With the number of objects launched into space skyrocketing (no pun intended), concerts have started to rise about the amount of junk and debris left in our atmosphere along with the moon and Mars. A rocket is launched about once every three days or between five and ten a month. Scientists have suspected that the space junk that has burned up by falling back into Earth's atmosphere could be polluting the planet's atmosphere and affecting the Earth's climate.
For the first time ever they have been able to detect these pollutants in the upper atmosphere. The group of scientists working on this project flew a high-altitude NASA aircraft over Alaska to sample the air in the stratosphere which is the second lowest layer of Earth's atmosphere. The stratosphere extends from about 6 miles from the earth's surface to about 30, with only the troposphere coming before it. They used NASA’s WB-57 and ER-2 aircraft to reach altitudes of up to 11.8 miles, which is about 5 miles above where commercial airlines usually fly. The scientists had sensors in the nosecone of the planes that were able to read the chemical composition of the air. However, the microscopic traces of burnt-up space debris would be extremely difficult to detect in the extremely clean air of the stratosphere, which is out of reach of the pollutants found on the earth's surface, so the sensors had to be extremely sensitive.
Over 20 different compounds were detected with the main ones being lithium, aluminum, copper, and lead were found in the samples. The amount of these compounds detected was much higher than what would be expected from other things entering our atmosphere such as asteroids. The compounds actually show up in the ratio of compounds found in the alloys used in satellites. One of the authors of the study on these pollutants, Dan Cziczo, a professor of Earth, atmospheric, and planetary sciences at Purdue University, said "We are finding this human-made material in what we consider a pristine area of the atmosphere," "And if something is changing in the stratosphere — this stable region of the atmosphere — that deserves a closer look."
Aluminum oxide, the main byproduct of the aluminum-based metals getting burned on reentry into Earth's atmosphere, is known for its ability to destroy Earth's ozone layer which protects the life on Earth from harmful ultraviolet radiation. The ozone layer also happens to be in the stratosphere which is right where the researchers found the pollutants.
With the number of low earth satellites only rising, with an additional 50,000 projected by 2030, the threat these pollutants have on Earth’s atmosphere is only going to rise. Also, these pollutants are only slowing the healing process of the ozone layer from the destruction by the use of ozone-depleting substances in refrigerators and aerosol sprays. A big problem with these particles is that they are more than likely never going to fall back down to earth so the concentration of them is only going to grow.
The use of mega-constellations, the low-lying chains of satellites, has also led to an increase in the pollutants in the stratosphere, as most of the satellites are designed to fall back to earth and burn up in the atmosphere once they have served their purpose. "Changes to the atmosphere can be difficult to study and complex to understand," Cziczo said. "But what this research shows us is that the impact of human occupation and human spaceflight on the planet may be significant — perhaps more significant than we have yet imagined. Understanding our planet is one of the most urgent research priorities there is."
“Annual Number of Objects Launched into Space.” Our World in Data. Accessed October 24, 2023. https://ourworldindata.org/grapher/yearly-number-of-objects-launched-into-outer-space.
Murphy, Daniel, Maya Abou-Ghanem, and Daniel Cziczo. “Metals from Spacecraft Reentry in Stratospheric Aerosol Particles.” PNAS, October 16, 2023. https://www.pnas.org/doi/full/10.1073/pnas.2313374120.
Pultarova, Tereza. “Burned-up Space Junk Pollutes Earth’s Upper Atmosphere, NASA Planes Find.” Space.com, October 19, 2023. https://www.space.com/air-pollution-reentering-space-junk-detected.
Owen Dustin is a sophomore at Poudre High School. This is his first year writing for the Poudre Press. At school, he is on the Alpine Robotics team and the unified flag football team. Outside of school he likes to mountain bike, play video games, and hang out with friends.