Humans have been changing the Earth’s atmosphere from the surface for nearly two centuries, and now in the Space Age, we’re also changing it from space. Atmospheric scientists recently discovered an unexpected trace of metal in the stratosphere. The stratosphere is the second layer from the bottom of the atmosphere where ozone exists and where meteors burn out and become shooting stars. In a study published last week in the journal Nature, researchers determined that the contamination occurred when the spacecraft re-entered Earth’s atmosphere. Proceedings of the National Academy of Sciences.
The study says it is “the first observational evidence that space activity is a very significant source of particulate pollution to the stratosphere.” Suliman Becchi atmospheric scientist Latmos Island I am not involved in the new work. “More importantly, no one knows the effect these particles have on the ozone layer,” he added, pointing to the importance of this molecule in protecting humans from dangerous ultraviolet rays.
Typically, the main concern of mission planners is to prevent space debris from hitting the ground where it could harm people or structures, but as this study points out, in the stratosphere What evaporates, even if it is not literal. That material must exist somewhere, and it appears to remain in the stratosphere. “We’re finding this man-made material in what we would consider to be a pristine region of the atmosphere. And if something is changing in the stratosphere (a stable region of the atmosphere). It’s worth a closer look,” said co-author and Purdue atmospheric scientist. Dan Chisso in a press release.
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The research team flew through the stratosphere over the continental United States in a specially designed high-altitude aircraft equipped with an air analyzer in its nose cone. These unique planes are— NASA’s ER-2 and WB-57—It cruises at about 65,000 feet, about twice the altitude of a typical jetliner. Flying up to 70,000 feet, the research vessel can exceed 99 percent of the mass of Earth’s atmosphere.
In the stratosphere, the collection equipment of these planes recorded traces of heavy metals. niobium and hafnium. These elements do not occur naturally in the atmosphere, but are typically used in rocket and spacecraft shells. The researchers also measured higher-than-expected concentrations of more than 20 metals, including copper, lithium, aluminum, and lead. Overall, about 10 percent of stratospheric aerosol particles contain metals.
Atmospheric scientists don’t know exactly how these changes will affect Earth. The stratosphere contains small chunks of sulfuric acid and is currently injected with metals from old spacecraft. The presence of these metals can change the chemical structure of the stratosphere, including how large droplets of sulfuric acid grow. Even small adjustments in the sky can affect how light bends, heat transfers, and ice crystals grow.
The big question is how these changes will affect human life on Earth. Unfortunately, there is no clear answer to this, but in the past small changes in the stratosphere have had big effects. CFCs Something that eats away at the ozone layer. Ultimately, additional environmental precautions may be required for spaceflight to prevent harm to the stratosphere.
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“The only way to prevent these particles from appearing in the upper atmosphere is to not launch satellites in the first place,” explains the atmospheric scientist at the University of Exeter. jamie shuttler People who were not part of the research team. “Possible ways forward include reducing the number of launches, increasing the lifetime of the satellites (therefore requiring fewer launches), or encouraging industry to make satellite components available to the public (so He added that the new findings “confirm our concerns” about stratospheric pollution.
But before solving this problem, “we have to consider the concept that atmospheric reentry can affect the stratosphere,” says the first author. daniel murphy, an atmospheric scientist at NOAA. He stressed that this idea is still incredibly new and more research is needed to understand the scale and potential impact of this contamination.
As spacecraft launch and reentry rates accelerate, the potential impacts are expected to increase further. In the past five years, space agencies and private companies have launched more than 5,000 satellites, study co-author Martin Ross, a climate scientist at Aerospace Corporation, said in a press release. “Most of them will be back within the next five years. We need to know what further impact that will have on stratospheric aerosols,” he said. The researchers say the proportion of particles containing metals could increase from 10 percent to more than 50 percent in the coming decades, especially thanks to future plans to reduce space debris by dumping it back into the atmosphere. I predict that there will be.
However, these efforts and future launches must be aware of their potential impacts on Earth, and researchers must conduct further studies to determine the extent of those impacts. “Understanding our planet is one of his most urgent research priorities,” he says Cziczo.
