Juan Carlos Gomez Martin (Instituto de Astrofísica de Andalucia) Injection of anthropogenic metals into the mesosphere by demised spacecraft and space debris: ablation, chemistry, smoke formation and pathways to stratospheric aerosols

Juan Carlos Gomez Martin (Instituto de Astrofísica de Andalucia) will deliver a talk on the topic "Injection of anthropogenic metals into the mesosphere by demised spacecraft and space debris: ablation, chemistry, smoke formation and pathways to stratospheric aerosols".

Abstract:

The projected surge of low-Earth orbit (LEO) satellites in the coming decades, coupled with disposal policies that rely on atmospheric demise, is generating significant concern regarding the environmental impacts of orbital debris and re-entry particles. Metals ablated from demised spacecraft in the mesosphere are expected to follow a similar fate to those evaporated from meteoroids between 80 and 110 km: they react with atmospheric constituents to form smoke particles. These particles are transported by the global circulation to the stratosphere, where they entrain stratospheric sulfate aerosols (SSA) and modify their properties. Recent measurements show that 10% of SSA already contain metals that can be unambiguously linked to the burning of satellites and rocket stages. The accumulation of these exotic metals in SSA suggests that unaccounted impacts on key atmospheric constituents (e.g., ozone) may occur via aerosol liquid-phase and heterogeneous chemistry.

In this presentation, I will describe the laboratory research I am leading at IAA-CSIC to investigate the products of oxidative ablation from spacecraft materials and the specific chemical pathways of anthropogenic metals—particularly aluminium and lithium—in the lower mesosphere and stratosphere. To accomplish this, I have developed the Space Materials Ablation Simulator (SMASI), currently the only ground-based facility designed to study spacecraft demise from an atmospheric chemistry perspective. Additionally, we are employing Pulsed Laser Photolysis – Laser Induced Fluorescence (PLP-LIF) to study the atmospheric chemical networks of these anthropogenic metals. Determining these networks, including the relevant reaction rate constants and photolysis rates, is essential for accurately modelling the chemistry and transport of anthropogenic metals in the atmosphere.