This workshop will address the impact of spacecraft re-entry on the atmosphere. The aim is to bring together atmospheric chemists and physicists, material experts, the space industry, and international space research related organizations to highlight the gaps in our understanding of the modelling and how we can improve testing to obtain relevant data and suggest appropriate mitigation and regulatory measures.
Addressing these challenges requires collaborative attention and action from all those involved in the space sector, including industry, academia, and regulators. It is crucial to fully understand the environmental impacts caused by space related activities, including climate change, ozone depletion, resource depletion, toxicity and biodiversity. As part of the life cycle assessment and eco design we need to drive towards the design of space products and services that have a minimum impact on the environment throughout their life cycle.
New measurements show that about 10% of the aerosol particles in the stratosphere contain aluminium and other metals that originated from satellite re-entry. In the next few decades, we are set for an increase globally of emissions for thousands of satellite launches and re-entry events. The influence of this sustained and increased level of metallic content on the properties of stratospheric aerosol is unknown, and there are only limited studies on the atmospheric effects of propellants.
A significant number of spacecraft materials/systems have not been characterised during re-entry and the high temperature chemistry is not well known. Satellite demise involves complex ablation processes that are accompanied with the release of different gases and /or particulates. It is the associated reaction of these residues in the relevant environment that needs our attention. There are areas in spacecraft aerothermodynamics where knowledge, data and models are lacking. A large element of uncertainty relates to particulate emission modelling, predicting the size distribution of emitted particles when an object is exposed to very high temperatures is notoriously difficult. For many spacecraft materials, such as CFRP, electronic circuit boards and optical glasses the models used need additional input, and it is clear that new material development for demise should be accompanied with understanding the reaction and effects on the atmosphere.
Aerosol particles in the atmosphere have a significant impact on the Earth's radiative energy balance. These particles in the stratospheric aerosol layer play an important role in stratospheric ozone depletion and in addition affect the Earth’s climate by absorbing and scattering solar-radiation. They serve as condensation nuclei for cloud droplets and ice-nucleating particles for ice crystals, and quickly alter a number of environmental variables. The roles of aerosols, such as aerosol–radiation interactions, the active aerosol–cloud interactions, and human driven contamination effects must be addressed. Thus, understanding the direct and indirect impact of space industry activities on Earth’s climate is of utmost importance if we want to lead future exploration in a sustainable manner.