Last month’s SpaceX Starship rocket disintegration over the Caribbean Sea released significant debris and harmful chemicals into the atmosphere, including around 45.5 tons of metal oxides and 40 tons of nitrogen oxides. Research highlights rising concerns over pollution from space activities, particularly heavy metals detected in the stratosphere. Aluminum oxide, a byproduct of spacecraft burn, poses risks to the ozone layer and contributes to climate change by affecting atmospheric reflectivity. The long-term environmental impacts of such incidents warrant further investigation.
Last month, the Caribbean Sea became the unexpected stage for a dramatic event as SpaceX’s Starship rocket disintegrated, showering the waters with fiery metal fragments. Shortly after its launch, at an altitude of approximately 146 kilometers, the rocket’s upper stage suffered a ‘rapid unplanned disassembly‘. Out of the 85 tons total weight of the vehicle, most of the fuselage succumbed to intense heat and friction, resulting in a release of various chemical compounds into the atmosphere. Notably, American astronomer Jonathan McDowell estimated that ‘several tons’ of debris ultimately plunged back into the ocean.
British atmospheric chemistry expert Connor Barker from University College London undertook an analysis to gauge the volume of gases and particles expelled into the Earth’s atmosphere during this incident. His findings suggest that the debris return could have produced approximately ‘45.5 tons of metal oxides’ and ‘40 tons of nitrogen oxides‘, as reported by space.com and shared through his LinkedIn publication. However, pinpointing the exact pollution levels caused by the Starship incident in the upper atmosphere remains elusive.
Understanding the Environmental Impact
Determining the precise environmental consequences of the recent Starship explosion, as well as previous incidents, poses a challenge. Given SpaceX’s dominant role in the aerospace industry, its impact is particularly noteworthy. In 2024, the Falcon 9 and Falcon Heavy rockets completed 138 launches from American soil, representing over half of all orbital launches that year, according to the Cité de l’espace.
In 2023, an Italian research team made a groundbreaking discovery by detecting significant levels of heavy metals in the stratosphere, the layer of atmosphere ranging from 10 to 50 kilometers high. Their analysis revealed around twenty chemical signatures matching those found in rocket alloys and satellite materials, including elements like lithium, copper, lead, and aluminum. This finding has raised alarms about the hidden pollution that could have far-reaching effects.
‘Changes in the atmosphere can be difficult to study and complex to understand. But this research shows us that the impact of human occupation and space flights on the planet can be significant, perhaps more significant than we have imagined so far‘, cautioned the study’s authors. They emphasized the need for ‘further examination‘ of pollution stemming from space activities and its long-term impacts, with a particular focus on aluminum oxide.
The Risks Posed by Aluminum Oxide
The chemical compound produced from the combustion of spacecraft alloys, aluminum oxide, poses a serious threat to the ozone layer. Although there are positive signs indicating that the infamous ozone hole is on the mend, scientists are concerned that substantial concentrations of aluminum oxide could hinder this recovery process. Additionally, pollutants at these altitudes can linger in the atmosphere for extended periods. It is also known that aluminum oxide alters the reflective properties of the Earth’s atmosphere, exacerbating the greenhouse effect, which is the principal driver of climate change.
At present, over 6,300 objects containing aluminum oxide orbit our planet. Once these objects fulfill their life cycle, they re-enter the Earth’s atmosphere, igniting and releasing numerous chemical compounds. Regardless of advancements like the Starship, the levels of aluminum oxide in the upper atmosphere are set to continue their upward trajectory.