Starlink plans to send 42,000 satellites into space. This is bad news for ozone

Starlink satellite internet has been an incredible boon for rural residents on the other side of the digital divide. It could also spell disaster for Earth’s ozone layer, according to 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 small particles of aluminum oxide. These migrate into the ozone layer, which absorbs harmful ultraviolet radiation. Researchers at the University of Southern California found that these oxides increased eightfold from 2016 to 2022.

Not all of them come 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 Starlink objects. According to Space.com, the company currently has permission to launch an additional 12,000 satellites and plans to launch up to 42,000 in the future.

These satellites are designed to last about five years. A 550-pound satellite will release about 66 pounds of aluminum oxide nanoparticles upon re-entry. Starlink’s satellites have gotten heavier over time, with the latest version weighing about 2,760 pounds.

The aluminum is mostly released between 30 and 50 miles above the Earth’s surface, but then migrates into the ozone layer, which would take about 30 years. We’re already seeing these impacts – the burning of satellites in 2022 caused a 29.5% increase in aluminum levels in the atmosphere above natural levels – but researchers said it would only get worse.

“This is primarily a concern given the large number of satellites planned to be launched in the future,” Joseph Wang, one of the study’s authors, told CNET. “We have forecast an annual exceedance of natural levels of more than 640%. Based on this forecast, we are very concerned.”

In contrast to other substances that deplete ozone, aluminum oxide particles are not consumed in the process, the researchers say. They continue to damage the ozone layer until they naturally sink to lower altitudes, which could take about 30 years.

If Starlink scales as hoped, more than 8,000 satellites could burn up in the atmosphere every year. The researchers applied a predictive model to account for the growing number of satellites in the sky and found that the amount of aluminum could rise to 360 tons – or 640% above natural levels.

Starlink has led to an exponential growth of satellites in the sky

Perhaps what’s most concerning about this new research is how much is still uncharted territory. “The environmental impacts of satellite re-entry are currently poorly understood,” the study says.

In the four years that Starlink launches satellites, it will be 40% of all satellites always started and plans to increase the fleet sevenfold. Starlink’s main competitor, Amazon’s Project Kuiper, is also planning to launch 3,232 satellites in the coming years.

An article published in Nature stated that 100,000 satellites in the sky are “not only feasible, but quite likely.” This is almost entirely due 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 weakened immune systems, as well as reduced crop yields and disruption of the marine food chain.

“As reentry 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.