Could Starlink satellites damage the ozone layer?
Satellites such as those used for Starlink’s internet service could damage Earth’s ozone layer if they are taken out of orbit, a new study funded by NASA and published in Geophysical Research Letters.
When Starlink’s satellites reach the end of their lives, they burn up in Earth’s atmosphere, leaving behind tiny particles of aluminum oxide. These travel to the ozone layer, which absorbs harmful ultraviolet radiation. Researchers at the University of Southern California found that these oxides increased eightfold between 2016 and 2022.
Not all of these satellites are from Starlink — the internet provider only launched its first satellites in May 2019 — but it currently has by far the largest fleet. Of the approximately 8,100 objects in low Earth orbit, more than 6,000 are from Starlink. The company currently has permission to launch 12,000 more satellites and has another 42,000 planned in the future, according to Space.com.
These satellites are designed to last about five years. A 550-pound satellite will release about 66 pounds of aluminum oxide nanoparticles during re-entry. Starlink’s satellites have gotten heavier over time, with the latest version weighing about 2,760 pounds.
The aluminum will be released primarily between 30 and 50 miles above the Earth’s surface, but will then drift down into the ozone layer, which would take about 30 years. We’re already seeing these effects — satellites burning up in 2022 caused a 29.5 percent increase in aluminum in the atmosphere above natural levels — but the researchers said it’s only going to get worse.
“This is particularly a concern given the large number of satellites that are going to be launched in the future,” Joseph Wang, one of the study’s authors, told CNET. “We predicted an annual excess of more than 640% above the natural level. Based on that projection, we are very concerned.”
Unlike other ozone-depleting substances, aluminum oxide particles are not consumed in the process, the researchers said. They continue to damage the ozone layer until they naturally descend to lower altitudes, which can take about 30 years.
If Starlink scales as hoped, more than 8,000 satellites could burn up in the atmosphere each year. The researchers applied a forecasting model to account for the growing number of satellites in the sky and found that the amount of aluminum could grow to 360 metric tons — or 640% above natural levels.
Starlink has led to an exponential growth of satellites in the sky
Perhaps most alarming about this new research is how much of it remains unexplored. “The environmental impacts of satellite reentry are currently poorly understood,” the study said.
In the four years that Starlink has been launching satellites, it has achieved 40% of all satellites ever and plans to expand its fleet seven times. Starlink’s main competitor, Amazon’s Project Kuiper, also plans to 3,232 satellites in the coming years.
A paper published in Nature found that 100,000 satellites in the sky “is not only feasible, but also highly likely.” This is almost entirely thanks to private companies like SpaceX, Amazon and OneWeb launching satellites to provide high-speed internet.
According to the EPA, Excessive UV radiation can lead to skin cancer, cataracts and a weakened immune system. It can also lead to lower crop yields and disruptions in the marine food chain.
“As return rates increase, it is critical to further investigate the concerns highlighted in this study,” researchers say.
Starlink did not respond to CNET’s request for comment.
