Abstract

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.

  • chemical_cutthroat@lemmy.world
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    5 months ago

    Nah, this is a different method. It’s the one where we get all of the facts before we take action. Maybe you aren’t up on it, but knee-jerk is so 1700s.

    • nevemsenki@lemmy.world
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      5 months ago

      Sure, PFAS were also considered a nonsignificant issue until they weren’t, only it’s too late to unfuck it now. Well, no harm in generating more potential ticking time bombs I guess.

    • gaael@lemmy.world
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      5 months ago

      Like maybe wait a few year and finance some science to check that your mega constellation of satellites (built to fail after only a few years to make sure your rocket company never goes out of work) won’t be a fucking nuisance on so many levels before you actually launch them ?
      This “get all the facts before taking action” ?

      • chemical_cutthroat@lemmy.world
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        5 months ago

        Oh, you mean a study on the Satellite Internet Constellations that have been in orbit since the 1990s, a full 30 years before Starlink launched? As with nearly everything else, Musk isn’t the first to do whatever he does, he’s just the loudest. If Starlink hadn’t launched we would still be facing the same problems. Thankfully, he’s a big enough ass that he makes a easy target for these kinds of things.

        • gaael@lemmy.world
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          5 months ago

          Maybe I didn’t get my facts straight, but iirc there are around 7.5k satellites up there, with starlink current count about 5.5k. And I think I read they got the greenlight for the 7.5k gen 2 sats launches.
          That looks like a scale change to me. Associated with the short lifespan (which contrasts with the situation 30 years ago, where launches were more expensive), it’s kind of a new situation and should have warranted a more careful approach.

          So musk isn’t the first one to launch satellites, I agree. But the way it’s done is kinda new, and mostly on the worse side. And I’m not saying the old way was good, and not absolving previous actors from responsability in the pollution.

    • OsrsNeedsF2P@lemmy.ml
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      5 months ago

      We don’t have to wait until it’s “fully confirmed” to start being concerned about it. Remember climate change denial? We were in the “we don’t know if humans are causing it” phase for a while.

      I also agree, let’s not jump on the anti-Musk team for this, but satellites burning up has always been a rather obvious source of pollution, and it’s good to see more discussion on it

      • intensely_human@lemm.ee
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        5 months ago

        Yeah, and now despite what the scientists say, everyone believes climate change is going to render Earth uninhabitable, and we are taking massive steps to avoid the problem as if it were an existential threat, which the science again does not support.

        We’re treating climate change as if it were as serious as a planet killer asteroid, and we’re massively violating people’s rights as if it were.

      • GoodEye8@lemm.ee
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        5 months ago

        We were in the “we don’t know if we’re causing it” phase for a long time because big oil knew about global warming and deliberately ran disinformation campaigns so they could keep profiteering. Had Exxon done the right thing in the 70s we wouldn’t have this looming crisis.

        • Peppycito@sh.itjust.works
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          5 months ago

          And now we’re in the “is burning up thousands of satellites bad?” phase of space exploration. I’ll be waiting for spacex to do the right thing.

          • GoodEye8@lemm.ee
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            5 months ago

            Don’t get me wrong. I’m not defending corporations here. I’m simply stating the fact that climate change denial wasn’t the case of waiting until it’s “fully confirmed”, it was pretty much confirmed back in the 70s. They even had predictions for the next century on how things will go bad if nothing is done and the last time I checked we were pretty on course with their predictions. When it came to the scientific consensus, it was pretty much “fully confirmed”. It was simply the public opinion where it wasn’t “fully confirmed” because corporations deliberately ran disinformation to make it seem like scientists didn’t know what they were talking about.

            But this paper isn’t really confirming anything. The paper itself says that the model does not account for all the factors and to literally quote the paper:

            As reentry rates increase, it is crucial to further explore the concerns highlighted in this study.

            This paper is not presenting a final conclusion, it’s presenting concerns that need further studies. let’s wait for further studies and if there’s scientific consensus about it being an issue I’m all for bringing out the pitchforks. In the mean let’s keep calm and dread over the doom and gloom that is climate change.

            • intensely_human@lemm.ee
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              5 months ago

              So you’re saying that in the 70s they had predictions about how things will go bad for the next century?

              Where are these predictions? It’s been 50 years so at least some of these predictions should be checkable now.

              I would feel so much better if I could see some examples of climate science predictions being proven accurate.

            • hglman@lemmy.ml
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              5 months ago

              It’s highlighting a potential significant risk. Major ozone loss is much worse than lack of internet. The high uncertainty of the paper is easily offset by the harm that would be caused if the paper is correct.

              • GoodEye8@lemm.ee
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                5 months ago

                So what are we supposed to do, halt all space flights until we figure this out?

                Without further research going into how much damage it’s doing there’s no way to say what our next steps should be. Maybe everything we’re doing is still within acceptable limits? Maybe we need tighter regulation on materials going into space. Maybe some materials need to be outright banned.

                The only reasonable thing we can do is study it further. Expecting instant result based on one study that only outlines a potential risk is quite frankly just doomerist behavior.