Another Looming Man made Disaster?

imhotep

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  • Mar 29, 2017
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    Defunct satellites burning up in the atmosphere could damage the ozone layer. Communications companies such as Starlink plan to launch tens of thousands of satellites into orbit around Earth over the next decade or so. The growing swarm is already causing problems for astronomers, but recent research has raised another question: what happens when they start to come down?

    When these satellites reach the end of their useful life, they will fall into Earth’s atmosphere and burn up. Along the way, they will leave a trail of tiny metallic particles.

    According to a study published last week by a team of American researchers, this satellite rain may dump 360 tonnes of tiny aluminium oxide particles in the atmosphere each year. The aluminium will mostly be injected at altitudes between 50 and 85 kilometres, but it will then drift down to the stratosphere – home to Earth’s protective ozone layer.

    The details of the specific injection of aluminium oxides by falling satellites would be quite complex. This is not the first study to highlight the growing stratospheric pollution from re-entering space junk.
    In 2023, researchers studying aerosol particles in the stratosphere detected traces of metals from spacecraft re-entry. They found that 10% of stratospheric aerosols already contain aluminium, and predicted this will increase to 50% over the next 10–30 years. (Around 50% of stratospheric aerosol particles already contain metals from meteorites.)

    PS:
    Media release
    From: American Geophysical Union

    SATELLITE “MEGACONSTELLATIONS” MAY JEOPARDIZE RECOVERY OF OZONE HOLE

    WHEN INTERNET-PROVIDING SATELLITES — NOW BEING LAUNCHED BY THE THOUSANDS — REACH END OF LIFE, BYPRODUCTS OF THEIR FIERY DEATHS IN EARTH’S ATMOSPHERE WILL CATALYZE CHEMICAL REACTIONS THAT DESTROY STRATOSPHERIC OZONE

    When old satellites fall into Earth’s atmosphere and burn up, they leave behind tiny particles of aluminum oxide, which eat away at Earth’s protective ozone layer. A new study finds these oxides have increased 8-fold between 2016 and 2022 and will continue to accumulate as the number of low-Earth-orbit satellites skyrockets.

    The 1987 Montreal Protocol successfully regulated ozone-damaging CFCs to protect the ozone layer, shrinking the ozone hole over Antarctica with recovery expected in the fifty years. But unanticipated growth of aluminum oxides may push pause on the ozone success story in decades to come.

    Of the 8,100 objects in low Earth orbit, 6,000 are Starlink satellites launched in the last few years. Demand for global internet coverage is driving a rapid ramp up of launches of small communication satellite swarms. SpaceX is the front runner in this enterprise, with permission to launch another 12,000 Starlink satellites and as many as 42,000 planned. Amazon and other companies around the globe are also planning constellations ranging from 3,000 to 13,000 satellites, the authors of the study said.

    Internet satellites in low Earth orbit are short-lived, at about five years. Companies must then launch replacement satellites to maintain internet service, continuing a cycle of planned obsolescence and unplanned pollution.

    Aluminum oxides spark chemical reactions that destroy stratospheric ozone, which protects Earth from harmful UV radiation. The oxides don’t react chemically with ozone molecules, instead triggering destructive reactions between ozone and chlorine that deplete the ozone layer. Because aluminum oxides are not consumed by these chemical reactions, they can continue to destroy molecule after molecule of ozone for decades as they drift down through the stratosphere.

    Yet little attention has yet been paid to pollutants formed when satellites fall into the upper atmosphere and burn. Earlier studies of satellite pollution largely focused on the consequences of propelling a launch vehicle into space, such as the release of rocket fuel. The new study, by a research team from the University of Southern California Viterbi School of Engineering, is the first realistic estimate of the extent of this long-lived pollution in the upper atmosphere, the authors said.

    “Only in recent years have people started to think this might become a problem,” said Joseph Wang, a researcher in astronautics at the University of Southern California and corresponding author of the new study. “We were one of the first teams to look at what the implication of these facts might be.”

    The study was published in the AGU journal Geophysical Research Letters, at open-access journal that publishes high-impact, short-format reports with immediate implications spanning all Earth and space sciences.

    SLEEPING THREAT

    Because it’s effectively impossible to collect data from a spacecraft that’s burning up, previous studies used analyses of micrometeoroids to estimate potential pollution. But micrometeoroids contain very little aluminum, the metal that makes up 15% to 40% of the mass of most satellites, so these estimates didn’t apply well to new “swarm” satellites.

    To get a more accurate picture of pollution from satellite re-entry, the researchers modeled the chemical composition of and bonds within satellites’ materials as they interact at molecular and atomic levels. The results gave the researchers an understanding of how the material changes with different energy inputs.

    In 2022, reentering satellites increased aluminum in the atmosphere by 29.5% over natural levels, the researchers found. The modeling showed that a typical 250-kilogram (550-pound) satellite with 30% of its mass being aluminum will generate about 30 kilograms (66 pounds) of aluminum oxide nanoparticles (1-100 nanometers in size) during its reentry plunge. Most of these particles are created in the mesosphere, 50-85 kilometers (30-50 miles) above Earth’s surface.

    The team then calculated that, based on particle size, it would take up to 30 years for the aluminum oxides to drift down to stratospheric altitudes, where 90% of Earth’s ozone is located.

    The researchers estimated that by the time the currently planned satellite constellations are complete, every year, 912 metric tons of aluminum (1,005 U.S. tons) will fall to Earth. That will release around 360 metric tons (397 U.S. tons) of aluminum oxides per year to the atmosphere, an increase of 646% over natural levels.
     

    jamiezue

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  • Jul 28, 2008
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    -~උලක් උඩ-~
    වායුගෝලයට උඩින් දැලක් දාන්න තියෙන්නෙ පොලව වටේට. දැල මහලා දුන්නොත් මම හරි දාල එනවා :rolleyes:
    satelites.jpg
     
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    imhotep

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  • Mar 29, 2017
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    මිනිස්සු සොභාදහම අභිබවා යන හැම වෙලාවේම මිනිස්සුන්ටම කෙළවෙන්න දෙයක් වෙනවා
    True.... History shows us many examples. Most famous disaster was Mao's "Four Pests Campaign". The slogan "man must conquer nature" became a rallying cry during the Great Leap Forward. He called upon people to eradicate flies, mosquitoes, rats and sparrows.
    Removing the Sparrows out of the equation became a complete disaster with 45 Million deaths (some estimates much more around 78 Million) in a devastating famine.

    A similar thing happened in Borneo under the WHO direction. In order to eliminate malaria, the WHO sprayed DDT. This got rid of the mosquitoes alright, but the led to a series of catastrophic events the start of which was the elimination of the parasitic wasps that preyed on thatch-eating caterpillars.
    Houses fell down, the food chain contaminated - geckos ate poisoned caterpillars, cats ate the geckos and died. Eventually typhus and other diseases took hold.
    The WHO had to air drop Cats - using the RAF. REad about the "Operation Cat Drop" :unsure:
     
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    Stimulus mind

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  • Feb 27, 2021
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    Los Alamos
    fossil fuels, burn කරන එකෙන් වෙන damage එක තරම්ම ලොකු damage එකක් පෘථිවි වායුගෝලෙට වෙයි වගේ මේක නිසා ඉස්සරහට. :dull:
     
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