THE European Space Agency faced a tense wait for an old satellite to plummet back to Earth this week.
What remained of its ERS-2 satellite eventually crashed into the Pacific Ocean, an event that’s set to become more common with the increase in satellites being sent to space.
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Space debris expert Professor John L. Crassidis spoke with The U.S. Sun about the dangers associated with debris and whether falling space junk is an increasing threat.
Crassidis says that whether space debris will become a common issue for us on Earth will depend on several factors.
“This really depends on a number of factors. Size being the biggest factor,” he told us.
“Most of the stuff that comes down is controlled to deorbit in an uninhabited region in the Pacific Ocean.
“Mostly every low-Earth orbiting satellite and debris burn up in the atmosphere.
“We are not allowed to build satellites out of hard materials, like titanium, because that will not burn up like aluminum.
“As the number of satellites increases, there will certainly be more coming down, but most of it gets burned up in the atmosphere. Some countries don’t follow our rules though.
“For example, some Chinese rocket bodies came back to Earth in an uncontrolled fashion. This can be avoided.”
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As Crassidis notes, the remains of a Chinese rocket booster fell back to Earth uncontrolled in late 2022.
This caused a lot of controversy and concern as it was unclear where the debris would fall and what damage it could cause.
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“Once again, the People’s Republic of China is taking unnecessary risks with the uncontrolled rocket stage reentry of their Long March 5B rocket stage. They did not share specific trajectory information which is needed to predict landing zones and reduce risk,” said Nasa Administrator Bill Nelson said at the time.
“It is critical that all spacefaring nations are responsible and transparent in their space activities and follow established best practices, especially, for the uncontrolled reentry of a large rocket body debris – debris that could very well result in major damage or loss of life,” Nelson warned in a statement.
The chance of a human being hit by a falling piece of space debris is still considered to be under one in 100 billion annually.
Crassidis says we don’t need to worry about the risk increasing for several more decades.
“No human has ever been hurt by space debris falling from the sky. Obviously, getting hit by lighting has a much bigger chance, so nobody should worry about space debris at this point.
“We are putting many more satellites in low-Earth orbit.
“This will obviously increase the chance, but it will still be several decades before it gets to a point where we should begin to worry.”
The expert flagged Kessler’s Syndrome as a bigger concern.
Kessler Syndrome is a concept thought up by the Nasa scientist Donald J. Kessler.
It refers to the idea that a chain reaction of exploding space debris could create so much space junk in the Low Earth Orbit that we’d be trapped on Earth.
This could also mean humans wouldn’t have the use of satellites because they’d be broken up during collisions.
“The biggest problem is space junk hitting satellites. Two big satellites collided in 2009,” Crassidis told us.
“That sent a HUGE message to us that we aren’t tracking even the big stuff as well as we think.
“Everything in space is traveling very fast at 17,500 MPH. They need to go that fast to achieve orbit, otherwise Earth’s gravity will pull them back.
“This goes directly back to Newton. When you see an astronaut “floating” in space you shouldn’t think of them that way.
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“They are actually falling at 17,500 MPH but never hitting the ground. The problem that we are worried about is that space junk collides with other space junk or satellites, which creates more space junk, leading to a cascading effect.
“This is known as Kessler’s Syndrome. Obviously, this will be bad if it becomes a reality.”
