The climate damage caused by growing space tourism must be urgently mitigated

Published today in the magazine Earth’s futureresearchers from UCL, the University of Cambridge and the Massachusetts Institute of Technology (MIT) used a 3D model to explore the impact of rocket launches and reentry in 2019, as well as the impact of scenarios of space tourism projects based on the recent Billionaire Space Race.

The team found that black carbon particles (soot) emitted from rockets are nearly 500 times more effective at trapping heat in the atmosphere than all other sources of soot combined (surface and aircraft) – this which leads to an increased climate effect.

Additionally, while the study found that the current loss of total ozone from rockets is small, current growth trends around space tourism indicate potential for future upper stratospheric ozone depletion in the world. arctic in spring. Indeed, pollutants from solid-fuel rockets and the re-entry heating of spacecraft and returning debris are particularly harmful to stratospheric ozone.

Study co-author Dr Eloise Marais (UCL Geography) said: “Rocket launches are regularly compared to greenhouse gas and air pollutant emissions from the aviation industry, which we demonstrate in our work is wrong.

“Soot particles from rocket launches have a much greater climate effect than airplanes and other land-based sources, so there need not be as many rocket launches as international flights to have a similar impact. What we really need now is a discussion among experts on the best strategy to regulate this growing industry.”

To calculate the results, the researchers collected chemical information from the 103 rocket launches in 2019 around the world, as well as data on the reusable reentry of rockets and space waste. They also used recent demonstrations by space tourism entrepreneurs Virgin Galactic, Blue Origin and SpaceX and offered annual offers of at least daily launches by Virgin Galactic to build a scenario of a formidable future space tourism industry.

This data was then integrated into a 3D atmospheric chemistry model to explore the impact on climate and the ozone layer.

The team shows that the warming due to soot is 3.9 mW m-2 from a decade of contemporary rocketry, dominated by emissions from kerosene-fueled rockets. However, this more than doubles (7.9 mW m-2) after just three years of additional emissions from space tourism launches, due to the use of kerosene by SpaceX and synthetic rubber hybrid fuels by Virgin. Galactic.

The researchers say this is of particular concern because when soot particles are injected directly into the upper atmosphere, they have a much greater effect on the climate than other sources of soot – with the particles being 500 times more effective at trapping heat.

The team found that in a scenario of daily or weekly space tourism rocket launches, the impact on the stratospheric ozone layer threatens to undermine recovery after the successful implementation of the Montreal Protocol.

Adopted in 1987, the Montreal Protocol’s global ban on substances that deplete the ozone layer is considered one of the most successful international environmental policy interventions.

Study co-author Dr Robert Ryan said: “The only part of the atmosphere showing strong ozone recovery after the Montreal Protocol is the upper stratosphere, and that’s exactly where the impact of rocket emissions will hit the hardest.We did not expect to see ozone changes of this magnitude, threatening progress in ozone recovery.

“We still have much to discover about how rocket launch and re-entry emissions influence the atmosphere – in particular, the future size of industry and the types and by-products of new fuels like liquid methane and biobased fuels.

“This study enables us to enter the new era of space tourism with eyes wide open to the potential impacts. The conversation about regulating the environmental impact of the space launch industry needs to start now so that we can minimize damage to the stratospheric ozone layer and climate.”

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Materials provided by University College London. Note: Content may be edited for style and length.

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