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Astronauts told to return to ISS after sheltering over air leak repairs

bbc.com

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Re: Astronauts told to return to ISS after sheltering over air leak repairs

#171

Post by Dylan16807 »

dotancohen wrote: post #158
Dylan16807 wrote: post #149

Earlier quoted context omitted.

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.

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.

Re: Astronauts told to return to ISS after sheltering over air leak repairs

#172

Post by Arch-TK »

photonair wrote: post #169

Does someone know if push come to shove, do they have a ready to go escape pod or ship to go back Earth anytime in an emergency? How many backups do they get?

The rule is that at all times enough return vessels must be docked to the ISS for everyone on board.

These are usually the same vessels they used to get up to the station.

This has the consequence that if they need to re-dock one of the vessels (for whatever reason) all the astronauts that would normally use that vessel must board it for that menuvre. Just in case it fails to dock again.

And they don't normally have spares.

IIRC, this is a good video on the topic: https://m.youtube.com/watch?v=82YHM12n2JI

Re: Astronauts told to return to ISS after sheltering over air leak repairs

#173

Post by l23k4 »

ActorNightly wrote: post #162
MrPouig wrote: post #34

Earlier quoted context omitted.

If things go wrong, they're already in the vehicle supposed to bring them back. It might be upsetting to be 3 locked doors away from your best way to come back home

[flagged]

Why did you feel the need to post this comment?

Re: Astronauts told to return to ISS after sheltering over air leak repairs

#174

Post by stronglikedan »

ordu wrote: post #64

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.

> But I wonder why it is impossible to do.

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

Re: Astronauts told to return to ISS after sheltering over air leak repairs

#175

Post by bamboozled »

Kye wrote: post #167

I remember reading about the ISS in the May 1998 issue of Popular Science, a full issue about the station. They were getting ready to launch the first module. Every time bad news happens, I think about this part (from a PDF I hang on to): >> "SOMEDAY, THE international Space Station will descend, but if you're frightened at the prospect of a million-pound hunk of metal falling out of the sky, take heart. NASA does ha…

I feel like NASA won’t be sling this anymore…

Re: Astronauts told to return to ISS after sheltering over air leak repairs

#176

Post by pyuser583 »

sam1714 wrote: post #164
ck2 wrote: post #65

Do they have things like Oxygen Candles or can those not be used in space?

Candles are useful when oxygen has been consumed because of respiration or a fire. They're not useful in a leak. Conservation of mass: if a cubic meter of air escapes, that's 1.25 kg, and you need at least that much in candles. (You actually need 2 kg because the candle isn't solid oxygen) There's ultimately 1.2 t of atmosphere on the ISS. This will also result in a pure oxygen atmosphere, which is dangerous. You nee…

I thought it had a pure oxygen atmosphere to prevent the bends? Why is it dangerous?

Re: Astronauts told to return to ISS after sheltering over air leak repairs

#177

Post by avmich »

photonair wrote: post #169

Does someone know if push come to shove, do they have a ready to go escape pod or ship to go back Earth anytime in an emergency? How many backups do they get?

For every human onboard ISS there is always place in the docked spaceship. Exceptions: when spaceships break, replacements are usually sent - like, when Soyuz lost coolant or Starliner was considered too unreliable. While waiting for replacements, those ploblematic spacecrafts still serve as lifeboats, except maybe Crew Dragons can carry more people than those 4 they usually carry...

Re: Astronauts told to return to ISS after sheltering over air leak repairs

#178

Post by firefax »

l23k4 wrote: post #173
ActorNightly wrote: post #162

Earlier quoted context omitted.

[flagged]

Why did you feel the need to post this comment?

>Why did you feel the need to post this comment?

Maybe parent feels like rocket science is a field that should have few launch failures?

I can't give you a quantitative answer since I'm usually focused on new research rather than what company/nation did said research... but their stuff does seem to blow up on the launchpad more often than NASA's :-)

Re: Astronauts told to return to ISS after sheltering over air leak repairs

#179

Post by bigyabai »

ActorNightly wrote: post #162
MrPouig wrote: post #34

Earlier quoted context omitted.

If things go wrong, they're already in the vehicle supposed to bring them back. It might be upsetting to be 3 locked doors away from your best way to come back home

[flagged]

Look on the bright side, at least you're not riding in Boeing's capsule.

Re: Astronauts told to return to ISS after sheltering over air leak repairs

#180

Post by themafia »

vitally3643 wrote: post #71
Quitschquat wrote: post #14

Earlier quoted context omitted.

Recently started an embedded hardware/software job. Shipping firmware to the manufacturer feels like that for the device classes that have no internet.

My first week on the job they told me they're about to manufacture 20k units and can you please fix this bug in the firmware by Friday? I've never shipped anything to real customers in the wild before, so let me tell you how insanely stressed I was to open the firmware and find a 10k lines of C contained entirely within a single switch statement. I think they used some no-code tool to graphically design a state machi…

Nearly the same experience. Had to fix an issue in a boot loader. It came down to improper setup of the memory controllers ECC engine. It would correct and ignore a single fault. If you managed to get two faults it would raise an exception that was not handled and the boot would fail. For the customer this meant that a reboot might randomly brick the unit until you go in and manually power cycle it.

Just convincing them that their problem boiled down to a single incorrect bit was difficult enough but then having to, in a day, build and successfully operate a test harness to prove the fix worked was the real stress.

I do not miss embedded engineering.

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