On February 19, 2025, a Falcon 9 rocket fell back toward Earth in an uncontrolled reentry, producing a massive fireball in the skies over Europe. On its way down, the rocket came near a lidar station in Saxony, Germany, where a team of researchers was able to use the remote-sensing instrument to measure the effect of the rocket reentry on Earth\u2019s atmosphere.<\/p>\n
\u201cWe planned to make the measurement on the chance that we might see something from the re-entry,\u201d Robin Wing, a researcher at the Leibniz Institute of Atmospheric Physics at the University of Rostock in Germany, told Gizmodo.<\/p>\n
Wing and his colleagues measured a 10-fold concentration of lithium atoms in the upper atmosphere around 20 hours after the uncontrolled re-entry of the Falcon 9 rocket. Increasing amounts of metal, such as lithium, as a byproduct of the modern-day space race, are beginning to alter the chemical composition of Earth\u2019s atmosphere.\u00a0The findings are detailed in a new study<\/a> published Thursday in Nature.<\/p>\n Skyfall <\/p>\n As spacecraft reenter through the atmosphere, they slowly disintegrate into smaller fragments that burn up and release metals into the upper atmosphere. Lithium, as well as aluminum and other metals used to construct spacecraft, vaporizes during atmospheric re-entry.<\/p>\n The researchers behind the new study chose to measure lithium because it\u2019s an effective tracer of space debris pollution and is commonly used in spacecraft. \u201cWe discussed several materials, and lithium gave a good compromise of expected signal and challenges in the lidar setup,\u201d Wing said. \u201cWe know that lithium is present in the aerospace-grade lithium-aluminum alloys used in spacecraft construction.\u201d<\/p>\n Although the risks of space debris falling onto the ground are well-studied, there is very little known about the effects of falling spacecraft on Earth\u2019s upper atmosphere.<\/p>\n Using lidar\u2014a laser-based remote sensing instrument used to measure atmospheric conditions\u2014the team of scientists behind the new study detected a sudden increase in the concentration of lithium atoms, around 10 times the baseline value found in the atmosphere, on February 20, 2025. This lithium plume stretched from around 58 to 60 miles (94 to 97 kilometers) above sea level.<\/p>\n The researchers observed the plume for 27 minutes until data recording stopped. They then traced the plume of pollution to the Falcon 9 reentry, linking its area of origin to the uncontrolled path taken by the rocket on its way down.<\/p>\n Uncertain future <\/p>\n