Photo: Twitter/SpaceX
The rapidly growing number of rocket launches could slow the recovery of the ozone layer, a study led by New Zealand scientists shows.
The ozone layer is healing because of countries phasing out CFCs - but rocket launches could slow its recovery if the space industry grows as fast as it wants to, found researchers from the University of Canterbury, Harvard, Saint Petersburg State University and elsewhere.
They are urging space companies to choose cleaner fuels to minimise ozone damage as rockets pass through the stratosphere.
"At the moment it's a not problem because the launches happen too infrequently," said University of Canterbury atmospheric scientist Laura Revell, one of the authors of the study.
"As we get more and more launches taking place - because there are companies out there with very bold ambitions to increase launch frequency - this is potentially going to be a problem."
Although most rockets are launched from the Northern Hemisphere, the worst impacts on the protective layer of ozone will be felt over Antarctica, with implications for sunburn and cancer-causing UVB rays reaching people living in Aotearoa.
In a conservative growth scenario where launches take place about once a week at all currently active launch sites - about 900 in total a year - "we do see some some ozone loss but not significant amounts," said Revell.
"But when we look at a more ambitious scenario, when we looked at the upper limits of what might be launched in future - around 2,000 launches year - we saw levels of ozone loss that are concerning in the context of ozone recovery," she said.
Based on current rates of licensing, that level could be reached in 2030, said the authors.
They said the industry had already grown from 102 launches worldwide in 2019, to 258 in 2024.
The ozone layer as seen from space. Photo: 123rf
Revell said the study was not saying there was going to be widespread depletion or that melanoma rates were going to skyrocket, "but a few per cent depletion, which is enough to offset the gains we have seen the past few years as CFCs have been phased out."
She said the Electron rockets launched from Mahia peninsula by Rocket Lab had a relatively minor impact because of their small size.
She said the space industry needed to consider its choices of fuel, as it grew.
"This is not locked in. It is possible to avoid a future in which we have a scaled up rocket launch industry and also a slowing of ozone recovery, but there needs to be care taken and global efforts to ensure we are very mindful of what is emitted and where."
"Not all fuel types actually cause ozone depletion."
Ozone losses are driven by the chlorine produced from solid rocket motor propellant, and black carbon which is emitted from most propellants, the study says.
Revell said the problem had been known about since the 1980s but was becoming more relevant as more rockets were launched.
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