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.
> 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.
> 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.
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.
In general, gaffer's tape is the superior product, but for this use case, I'm thinking that duct tape with its solid backed film and thicker adhesive might be more airtight.
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.
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.
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.
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.
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.
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.
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)
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.
Obviously they can't, it looks like an obvious solution they couldn't have missed. But I wonder why it is impossible to do.