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but those 100 tons do not contain that much aluminum. I remember a story where the aluminum aerosols may have a strong effect https://cires.colorado.edu/news/wi

but those 100 tons do not contain that much aluminum. I remember a story where the aluminum aerosols may have a strong effect https://cires.colorado.edu/news/within-15-years-plummeting-satellites-could-release-enough-aluminum-alter-winds-temp https://cires.colorado.edu/news/within-15-years-plummeting-s...

timschmidt 11mo ago
At least 1.4% of Earth is aluminum. Meteors will have similar composition on average. Aluminum smelting likely vaporizes a much larger volume of material.
- eesmith 11mo ago
  That aluminum is not in the upper atmosphere. Quoting https://www.nature.com/articles/s41598-021-89909-7.pdf https://www.nature.com/articles/s41598-021-89909-7.pdf > ... the satellites are mostly aluminum; most meteoroids, in contrast, contain less than 1% Al by mass 25 . Thus, depending on the atmospheric residence time of material from reentered satellites, each mega-constellation will produce fine particulates that could greatly exceed natural forms of high-altitude atmospheric aluminum deposition, particularly if the full numbers of envisaged satellites are launched. Anthropogenic deposition of aluminum in the atmosphere has long been proposed in the context of geoengineering as a way to alter Earth’s albedo 26 . These proposals have been scientifically controversial and controlled experiments encountered substantial opposition 27 . Mega-constellations will begin this process as an uncontrolled experiment 28 . Or from https://www.science.org/doi/pdf/10.1126/science.adr9689 https://www.science.org/doi/pdf/10.1126/science.adr9689 > Concerns are mostly focused on aluminum, the most common component in satellites. If the disintegrated metal ends up as aluminum oxide or hydroxide, it can react with hydrogen chloride — the main reservoir of chlorine in the stratosphere, a hangover from the days of chlorofluorocarbons — to produce aluminum chloride. Hydrogen chloride is a relatively safe repository for chlorine, but aluminum chloride is easily split apart by light, freeing the chlorine to destroy ozone. Metal aerosols could also seed the creation of more polar stratospheric clouds, which catalyze reactions that liberate destructive forms of chlorine. “One can speculate, but without critical laboratory measurements of the chemistry, it’s very hard to know [the effects],” says John Plane, an atmospheric chemist at the University of Leeds. ... “You have to wonder whether [SpaceX] is creating a major problem 30 years from now,” Lionnet says.
  - timschmidt 11mo ago
    It's tough to find figures, but the amount of aluminum lost during smelting not accounted for in dross is as much as half a percent. World smelting capacity is 113 million tons per year. Which maths to as much as 565,000 tons of vaporized aluminum per year. You're right that it's released into the lower atmosphere, though I'm sure smoke stacks loft that significantly in many cases. And it's difficult for me to believe that a few hundred kg per day, even if all of it ended up in the upper atmosphere, is anything more than a blip in comparison to what lofts up from industry. The difference would have to be many thousands of times worse for upper atmosphere releases for it to even register.
    - eesmith 11mo ago
      > though I'm sure smoke stacks loft that significantly in many cases It must be nice believing that your personal views are always correct. To know that those geoengineers who want to disperse aluminum oxide to reduce the Earth's albedo clearly don't know how insignificant those aircraft deployed aerosols are compared to the byproducts of aluminum smelting. To understand that conclusions like 'We find that the population of reentering satellites in 2022 caused a 29.5% increase of aluminum in the atmosphere above the natural level, resulting in around 17 metric tons of aluminum oxides injected into the mesosphere' can be ignored because 17 metric tons should be a blip compared to what lofts up from industry. (Quoting https://agupubs.onlinelibrary.wiley.com/doi/pdfdirect/10.1029/2024GL109280 https://agupubs.onlinelibrary.wiley.com/doi/pdfdirect/10.102... ) That statements like "The natural entry of aluminum (Al) into Earth's atmosphere, primarily from meteoroids, is estimated at 141.1 metric tons (Mg) per year" is a deliberate obfuscation because it doesn't include antropogenic ground contributions. (Quoting https://www.viasat.com/content/dam/us-site/corporate/documents/Environmental_Impact_of_Large_LEO_Constellations_-_13th_IAASS.pdf https://www.viasat.com/content/dam/us-site/corporate/documen... ) That people looking into wood-composite alternatives to aluminum, due to concerns about "increased metallic aerosols in the stratosphere" (https://conference.sdo.esoc.esa.int/proceedings/sdc9/paper/87/SDC9-paper87.pdf https://conference.sdo.esoc.esa.int/proceedings/sdc9/paper/8... ) are wasting their time.
      - 11mo ago

timschmidt 11mo ago

At least 1.4% of Earth is aluminum. Meteors will have similar composition on average. Aluminum smelting likely vaporizes a much larger volume of material.

eesmith 11mo ago
That aluminum is not in the upper atmosphere. Quoting https://www.nature.com/articles/s41598-021-89909-7.pdf https://www.nature.com/articles/s41598-021-89909-7.pdf > ... the satellites are mostly aluminum; most meteoroids, in contrast, contain less than 1% Al by mass 25 . Thus, depending on the atmospheric residence time of material from reentered satellites, each mega-constellation will produce fine particulates that could greatly exceed natural forms of high-altitude atmospheric aluminum deposition, particularly if the full numbers of envisaged satellites are launched. Anthropogenic deposition of aluminum in the atmosphere has long been proposed in the context of geoengineering as a way to alter Earth’s albedo 26 . These proposals have been scientifically controversial and controlled experiments encountered substantial opposition 27 . Mega-constellations will begin this process as an uncontrolled experiment 28 . Or from https://www.science.org/doi/pdf/10.1126/science.adr9689 https://www.science.org/doi/pdf/10.1126/science.adr9689 > Concerns are mostly focused on aluminum, the most common component in satellites. If the disintegrated metal ends up as aluminum oxide or hydroxide, it can react with hydrogen chloride — the main reservoir of chlorine in the stratosphere, a hangover from the days of chlorofluorocarbons — to produce aluminum chloride. Hydrogen chloride is a relatively safe repository for chlorine, but aluminum chloride is easily split apart by light, freeing the chlorine to destroy ozone. Metal aerosols could also seed the creation of more polar stratospheric clouds, which catalyze reactions that liberate destructive forms of chlorine. “One can speculate, but without critical laboratory measurements of the chemistry, it’s very hard to know [the effects],” says John Plane, an atmospheric chemist at the University of Leeds. ... “You have to wonder whether [SpaceX] is creating a major problem 30 years from now,” Lionnet says.
- timschmidt 11mo ago
  It's tough to find figures, but the amount of aluminum lost during smelting not accounted for in dross is as much as half a percent. World smelting capacity is 113 million tons per year. Which maths to as much as 565,000 tons of vaporized aluminum per year. You're right that it's released into the lower atmosphere, though I'm sure smoke stacks loft that significantly in many cases. And it's difficult for me to believe that a few hundred kg per day, even if all of it ended up in the upper atmosphere, is anything more than a blip in comparison to what lofts up from industry. The difference would have to be many thousands of times worse for upper atmosphere releases for it to even register.
  - eesmith 11mo ago
    > though I'm sure smoke stacks loft that significantly in many cases It must be nice believing that your personal views are always correct. To know that those geoengineers who want to disperse aluminum oxide to reduce the Earth's albedo clearly don't know how insignificant those aircraft deployed aerosols are compared to the byproducts of aluminum smelting. To understand that conclusions like 'We find that the population of reentering satellites in 2022 caused a 29.5% increase of aluminum in the atmosphere above the natural level, resulting in around 17 metric tons of aluminum oxides injected into the mesosphere' can be ignored because 17 metric tons should be a blip compared to what lofts up from industry. (Quoting https://agupubs.onlinelibrary.wiley.com/doi/pdfdirect/10.1029/2024GL109280 https://agupubs.onlinelibrary.wiley.com/doi/pdfdirect/10.102... ) That statements like "The natural entry of aluminum (Al) into Earth's atmosphere, primarily from meteoroids, is estimated at 141.1 metric tons (Mg) per year" is a deliberate obfuscation because it doesn't include antropogenic ground contributions. (Quoting https://www.viasat.com/content/dam/us-site/corporate/documents/Environmental_Impact_of_Large_LEO_Constellations_-_13th_IAASS.pdf https://www.viasat.com/content/dam/us-site/corporate/documen... ) That people looking into wood-composite alternatives to aluminum, due to concerns about "increased metallic aerosols in the stratosphere" (https://conference.sdo.esoc.esa.int/proceedings/sdc9/paper/87/SDC9-paper87.pdf https://conference.sdo.esoc.esa.int/proceedings/sdc9/paper/8... ) are wasting their time.
    - 11mo ago