Growing human activity in space is expanding its environmental footprint, driven by the increasing number of satellites that re-enter Earth’s atmosphere at the end of their operational life. This practice is especially common in low Earth orbit, the region of space closest to the planet. It is the main way to prevent the build-up of space debris, but it involves satellites breaking apart during re-entry and releasing gases and aerosols as a result of extreme temperatures and friction with the atmosphere. At present, these satellites represent only a small share of those expected to be launched over the next decade, suggesting that the scale of this impact is likely to increase in the years ahead.
In 2023, the global space economy surpassed half a trillion dollars and could approach two trillion by 2035, driven by technological advances and expanding commercial opportunities. This growth is closely linked to the increasing reliance on satellites in low Earth orbit for communications, Earth observation, security, and scientific research. As a result, space activity is rising steadily: around 11.000 active satellites are currently orbiting the Earth, with projections of up to 50.000 additional satellites to be launched by 2030.
Without adequate regulatory measures, this growth could intensify atmospheric pollution. During re-entry into the atmosphere, satellites often break apart and partially disintegrate due to extreme temperatures, losing up to 95% of their mass, which is mostly made of aluminum. This metal reacts with atmospheric oxygen to form oxides with a high pollution potential, capable of disrupting stratospheric ozone chemistry and accelerating its depletion, thereby putting the gradual recovery of the ozone layer at risk.
The scale of the impact is already measurable. Between 2016 and 2022, the concentration of metallic oxides in the atmosphere increased eightfold. Given the large number of satellites and debris currently in orbit, emissions of solid particles, mainly metallic oxides, could rise from around 1.000 tonnes per year today to as much as 30.000 tonnes by 2040. This volume would be comparable to the natural input of material from micrometeorites and small meteoroids.
In light of the atmospheric impacts linked to the growing pace of space activity, scientific evidence highlights the need to strengthen governance of the space environment. Coordinated use of global atmospheric models is essential to assess these effects at a planetary scale, alongside the development of standardized emissions scenarios for the space industry to anticipate and compare environmental and human health risks. In this context, the pioneering Draco mission of the European Space Agency, led by the Spanish company INDRA-Deimos, represents a strategic initiative to study the atmospheric impact of re-entry. Its aim is to reduce the uncertainties surrounding this process by collecting experimental data on how satellites actually break apart and how their materials interact with the atmosphere. These tools must be complemented by strict space debris mitigation practices, especially the effective disposal of satellites at the end of their missions, to limit the accumulation of material re-entering the atmosphere. In line with these recommendations, the European Union has begun to take action through legislative initiatives such as the EU Space Act, which strengthen the monitoring and tracking of objects in orbit, promote environmental sustainability, and support innovation in debris mitigation and removal technologies, laying the groundwork for a safer and more sustainable use of space in the long term.
For further information, see:
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