What is Kessler syndrome? Could it become a reality? What to know

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Decommissioned satellites and other debris often remain in orbit above Earth, creating a growing space junk that poses a threat to our future in space. Here’s what’s being done to combat it.

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For decades, spacefaring countries have sent thousands and thousands of satellites and other objects into orbit, where they have become an integral part of modern society.

From hundreds of kilometers above Earth, satellites can help scientists make observations about our planet and the surrounding universe, or even give us access to television and entertainment.

But what happens when these aging satellites are decommissioned and no longer active?

Well, many of these objects – or fragments of them – are still there, languishing above Earth in an ever-growing space junk. Because they are expensive to remove, retired satellites are often left in low Earth orbit, where their presence poses a growing threat to both future satellite launches and manned space missions, according to NASA.

Just this November, an incoming piece of space debris prompted the International Space Station to take steps to maneuver itself out of harm’s way. A Russian cargo ship docked with the space station fired its thrusters for more than five minutes to “give an extra distance margin” to the amount of debris, NASA said. While the incoming object, which was debris from a decommissioned weather satellite, wasn’t necessarily on a collision course with the station, NASA said the evasive maneuver gave it a little more cushion to safely zip by.

All this debris floating around in space could lead to a theoretical scenario known as Kessler syndrome. Here’s what you need to know about space junk, why it’s a problem, and what’s being done about it.

What is space junk?

Also called space junk, space junk consists of non-operational satellites and other man-made objects that continue to whiz around Earth’s orbit long after they have served their purpose.

Spacecraft, spent rocket boosters, and even astronauts’ lost tool bags can combine with old satellites to create a halo of orbital debris that lasts for decades.

Since the beginning of the space age in the 1950s, humanity has sent about 50,000 tons of material into, according to ESAwhich cited data from the US Space Surveillance Network. The total mass of all space objects in orbit is estimated to be more than 13,000 tons from September 2024. And of the 19,590 satellites launched into space since 1957, 13,230 of them – of which 10,200 are operational – continue to whiz around space at high speeds as of September, says the space agency.

And the pace of satellite launches is increasing.

Why is space debris a problem?

The risk of all these new objects shooting off into space?

When combined with all the satellites that have been there for decades, the ESA warns that the increasing threat of collisions calls into question humanity’s future in space.

In one incident in 2009, two satellites crashed into each other over Siberia. Not only were both satellites — one of which was still active — destroyed, but the collision created a whole lot more debris in the process, according to a report at the time from the American scientist.

By December 2022, the International Space Station had moved out of the way of space junk 32 times since 1999, according to a quarterly report for 2022 from NASA. By October 2023, this number had increased to 37 maneuvers to avoid orbiting debris, including two in August of that year alone.

When the ISS maneuvered away from space debris in November this year, it marked its 39th predetermined avoidance maneuver.

It’s also not uncommon for some of these objects to crash back to Earth, scientists say.

Earlier this year, a family in Naples, Florida, filed a claim against NASA for more than $80,000 in damages to their home after some space debris from the International Space Station tore through their roof.

What is Kessler syndrome?

All this increases the likelihood, warns the ESA, that a theoretical scenario known as Kessler syndrome could come true: If unchecked, the multiplying debris and subsequent cascade of collisions could render Earth’s orbit unusable for space travel.

“We see a dramatically increased use of space, but still insufficient technology to prevent the risks that follow,” Holger Krag, ESA’s head of Space securitysaid one declaration last year.

What are NASA, ESA, others doing about space debris?

The movement to crack down on the hazardous debris hurtling through outer space has seemed to gain strength in recent years.

Many scientists have been sounding the alarm for years about Earth’s fast-crowded orbit, but now the European Space Agency, NASA and other organizations around the globe are starting to take more concrete action. Last year, the ESA adopted Zero Debris Charterwhich seeks a global commitment to nearly eradicate so-called space junk by 2030.

“As the space infrastructure has become the backbone of our modern society, the spread of space debris threatens our way of life,” Director General Josef Aschbacher said in a statement at the time. “Now is the time to act as a community to channel our collective efforts.”

In the US, NASA has its own Orbital Debris Program based in Houston, Texas with the mission of creating less orbital debris and designing equipment to track and remove space junk.

An earlier version of this story was published in November 2023.

Cast: Max Hauptman, USA TODAY

Eric Lagatta covers the latest and trending news for USA TODAY. Contact him at [email protected]