Why space junk orbiting the Earth could cause problems

Published 2021-08-06 08:30

Even a tiny fleck of paint could punch hole through a satellite


No one on Earth has ever been hit by a piece of a spacecraft falling out of the sky.

But people were keeping a close watch when China launched a massive rocket in late April.

After 10 days, its empty fuel booster dropped out of orbit in an uncontrolled fall. Fortunately, it landed in the Indian Ocean, far from human populations.

That’s one kind of space junk. But the junk that stays up in orbit poses a different kind of problem.

The existing debris could cause problems for the satellites we have come to depend on for global communications. Thankfully, there are some solutions in the works.

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Where does space junk come from?

Since the Sputnik satellite was first launched by the Soviet Union in 1957, thousands of objects have been launched into space.

Human-made satellites are pieces of technology used to collect information or for communication.

There are currently about 4,500 active satellites orbiting the Earth and another 3,000 satellites that are no longer working, according to the European Space Agency (ESA).

Launch of new Chinese space station.

China launched the core of its new space station into orbit on April 28. The empty rocket booster fell back to Earth 10 days later, landing in the Indian Ocean. (Image credit: Reuters)

New “mega constellation” arrays of satellites, designed to bring high-speed internet service to remote areas (like Elon Musk’s Starlink system), will add thousands more.

Add to that some abandoned rocket stages and mission-related debris — including dropped tools — and you’re left with a lot of junk orbiting the Earth.

How much junk is orbiting Earth?

NASA and the U.S. Department of Defense constantly monitor satellites and the larger bits of space junk — essentially, anything larger than a softball.

Illustration shows thousands of piece of debris orbiting Earth.

About 23,000 pieces of space debris are monitored from Earth. Many more are too small to be tracked. This illustration does not show them at actual size. (Illustration credit: NASA)

They estimate that there are about 23,000 such pieces of debris orbiting the Earth.

There are also half a million pieces that are 1 centimetre or larger, about 100 million that are 1 millimetre or larger and countless smaller particles.

What will happen to all that junk?

Their momentum will keep these objects orbiting the Earth for years.

Travelling at speeds up to 28,000 km/h, even tiny flecks of paint could damage a satellite or spacecraft.

In 2011, NASA alerted the International Space Station (ISS) that it was on course to collide with a piece of debris.

Unable to change course in time, the astronauts prepared to evacuate if necessary.

International Space Station orbits in space.

The International Space Station experienced a near-miss from space debris in 2011. (Image credit: NASA)

The debris missed the ISS by the width of a football field. A direct hit could have destroyed the station.

So far, collisions with satellites have been rare. But when they do occur, they create a mess.

More examples of collisions in space

In 2009, a defunct Russian satellite slammed into — and destroyed — an American commercial satellite.

That collision added more than 2,300 pieces of large, trackable debris and many more smaller bits to the inventory of space junk.

Illustration shows collision path and damaged caused by defunct Russian satellite Kosmos.

This illustration shows the collision path of the defunct Russian satellite Kosmos with an American commercial satellite in 2009, left, and the debris field 50 minutes later, right. (Image credit: Rlandmann/Creative Commons)

In May, it was discovered that a small piece of space debris punched a 5-mm hole through the insulation covering the robot Canadarm on the ISS.

The robotic arm still works, but the impact signals the dangers of space junk.

Canadian-made robotic arm Canadarm with hole circled.

The yellow circle, left, and the close up, right, show the Canadarm’s puncture by space debris. (Image credit: NASA-CSA)

What happens next?

Objects in low orbit will eventually lose momentum, fall to Earth, and burn up in the atmosphere. But “cleaning up” space in this way will take many years.

In the meantime, there is a risk that more collisions will create more fragments, raising the risk of even more collisions, in an escalating cascade of accidents.

That would make lower Earth orbit dangerous for the satellites we have come to depend on for global communications.

How do we solve this problem?

Space agencies like NASA already have guidelines in place to avoid major collisions.

And a Montreal-based company has announced plans for a small fleet of satellites that will be able to track space junk more effectively than ground-based systems.

When it comes to cleaning up the junk, the space agencies of Europe and Japan are experimenting with satellites that will pull large pieces of debris out of orbit.

Chinese researchers are also studying the use of lasers to move debris, either back into the Earth’s atmosphere where it will break up, or even into a different planet’s orbit.

But many scientists say the real solution to the problem of space junk, is to avoid leaving it behind in the first place.

That would require an international law to force every country to meet the same standard.

With files from Bob McDonald, Nicole Mortillaro/CBC, NASA

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