Spacecraft, Ablation Processes, and Metals in the Stratosphere

Both metals from meteoroids and metals from the reentry of rocket boosters and satellites are incorporated into natural sulfuric acid particles in the stratosphere. Numerous elements from both meteoroids and spacecraft reentry have been measured in stratospheric particles.In many cases, the measurements can separate how much of a given metal came from meteoroids and how much from spacecraft. These data provide constraints on both the amounts of ablated metals and the ablation process. For example, the aluminum to iron ratio in particles from meteors constrains the ablation fraction for aluminum. The amounts of metals from spacecraft can be compared to an inventory of the composition of objects re-entering the atmosphere.