One hull crack located in ISS, another one suspected • Hacker News Board

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

#121

Post by throwanem » Sat, Jan 23, 2021, 2:43 AM UTC

csours wrote: post #98

ortusdux wrote: post #46

What are there reserves like? How long could they sustain a 0.5 - 1.0 mmHg / min leak?

I wonder what that means in grams/min

You'd have to take the derivative with respect to time, I'd think, because the ejection rate might decrease with pressure.

Instantaneously, with a 1mmHg/min leak I think you'd lose roughly 1.5kg or a little over a cubic meter's worth in the first minute, given the 915.6 m^3 pressurized volume and a mass of ~1.3kg/m^3 for air at sea level (760mmHg, which is close enough). How long it takes to get down to an unsurvivable ~250mmHg (assuming an Earth-air-like breathing gas aboard ISS, which seems reasonable) takes more trouble to figure out than I care to go to on a Friday night, but the lowest possible bound (assuming a constant ejection rate) would be somewhere around 500 minutes, or between eight and a bit to nine-ish hours.

Honestly I'm more curious what area a breach would have to have to produce that kind of leak rate.

edit: Actually, given the effectively infinite volume at effective vacuum outside the hull, you wouldn't see the same "counterpressure" effect you would in atmosphere, that causes pressure equalization to slow down as it approaches equality - there's no equalization that can happen here. That said, you'd still lose less mass per unit time over time, as the internal pressure and thus the mass per unit volume drops.

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

#122

Post by lmm » Sat, Jan 23, 2021, 2:49 AM UTC

ChuckMcM wrote: post #73

rtkwe wrote: post #66

Earlier quoted context omitted.

There has to be some revenue stream beyond just satellite launches and government research. Right now there's only so many reasons to go to space and a lot of those are pretty small markets or able to be served by one or very few provider(s) pretty well.

Frankly, I expect the zero-g sex market to be a pretty big draw for the folks with more money than sense.

A few people will do it once or twice, sure. Doubt that's a sustainable market unless you can get the cost way down.

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

#123

Post by snoshy » Sat, Jan 23, 2021, 2:49 AM UTC

onethought wrote: post #95

snoshy wrote: post #51

Earlier quoted context omitted.

Largely because it's a fantastically expensive undertaking, and hasn't quite borne out the fruits that were speculated about over the years. USA provides a huge bulk of the funding, expertise, and personnel required to keep the program running. That's not to say that Russia, Canada, Japan, etc. don't do their part, but it's really not as much of a truly global joint effort as you might be led to believe. Then there's…

The problem with Privatised space industry is your country doesn't control the agenda. SpaceX is a pretty rare thing, the rest of the private space industry (Blue Origin, Virgin, Boeing) is as much of a money pit as NASA was. Then you have rapidly progressing government run space programs like China and India. The fact that the US banned China from the ISS and banned Non-Americans from participating in what it deems…

Echoing the sister comment to add more color, I think when it comes to this scale of money, it becomes too easy to conflate public and private capability. The ISS cost $150 billion. That is a kind of cost that even the tech behemoths of the world today would not be able to stomach. Some efforts really require country-coffer levels of money to be realized.

That means the US government directly controls which projects live and die, simply because they control the purse. Most space endeavors don't require this scale of money, and even a small token of innovation incentives can often result in outsized societal benefits. Even for SpaceX to just think about the Starship program, they literally had to corner the global orbital launch market for nearly a decade to come.

While I do agree that Boeing is a money-pit due to their involvement with SLS, I still wouldn't put Virgin or Blue Origin in anywhere close to that bucket. While these two might not be as incredibly innovative and capital efficient as SpaceX, they're still orders of magnitude better than anything like the SLS, Boeing, Lockheed Martin, and others that are considered "old space".

China is pouring an absurd amount of its own money through thinly guised military development arms, and they're excelling at it. It's truly a shame that the US cut them off from the ISS, and its even more detrimental that the rest of the world has not paid close enough attention to their efforts. They're about the only player that's even close to competing with anything like SpaceX.

I wouldn't put India in the same club as China either. India has done extremely well at making cheap reliable orbital class launch vehicles by cost cutting and incremental improvements. Once SpaceX comes to the scene, they will be obsolete. They do not have the public appetite to invest the scale of money required to build programs the likes of US & China can build.

Russia meanwhile seems obsessed with trampolines.

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

#124

Post by throwanem » Sat, Jan 23, 2021, 2:52 AM UTC

NickNameNick wrote: post #31

artiscode wrote: post #12

I wonder if radiation will become an issue at some point. It is being irradiated all the time, doesn’t it also start to leak inside? Can that be an issue in the future for inhabitable objects in space?

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.

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

#125

Post by lmilcin » Sat, Jan 23, 2021, 2:55 AM UTC

waheoo wrote: post #103

maxerickson wrote: post #35

Earlier quoted context omitted.

These discussions about materials are often difficult, because there are meaningfully different processes that are lumped together in everyday language. Mechanical stresses leading to failure at a particular point are certainly a form of degradation, but I believe they mean degradation in the sense where the entire body of the material is undergoing some change (like a plastic bottle fogging or such). I think seeking…

> "gotcha" game is tedious I agree but you can say the same thing in reverse. This is a public forums, you don't need to claim something isn't right because it doesn't fit the technical description.

Just stop this already.

The post said "is this materials decomposing or degrading".

While I may have not been precise about "degrading" part, we can assume the metal is definitely not "decomposing".

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

#126

Post by bluGill » Sat, Jan 23, 2021, 2:57 AM UTC

calibas wrote: post #87

YetAnotherNick wrote: post #74

Earlier quoted context omitted.

> It helps to answer the question of whether or not humans can even survive long term away from Earth How will it answer that question that we already don't know of? I don't think that was the aim of ISS anyways and will definitely won't be the aim of second ISS. Humans can survive in space for year without significant physical damage but with lot of training.

To me, it's just so odd that people don't seem to understand why we have an ISS. Is the main argument "We've already learned what's needed about life in space, and now we don't need a space station anymore"? That seems absurd.

The ISS exists to give Russia cover to keep the ex Soviet rocket scientists employed and thus not tempted to work for some evil dictatorship.

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

#127

Post by fuoqi » Sat, Jan 23, 2021, 3:05 AM UTC

godelski wrote: post #117

bnralt wrote: post #92

Earlier quoted context omitted.

> The first big space push was mostly a political pissing match (i.e. not really driven by doing it for its own sake). My understanding is that the Defense Department was interested in human manned spy satellites liked the planned Manned Orbital Laboratory early on, but that automation progressed to the point where it was preferable. I think that's one thing people miss when they talk about lack of progress in space.…

There's still a lot of defense reasons to go to the moon. You can put much larger telescopes there, though you're back to windows of time you can look at a location but you can have good will and dedicate time to scientists. Though they might not want to reveal the resolution even though this can be roughly back tracked through size. There's also the weapons incentive even though that's illegal. But if you're able to…

>being able to take out enemy satellites (nav, surveillance, missile launch detection, etc)

You can easily do it without having objects in orbit. You can simply launch a ballistic cloud of debris at suborbital speeds and kinetic energy of the targeted satellite will do the rest. Time to hit could be shorter for an orbital system, but not significantly so. This is why I consider the recent news about the Russian orbital satellite killer to be a cheap fearmongering.

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

#128

Post by WalterBright » Sat, Jan 23, 2021, 3:06 AM UTC

akiselev wrote: post #10

ChuckMcM wrote: post #2

Materials aging in space is a pretty deep subject. That it is the Russian Zvevda module that is leaking/cracking is likely related to the fact that it is also the oldest module in the ISS. The ISS is/was scheduled to be retired in 2024 (aka 3 years from now) but there are calls to keep it going. My fantasy would be to have SpaceX move it into the Lunar L1 Lagrange point which would keep it in use but it would have to…

> That it is the Russian Zvevda module that is leaking/cracking is likely related to the fact that it is also the oldest module in the ISS. Definitely sounds like it. They can't identify the leak on the inside so it doesn't sound like a micrometeoroid impact and they suspect a second leak that is so small they need a microscope to verify: > "So far, we have found one place and suspect another, where as some kind of l…

If the leaks are that small, sounds like putting an elastic coating on it should fix it.

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

#129

Post by WalterBright » Sat, Jan 23, 2021, 3:08 AM UTC

lsllc wrote: post #42

ChuckMcM wrote: post #2

Materials aging in space is a pretty deep subject. That it is the Russian Zvevda module that is leaking/cracking is likely related to the fact that it is also the oldest module in the ISS. The ISS is/was scheduled to be retired in 2024 (aka 3 years from now) but there are calls to keep it going. My fantasy would be to have SpaceX move it into the Lunar L1 Lagrange point which would keep it in use but it would have to…

I think we need a "Space New Deal", I'm honestly saddened by the lack of progress in space in my lifetime. I mean we've done some great work, but we haven't made any giant leaps since getting to the moon 51.5 years ago. Thankfully, we do have SpaceX et. al. who really are making some big strides -- but how do we multiply & speed up that effort? ... sorry, I'm being selfish, but I really want to go to Mars.

It is simply too expensive for government to do it. It'll have to be private enterprise. (Not that private enterprise could pay what NASA spends either, but that it would be 10x cheaper for private enterprise to do it.)

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

#130

Post by namibj » Sat, Jan 23, 2021, 3:13 AM UTC

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.

Carbon-Carbon composite has a cycle life in the millions when cyclically loaded between 0% and 85% of ultimate tensile strength. Furthermore, that material has a very low thermal expansion coefficient and remains structurally sound at high temperatures.

It does oxidize at high temperature, so you'll have to coat it with something. It's also fairly brittle, basically a strong ceramic (it caused us to loose Columbia during re-entry).