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

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

#211

Post by alex_duf » Sat, Jan 23, 2021, 10:47 AM UTC

deepsun wrote: post #181

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…

Make it robotic only. Stop/dump all life support, but leave manipulators/robots like Canadarm, and accept robotic add-ons and commercial sub-satellites.

A good chunk (arguably the most important one) of the research is actually done on the live subjects that go up there.

So you'd lose a lot of research capability.

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

#212

Post by HPsquared » Sat, Jan 23, 2021, 10:48 AM UTC

mycall wrote: post #195

namibj wrote: post #130

Earlier quoted context omitted.

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 du…

What is the difference between "Carbon" and "Carbon-Carbon"? It seems incongruous.

There's plain old "carbon fiber" which is short for carbon fiber reinforced polymer/plastic (CFRP). This is the much more common type, and is a polymer matrix reinforced by carbon fibers. This is very strong and light, but not terribly heat-resistant. In a carbon-carbon composite, on the other hand, the plastic component is also replaced by graphite. This gives a very strong and heat-resistant, though somewhat more brittle, material.

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

#213

Post by HPsquared » Sat, Jan 23, 2021, 10:51 AM UTC

lanstin wrote: post #182

chaboud wrote: post #167

Earlier quoted context omitted.

Climbers and riggers should all be familiar with fatigue limits. It can be as high as 50% max tensile strength for steel, but I use 30% as my working figure when rigging, and I regularly re-inspect and age-retire gear (at least use annualized color coded markings). When I’ve rigged circus in the past I’ve taken to replacing aluminum gear I find with steel, especially if it’s going to be installed for a while. That sa…

I had an aluminum bicycle where the front fork failed suddenly. Not instantly but in maybe one or two seconds (just slowly enough to let me not have a terrible fall). My next bike was chrome/steel.

This solves something I'd wondered for a while - why my aluminium bike has a steel fork.

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

#214

Post by midasuni » Sat, Jan 23, 2021, 10:54 AM UTC

fastball wrote: post #180

geocrasher wrote: post #165

Earlier quoted context omitted.

Brings my mind to the ultimate acronym: PCMCIA People Can't Memorize Computer Industry Acronyms

I personally prefer TLAs.

And ETLAs?

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

#215

Post by GordonS » Sat, Jan 23, 2021, 10:59 AM UTC

jccooper wrote: post #149

WalterBright wrote: post #128

Earlier quoted context omitted.

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

They have put tape on suspected leak areas in Zvezda before.

So bizarre to imagine a space station patched up with duct tape o_O

Assuming the ISS is never going re-enter the Earth's atmosphere, how permanent a solution is tape? Presumably the fracture underneath will get worse with time.

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

#216

Post by exDM69 » Sat, Jan 23, 2021, 10:59 AM UTC

saberdancer wrote: post #199

godelski wrote: post #117

Earlier quoted context omitted.

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…

Putting a spy telescope on Moon seems like a bad idea. - Moon moves across the sky very slowly (relative to stars) which means that your spy satellite would have about 30 days to cover full earth, and would be able to see only a part of Earth at any given moment (theoretically half, but lot of it would be from very bad angles) - Moon is in an ecliptic? orbit, so spying on anything close to the poles will be from an a…

The moon moves slowly but the Earth rotates quickly. Most of the earth surface can be seen during one day. The earth is not illuminated by sunlight all the time, about half of the lunar month would be completely dark.

Moon is in an inclined orbit, which is slightly elliptic. I assume this is what you meant by "ecliptic" (which refers to the orbital plane of the Earth around the Sun). The orbital inclination has the most significant implications to Earth surface visibility, but the Moon is far enough that almost half of Earth surface is visible at all times.

For Earth observation, satellites are better positioned than a lunar surface observatory.

The moon isn't a great place for an outpost or staging point for exploration. Launches and descents are expensive and spoil all the savings. Maybe if LH2/LOX could be manufactured on the moon very cheaply (from water ice), it could make sense to do refueling for exploration vehicles parked on a halo orbit near Lagrange points.

But orbital refueling of cryogenic propellants (especially hydrogen) or manufacturing them on the moon aren't viable in the near future.

There aren't a lot of good economic or exploration incentives to go to the moon, unfortunately. It only has scientific and prestige value. The long lunar night (14 earth days) makes it a poor location for a permanent outpost.

All of that said, I'm all for going to the moon with humans on board.

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

#217

Post by robryk » Sat, Jan 23, 2021, 11:11 AM UTC

HPsquared wrote: post #213

lanstin wrote: post #182

Earlier quoted context omitted.

I had an aluminum bicycle where the front fork failed suddenly. Not instantly but in maybe one or two seconds (just slowly enough to let me not have a terrible fall). My next bike was chrome/steel.

This solves something I'd wondered for a while - why my aluminium bike has a steel fork.

I was told once that the reason for that was stiffness: apparently aluminum forks are stiffer, so unsuspended ones are way less comfortable (in terms of vibrations being transmitted to the frame and handlebars) than steel unsuspended forks.

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

#218

Post by GordonS » Sat, Jan 23, 2021, 11:17 AM UTC

ChuckMcM wrote: post #109

pixl97 wrote: post #85

Earlier quoted context omitted.

I can only guess that it would be much harder to accomplish than one would imagine. Definitely want a padded room so you dont bang your head, or other parts slamming into sharp objects.

I note that the Bigelow Aerospace semi-inflatable module[1] that is attached currently to the ISS has no windows and padded walls. [1] https://bigelowaerospace.com/pages/b330/

Putting aside space-sex, I really like the idea of an inflatable module that can quickly (and presumably fairly cheaply) increase the space on a station.

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

#219

Post by pasabagi » Sat, Jan 23, 2021, 11:18 AM UTC

WalterBright wrote: post #168

geocrasher wrote: post #166

Earlier quoted context omitted.

Can you imagine the infomercial mileage they'd get out of that?

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.

The trick with superglue is to make sure you have a really good contact between two clean surfaces. If you don't have that, superglue will do nothing for you and you're better off with something else. If you do, it's quite strong.

The annoying thing is, glues work best when you use them in the exact situation (material, pressure, etc) they are designed for, but manufacturers are really vague about active ingredients or fillers, so you end up having to buy broad-spectrum glues that are not particularly good at anything.

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

#220

Post by mikro2nd » Sat, Jan 23, 2021, 11:39 AM UTC

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.

I shudder to think what the inside of those space suits must smell like...