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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

#191

Post by 7952 »

wahern wrote: post #158
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.…

10 years ago the consensus--scientists, engineers, etc--was that self-driving cars would be ubiquitous or on the cusp of ubiquity today. That same common but woefully mistaken wisdom is also behind the preference for remote space exploration and exploitation. We clearly have issues with underestimating the complexity of these engineering problems and overestimating the pace of technological progress. I'd also argue,…

Engineering difficulty is often put forward as a limiting factor. But actually I think history suggests that with enough resources we can accomplish things. And in fact it is possible for a project to have astonishingly brilliant engineering and still be disappointing in terms of wider impact (see the space shuttle).

The limiting factor is much more mundane. Getting humans to collaborate selflessly on complex projects is difficult. Effective communication in large groups is a massive unsolved problem. That is what holds us back, not engineering complexity. Perhaps the true genius of SpaceX is using Mars to bring people together. Something the bean counters at Boeing never thought of!

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

#192

Post by a9h74j »

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.

I hate glue for almost everything, but as proof-of-principle check out VHB acrylic adhesive tape[1], or Gorilla double-sided[2]. VHB adhesive is also available on mushroom-head dual-lock fastener, in rolls.[3] (Also no financial interest.)

[1] https://www.3m.com/3M/en_US/vhb-tapes-us/ [2] https://www.gorillatough.com/product/gorilla-double-sided-ta... [3] https://www.itapestore.com/3M-DualLock

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

#194

Post by sudosysgen »

WalterBright wrote: post #137
lordlic wrote: post #132

Earlier quoted context omitted.

You think NASA, ESA, Roscosmos, etc can build the ISS but they can't raise it to a higher orbit? Honestly, this cheering for privatization of space research is getting out of hand.

I'm saying that the bill for NASA doing it would be 10x what a free market operation could do it for.

In 2021, the cheapest and most reliable way to send a man to space is to use a Soyuz, for a cost of 19-22 million dollars per person. This is of course a communist design launched by a public space agency built by a majority public ownership factory.

I think it might be time to accept that in these cases its pretty often not the inherent efficiency of the free market - which can often be less efficient than alternatives - but the ineptitude of the US government and it's agencies as far as doing things efficiently.

There are US politicians and functionaries that admitted publicly that they made the government less efficient for ideological reasons to make the free market look better.

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

#195

Post by mycall »

namibj wrote: post #130
HenryKissinger wrote: post #89

Earlier quoted context omitted.

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 du…

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

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

#196

Post by theodric »

derekp7 wrote: post #91
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…

For future spacecraft, would it be possible to have a double hull with a self-healing jell in the middle? (In concept, I'm thinking similar to tire sealer, something with clotting agents in it).

That'd stop the leaks but not mitigate the risk of catastrophic hull failure caused by untreated cracks originating from repeated thermal cycling stresses

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

#197

Post by hutzlibu »

lenkite wrote: post #154
NortySpock wrote: post #80

Earlier quoted context omitted.

China's public plans include a semi-permanent base on the Moon. That oughta ruffle some feathers in Congress. Chinese paper on plant-based life support systems for extended crew stays. https://www.biorxiv.org/content/10.1101/2021.01.12.426282v1

Really hope China ditches the Outer Space Treaty and claims sovereign territory on the moon. Only then will the space race ignite again. It seems only competition makes the human spirit move.

I suspect any player powerful enough to have the means to claim territory on the moon, will ditch the outer space treaty eventually. Unless it is a purely scientific mission, but that is un likely at the moment.

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

#198

Post by ygra »

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.

I think this is this: https://en.wikipedia.org/wiki/Reinforced_carbon%E2%80%93carb...

which is carbon-fiber in graphite, apparently, so the name is apt in that it's a composite of two different forms of carbon with different properties.

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

#199

Post by saberdancer »

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…

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 angle - this might not be bad in all cases but the lack of flexibility is a big thing - Putting any mass on the Moon requires much more delta V than putting something in orbit. If you can put a big telescope on Moon, you can put several in Earth orbit or put one much bigger one.

Having capability to stage on the Moon would be interesting, especially if fuel can be made on the moon. It would be easier on human bodies and you have access to lot of resources. If you can find water and decent metals, that's a pretty good spot to fuel your rockets.

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

#200

Post by philistine »

spike021 wrote: post #32

Not a big space person, but this makes me wonder: why have we not planned for a new ISS? We must have better tech nowadays from all the working countries/groups currently involved, plus SpaceX and other space companies' backing that would not have existed as it does now back when this ISS was first designed/created.

It's literally the most expensive single structure built in the history of our species. Perhaps this little fact can put in perspective why we have yet to plan for another one.
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