[ordu]

Can't they just get things out of the module and paint it fresh? Maybe with some special paint, or with several layers of a paint?

Obviously they can't, it looks like an obvious solution they couldn't have missed. But I wonder why it is impossible to do.

[malfist]

For every complex, difficult and hard problem, there is a simple, easy and wrong solution.

Paint obviously is not the right tool for making seals air tight.

[tclancy]

You ever try to open an old paint can? Checkmate, atheist.

[Dylan16807]

It is not obvious to me that there is no specialized type of paint that would be appropriate.

Doing the whole module sounds like a lot of mass though.

[dotancohen]

It's hard vacuum on one side. There's a reason the word "hard" is used to describe it.

A few years ago a Soyuz was improperly drilled during manufacture. This was patched with a super epoxy... and then began leaking air on orbit. Paint won't seal what a super aerospace epoxy failed to seal.

[Dylan16807]

> There's a reason the word "hard" is used to describe it.

Because it's more extreme.

Do you think a soft vacuum of 0.002 atmospheres of pressure would be notably easier to prevent leaks into?

> A few years ago a Soyuz was improperly drilled during manufacture. This was patched with a super epoxy... and then began leaking air on orbit. Paint won't seal what a super aerospace epoxy failed to seal.

Wasn't the fix on the ground a secret patch by the person that drilled the hole? I don't trust that to have been done properly.

And then when they noticed it was leaking... they used the super aerospace epoxy. Which was labeled as temporary but as far as I know it's still the fix.

Also that was a serious hole, 2mm wide, not a microhole like you'd try to fix with paint.

[malfist]

The odds of the leak being on a surface that can be painted is low. Most likely it's in a gasket or seal that has degraded

[ordu]

> For every complex, difficult and hard problem, there is a simple, easy and wrong solution. > Paint obviously is not the right tool for making seals air tight.

So my obvious solution is obviously too obvious to be right, and obviously the right solution is not obvious.

The sad thing, is you are just reiterating what I've said already, without providing any useful answer. "Paint obviously is not the right tool" is a statement that not just not obvious for me, it looks simply wrong. They search for microcracks and use a sealant to seal them. Sealant is not a paint obviously, but in the same ballpark.

[IAmBroom]

The sealant has to be self-setting; it cannot rely on atmosphere to "dry" it, because the side facing the hole will never dry. In order for it to dry, it would have to be air-permeable, so not a good sealant at all.

So, the sealant has to be either a 2-part epoxy (harder to mix and apply), or a UV-cured epoxy. It has to adhere to a vast array of surfaces, since we cannot predict if the next leak will be in aluminum, cracked ceramic, silicone gasket, rubber gasket, plastic.... Anything it outgasses must be extremely inert, so that it doesn't cause a new problem when it reacts with a different surface (the gas on the ISS is never diluted by a giant planetwide reservoir).

Paint is obviously not a two-part epoxy nor a UV-curing epoxy; nor is it guaranteed to have fully inert outgases; finally it is not likely to be adherent to all the possible surfaces.

It's as if the situation requires a robotic diamond drill, and you propose we hit it with a big rock. The big rock won't do.

[Whatarethese]

Flexseal obviously

[honeycrispy]

You're being sarcastic, but I would like a technical explanation of why this would not work.

[dotancohen]

Delta P

[guyzero]

Delta P is one atmosphere or less, like 15 PSI. Lots of stuff can handle 15 PSI.

Now, will it immediately off-gas and embrittle on exposure to vacuum? Different question.

[kortilla]

Yeah, that’s like being 33ft under water. Not extreme by any means.

[rzzzt]

How about _Space_ Flexseal?

[itishappy]

Obviously you need to use air tight paint.

[setopt]

How about glue?

[justinator]

Bubble gum? Like do they chew space bubble gum that they could then smoosh in the holes?

In college, we'd use toothpaste for the holes left from nails in the walls we hung up our posters with.

[ornornor]

Don’t try this if your toothpaste is the blue or green minty flavoured type. You’re welcome.

[taolson]

We actually did this in my freshman dorm room, as the paint color almost exactly matched the original Crest "green".

[dylan604]

Isn't the main problem finding the hole and not what should be used to fill the hole?

[dotancohen]

They're not teenage boys.

[Auracle]

Just spray Fix-a-Flat everywhere.

Or coat the outside with a soapy water solution.

[justinator]

You'd think after 8 years, they'd have found the hole!

[stackghost]

They need Matt Damon, a chopped up wooden crucifix, and some silicone caulking

[jmaw]

They need Phil Swift, "To show the powerful adhesion of flex-seal, I sawed this space station in half!"

[doublerabbit]

It's time to kick ass and chew bubble gum... and I'm all outta gum

[JTbane]

They did use space tape (Kapton) and epoxy for that weird case with the hole drilled in the ISS.

[opan]

The same kapton tape used in electronics? Never heard it called space tape.

[malfist]

It was invented for NASA

[picofarad]

Regardless of the veracity of this statement I will now use this term for at least the rest of my life.

[MSKJ]

Duct Tape, the answer is always duct tape

[Forgeties79]

Found the scrub who doesn’t know about gaff tape

[ChoGGi]

I don't think you can be an astronaut on the ISS without being a handyman, and the handyman's secret weapon is duct tape.

[Forgeties79]

Trust me, grab some yards of gaff tape and try it out. You’ll thank me later!

[jbxntuehineoh]

can't one of them just put his thumb in the hole? duhhh

[echoangle]

Some problems i can see with that:

It might be hard to access the actual pressure hull from the inside (there's probably insulation and padding on top)

If you use paint, you somehow have to get rid of the solvent in it when it dries, which might be a problem when painting a whole module

[Lalabadie]

Air filtration is one of the hardest things do deal with in space.

I don't know what solvents would do, but I remember that astronauts' bone density loss in space means there are challenges around managing the significant amount of calcium captured by the air scrubbers in the ISS.

[kakacik]

Do they literally sweat their bones away? I can imagine how it would work on molecular level via sweat / breathing, but I would expect >99% to be simply pissed and shat away.

[Lalabadie]

Edit: My bad, with calcium it's the liquid filters that deal with it, not the air scrubbers.

Quoting an ISS astronaut: Today's coffee is tomorrow's coffee.

[PaulHoule]

Wouldn't the calcium go out in your urine?

[schiffern]

Yes. It was the urine processor that had problems with excess calcium, not the air scrubber.

https://ttu-ir.tdl.org/server/api/core/bitstreams/f8ca865b-1...

[Lalabadie]

Appreciate the correction!

[hgoel]

If you mean on the outside, paints that apply well in vacuum and microgravity probably need to be developed and tested first.

If you mean on the inside, it'd be a lot of time and disruption to devote to maintenance on a station that's already having to spend an increasing amount of time on maintenance instead of science.

The modules have a lot of stuff that has been wired between them over the years, all that would need to be sorted out, consequences understood and more before ever starting the work, and by then it'll be time for the ISS to retire anyway.

[nomel]

> well in vacuum and microgravity probably

Wouldn't all paint works well in microgravity? If it didn't, I would think you wouldn't be able to apply it to your floor, walls, and ceiling, with the same paint.

[hgoel]

I think it's hard to say. Water sprayed at a ceiling doesn't congeal into a ball the way water floating in microgravity does.

Paint that would fall to the ground if it didn't stick to anything on Earth, would just be floating around in microgravity. Any dissolved gasses or moisture can usually passively sort themselves out due to their differing masses, but again, not in microgravity.

[nomel]

Yeah, the application system is probably the tricky bit, rather than the paint.

> Any dissolved gasses or moisture can usually passively sort themselves out due to their differing masses, but again, not in microgravity.

This is a solved problem with the ECLSS system [1], required from humans releasing ~3.3 lbs of water per day, and exhaling gases that must not accumulate or form dead zones, and normal VOCs scrubbers [2] due to most modern materials releasing them.

I suspect it would be more of a "how many extra filters do we send" type problem and cycling the collected water a couple more times.

[1] https://www.sciencedirect.com/science/article/abs/pii/S13640...

[2] https://www.researchgate.net/figure/Typical-concentrations-o...

[alpinisme]

Not OP but I’d imagine the big problem with microgravity is not after application but during application. No idea the scale of that problem but obviously open cans of liquid paint are not realistic (not that anyone was suggesting they were)

[numpad0]

yeah, why can't they just make astronauts wear goggles, then stop the fans, and tell them to squirt some superglue in the air to let it clog the hole?

[snickerbockers]

Put a bit of spare sheet metal over the hole and let the pressure differential hold it down. For added safety affix a post-it not with DO NOT REMOVE written on it in all capital letters and underlined. They can even use those special zero-g ballpoint pens they spent eleventy-billion dollars inventing back during the johnson administration.

[numpad0]

But they still haven't located the leak. My blob of glue idea solves that by automatically permeating into the cracks.

wait, do they have to have matched CTE and k to the existing material... hmm

[NetMageSCW]

Do you know what causes superglue to harden? Do you think that will be found in a vacuum?

[numpad0]

ok, droplets of UV-curing resin first, then CA glue, then water.

[switchbak]

Oh come on you can't be serious.

Clearly this needs some JB-Weld :P

[dylan604]

Flex Seal would be my suggestion. It works as seen on TV

[jmaw]

"To show the powerful adhesion of flex-seal, I sawed this space station in half!"

[adaml_623]

Cardboard's out. No cardboard derivatives.

Paper?

No Paper. No string. No sellotape.

[soupspaces]

Some fire decal while they're at it?

[stronglikedan]

> But I wonder why it is impossible to do.

Because, space. It's hard. Unbelievably hard.