Satellites like SpaceX’s Starlink may weaken the ozone layer due to pollution released during their re-entry into the atmosphere.
In a study published in the journal Geophysical Research Letters, a team of scientists from the University of Southern California estimated the negative impact of satellites releasing harmful pollutants such as aluminum oxide into the upper atmosphere as they fall back and burn up, Futurism reported on June 16. These decommissioned satellites could significantly contribute to the depletion of the ozone layer – “the sun shield” that protects Earth from excessive ultraviolet radiation from the sun.
Illustration of a satellite falling into the atmosphere and burning up. (Photo: ESA).
Currently, researchers are primarily focused on the pollutants released by rockets during launches, while they have only begun to understand the impact of thousands of decommissioned or malfunctioning satellites burning up in the atmosphere. This impact is growing as SpaceX has launched nearly 6,000 Starlink satellites and plans to launch tens of thousands more. SpaceX’s ambitions are also driving the establishment of similar massive satellite networks around the Earth.
“In recent years, people have started to think that it could become a troublesome issue. We are one of the first teams to study the impact of this,” said Joseph Wang, co-author of the new study and a space exploration expert at the University of Southern California.
Accurately collecting data on the pollutants emitted by satellites as they re-enter the atmosphere is nearly impossible, so the team of scientists can only estimate their impact on the surrounding environment. By studying how common metals used in satellite manufacturing interact, they estimated that the presence of aluminum in the atmosphere increased by nearly 30% just in 2022.
The research team noted that a 250 kg satellite produces about 30 kg of aluminum oxide nanoparticles during its re-entry. These particles can take up to 30 years to settle into the stratosphere. Overall, if satellite networks like Starlink continue to develop as planned, the amount of aluminum oxide in the atmosphere could increase by up to 646% annually compared to natural levels.
“The environmental impact of the satellite re-entry process is not yet well understood. As the number of re-entering satellites increases, it is crucial to further investigate the issues raised in this new study,” the team of experts wrote.
