Metals from spacecraft reentry in stratospheric aerosol particles

• DOI: 10.1073/pnas.2313374120
• Publication Date: 2023-10-16T19:13:23Z
• Authors: Daniel M. Murphy; Maya Abou-Ghanem; Daniel J. Cziczo; Karl D. Froyd; Justin Jacquot; Michael J. Lawler; Christopher Maloney; John M. C. Plane; Martin N. Ross; Gregory P. Schill; Xiaoli Shen
• Keywords: Reentry; Atmospheric entry

Large increases in the number of low earth orbit satellites are projected coming decades [L. Schulz, K.-H. Glassmeier, Adv. Space Res.67, 1002-1025 (2021)] with perhaps 50,000 additional by 2030 [GAO, constellations satellites: Mitigating environmental and other effects (2022)]. When spent rocket bodies defunct reenter atmosphere, they produce metal vapors that condense into aerosol particles descend stratosphere. So far, models spacecraft reentry have focused on understanding hazard presented objects survive to surface rather than fate metals vaporize. Here, we show vaporized during reentries can be clearly measured stratospheric sulfuric acid particles. Over 20 elements from were detected present ratios consistent alloys used spacecraft. The mass lithium, aluminum, copper, lead was found exceed cosmic dust influx those metals. About 10% larger 120 nm diameter contain aluminum reentry. Planned within next few could cause up half influence this level metallic content properties is unknown.