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submitted 4 weeks ago* (last edited 4 weeks ago) by [email protected] to c/[email protected]

Abstract from the paper in the article:

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024GL109280

Large constellations of small satellites will significantly increase the number of objects orbiting the Earth. Satellites burn up at the end of service life during reentry, generating aluminum oxides as the main byproduct. These are known catalysts for chlorine activation that depletes ozone in the stratosphere. We present the first atomic-scale molecular dynamics simulation study to resolve the oxidation process of the satellite's aluminum structure during mesospheric reentry, and investigate the ozone depletion potential from aluminum oxides. We find that the demise of a typical 250-kg satellite can generate around 30 kg of aluminum oxide nanoparticles, which may endure for decades in the atmosphere. Aluminum oxide compounds generated by the entire population of satellites reentering the atmosphere in 2022 are estimated at around 17 metric tons. Reentry scenarios involving mega-constellations point to over 360 metric tons of aluminum oxide compounds per year, which can lead to significant ozone depletion.

PS: wooden satellites can help mitigate this https://www.nature.com/articles/d41586-024-01456-z

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[-] [email protected] 70 points 4 weeks ago

Before anyone jumps on the Anti-Musk train, read the article, please. They admit that they don't understand the complications that could arise and that they don't have any hard figures for the damage being caused. I'll be the first to jump in and say that it's probably a bad thing to just let metals burn in in atmo, but let's make sure we discuss the facts, and not just the politics of the potential polluter.

[-] [email protected] 49 points 4 weeks ago

Ah yes, the usual method of waiting until the issue becomes confirmed and also way too severe to fix instead of acting on precaution and harming profits of private companies. What could go wrong?

[-] [email protected] 36 points 4 weeks ago

Yeah, PFAS comes to mind. It took decades to confirm it's harmful to humans but at this point it is everywhere and hard to get rid of. Worst part is they try to use other chemicals to replace PFAS, but again how harmful they are we don't know and we will learn that decades later too because companies don't want to make long term research before releasing the product. Enviroment shouldn't be a billionaire's testing ground.

[-] [email protected] 1 points 4 weeks ago

So if moving from PFAS to alternate chemicals means moving foolishly into untested chemicals, why didn’t they wait to test them? Were they forced to make the change?

[-] [email protected] 7 points 4 weeks ago

There is a line somewhere I think. Like people weren't 100% sure the atomic bomb won't ignite the atmosphere (it's only very unlikely), but they still tested it. Similarly the probability of creating micro blackholes at LHC is not zero either, yet they still ran it.

If we have to make sure everything is 100% safe before we can do anything, we will be stuck with the status quo.

[-] [email protected] 2 points 4 weeks ago

We will die of starvation because nothing is 100% safe, so waiting until we find that level of safety means we just won’t do anything.

[-] [email protected] 1 points 4 weeks ago

I don't know how that is usual in your mind. Since from my perspective I see it constantly.

[-] [email protected] 1 points 4 weeks ago

As opposed to acting before you understand the effects of your actions? Neither seem like good choices.

Probably the best option would be to research harder. Make the polluter fund a much larger scale research program to understand the problem and viable solutions as quickly as possible.

[-] [email protected] -4 points 4 weeks ago* (last edited 4 weeks ago)

Ah yes, the usual method of waiting until the issue becomes confirmed and also way too severe to fix instead of acting on precaution and harming profits of private companies.

No, but as even them don't understand what the complications are and how much the damages could be, maybe to wait to have at least some hard number looks like a good idea.

What could go wrong?

And what could go wrong if we start to fight a problem that we don't understand how big it is, maybe using the wrong solution on a wrong scale ?

[-] [email protected] 10 points 4 weeks ago

maybe to wait to have at least some hard number looks like a good idea.

Good plan. So they're holding off on starlink launches to let the science catch up, right?

[-] [email protected] 5 points 4 weeks ago* (last edited 4 weeks ago)

Perfect is the enemy of good.

If it is worth doing, it is worth getting it done, even if we aren't 100% certain or ready on a lot of things. Doctors don't wait for the worst before starting treatment. Specially if corrections carry none or way less risks than what is currently being done.

[-] [email protected] 4 points 4 weeks ago

Doing scientific experiments to understand the risks is worth doing.

[-] [email protected] 1 points 4 weeks ago

Perfect is the enemy of good.

I agree on this.

If it is worth doing, it is worth getting it done, even if we aren’t 100% certain or ready on a lot of things.

From the article it seems we are not even 10% certain. In summary, we don't understand (yet) the problem, we have no clue on how complex is, we have no hard number to tell us how big it is.
I agree, something need to be done. But for now the "something" is just to try to understand better the problem, or at least how big it is.

Doctors don’t wait for the worst before starting treatment.

True, but they start treatment when they know what they need to cure or at least they have solid evidence that indicate something, not before.

Specially if corrections carry none or way less risks than what is currently being done.

Hard to decide that corrections carry lower risks of something we don't understand.

[-] [email protected] 1 points 4 weeks ago

One of the big risks of not having a global communications satellite network is that people can get cut off from the internet by land-based ISPs loyal to whatever local government they’re trying to be free of.

So there’s a danger of just saying “no satellite clusters”.

We’re always balancing dangers against other dangers. There’s danger in not acting, not growing too.

[-] [email protected] 5 points 4 weeks ago* (last edited 4 weeks ago)

I was actually reviewing the O3 depletion process https://en.m.wikipedia.org/wiki/Chlorine_monoxide and Cl only stops reacting with O3 when it ends up as ClO2, but that is rare, because ClO usually is too short-lived to react with another Cl into Cl2O, so it may be possible that a catalyst like Al2O3 could actually clean up Cl interfering with the ozone layer along with the effect of speeding up the nefarious reaction with O3 :D

[-] [email protected] 1 points 4 weeks ago

Guys, let's not jump into conclusions. I'd say that it is not a real issue until at least a billion people have died from it.

[-] [email protected] -5 points 4 weeks ago* (last edited 4 weeks ago)

If they don't have grounds to accuse SpaceX then SpaceX can sue them for defamation. SpaceX doesn't need YOU to defend them.

OP listed the referenced study in the description, it has "hard numbers" from simulations and citations to many other studies as well.

this post was submitted on 17 Jun 2024
705 points (96.0% liked)

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