241–250 of 330 posts
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Hmm... my first encounter with "IANAMS" in the wild. Assume it means "I am not a materials scientist"? I like it.
Part of the joke is that's it's NASA. (NASA stands for Not A Standard Acronym, of course.)
-It's a reference to the seven people on the Columbia Disaster; - https://en.wikipedia.org/wiki/Space_Shuttle_Columbia_disaste...
I think it’s time to build a rotating space station.
We’ve got all the knowledge from a microgravity space station, as we’re going to get. The conclusion is that it sucks. Humans are not meant to live in space without gravity. The muscle and bone deterioration is too great. And the eye damage is too great.
We need gravity. The question is whether we can get it from centripetal acceleration instead, to provide a long term habitation in space for humans.
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> 19-22 million dollars per person That doesn't mean it was profitable. The price could have been set for political reasons. Or it could have been set by the marginal cost of the launch, ignoring entirely the development cost that was written off when the USSR collapsed. Or it could have been enough to simply pay for the weight of the astronaut in a rocket that was going up anyway, like a hotel will sell rooms at a d…
> If communism produces goods and services cheaper than the free market, we'd be awash in Soviet goods. Which we aren't, because they're undercut by Chinese goods...
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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.
As if millions of voices suddenly cried out in terror and were suddenly silenced.
I hope JB Weld and Shoe Goo work in space, or our hopes of interstellar travel are dashed.
But Scotchweld is as easy to use as JB Weld and also very cheap.
Source: Am an spacecraft AIT engineer responsible for much gluing
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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.
Brittle materials are more temperature sensitive and can rapidly fail. Brittle fracture is no joke look for WWII Liberty ships split in two as an example. We didn't really understand why at that point in time.
The answer though is actually pretty simple and why you can't get a perfect material. The lattice structure of the molecules connected to each other can be soft (plastic) or hard (steel).
In the plastic example just take a milk jug and poor boiling water into it. Don't actually do this without protective gear (oven mit should be fine). The molecules holding everything together get excited from the energy (heat) move around and since they are not closely bonded end up in a different configuration. Your milk jug at this point does not look the same and is deformed.
In the hard example just boil the water you are using for the plastic test. The pot you used does not change because the molecules are tightly bonded.
It turns out the the tighter the molecules are bonded there is still a point where that bond will break. Hence the brittle fracture, which is every molecule mic dropping and going home at the same time.
While I could go down another rabbit hole to the atomic, subatomic, level of how those lattice structures work. I won't as I think this example gives you what you need.
Finally in this case we have a very old, by modern space technology, structure that is made of material that was most likely never expected to last this long. If you want a space ship to last you just have to make sure the engineers understand what "last" means. :)
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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.
I've been watching a lot of documentaries about Mars and the more I learn the more it seems so incredibly daunting and overwhelming. The atmosphere isn't even thick enough to slow down properly from the massive speed you need to get there at a time scale that works. How do you land large colonization facilities, landers, etc. in an atmosphere that is 1% as dense as Earth's? How do you then have enough fuel to leave?…
It is supposed to be retired in 2024. But politicians will push it to 2030 so that ISS contractors keep getting paid.
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…
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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
Did the Chinese build their own biosphere 2 (Arizona)?