Rockets present a potential new threat to the ozone layer

Photo of the SpaceX Falcon 9 rocket launch from Kennedy Space Center in Florida

THE rapid increase in the number of space launches could pose a new threat to the Earth’s critical ozone layer, according to a growing body of scientific research.

Our ozone layer is often touted as a global environmental success story. Since the signing in 1987 of the Montreal Protocol, an international treaty aimed at protecting the ozone layer, countries around the world have mobilized to stop producing and emitting the chemicals that contributed to the spectacular slimming of the ozone layer above Antarctica. Despite a brief setback in the 2010s, the latest United Nations report, published in January, indicates that we are on track for full ozone recovery by 2066.

Image of the ozone hole over Antarctica

Yet the UN assessment also included a caveat: Just because we’re moving toward ozone recovery doesn’t mean it’s a guarantee. Many dangers, old and new, could arise and derail decades of global progress. Among these potential ozone hazards are geo-engineering proposals aimed at mitigating climate change. There is also the threat of climate change itself; more aerosol and greenhouse gas emissions may affect ozone recovery. And as the UN points out, space launches are yet another thing to consider.

“Rocket launches currently have a small effect on total stratospheric ozone,” the scientists write in their report. But that is likely to change with new thrusters, satellite constellations and the continued increase in the number of space launches, the report notes. More than 180 rockets have been launched into space in 2022 – the highest number on record in a year – while the number of satellites launched has increased exponentially, according to a balance sheet study published last month in the Journal of the Royal Society of New Zealand.

“We have known since the early 1990s that rocket launch emissions could lead to the destruction of the ozone layer. But that’s never really been a big deal before because we’ve had so few launches that the effects are negligible,” said Laura Revelatmospheric chemist at the University of Canterbury in New Zealand and lead author of this study, in a video call with Gizmodo.

But that’s starting to change, which means space research, monitoring and exploration must also change, Revell noted. The impact of rocket launches on the upper atmosphere is largely unmonitored and unregulated, she said. “But we think it’s a good time to address that, before the number of launches around the world really increases.”

Revell’s recent review, conducted with two other researchers, assessed the growing threat from space launches. Across the dozens of past studies the scientists reviewed, they found evidence that several products of emissions from launches can negatively impact ozone through various chemical reactions or temperature changes that occur. they provoke. These emissions of concern include water vapour, nitrogen oxides, carbon black, alumina particles, hydrogen gas and hydrogen chloride. Additionally, the mechanism of the launches means that these ozone-damaging gases and particles are delivered directly to where they can do the most damage: the stratosphere, where 90% of atmospheric ozone resides.

Although some researchers have begun to examine the actual impacts of individual launches, this remains an understudied area where the science relies more on models than actual observations. There are a lot of things we still don’t know, Revell pointed out. “Exhaust plume measurements are limited, and most current data relies heavily on plume modeling or best-estimates from combustion calculations. Even the most common fuel, liquid kerosene, is still relatively poorly modeled in exhaust concentrations,” the study authors wrote.

Related article: Rocket launches could pollute our atmosphere in new and unexpected ways

When researchers assess the specifics of individual launches, they ohoften find disturbing results. A study 2022 who modelsd the launch in 2016 of the Falcon 9 of the Thaicom-6 satellite found that this single launch probably produced a metric ton of ozone depleting nitrogen oxides— equivalent to approximately 1,400 cars of annual emissions. According to Model 2022Study in progress.

For context: most living things on Earth depend on an intact ozone layer to survive and thrive. The protective blanket of atmospheric ozone absorbs the sun’s most harmful rays, known as UVB light wavelengths, which cause skin cancer, cataracts and crop damage, among others. A healthy ozone also protects us from an even worse version of climate change. Without it, the world would be 4.5 degrees Fahrenheit warmer than today.

However, just because rocket launches are increasing doesn’t mean the ozone layer has to shrink. Beyond identifying the problem of increased space launches and potential ozone damage, Revell and his co-authors also suggested a way forward for atmospheric researchers and private space companies to solve the problem. issue. According to them, a sustainable future for spaceflight is within reach, and the sooner we make changes, the better.

Some of their suggested changes include more research and monitoring to keep tabs on launch shows and better access to open launch show data. Another recommendation is that launch vendors consider the stratospheric effects of their rockets at the design and testing stage.

“It’s not a doomsday-type prediction,” said Tyler Brown, a researcher in astrophysics at the University of Canterbury and first author of the review study, in an email to Gizmodo. “A lot can and will change in the future. Our main goal is to get people talking about a sustainable rocket industry in the present with a serious goal of action, not just awareness.

More: Fuel cleanup in progress after rocket crash in Alaska

Leave a Comment