Thanks to new resonance lidar measurements, researchers in Germany, the UK and Peru have successfully measured and traced a lithium plume created by a rocket stage as it uncontrollably re-entered and broke up in the upper atmosphere. The work represents the first time that upper-atmospheric pollution from space debris re-entry has been directly detected, they say. Such pollution is a growing concern and is only likely to worsen as more and more satellites are being launched into space, and in particular into low-Earth orbit. The number of satellite and rocket launches has increased dramatically over the last decade and this number is set to increase as ever more commercial mega-constellations are deployed. For example, the Starlink constellation is planned to consist of over 40 000 satellites, each with a mass of between 305 and 960 kg.…