SpaceX’s Starship might have released harmful air pollutants into the atmosphere, as well as shards of hot metal.
SpaceX’s rocket exploded on January 16 at an altitude of 90 miles, causing red-hot fragments of metal to fall from the sky across the Caribbian. The rocket weighed 85 tons and its fall back through the atmosphere might have also released some pollutants, as well as the debris.
Synced up every video I could find of the explosion and re-entry of @SpaceX's #Starship upper stage. UTC timecode included for easy coordination. pic.twitter.com/4iE9CxhhiS
— TheSpaceEngineer (@mcrs987) January 20, 2025
According to research published last year by University College London atmospheric chemistry researcher Connor Barker and summarised again in a more recent LinkedIn post, the falling rocket could have released as much as 45.5 metric tons of metal oxides and 40 metric tons of nitrogen oxides into the upper levels of the atmosphere, based on estimates.
“To put these numbers into context, the metal oxide input emissions are around 35% of the amount of aluminium that enters the atmosphere from meteors annually!” wrote Barker in the social media post.
The most concerning pollutant is the latter, as nitrogen oxides are potentially very harmful to Earth’s ozone layer, which protects the planet from the sun’s ultraviolet radiation. While the numbers noted above are speculative, it does stress the impact of space exploration and experimentation on the environment.
The environmental impact of SpaceX and other space explorers
While SpaceX’s Starship rocket was made up of stainless steel rather than aluminum, many satellites and other rockets are made out of the latter metal. This could cause future problems, as when aluminum burns – as it would upon re-entry to the Earth’s atmosphere – it produces aluminum oxides, or alumina. This white powdery substance, like nitrogen oxides, is known for its potential to damage the ozone.
As SpaceX and companies like it have grown, more and more satellites have begun to orbit the Earth – but they can’t stay there forever. To put it into context, in 2022, there were about 6,000 but by 2030, some estimates suggest that there will be nearly 60,000 satellites in orbit around our planet if current trends continue.
Indeed, SpaceX just announced plans to launch another 21 satellites. When they inevitably fall or even just from existing up there, air pollution in the mesosphere and upper stratosphere has been increasing to concerning levels.
If those predictions prove correct, the subsequent rise of alumina and nitrogen oxides could have a stark impact on the Earth’s protective ozone layer and knock-on effects on the planet’s already unstable climate. This could lead to more extreme weather patterns, such as storms and freak events.
Featured image: Flickr, licensed under CC BY-NC 2.0