LiDAR lasers trace space junk's footprint in the upper atmosphere

Scientists are using ground-based LiDAR to detect ablation from reentering space debris in the upper atmosphere. A lithium cloud linked to SpaceX’s Falcon 9 upper-stage reentry was observed, and Leibniz Institute researchers are testing a three-channel multi-species LiDAR to detect metals and propellant residues (e.g., copper, aluminum oxide, hydrogen fluoride). The findings suggest debris reentry is altering the mesosphere and upper stratosphere, with potential implications for the ozone layer as satellite megaconstellations grow; experts call for expanded monitoring and dedicated efforts to track space waste reentry.