Lasers shine a new light on the space junk air pollution problem

The Leibniz Institute of Atmospheric Physics in winter, with three green lasers measuring winds and temperatures in the stratosphere and mesosphere. (Observational evidence is being gathered that the ablation of space debris can be detected by ground-based light detection and ranging (LiDAR), a remote-sensing technology that uses laser beams to measure precise distances and movement in an environment, in real time.Anthropogenic impacts"Lithium is a crucial species for investigating anthropogenic impacts on the middle atmosphere because of its extensive use in the space industry," reported Michael Gerding, a scientist in the optical and rocket soundings department of the Leibniz Institute of Atmospheric Physics (IAP) at the University of Rostock in Kühlungsborn, Germany."Ablation of reentering satellites and rocket stages is expected to become a significant source of metals in the mesosphere, yet systematic observations remain limited so far," Gerding reported at the 2026 European Geosciences Union, which was held May 3-8 in Vienna.Gerding also showed the first results of IAP's new three-channel multi-species lidar that's set up to search for different materials expected to be ablated by reentering space debris. These materials include copper, aluminum oxide, and hydrogen fluoride, which is used as a propellant in some rocket engines."These materials, which naturally occur only in trace amounts at such altitudes, are influencing the mesosphere and upper stratosphere to an extent not previously documented. This influence is expected to intensify further in the coming years," explains the IAP website. While natural metal layers form in the upper mesosphere due to meteor ablation, new LiDAR measurements have found that additional mass and elements are being introduced via the reentry of space hardware. This type of pollution has unknown consequences for the upper atmosphere and ozone layer. (/Communications Earth & Environment)Test measurementsAccording to the IAP, with the rising number of satellite launches and space activities — particularly the surge in placing satellite megaconstellations into Earth orbit — the composition of the upper atmosphere is changing.Robin Wing, also an IAP scientist, told Space.com that the new multi-species lidar system is coming along. "We have done test measurements," Wing said, "and are currently improving some subsystems."Wing said the upgraded lidar gear includes a survey channel that systematically looks for each spacecraft element, with copper being the first target. Backward trajectories, including wind variability as measured by radar, traced air masses to a SpaceX Falcon 9 reentry path at roughly 60 miles (100 kilometers) altitude, west of Ireland, in February 2025. (/Communications Earth & Environment)Space wasteLeonard Schulz is a researcher at the Technische Universität Braunschweig's Institute of Geophysics and Extraterrestrial Physics in Germany.In a study published in the May 1 issue of the journal Advances in Space Research, Schulz and colleagues pointed out that incoming "space waste" is injecting a significant amount of its matter into the mesosphere and lower thermosphere — enough to cause concern for Earth's ozone layer."There is a need for dedicated searches for space waste that survived reentry and impacted ground, detailed observations of space waste ablation, and further ground experiments representative of the conditions of atmosphere reentry," Schulz and team members wrote in the study."Today's large satellite constellations amplify the problem of on-orbit space debris as well as the ground risk from impacts," the researchers added."Beside these well-discussed problems," they concluded, the new findings "indicate a substantial risk