Space junk re-entering Earth’s atmosphere is causing metal pollution in the upper atmosphere, according to a recent study published in the journal Communications Earth & Environment. Led by Robin Wing from the Leibniz Institute of Atmospheric Physics in Germany, the research team used highly sensitive lasers to observe a plume of lithium pollution, linking it to the uncontrolled re-entry of a discarded SpaceX Falcon 9 rocket upper stage.
This groundbreaking study provides the first observational evidence that re-entering space debris leaves a detectable human-caused chemical fingerprint in the upper atmosphere. It also marks the first time a pollutant plume from a specific space junk re-entry event has been monitored from the ground.
The upper atmosphere, which includes the upper stratosphere, mesosphere, and lower thermosphere, is a crucial but understudied part of the Earth system. This region plays a significant role in radio and GPS communications, upper atmospheric weather patterns, and stratospheric ozone. However, it is now facing an increasing threat from the growing quantities of metals and pollutants introduced by satellites, rocket bodies, and space debris.
The impact of this pollution on the stratospheric ozone layer, essential for protecting life on Earth from harmful ultraviolet radiation, is not yet fully understood. Early research suggests that emissions from rocket launches and re-entries, such as aluminium and chlorine, could impede the ozone layer’s recovery. Additionally, soot from rocket launches is likely to contribute to warming in the upper atmosphere.
Using a laser-based sensor, the researchers detected a sudden increase in lithium ions on February 20, 2025, directly linking it to the re-entry path of a discarded Falcon 9 rocket stage. This discovery highlights the urgent need for governments and the space industry to address the growing problem of space debris and its impact on the Earth’s upper atmosphere.
With the number of satellites in orbit rapidly increasing, the issue of space debris pollution is escalating. Estimates suggest that by 2030, several tonnes of spacecraft material will burn up in the upper atmosphere daily. There is currently no regulatory framework for these emissions, limited monitoring options, and insufficient scientific understanding of the potential impacts.
The detection of lithium pollution from re-entry events underscores the importance of establishing international regulatory bodies to monitor and regulate upper-atmospheric emissions. As the space industry continues to expand, efforts to understand, monitor, and mitigate the effects of space debris pollution must keep pace to protect the Earth’s atmosphere and environment.
This article was republished from The Conversation under a Creative Commons license. Read the original article for more information on the impact of space junk on the upper atmosphere.
