With more rockets launching now than ever before in human history, a growing threat to spacecraft is space junk. With the capability to destroy other satellites or punch holes through manned capsules, space junk is proving to be a difficult, but necessary, problem to solve for space flight to continue.
What is space junk?
Space junk is any piece of man-made debris that has been left in space. Space junk can range from something as small as a single bolt, or metal shards, to much larger structures like expended rocket stages, dead satellites or defunct space stations. Space junk can be both intentional and accidental. Often times, when satellites are approaching their mission end they are not de-orbited, but are instead left to orbit the Earth until their orbits decay naturally. This is often the case for satellites in Low Earth Orbit (LEO) or has been the case historically for larger rocket boosters like the second stage of the Saturn V rocket. Sometimes, via breakages or malfunctions, debris or spacecraft are left to a similar fate – for example, last year a batch of Starlink satellites failed to reach orbit due to a solar storm, and remained in orbit for weeks before falling back to Earth.
Why is space junk an issue?
Over decades and thousands of launches however, the amount of space junk has built up in LEO and beyond. While all space junk in Earth orbit will eventually fall down due to minute amounts of air resistance, this process can take many years, meaning, we are launching more junk into space than is returning from space.
Presently, it is believed there are more than 130 million pieces of space junk larger than 1 mm orbiting the Earth. Each of these pieces is travelling over 8 km/s. This results in projectiles containing tremendous amounts of energy, and if a collision occurs between two pieces of space junk – or a piece of space junk and an active craft – the outcome could be catastrophic. Depending on the size of the space junk, a hole could be punctured in a craft – like the recent Soyuz fuel leak – to the obliteration of both objects – like the 2009 satellite collision. Needless to say, companies in the space industry are beginning to feel the pressure of space junk.
So what’s being done about the problem?
Unfortunately, there is no simple solution to space junk – at least at the time of writing. Any efforts to manage space junk are currently preemptive, rather than reactive. Rocket companies are making efforts to reduce the number of spent booster stages left in orbit – for example, companies like SpaceX reuse their rockets first stages – and satellites are beginning to be routinely deorbited by their controllers at the end of their life times.
But what’s being done about the dead spacecraft, or pieces of metal floating around in Earth obit? That’s where space junk tracking comes into the picture. The best way to avoid crashing into space junk is to know where it all is, and adjust your orbit to prevent collisions. While this sounds like a great idea on paper, the limitations become present quickly as most pieces of space junk are simply far too small to be detected by Earth space radars.
Fortunately, space information company LeoLabs are spearheading the effort to detecting these tiny pieces of spacejunk. With a network or radars around the world – the newest of which is based in Collie, Western Australia – LeoLabs uses powerful radars to detect space junk as small as 10 cm in size from hundreds of kilometers away! LeoLabs works alongside members of the space industry to predict and avoid collisions with other satellites and space junk alike.
Riley is an experienced astronomy guide who has been working within the astronomy community for several years. He is incredibly passionate about the night sky and holds a Bachelor’s Degree in Science, Math and Education.
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