Thousands of satellites are currently in low Earth orbit, and some will eventually become defunct and fall back into our planet’s atmosphere. When they reenter the atmosphere, satellites leave behind a trail of chemicals that eat away at the ozone layer. A new study warns that the growing number of internet satellites have contributed to a shocking eightfold increase in harmful oxides in the Earth’s atmosphere in the space of six years.
Not all satellites are created equal. Internet satellites typically have a shorter lifespan of about five years, after which they be removed from Earth’s orbit and plunged into Earth’s atmosphereOf the nearly 10,000 satellites currently orbiting the Earth, two-thirds belong to Starlink, SpaceX’s broadband network.
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 Origins Project Kuiper is also planning to launch 3,000 satellites into space, while the European OneWeb wants to build a constellation of 648 satellites. These figures give us great fear of the Kessler syndrome.
Related article: What You Need to Know About Kessler Syndrome, the Ultimate Space Disaster
Aside from the increasing risk of collisions, internet satellites rotate more frequently than their more durable counterparts, with companies repeatedly launching replacements to maintain their broadband services. At the end of their short lives, the satellites generate pollutants as they fall through the atmosphere. The return of satellites produces small particles of aluminum oxide, which trigger chemical reactions that destroy the ozone in the stratosphere, according to recent studies. study published in Geophysical research lettersThe oxides do not react chemically with the molecules of the ozone layer; instead, they cause destructive reactions between ozone and chlorine that ultimately break down the protective layer in Earth’s atmosphere.
“It’s only in recent years that people have started to think this could be a problem,” Joseph Wang, an aerospace researcher at the University of Southern California and lead author of the new study, said in a rack. “We were one of the first teams to investigate what the implications of these facts could 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, of which aluminum makes up 30 percent of the mass, generates about 66 pounds (30 kilograms) of aluminum oxide nanoparticles (1 to 100 nanometers in size) during reentry. Based on that modeling, the study revealed that returning satellites increased the amount of aluminum in the atmosphere by 29.5 percent over natural levels from 2016 to 2022.
It only gets worse from here. According to the study, it would take about 30 years for the aluminum oxide particles to drift to the same altitude as the Earth’s stratosphere, where 90 percent of the ozone is located. By the time the planned low-Earth orbital internet constellations are built, 1,005 tons of aluminum will have fallen into the Earth’s stratosphere. This will release about 397 tons of aluminum oxide into the atmosphere each year, a 646 percent increase 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 Programme found that the The ozone layer is on track for a full recovery by 2066. Nearly 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 recent research shows that better regulation is needed to limit the effects of a growing space industry. This industry likes to place satellites on Earth.
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