Thousands of satellites are currently parked in low Earth orbit, with some eventually decommissioning and falling back into our planet’s atmosphere. As they re-enter the atmosphere, satellites leave behind a trail of chemicals that eat away at the ozone layer. A new study warns against the growing number of Internet satellites, which have contributed to a shocking eightfold increase in harmful oxides in the Earth’s atmosphere over a six-year period.
Not all satellites are created equal. Internet satellites tend to have a shorter lifespan of about five years, after which they are deorbits and falls towards the Earth’s atmosphere. Of the nearly 10,000 satellites in orbit today, two-thirds belong to SpaceX’s Starlink broadband constellation.
SpaceX has launched more than 6,000 Starlink satellites into orbit, and the company’s billionaire founder Elon Musk hopes to build a massive constellation of 42,000 satellites. SpaceX isn’t the only company building a constellation in low Earth orbit. Blue Origin’s Kuiper Project also plans to send 3,000 satellites into space, while Europe’s OneWeb wants to build a constellation of 648 satellites. These numbers are giving us great Kessler Syndrome anxiety.
Related article: What you need to know about Kessler syndrome, the biggest disaster in space
In addition to the increased risk of collision, Internet satellites are on a more frequent rotation than their longer-term counterparts, with companies constantly launching replacements to maintain their broadband services. At the end of their short lifespans, satellites generate pollutants as they fall through the atmosphere. Satellite reentry produces tiny particles of aluminum oxide, which cause chemical reactions that destroy stratospheric ozone, according to recent data. STUDY published in Geophysical Research Letters. Oxides do not react chemically with ozone layer molecules; instead they initiate destructive reactions between ozone and chlorine that end up depleting the protective layer in the Earth’s atmosphere.
“Only in the last few years have people started to think that this might become a problem,” said Joseph Wang, an astronautics researcher at the University of Southern California and lead author of the new study. STATEMENT. “We were one of the first teams to look at what the implication of these facts might be.”
Using a model of the chemical composition of the material used to build satellites, the researchers found that a typical 550-pound (250-kilogram) satellite, with aluminum making up 30% of its mass, would generate about 66 pounds (30 kilograms) of . of aluminum oxide nanoparticles (from 1 to 100 nanometers in size) during its reentry collapse. Based on that modeling, the study found that reentry into satellites increased the amount of aluminum in the atmosphere by 29.5% above natural levels from 2016 to 2022.
It only gets worse from here. According to the study, it would take about 30 years for aluminum oxide particles to descend to the same height as the Earth’s stratosphere, where 90% of the ozone is located. By the time the planned Internet constellations are built in low Earth orbit, 1,005 tons of aluminum will have fallen into the Earth’s stratosphere. This will release about 397 tonnes of aluminum oxide per year into the atmosphere, an increase of 646% over natural levels.
Just when things were starting to look up for the Earth’s ozone layer. A recent assessment by the United Nations Environment Program found that The ozone layer is on track for a full recovery by 2066. Almost 99% of ozone-depleting chemicals have been phased out since the 1980s thanks to an international treaty to protect our ozone signed in 1987.
The latest study highlights the need for better regulations to help mitigate the effects of a growing space industry — one that likes to put satellites all over Earth.
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