The frantic pace of space launches marks a deep transformation of our relationship to terrestrial orbit. In the space of a few years, the constellations of satellites deployed by companies like SpaceX or Oneweb have leaped the number of objects sent to space, to the point of making these movements visible to the naked eye from the ground. But this multiplication of missions, often presented from the angle of global connectivity, hides a much more worrying reality: pollution of the atmosphere by rockets and satellites.
A spatial activity in full acceleration and a new type of pollution
The space industry is experiencing dazzling growth. Between 2020 and 2024, the number of orbital launches increased from 114 to 259 per year according to the team of Professor Eloise Marais of the University College London (UCL). This dynamic is largely carried by the programs of satellite megaconstellations, such as Starlink (SpaceX), Oneweb or Thousand Sails. They predict, moreover, tens of thousands of satellites in low orbit.
These massive deployments involve increased consumption of fuels. In 2024, more than 153,000 tonnes of fuel were burned during launches, according to data compiled by Marais and Dr Connor Barker (UCL), reports the Guardian. This represents a considerable increase compared to previous decades, where only 100 to 200 objects were sent annually.
Contrary to popular belief, pollution generated by these activities is not limited to the launch phase. The end -of -life satellites are designed to disintegrate in the atmosphere, relaxing potentially reactive metallic particles. In 2024, 2,539 objects thus reinstated the atmosphere, generating 13,500 tonnes of burned materials. Or an increase of 26 % in one year.
This pollution is neither visible nor comparable to industrial terrestrial emissions in volume. But its location in the upper atmosphere – stratosphere and mesosphere – gives it much more marked climatic efficiency, up to 500 times higher for certain particles such as soot, according to the marsh work taken up by the Britain Herald. Space activity thus opens a new era of pollution, quieter but deeply problematic.
Highly persistent and harmful emissions for the atmosphere
Spatial launchers' emissions do not stop at fuel combustion alone. They include a cocktail of chemical compounds with lasting and still poorly measured effects. Among the most worrying: soot particles (black carbon), nitrogen oxides (NOx), chlorinated compounds, carbon dioxide, alumina (al₂o₃) and water vapor. These substances are rejected directly into the high layers of the atmosphere, between 15 and 80 kilometers above sea level. Their lifespan is much longer than at ground level.
According to the study published in Nature Scientific Data In 2024, these emissions were now mapped in three dimensions over the period 2020–2022. The megaconstellations would already represent 33 % of global space emissions in 2022, with a share reaching 40 % for carbon emissions. The researchers identified that 63 GG of fuel had been consumed in 2022. And the majority of which in the troposphere and the stratosphere.
The combustion of solid fuels – used in particular by certain European rockets – produces chlorinated compounds. They participate in the destruction of the ozone layer, just like alumina and nox. Alumina emissions, for example, absorb outgoing infrared radiation, contributing to global warming. As for the soot, its impact is multiplied at high altitude. Researchers estimate that more than 78 % of CO and SUIE emissions linked to rockets are above 40 km above sea level.
These releases disrupt atmospheric chemistry and are added to the known effects of air transport. What distinguishes the space industry is the vertical concentration of its emissions in climaticly sensitive areas, and their disproportionate radiative efficiency, according to the models validated by the UCL.
The tempo mission: measure the invisible from the orbit
Faced with the scale of air pollution linked to human activities, including space, NASA launched in 2023 the tempo mission (Tropospheric Emissions: Monitoring of Pollution). It is an ambitious air quality monitoring program from space. Placed in geostationary orbit at 36,000 km, the Tempo instrument measures the concentrations of no₂, ozone and formaldehyde every hour above North America.
This device, first of its kind, allows continuous observation during the day, with a spatial resolution of a few square kilometers. This granularity is crucial to detecting punctual episodes of pollution, such as urban peaks, forest fires or punctual emissions of rockets. “” It's a big leap forward “, Underlines Laura Judd, researcher at NASA Langley Research Center. “” We go from daily images to hourly coverage, which completely changes our analytical capacity ».
Tempo has already validated alert models in less than three hours, useful for public health agencies to disseminate pollution alerts. More than 800 unique users have already operated two data petacts produced in one year.
In collaboration with the NOAA and the Center for Astrophysics | Harvard & Smithsonian, Tempo also refines the distinction between particles of smoke and dust, their altitude and their vertical distribution. Future mission extensions should integrate aerosol products from space re-entrees. This will further strengthen the measurement capacity of these emerging sources of pollution.
A persistent legal vacuum in the regulation of spatial activities
While the environmental consequences of space launches are increasingly documented, the international legal framework remains surprisingly uncompromising. Spatial law is still based on the principles of the Treaty of Space of 1967, inspired by maritime law. “” A spatial object remains under the jurisdiction of the country which launched it. And this regardless of its behavior or its effects ».
For Stuart Martin, president of UK National Space Centerthis situation makes almost impossible a coordinated management of pollution or debris. “” This is one of the major reasons why cleaning debris is so complicated “, He explains to Guardian.
No obligation today forces private operators to limit their emissions. Nor to account for the climatic impacts of their activities. Satellites are often designed to completely disintegrate at the start of the school year. But this process releases metallic particles and reactive compounds at high altitude, as mentioned above. In addition, their consequences are still poorly surrounded.
However, efforts exist. The European Union and certain agencies, such as the Federal Communications Commission (FCC) in the United States, are trying to impose limits of lifespan in orbit, even active desorbitation provisions. But these initiatives remain non -universal and largely inapplicated within the framework of commercial projects on a very large scale.
The study of Marais and Barker (UCL), coupled with tempo data, however shows that current acceleration could compromise the benefits of the Montreal Protocol. Especially in terms of protection of the ozone layer. The absence of common governance in the face of global pollution becomes a strategic flaw. Researchers are calling for urgent international regulation, integrating new space challenges in global climate negotiations.
With an unwavering passion for local news, Christopher leads our editorial team with integrity and dedication. With over 20 years’ experience, he is the backbone of Wouldsayso, ensuring that we stay true to our mission to inform.
