Space junk is piling up fast - can we still clean it up?

High above the sky, in the stretch of space where satellites race around Earth, a crowded ring of old metal is whipping along at more than 15,000 miles per hour. People call this space junk. Scientists call it orbital debris, and it’s piling up fast.

The objects include dead satellites, broken parts from past missions, and tiny fragments arising from explosions or collisions. This mess isn’t sitting still, either.

Every object, even one the size of a grain of rice, moves at a speed that turns it into a threat. GPS, weather satellites, internet systems, and even astronauts on the International Space Station depend on clean, safe orbits.

According to experts, a tiny piece of space debris can cripple a billion-dollar satellite.

The rising risk of space junk

Professor Hao Chen from Stevens Institute of Technology, who studies space systems design, explained how risky the situation is.

“Even if a tiny, five-millimeter object hits a solar panel or a solar array of a satellite, it could break it,” he said.

“And we have over 100 million objects smaller than one centimeter in orbit. So if you want to avoid a collision, you have to maneuver your spacecraft, which takes up fuel and is costly.”

Even astronauts on the International Space Station are at risk from space junk. Occasionally they must go outside the spacecraft, and this means they can also be hit by flying debris.

There is no global rulebook pushing countries or companies to clean up after themselves. There is no “polluter pays” system with real consequences.

The result is what Chen calls a cosmic free-for-all. His latest study looks at how to change that.

Options for clearing the space junk

Chen and his team studied three possible paths for getting rid of space debris. Each approach uses a special spacecraft called a remediation vehicle that grabs junk and does something useful or safe with it.

One option is uncontrolled re-entry. The servicer pulls each piece of debris down to about 220 miles above Earth and lets nature finish the job.

The object keeps orbiting until it gets dragged into the atmosphere, where it either burns up or lands somewhere.

“It will either burn or drop somewhere on Earth, but we don’t know where because it depends on the atmospheric drag it receives,” said Chen. This method is the cheapest because the vehicle doesn’t need to travel far.

Another option is controlled re-entry. Here, the servicer brings debris down to around 30 miles.

“Controlled re-entry is more expensive because the servicer needs to bring the debris down closer to earth and then fly up again to get the next piece of debris,” noted Chen. “That consumes more energy and more fuel than an uncontrolled re-entry.”

Recycling the junk in space

This idea seems costly at first, since the servicer must transport debris to a recycling center in orbit.

But reusing metals like aluminum on site can save enormous amounts of energy and money.

“It takes about $1,500 per kilogram to launch anything from Earth to space,” Chen said. Recycling cuts down on how much material needs to be launched at all.

Motivating companies to clean up

Even with smart technology, cleaning space is not a charity project. Someone has to pay for the missions and equipment.

Chen’s team applied Game Theory and Nash Bargaining Theory to design a fair system for dividing costs and benefits between the parties involved. This approach balances the interests of satellite operators and the specialists who remove orbital debris.

“The debris remediators pay for the missions, the technology, and the actual work. Without some kind of financial incentive, they don’t really gain anything from it – they bear all the costs while others reap the benefits,” Chen said.

Operators, on the other hand, enjoy safer orbits and fewer emergency maneuvers without lifting a finger. “However, they don’t actually do anything to remove the debris themselves – they just enjoy the cleaner, safer environment,” he noted.

Incentive to remove space debris

Chen’s team suggests a fee system where operators pay into a fund that rewards companies who remove debris.

“We will need some agency to create an incentive for the debris remediators,” Chen said. “The money should come from the people who enjoy all those benefits.”

“Our analysis shows that there is a surplus to be generated from the remediation of orbital debris, and that surplus can be optimally shared by space operators and debris remediators.”

Space needs a plan forward

More satellites launch every year. More pieces of hardware are left behind. If nothing changes, the situation will keep getting worse.

Chen believes the path forward requires action and incentives that make safety and profit work together. “That is what’s needed to move us closer to a space industry that is safer, more sustainable, and still profitable.”

The sky may seem endless, but the useful parts of Earth’s orbit are not. Whether companies choose recycling, controlled re-entry, or cheaper drop offs, the message is clear.

If we want a future where space remains open for discovery and exploration, the clean-up has to start now.

The study was published in the journal Aerospace Research Central.

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