Burned-up space junk pollutes Earth’s upper atmosphere, NASA planes find

Researchers have detected pollutants in the Earth’s stratosphere that are believed to originate from space junk burning up in the atmosphere. Using high-altitude NASA aircraft, the team found traces of lithium, aluminum, copper, and lead. The concentrations of these compounds were significantly higher than what could be expected from natural sources, such as cosmic dust or meteorites. The ratios of these compounds were also consistent with those found in alloys used in satellite manufacturing.

This discovery raises concerns about the potential impact of these pollutants on the Earth’s climate. Aluminum oxide, a product of the burn-up of aluminum-based alloys, can destroy ozone. This could potentially hinder the recovery of the Earth’s ozone layer, which has been damaged by the use of ozone-depleting substances in refrigerators and aerosol sprays. Aluminum oxide particles can also alter the Earth’s albedo, or ability to reflect light, leading to potential temperature changes in the stratosphere and unforeseen consequences for the Earth’s climate.

The issue is further exacerbated by the increasing number of satellites being launched into orbit, particularly with the advent of megaconstellations like SpaceX’s Starlink. These satellites are designed to fall back to Earth and burn up in the atmosphere at the end of their missions, leading to a rise in the concentrations of chemicals created by their burn-up in the upper layers of the atmosphere. The researchers warn that these particles dispersed at high altitudes are unlikely to ever fall to Earth, meaning their concentrations will only continue to rise over time.

The researchers stress the importance of understanding the potential impact of human occupation and human spaceflight on the planet. The study was published in the journal Proceedings of the National Academy of Sciences.