A million data centre satellites will usher in a new era of space pollution

The SpaceX filing for authorization to launch a million satellites to operate orbital data centres lacks details needed to evaluate the environmental risk posed by pollutant emissions from massive upscaling of launches and re-entries. First-order estimates of total launch emissions of all byproducts and of re-entry nitrogen oxides (NOx) suggest increases of 70- to 150-fold relative to contemporary emissions. An even greater 200- to 280-fold increase in re-entry mass is determined, but associated ablation emissions dominated by metals cannot be deduced, as even broad material composition of satellites is absent. Re-entry NOx from reusable and single-use objects is at least 6 times more than the natural meteoritic influx. At the launchpad, NOx emissions surpass other Earth-bound US sources subject to emissions controls, and methane venting rates rival large US oil and gas extraction basins. The unprecedented increase in anthropogenic chemicals stands to modify stratospheric aerosols, deplete ozone, alter climate, perturb mesospheric nitrogen, and degrade air quality. These risks should incite regulators to demand provision of information needed to calculate emissions and enable environmental impact assessments. Our estimates show that, at a minimum, information should include rocket specifications (propellant type, payload capacity, reusability, re-entry masses, heat shield material and percent ablated), satellite details (composition, mass, re-entry rates), and propulsion technology (fuel, usage rates). Greater knowledge of environmental harm resulting from impact assessments would steer research investment to address scientific gaps and spur technological innovation for more sustainable space operations.