How big a deal is space junk and what should we do about it?

Every year, space junk seems to be attracting more attention. As the number of satellites orbiting Earth grows, the chances increase of some of them colliding. The more fragments that exist, the likelier further collisions. In extreme scenarios, significant amounts of space debris could hinder human expansion off-planet. To learn more about space junk, we spoke to Annie Handmer, a graduate student at the University of Sydney, Australia who studies international cooperation in space. She also manages Space Junk Podcast (which also has an associated YouTube channel).

How much of a problem is space junk?

The answer to this question depends on the context. Every time a piece of debris collides with another piece, they smash into thousands of smaller pieces all flying in different directions. In theory, repeated collisions and increasing debris could eventually result in something called the “Kessler Effect”, where a chain reaction creates a sort of “soup” of small debris fragments. Practically speaking, though, for satellite operators and launch services, despite space junk being a significant problem, it is not an overwhelming one. 

Many organizations exist which track debris, particularly in Australia and the United States. This field is called Space Situational Awareness, and it has been around ever since Sputnik blinked across our skies. Computational models provide predictions as to when conjunctions might occur. They can’t be certain, but if there’s a high enough mathematical probability then an alert may go out to a satellite operator to warn them. Of course, they can only track what they can detect. It’s very hard to track small fragments, which might still cause a lot of damage because they’re travelling at staggeringly high relative velocities. Imagine if the fly that hit your car windscreen on the highway was travelling at 30,000 km/h. It wouldn’t be pretty.

Once a likely conjunction has been detected, then it becomes an issue of Space Traffic Management. This is where things start to get difficult. The further away questions move from technical capability (“is”) towards policy or law (“ought” or “must”), the less certain things become. We are good at saying “there is a problem” and less good at saying “this is what must occur”. 

We don’t currently have a robust system of Space Traffic Management. If two things are set to collide, then generally whoever can move does move. For two functioning satellites, this will be negotiated on a case-by-case basis. In the case of a debris collision with a satellite, the satellite has to move because the debris can’t be controlled. In a potential debris-on-debris collision, it becomes a case of “fingers crossed”.

What is being done to deal with space junk and what more ought to be done?

From an international law and policy perspective, debris is a problem that we are beginning to solve through trying to prevent the creation of new debris (“debris mitigation”). In 2007, the United Nations Committee on the Peaceful Uses of Outer Space endorsed a set of non-binding guidelines on debris mitigation. The guidelines focus on reducing new debris through practical measures including end-of-life mission planning. But international agreements take time; discussions on these guidelines began back in 1994, the year I was born, and it took until I was in high school for a non-binding agreement to be reached. Then again, slow and steady progress is valuable. People and governments are more likely to follow rules that they have helped to create. 

There are also some new companies and organizations which are developing technology to remove debris currently in orbit. There are several challenges here, the least of which is technical. Space law attributes jurisdiction over debris or parts thereof to the launching state, which complicates efforts to remove or destroy it. 

From a regulatory perspective, many technologies which can remove space debris would be considered “dual use technologies” (i.e. technologies with military applications), which means that they could be subject to export controls. 

There are also issues around heritage. Which defunct satellites should be retained for their historic significance? 

Of course, planned mega-constellations (or, to be more accurate, “large” constellations) will challenge all of our existing infrastructure and processes. It’s likely that we will need to create new laws and regulations. All of this will create a demand for people with technical, policy, and legal expertise specific to space to work in insurance, regulation, finance, government, and private industry. 

How did you become interested in space junk?

I first came across the problem of space debris when I was in high school, competing in a competition called “Future Problem Solving”. The scenario posited a world in 2040 where space debris was an overwhelming problem, falling on people and generally getting in the way of things. My team proposed that we construct a small, well-monitored, and internationally governed black hole next to Earth using the Large Hadron Collider (at that time, very fashionable). The science was hazy, but we were persuasive enough to win a trip to the Gold Coast to compete at Nationals, and a trip to Sea World. 

Since then, I’ve learned much more about science and space debris, but that initial feeling of excitement has stayed with me. The idea of hundreds of thousands of objects zooming through space and generally causing no trouble, but occasionally hitting something with catastrophic effects, and, in doing so, increasing their number exponentially, is one I still find fascinating. 

How should we even conceptualize risk in such a scenario? Damage from space debris to houses, for example, is covered in Australia by the home and contents insurance of Australian Associated Motor Insurers. To the best of my knowledge, though, AAMI doesn’t attempt to build such potential damage into their models. I’m not sure if other providers cover it but they probably do. The unimaginable complexity of the problem can’t help but draw you in.

To me, space junk is a unique coalescence of a number of things I find fascinating. The history of science and technology is of course relevant to how we approach the problem, but so is international law, politics, military strategy, and heritage management. At the same time, it’s a massive technological challenge. It sits at the very edges of our capabilities as a species.

I’m not convinced that my team’s idea of creating a black hole was a sensible one (in fact, I’m certain it wasn’t). That being said, I do think that the other elements – cooperative, internationally governed, and continually monitored – are still the right things to be thinking about. I hope that in my lifetime we will find an elegant solution that can encapsulate the full spectrum of complex entanglements surrounding this thing we call “space junk”.