- cross-posted to:
- furry_scientists@pawb.social
- cross-posted to:
- furry_scientists@pawb.social
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
About 48 tons of meteorites enter the atmosphere every day. I couldn’t find the elemental distribution, but I’d guess there is some aluminum in there. How much of an increase is 14 tons aluminum per year over the many tons of aluminum entering the atmosphere already? That might be good to get a rough estimate of how impactful this is.
Even assuming the meteorites are 100% aluminum it’s a 30% increase which is quite significant.
From a short google search apparently only ~8% of asteroids in our solar system are metal rich which is mostly iron nickel. Rarer metals can be as rare as 100 grams per ton.
Which means of the 48 tons only 4.8 kilos could be aluminum. Compared to that the 14 tons would be a whopping ~3000% increase.
The asteroid weights are given per day while the sats per year.
Still only 1752 kg per year
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4.8 kg not 48kg
Isn’t it 48 tons of meteorites per day vs 14 tones of satellites per year?
Where are you getting a 30% increase?
Adding 14 tons a year to the 17,520 (48 x 365) tons of meteorites per year is a 0.07% increase (assuming that every meteorite is 100% aluminum and burns up entirely, which is definitely not reality)
Al is a major element in the solar system. Most rocks have Al2O3 on the order of 3-10 wt.%. That includes chondrites (the major class of meteorite) which have plenty of feldspar, a mineral that’s like 20 wt.% Al2O3, and calcium-aluminium inclusions (CAIs), which are as their name suggests, Al-rich.
4.8kg per day gives 1.75 tons per year, giving an 800% increase. That’s still really big, thanks for tracking down the numbers.
I would put money down the meteorites are below 30% aluminum so I can’t see it being less than doubling.
48 tons per day, so it’d need to be less than 0.08% aluminum to double it.
ah. missed the per day vs per year thing.
https://en.m.wikipedia.org/wiki/Abundance_of_the_chemical_elements
That article discusses how to determine the average distribution of the elements. Considering that only 2% is not Hydrogen or Helium, I would guess that the amount of aluminum in those meteorites is either not burned up in the atmosphere, or is negligible enough to not make a difference.
I assume that claim comes from:
I kind of doubt that hydrogen or helium comprise 98% of the mass of the 48 tons of meteors per day. I kinda suspect that the 48 tons of meteors are comprised almost entirely of “other” elements.