Introduction: Rising Aluminum Oxides from Satellites
The ozone layer is being increasingly threatened by rising aluminum oxides from satellites re-entering Earth’s atmosphere. Given the recent study, the quantity of these harmful particles has risen eightfold from 2016 to 2022. As the number of satellites in low-Earth orbit rises, this increase is expected to continue, potentially slowing the recovery of the ozone layer notably.
The ozone layer is destroyed by tiny aluminum oxide particles released by dead satellites when they break apart and re-enter Earth’s atmosphere. Given the recent study, the quantity of these particles increased eightfold between 2016 and 2022, and this increase is predicted to continue as the number of satellites in low-Earth orbit rises. The ozone hole over Antarctica has shrunk thanks to the 1987 Montreal Protocol, which effectively confined ozone-damaging CFCs. A recovery is anticipated during the following 50 years. Still, the sudden rise in aluminum oxides may slow down the recovery of ozone in the following decades.
Rapid Increase in Satellite Numbers and Aluminum Oxide Emissions
Six thousand of the 8,100 objects in low Earth orbit are Starlink satellites that were put into orbit recently. The need for widespread internet connectivity is propelling a swift increase in the number of small communication satellite swarm launches. With clearance to launch an additional 12,000 Starlink satellites and plans to launch up to 42,000, SpaceX is leading this enterprise. According to the study’s authors, Amazon and other businesses worldwide are also preparing constellations of three to thirteen thousand satellites. The lifespan of internet satellites in low Earth orbit is only five years. The cycle of planned obsolescence and unplanned pollution is then perpetuated by businesses having to launch replacement satellites to continue internet access.
Aluminum Oxides’ Impact on the Stratospheric Ozone
The chemical processes that aluminum oxides initiate lead to the depletion of stratospheric ozone, which shields Earth from damaging ultraviolet light. Instead of interacting chemically with ozone molecules, the oxides cause harmful ozone-chlorine interactions that cause the ozone layer to be destroyed. Aluminum oxides can continue to demolish ozone molecules for decades as they drift through the stratosphere because they are not eliminated by these chemical reactions.
Comparison with Previous Studies on Satellite Pollution
Pollutants created when satellites burn up in the upper atmosphere, however, have not received much attention up to this point. Prior research on satellite pollution mostly concentrated on the fallout from launching a launch vehicle into orbit, including rocket fuel leakage. According to the authors, the new study, conducted by a team of researchers from the University of Southern California Viterbi School of Engineering, is the first accurate assessment of the magnitude of this persistent pollution in the upper atmosphere.
According to Joseph Wang, corresponding author of the new study and astronautics researcher at the University of Southern California, “People have only started to think this might become a problem in recent years.” “We were among the initial groups to examine the potential implications of these facts.” Geophysical Research Letters, an open-access AGU journal, offers high-impact, short-format research with urgent significance spanning all Earth and space disciplines. This study was published in the journal.
A spacecraft that is on fire makes it practically hard to gather data, thus prior research estimated prospective pollution by analyzing micrometeorites. These estimations, however, did not hold up well to modern “swarm” satellites because micrometeoroids contain very little aluminum, the metal that accounts for 15% to 40% of the mass of most spacecraft. The researchers modeled the molecular and atomic interactions between the materials of satellites to provide a more realistic image of the pollution caused by satellite re-entry. The findings helped the researchers comprehend how the material changes in response to various energy inputs.
Future Projections: Aluminum Oxide Levels and Their Long-term Effects
The observer came across that in 2022, aluminum levels in the atmosphere rose by 29.5% above natural levels due to reentering satellites. Given the simulation, during the reentry jump, a typical 250-kg (550-pound) satellite with 30% aluminum mass will produce roughly 30 kg (66 pounds) of aluminum oxide nanoparticles, which range in size from 1 to 100 nanometers. The mesosphere, which is 50–85 kilometers (30–50 miles) above the Earth’s surface, is where a big part of these particles are formed.
Conclusion: Addressing the Growing Concern of Satellite-Induced Pollution
After that, the scientists estimated that it might take up to 30 years for the aluminum oxides to travel down to stratospheric heights, which are home to 90% of Earth’s ozone. This estimate was based on particle size. The researchers calculated that 912 metric tons of aluminum (1,005 U.S. tons) will fall to Earth annually by the time the currently planned satellite constellations are completed. That represents a 646% increase over naturally occurring levels of aluminum oxides, releasing around 360 metric tons (397 U.S. tons) annually into the environment.