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One hull crack located in ISS, another one suspected

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Re: One hull crack located in ISS, another one suspected

#301

Post by WalterBright »

dotancohen wrote: post #240
WalterBright wrote: post #168

Earlier quoted context omitted.

Full Disclosure: I have no financial interest in flex-seal. My general experience with glues is I'll use bolts. I can't get superglue to stick anything together other than my fingers. My rear view mirror fell off again, the third time I glued it on with superglue.

Superglue is horrible for rear view mirrors, for a few reasons none of which I remember offhand. There exists special rear-view mirror glue, which is easy to use and is a permanent fix.

I used superglue because the special rearview mirror glue was pretty expensive. And the latter failed anyway, which is why I was looking to glue it back on.

I was also suspicious of the special rearview mirror glue being special. For example, I have a VHS head cleaner tape that comes with magic head cleaner fluid, refills cost $$$$. One sniff told me what it was - alcohol. I use alcohol with it, and it works just great.

I also remember years ago you could buy special vinyl record cleaning fluid for $$$$. It's just vinyl. I use liquid dish detergent, which does a superb job. Doesn't hurt the vinyl one bit, and all the grease, dirt, hair, and who-knows-what-that-is is all gone. (I buy old records at the thrift store because I like the easy listening style from the 60s and 70s.)

Re: One hull crack located in ISS, another one suspected

#302

Post by onethought »

dotancohen wrote: post #293
onethought wrote: post #229

Earlier quoted context omitted.

But space x work in spite of the nasa system... could you dream of nasa celebrating SN8 plowing into the ground as a raging success... it’s a huge cultural shift, not so much driven by private sector competition (Honestly who competes with space x?), more to do with leadership style. BlueOrigin is a perfect Nasa 2.0 comparison.

> could you dream of nasa celebrating SN8 plowing into > the ground as a raging success. Nobody is celebrating SN8 plowing into the ground. We are celebrating the fact that SN8 plowed into the correct square meter of ground. We also celebrate the fact that SN8 plowed into that particular meter of ground while oriented in the direction that we hoped, but barely dreamed, that it would be oriented.

That’s my point... I’m not saying space X is bad or irresponsible, they are just different (and I think in a good way). Agree SN8 was amazing! And something NASA would never have done. Nor would they livestream it, nor keep it available on their website.

Re: One hull crack located in ISS, another one suspected

#303

Post by nine_k »

HenryKissinger wrote: post #89
HPsquared wrote: post #37

Earlier quoted context omitted.

Those are the cause of the stress cycles. Components don't expand/contact uniformly, resulting in deformation and therefore stress. This process goes through cycles, causing stress cycles which eventually cause the growth of cracks (fatigue).

Have we invented a material that is resistant to these thermal cycles indefinitely, or at least within a range of temperatures of several thousand degrees? I'm never going to have my own Star Destroyer if we continue to use subpar materials.

I would suggest a thin, non-load-bearing, and easy to replace insulation / reflection layer above the pressurized hull. It could reflect much of solar energy back to space, and much of the hull's radiation back to the hull, keeping the difference of temperatures on the hull much lower.

I wonder if it's already implemented.

Re: One hull crack located in ISS, another one suspected

#304

Post by jccooper »

WalterBright wrote: post #300
gregmac wrote: post #286

Earlier quoted context omitted.

This reminds me of one of my favorite Futurama lines as their ship is going underwater: "Dear lord! That's over 150 atm of pressure!" "How many atmospheres can the ship withstand?" "We'll, it's a spaceship, so I'd say anywhere between 0 and 1." https://youtu.be/Ewu-zHH5Qwg

Space craft are run at much less than 1 atm.

The ISS and all spacecraft that dock with it run at 1 atm. Which is nearly all currently flying spacecraft. (And probably Shenzhou does too, since it's basically a Soyuz.)

Re: One hull crack located in ISS, another one suspected

#305

Post by segfaultbuserr »

TomK32 wrote: post #284
segfaultbuserr wrote: post #148

Earlier quoted context omitted.

> He underscored that air loss due to the crack are insignificant. "This leak is like as if you’d drill the hull with a 0.2 mm diameter drill. I’m not sure such drills even exist in household. I had to check my collection of PCB drill bits when I was reading it, and yes, I confirm that I'm a proud owner of a 0.2 mm drill at home, it was the smallest one in the box ;-)

still unused?

Still unused. The smallest bit I've used is a 0.8 mm one. Anything smaller, it's impossible to even see where you are going without a microscope.

Re: One hull crack located in ISS, another one suspected

#306

Post by segfaultbuserr »

HeyLaughingBoy wrote: post #292
nosianu wrote: post #234

Earlier quoted context omitted.

The existence of a drill is no guarantee that you can actually create a hole. I once was a battle tank maintenance guy and we had to replace a cover placed in front of the armor. The replacement had holes in different positions, no problem, just drill a new hole, right? An hour and a few broken drills later we gave up. No doubt there are drills that work on that armor-steel, my point is, depending on the material jus…

True. But if it's a PCB drill as (s)he said, then it's likely either solid carbide or has a carbide tip. Hold everything rigidly enough and run that drill at the right speed and feed rate, and there's a good chance that it will drill armor plate.

Full product catalog from the manufacturer if anyone's interested:

https://www.uniontool.co.jp/assets/pdf/catalog/drill_router2...

Re: One hull crack located in ISS, another one suspected

#307

Post by azornathogron »

throwanem wrote: post #124
NickNameNick wrote: post #31

Earlier quoted context omitted.

That depends on what you mean by radiation, and 'leak inside' On the ground, most radiation 'leaks' are mostly chemical contamination problems. In space the volume of free material, and the pressure gradient should prevent anything outside coming in. Except perhaps on the exposed surfaces of the airlocks/docking adapters. Come types of particle radiation might cause transmutation/activiation of the hull material - th…

Suits can bring material in, and do. I forget if it was the "smell of space" or the "smell of the moon" they were talking about, but I remember reading that one astronaut described the odor as like that of burnt gunpowder, and that suitborne particulates proved to be the source.

It was moon dust [1]. I don't think space itself smells of anything - surely there isn't enough atmosphere even at the ISS's orbit to smell?

[1] https://www.nasa.gov/exploration/home/30jan_smellofmoondust....

Re: One hull crack located in ISS, another one suspected

#308

Post by Something1234 »

andi999 wrote: post #250
Something1234 wrote: post #102

Earlier quoted context omitted.

Did the Chinese build their own biosphere 2 (Arizona)?

Since you mentioned biosphere 2, I was really surprised to learn the Steve Bannon was director for 2 years of the project.

I wonder what impact he had. Looking at his wikipedia page he had a very long career.

Re: One hull crack located in ISS, another one suspected

#309

Post by sudosysgen »

WalterBright wrote: post #298
edgyquant wrote: post #290

Earlier quoted context omitted.

Yes what you present is anecdotal evidence. Also nobody is saying they like the Soviet Union that is an idiotic strawman. My point is that they could be made but the USSR wasn’t gearing its economy towards consumer goods because it was a military state who cared almost entirely about heavy industry to benefit its military industrial complex and competition with the US.

The US free economy produced a better military and plenty of high quality consumer goods.

While that is true, the USSR produced a better military and more, higher quality consumer goods than most nations of it's size.

That said, it is certain that the soviet system was suboptimal in a great many ways.

But, crucially to the fact at hands, 1960s' USSR produced better rockets to send people to the ISS, at a lower cost, than 2021's USA, so there something beyond the free market in this particular case.

Re: One hull crack located in ISS, another one suspected

#310

Post by throwaway0a5e »

HenryKissinger wrote: post #89
HPsquared wrote: post #37

Earlier quoted context omitted.

Those are the cause of the stress cycles. Components don't expand/contact uniformly, resulting in deformation and therefore stress. This process goes through cycles, causing stress cycles which eventually cause the growth of cracks (fatigue).

Have we invented a material that is resistant to these thermal cycles indefinitely, or at least within a range of temperatures of several thousand degrees? I'm never going to have my own Star Destroyer if we continue to use subpar materials.

>Have we invented a material that is resistant to these thermal cycles indefinitely

Yeah. It's called steel and it's too heavy to put in space in the quantities needed for a space station.

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