Wednesday, July 17, 2024
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Is space travel good for the environment? No

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SPayX has never been one to hesitate to brag, especially when it comes to its famous Falcon 9 rocket. since 2010, as a company toteboard shows, 217 Falcon 9s have flown, with 61 launches in 2022 alone, making it The workhorse of the current global space fleet. So what’s not to like? A lot, actually—at least if you care about the environment.

The Falcon 9 uses a fuel mixture of liquid oxygen and simple kerosene, and while the oxygen does no harm to the skies, the black soot created by burning kerosene is injected directly into the stratosphere – the air’s The layer ranges from 12 km (7.5 mi.) to 50 km (31 mi.) above the Earth. there is soot up to five years, absorbing heat, contributing to climate change and damaging the ozone layer, which exposes the planet to dangerous ultraviolet (UV) radiation. And SpaceX isn’t remotely alone.

according to a Study By the National Oceanic and Atmospheric Administration (NOAA), global rocket launches (of which there were 180 last year, the study notes) inject about 1,000 tons of soot into the upper atmosphere per year. NOAA warns that this will only get worse, as the industry continues to expand. “The bottom line is estimates that an increase in rocket launches could expose people in the Northern Hemisphere to [where most rocket launches take place] to increase harmful UV radiation,” said environmental scientist Christopher Maloney, lead author of the study, said in a statement,

By themselves, rocket launches are small contributors to overall atmospheric pollutants. aviation industry burns 100 times more fuel That’s more than all the rockets launched globally each year combined. But there is an important atmospheric difference: airplanes fly in the troposphere, about 11 km (6.6 mi) above the ground. Soot precipitates faster from this boundary than stratospheric soot, which tends to stick around for much longer. Indeed, according to NOAA reports, a passenger aboard a rocket is responsible for 100 times more climate-changing pollution than a passenger aboard an airplane.

All this not only warms the planet and damages ozone, NOAA scientists warn, but could also lead to temperature changes slow subtropical jet streamsThe summer monsoon is deteriorating in Africa and India. “We need to learn more about the potential impact of hydrocarbon-burning engines on climate in the stratosphere and at Earth’s surface,” Maloney said.

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The type of fuel used in the rocket can make a difference. SpaceX’s massive, 33-engine Starship spacecraft, for example, uses methane in place of kerosene. While methane is a potent greenhouse gas in its own right, it burns cleaner than kerosene, producing less black soot. blue origin New Shepherd Rocket Still clean, burns liquid oxygen and liquid hydrogen, and produces only water vapor as exhaust – water vapor in the upper atmosphere still captures and retains heat, but not nearly as much as black Soot, methane or carbon dioxide do.

None of this means that private rocket industries or rising space powers like China, India and the United Arab Emirates – to say nothing of the US – will slow down their launch schedules or become less pollution-intensive any time soon. . Indeed, NASA’s new Space Launch System Moon rocket, first launched in November 2022, is a particularly dirty machine. While it uses a liquid oxygen-hydrogen mixture in its four main engines, its two enclosed solid fuel engines, which account for most of the vehicle’s thrust, produce the ozone-damaging pollutant chlorine.

The thriving space industry is generally seen as a boon to both the economy and human exploration – and it is. But the launch of monster rockets — with monster exhaust — like SpaceX’s anticipated Starship is a reminder that there can be too much of a good thing. If we continue to increase not only the size of rockets but the number of launches, we do so at a cost; And like many other things, it’s the climate that pays.

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write to Jeffrey Kluger at [email protected].