A SpaceX rocket that burned up after re-entering the atmosphere unleashed a plume of vaporised metals over Europe, a type of pollution that is expected to increase as spacecraft and satellites multiply.

The upper stage of a Falcon 9, which is designed to splash down in the Pacific Ocean for possible re-use, lost control due to engine failure and fell from orbit over the north Atlantic in February 2025.

People across Europe saw fiery debris streaking through the sky, some of which crashed behind a warehouse in Poland. Seeing the news, at the Leibniz Institute of Atmospheric Physics in Germany and his colleagues turned on their lidar, an instrument for atmospheric sensing. Twenty hours later, it detected a 10-fold spike in lithium, a key component of rocket hulls, in the upper atmosphere as the plume of vaporised metal drifted over it.

Atmospheric modelling suggested this plume had drifted 1600 kilometres from the area where the Falcon 9 re-entered the atmosphere. The study is the first to trace high-altitude pollution to a specific spacecraft re-entry.

The tiny metal particles 鈥渃ould be catalysing ozone destruction, creating clouds in the stratosphere and mesosphere, affecting the way that sunlight travels through the atmosphere鈥�, says Wing. 鈥淏ut all of this is understudied.鈥�

Worries about this type of pollution are growing as commercial space launches skyrocket and companies expand their mega-constellations of satellites, like SpaceX鈥檚 Starlink and Amazon鈥檚 Leo. About 14,500 satellites are already in orbit, and last month SpaceX applied to launch 1 million more for Elon Musk鈥檚 goal of creating orbital data centres to power artificial intelligence.

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To avoid a runaway cycle of collisions producing ever more space debris, satellites are typically allowed to fall and burn up at the end of their lifespan. Experts say the amount of space trash particles could grow by 50 times in the next decade and exceed 40 per cent of the mass that meteoroids currently bring into the atmosphere.

There is a misconception that space debris burns up in the atmosphere and disappears, says at Purdue University, Indiana, who wasn鈥檛 involved in the study. 鈥淟et鈥檚 tap the brakes here, and let鈥檚 really do some thorough analysis of what effect this material could have.鈥�

The Falcon 9 plume contained an estimated 30 kilograms of lithium. But given the composition of the alloys in rocket hulls, it would have contained a far greater amount of aluminium.

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Vaporised aluminium reacts with atmospheric oxygen to form particles of aluminium oxide, which provide a surface where chlorine compounds can more easily break down. The chlorine radicals freed by this process react with and destroy ozone molecules in the stratosphere.

Researchers estimate that spacecraft burn-up is 1000 tonnes of aluminium oxide into the atmosphere each year and growing. This threatens to expand the southern hemisphere鈥檚 ozone hole, which has been shrinking as countries phase out ozone-depleting refrigerant gases. The loss of ozone could allow in more of the sun鈥檚 ultraviolet rays, which cause skin cancer.

鈥淚n terms of metals, we鈥檙e sort of moving into this new paradigm where the upper atmosphere is increasingly more influenced by anthropogenic pollution than natural sources,鈥� says at University College London. 鈥淪pace debris is starting to undo the progress with the ozone hole.鈥�

The metal oxide particles can also serve as nuclei upon which water vapour can condense into droplets, forming cirrus clouds in the upper troposphere, which tend to trap heat.

女生小视频s have measured particles from burned-up spacecraft in cirrus clouds. If they are encouraging cirrus cloud formation, it could worsen global warming, although this impact would still be small compared with that of greenhouse gases like carbon dioxide.

鈥淭here is a lot of scientific evidence that this material could be having deleterious effects on our atmosphere, and now it鈥檚 on us as scientists to figure out if those effects are taking place and how bad are they,鈥� says Cziczo.

There may be solutions, such as building satellites out of materials like wood 鈥� although that could still release black carbon soot upon re-entry 鈥� or retiring more of them to high-altitude 鈥済raveyard orbits鈥�.

鈥淲e need to take a little bit of time and think about what we鈥檙e doing before we do it,鈥� says Wing. 鈥淭his explosion of satellites鈥� it鈥檚 very fast, and we don鈥檛 know the consequences.鈥�

One in three images taken by the Hubble Space Telescope could be ruined if space companies鈥� plans to launch hundreds of thousands of satellites go ahead.

More than three-quarters of the nearly 14,000 satellites currently in orbit around Earth were launched in the past five years, many of them part of so-called mega constellations like that of Starlink, Elon Musk鈥檚 satellite internet company. But these numbers could be dwarfed if space companies鈥� proposals go ahead, with as many as half a million satellites planned to launch by the end of the 2030s, according to US Federal Communication Committee (FCC) filings.

Astronomers have already raised alarm at how these satellites could affect telescopes on Earth, but now at NASA Ames Research Center in California and his colleagues have found that they could seriously endanger space-based telescopes, too.

鈥淲hen you position a telescope in space, it鈥檚 usually a very pristine environment. You don鈥檛 have any atmosphere, or city lights,鈥� says Borlaff. 鈥淣ow, for the first time, you have man-made objects that are somehow polluting the images 鈥� that was very striking.鈥�

Borlaff and his team used FCC and International Telecommunication Union filings to predict how many satellites could be launched in the next decade and their planned orbits. Then they simulated how these could interfere with observations from four space observatories, including the Hubble and Chinese Xuntian telescopes, as well as the ARRAKHIS dark matter telescope, set to launch in 2030, and the SPHEREx galaxy telescope, which launched in this year.

The team found that if 560,000 satellites are launched as planned, there could be an average of two satellite trails for each Hubble photo and around 90 for each Xuntian photo, due to its larger field of view and orbital height.

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They checked their simulations by predicting that with current satellite numbers, 4 per cent of Hubble images are affected by satellite trails, and this matched with an analysis of real images.

These predictions could come true if the planned satellite launches go ahead, says of Dark Sky Consulting, a company based in Tucson, Arizona, but it鈥檚 unclear how many satellites will really be launched. 鈥淢any experts feel that the number of satellites that will actually orbit the Earth within about the next 15 years will reach a steady-state value of something more like 50,000 to 100,000.鈥�

If the actual number of satellites is only a tenth of what is planned, then the consequences for space telescopes will be much less severe, says Barentine. 鈥淭he number of trails per image will be only a factor of a few higher than it is now for ARRAKHIS and Xuntian and virtually unchanged for SPHEREx and HST.鈥�