were in charge I would have already shut off that module on the risk/benefit analysis of catastrophic loss of the station vs. not being able to evacuate as quickly in a less catastrophic emergency. Maybe they are worried they won't be able to get the hatch open again if they can't equalize the pressure again?
For historical reference, consider Aloha Airlines Flight 243[1].
https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243
> Maybe they are worried they won't be able to get the hatch open again if they can't equalize the pressure again?
Well note that they currently keep the hatch to the docking port closed unless they're using it, so that presumably mitigates some of the risk (assuming the leak is confined to that location). Not using the whole Zvezda module itself would be more or less impossible from my understanding.
If they decided to stop using that dock port at all then I think that complicates planning and makes everything overall riskier, so while it wouldn't be a disaster to do there's still risk you have to weigh.
Disclaimer: I don't know how space modules are welded or what forces act on a space module.
Welds fail for multiple reasons - heating too fast, cooling too fast, material defects, human error, equipment issues, oxidation. The best human welder will still have some variance in their weld even if they lay a perfect bead.
Once a weld begins to fail, under normal conditions (vibration, stress, etc), it will slowly get worse, but that can also mean deformation around the weld or even sometimes shearing right next to your weld. The article doesn't mention that the growth has been linear only that it is increasing. I expect that the leak is increasing over time in a non-linear fashion as force is applied to the weak area and metal continues to separate and/or shear. Still, 3.7 pounds of atmosphere a day is a very slow leak (relatively), a few bike tires a day.
My back of the napkin math tells me a .2 mm puncture would do this. This must be a very tiny crack.
I'd just paint over all the welds and be happy until it unseals itself again.
From the article, it started leaking years ago, and almost doubled between Feb and Apr of this year, so it is definitely not growing linearly.
> Is a fracture like this likely to continue to grow in a linear-ish domain, or is there a point where propagation goes non-linear assuming the loads stay constant-ish? Is this even a sane question to ask?
It depends on so much that we don't know from the article.
Non-expert, pure speculator here: I cannot help but think of the Titan submersible and its minor flaw in the hull that slowly became more and more of an issue with each dive and pressurization cycle. I wonder if the 'untenable' leak rate that isn't agreed upon is the rate at which an accelerated and catastrophic runaway event occurs?
There was no "minor flaw" in the Titan submersible.
It was a very bad design[1], using substandard material[2] in new and untested ways[3] with poor assembly practices[4]. It was fatally flawed from the start.
1 - Asked about the carbon composite used in Titan’s experimental design, Cameron said, “It’s completely inappropriate for a vessel that sees external pressure.” He went on to say that carbon fiber is very helpful when used for applications subject to internal pressure, like scuba tanks. But, he said, “for something that’s seeing external pressure, all of the advantages of composite material go away and all the disadvantages come into play.”
2 - Another possible "shortcut": https://www.latestly.com/world/titan-submersibles-hull-was-a...
"Expired" bare carbon fiber might be ok; expired prepreg is likely not ok. And I still can't get my head around the apparent mixing of prepreg and wet winding resins in the same laminates.
That article says Boeing has no record of ever selling oceangate composite material. So either he got it for free (Dumpster diving?) or it came from someone else. Maybe some guy in a parking lot: My boss told me to deliver this stuff to Boeing but they wouldn't take it because its expired, I'll sell it to you cheap.
3 - "Thickness, he says, was estimated using micromechanics, and then verified with finite element analysis (FEA).”. >Wonderful. That sort of maybe can work for tension stresses, but can be highly unreliable for compression loading
4 - https://www.youtube.com/watch?v=4PUTbK5AqY8 : >For such a critical joint I see some questionable prep work >in the video. >-Bare hands touching the bond surface. >-Solvent wiping used instead of caustic degreasers. >-Poor wiping technique >-no surface profile/grit blast immediately prior to fixing.
All sources are from commenters on: https://www.eng-tips.com/viewthread.cfm?qid=508005
It's important to remember that the pressures involved are very different. The ISS pressure vessels only have to hold 1atm in, and not several atmospheres out.
To reinforce this point, it is around 375 atmospheres at the titanic. The deep sea is a crazy place.
Equally important is that the ISS is under tensile load (the cylinder is trying to explode), while a submersible is under compressive load (the cylinder is trying to implode).
It's just 1 atm. You can't even say it's trying seriously.
When I read this I understood _cracking_ in its sense of software piracy aka "hacking."
A mental subprocesses spawned to predict whether the cracking was _of_ the systems on the station—possibly inspired by that movie trailer I saw for the thriller about a new cold war in space after a nuclear war—or _from_ the space station, by bored occupants, either of their own systems or of some system they interact with on the ground.
A bit deflated by the reality, tbh.