SPACE JUNK PARTICLES DETECTED IN EARTH’S ATMOSPHERE

We humans have transformed out attitudes about junk over the course of my lifetime. I can remember the kids on the street where I grew up comparing, and feeling quite competitive, about how much trash our families set out on the curb.

Trucks rolled around every week and hauled anything we set on the boulevard off to the dump on the edge of town. The guy who looked after the dump either burned or buried it, and nobody gave it any more thought.

Today, we recognize that waste management is a much bigger issue than we’d realized half a century ago. Concerns about pollution, habitat destruction, sanitation, public health and climate change have led to regulations and policies that tell us all how to go about getting rid of our junk sustainably.

SPACECRAFT AND SATELLITES LEAVE SPACE JUNK BEHIND

Ever since humanity began launching objects into space back in 1957, we’ve also been leaving space junk behind, like spent rocket stages and discarded equipment. For example, the Apollo moon landings had to discard over 95% of their rockets’ launch mass in order to escape from Earth’s gravity.

Over time, space agencies started to recognize that old space junk causes problems for later missions. A new field arose called “space debris mitigation” to reduce the amount of trash spacecraft leave behind and to try to find ways to safely remove defunct satellites from orbit.

Dr. Daniel Murphy has been studying aerosol properties and processes in our atmosphere for the past two decades. He’s a research chemist at the US National Oceanic and Atmospheric Association NOAA.

NEW FINDINGS RAISE ANOTHER ASPECT OF SPACE JUNK ISSUE

Professor Murphy is the lead author of a study that the Proceedings of the National Academy of Sciences published last week. The findings raise another aspect of the space junk issue.

The researchers have found traces of metals from satellites and rocket boosters in the stratosphere, more than seven miles above the Earth’s surface. When space junk re-enters the atmosphere, it gets vaporized by the intense heat.

Meteors have always entered our atmosphere, and they leave space dust behind in the upper atmosphere. It now appears that as space junk burns up on re-entry it leaves particles of rare metals within that layer of space dust.

HIGH-ALTITUDE RESEARCH PLANE FLEW OVER ARCTIC

The findings are part of a NOAA Chemical Science Laboratory mission called Stratospheric Aerosol Processes, Budget and Radiative Effects, or SABRE for short. The team flew a high-altitude research plane over the Arctic to investigate aerosol particles in the stratosphere.

The stratosphere contains the ozone layer and it also moderates Earth’s climate. The scientists custom built a highly sensitive instrument called the Particle Analysis by Laser Mass Spectrometer (PALMS) and mounted it in the nose of one of NASA’s WB-57 research aircraft with a large, forward-facing air intake.

The PALMS instrument gathered and analyzed the mass spectra of over 500,000 individual aerosol particles during the flight. About 10% of those particles contained aluminum and exotic metals that appear to be traces of space junk.

‘RARE ELEMENTS THAT ARE NOT EXPECTED IN THE ATMOSPHERE’

“Two of the most surprising elements we saw in these particles were niobium and hafnium,” Professor Murphy explained. “These are both rare elements that are not expected in the stratosphere.”

“It was a mystery as to where these metals are coming from and how they’re ending up there,” Professor Murphy said. Niobium and hafnium don’t exist in nature as free elements.

Chemical processing facilities extract these elements from mineral ores. These rare metals play a key role in semiconductors and superalloys.

“POINTED US TO THE AEROSPACE INDUSTRY”

Along with these rare elements, the scientists also found copper, lithium and aluminum at levels far beyond the normal range for space dust. “The combination of aluminum and copper, plus niobium and hafnium, which are used in heat-resistant, high-performance alloys, pointed us to the aerospace industry,’’ Professor Murphy said.

Now that they know that space junk particles exist in the stratosphere, the scientists want to determine how they interact with other aerosols. Space agencies expect to see huge increases in space traffic over the next couple of decades, and potentially more collisions, creating even more space junk.

For example, the Starlink network has over 4,519 satellites in orbit, and plans to have up to 42,000 of them in orbit over the next few years. So, its important to understand the affect this increased traffic could have on the ozone layer.

SPACE JUNK TRACES COULD RISE FROM 10% TO 50% DUE TO TRAFFIC

The researchers project that the percentage of stratospheric particles with space junk traces cold rise from 10% to 50% or more because of all this increased traffic. Satellite operators are planning to have more satellites burn up in the atmosphere to avoid future collisions, but based on these new findings, it will also raise the volume of rare metals in our stratosphere.

Meanwhile, some companies have proposed seeding the stratosphere with sulphur aerosols to reduce climate change. Professor Murphy and his team want to assess how the space junk traces might affect those plans as well.

AND ANOTHER THING…

It seems that no matter what we do or where we go, we humans leave behind traces of our activities. Yet, we don’t seem to be very good at anticipating the negative effects those traces might have on our natural world.

Finding out more about our atmosphere’s chemistry, and how space junk might affect it, helps piece together the New Story humanity needs to make sense of nature and our place within it. We’re learning to apply science not merely to exploit natural resources but instead to understand how to live sustainably with them.

According to the website Orbiting Now, there are now about 8,697 artificial satellites in orbit, of which 7,892 will be burning up on re-entry some day. “There will be a lot of work to understand the implications of these novel metals in the stratosphere,” Professor Murphy concluded.

We always have more to learn if we dare to know.

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PUBLISHED BY DAVID MORTON RINTOUL

I'm a freelance writer and commercial blogger delivering content services to selective business to business marketing clients. I have extensive experience in content creation, technical writing and training, working as a consultant and later in management roles with many of Canada's most successful organizations. Specialties: Content Marketing, Social Media, Technical Writing, Training and Development