Fun fact, in January, 120 starlink satellites were burned up in the atmosphere. Annually they're pumping tones of aluminum oxide into the atmosphere as a result of these burnt satellites, which is not great for our ozone layer.
Elon and his space garbage is literally becoming an existential threat to humanity.
I needed to do math. The starlink satelite weights around 250kg, AGU Aplications said that of 250kg of Aluminium can produce 30kg of aluminium oxide. So in total we have one metric tone of aluminium oxide released. Thats extreamly low number. Starlink alone would need to fire those satelites for thousand of years to make significant impact. But at the same time. The increase of launches in total might contribute to steady rise of falling satelites and if something is not a problem today but might be tomorow the we shoild start working on it now to fix it.
Your only mistake is that you're trying "convert" mass to mass, while you need do it by moles. Here the balanced chemical reaction:
6Al + 3O2 = 3Al2O3
As seen, for every 6 moles of aluminium we get 3 moles of oxide. If then you calculate the mass using your correct molar masses, you'll get 472kg, like one of commenters.
It for sure is not 200kg of pure aluminium. People just say aluminium to anything that contains it although often it isn’t pure aluminium but some alloy.
...but we're talking about it falling at near-orbital speed into an environment with a super abundance of Oxygen and energy available to drive the reaction towards completion...
...your idealised reaction in a test tube, would probably be a less ideal environment and leave more unreacted residue behind in practice.
Unless you refer to the possibility of chunks of Aluminium structure large enough to survive intact and remain unburnt hitting the ground, or reacting with other elements and producing other Aluminium compounds on the way down?
Otherwise I fail to see where you think all that Aluminium falling into the sky from outside at incredible speeds is going to disappear to, where it can avoid being oxidised in the oxygen-rich blast furnace furnace of reentry, other than some miniscule fraction.
Not that this isn't worth further investigation, but only the proportion of oxygen to other gasses stays the same in upper earth atmosphere. There's significantly less of it the higher you go. There's a study based off a model linked in this comment chain that says for every 250 kg satellite you wind up with 30 kg of aluminum oxide. There are a ton of simplifying assumptions made in that model though.
You're right, I recheck my figures and it's 52.92% of the total mass.
Making the result 57 metric tonnes of AL2O3, rather than 113 metric tonnes.
Thanks and my apologies, it's been a few decades since I studied chemistry and neglected to double for the 2 moles of Al per 1 mole of oxide.
Either way all that Aluminium certainly isn't going to disappear up it's own asshole, even with incomplete reaction you're going to have a significantly larger, mass of Aluminium Oxide than the mass of Aluminium of you started with. Dozens of times more than they suggested.
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024GL109280 Maybe should have read the article before speculating. Seems pretty reliable to me, obviously its not without flaws, but they simulated the environment that a satellite encounters when reentering the atmosphere on an atomic scale. During reentry when the satellite burns up, it does so in an oxygen deficient environment (there is obviously oxygen, but not enough to react with all of the aluminum) so no, no where near 100% of the aluminum will turn into aluminum oxide. The rest of the aluminum just stays aluminum, it does nothing
This is a bullshit fact. Not that its not true, but those few tonnes of burned aluminum are nothing to the literal thousands of tonnes burned monthly in waste incinerators world wide.
I mean, this is definitely worth further investigation but that study is not definitive in the way you're presenting it to be. There's a lot of "could" and "may" in there, along with a boatload of simplifying assumptions being run in a model built off those simplifying assumptions.
Welcome to science. All Models are wrong, but some are useful. SpaceX will for sure not care about it before serious damage is done. So we better investigate this further.
Right. But the ones that haven't been tuned with a bunch of real data aren't particularly useful except to spur further investigation. That's why I said further investigation is warranted.
Waste incinerator produce aluminum nanoparticles which are reaching the ozone layer? Doubt that.
Edit: If you downvote, at least provide facts disproving me. "Not that its not true, but those few tonnes of burned aluminum are nothing to the literal thousands of tonnes burned monthly in waste incinerators world wide." What is even the logic here? Producing aluminum oxide on the ground is a complete different issue especially in a waste burning facility where it will most stay in the clinker than the issue of producing it in the upper atmosphere in fine particle size.
Lol, that guy discredits himself by making Hitler salutes. Stating a completely orthogonal problem, like wasting burning, does not help this guy either.
If you want to talk space junk, then you need to look at the primary offenders. China. Starlink burning into the atmosphere is the right way to do it, whereas China just leaves shit floating in orbit forever.
Aww, sounds like someone's just upset they made felating a nazi south afrikan milk baby a core personality trait.
It's okay though. Unlike that perma-bent dick thing you got going on, you can always sell off your tesla. Judging from your post history, it won't fix the... other gross shit you got going on upstairs, but it'll at least conceal your shame publicly until you start talking.
2.5k
u/redactid55 Mar 06 '25
Polluting so much even space needs to be cleaned