Space Junk

Spotting a “No Littering” sign in your local park is pretty common. But would you expect to spot one in outer space? “Space littering” is a growing and increasingly dangerous problem. Let’s learn what this is, why it’s dangerous, and what scientists, engineers and politicians can do to solve it!

What is space junk?

Some things in space are supposed to be there, like working satellites and space stations. Other things are considered orbital debris, or space junk. It is hard to guess exactly how much space junk is in Earth’s orbit, but the European Space Agency estimated there was more than 8,500 tonnes of it in 2019. That means if you added all of that junk together, it would equal around 100 space shuttles.

NASA has been dealing with the space junk problem for years. In 2013, they kept track of over 500,000 pieces travelling at speeds of up to 28,000 km/h! These floating, trackable objects range from small pieces the size of a marble to entire broken satellites.

So what exactly is this junk? Lots of different things! For example, there are rocket boosters that have detached during rocket launches. There are the leftovers of accidental or intentional explosions. Some of these intentional explosions are the result of anti-satellite weapons testing, such as those conducted by the U.S. government in 1985, the Chinese government in 2007, and the Russian government in 2021. There’s even an odd collection of equipment lost by astronauts: a glove, a camera, tools and garbage bags!

Did you know?

One of the larger pieces of space junk currently in orbit is the broken-down Envisat satellite, which weighs 8 tonnes and could stay in orbit for up to 150 years!

The really dangerous stuff is often the tiny bits that NASA can’t keep track of. Most of the space junk scientists worry about is in a region called low Earth orbit (LEO). This is where the International Space Station and the majority of satellites are located because it takes less energy to get there than to orbits further away and because it’s easier to observe the Earth’s surface from (relatively) close by. It’s the area that lies between an altitude of 180 and 2 000 km above the Earth’s surface.
The closer you are to the earth when you are orbiting, the faster you go - LEO objects are travelling at nearly 28 000 km/h - going ¾ of the way around the earth every hour. (and if they’re colliding they’re often going in opposite directions). At those speeds even something as tiny as a fleck of paint can do a surprising amount of damage! 

But how bad can all this space junk really get?

Luckily for us on Earth, there’s a whole lot of space out in space! On average, you would have to travel about 125 km in low Earth orbit before coming across a piece of space junk large enough to be tracked by NASA. That’s like driving from Toronto to Niagara Falls.

Did you know?

On average, one piece of space junk has fallen back into Earth’s atmosphere every day for the last 50 years.

But that is not to say we have nothing to worry about! The 2013 sci-fi movie Gravity showed astronauts in the middle of a very possible scenario called the Kessler effect. That’s a critical point at which the space junk has gotten so dense that a single collision could start a domino effect of more and more collisions, eventually destroying almost everything out there!

This would be a disaster, since here on Earth we have grown very dependent on orbiting satellites. They help humans with everything from communications to navigation. This is why everyone from NASA to tech companies to entire governments are researching ways to get rid of the space junk that’s already out there.

Did you know?

There is no international law about minimizing space junk, although space agencies are working together on the problem.

How to get rid of space junk

One of the easiest ways to get rid of space junk is to change its orbit so it gets close enough to Earth that it hits the atmosphere - and at the speed they are travelling, small objects will just burn up. There are different possible ways to do this. For example:

• Small rockets on the broken junk satellites themselves can push them into a lower orbit. 
• Scientists can blast a laser at pieces of space junk to nudge them around. The laser could even be located on the Earth’s surface if it were built to be precise enough!

Right now, scientists are only using rockets to destroy space junk. They’re not using lasers yet because governments are worried about the dangers of lasers in space. After all, they could potentially damage things that aren’t space junk.

Some companies have proposed sending up a ship or giant net that could physically drag the space junk into falling orbits. That way, it could either burn up or fall into a sort of“graveyard orbit” far away from all the good, working satellites.

The latest idea from NASA is a brand new type of ‘space velcro’ that could grab all the space junk. This idea was inspired by geckos! Their feet can grip onto walls using small flaps that create a static electric charge. This is just like when you rub a balloon against your hair to create an electric charge and then stick the balloon to the wall. Astronauts tested this inside the International Space Station in 2017.

What’s next?

As humans push the limits of space exploration and send more and more people beyond Earth, fixing the problem of space junk is getting really important. Luckily, some of the world’s best scientists and engineers are on the case. Who knows? We may one day see the start of a brand new industry: space junk removal!