What do we do with all of our space junk?

How a new method of harnessing magnets can extend the life of space junk
12 December 2022

Interview with 

Jake Abbott, University of Utah


this is a picture of a satellite orbiting Earth


Up into space and how researchers are seeking to use magnetic fields to grapple with a large and growing problem: the hundreds of thousands of pieces of discarded junk that now orbit the planet and pose a hazard to our satellites, spacecraft and astronauts. Much of this stuff isn’t made from iron or one of the handful of “ferromagnetic materials”, so it’s not just a case of waving a magnet around to grab it. That won’t work. Instead the solution’s far more ingenious: by creating a changing magnetic field you can induce an electric current to flow in conductive materials, which in turn produces its own magnetic field that you can then push or pull against. Jake Abbott is working on the idea at the University of Utah…

Jake - Every day, our society keeps putting more stuff into space. And it's all going in basically the same orbit. Many, many tens of thousands of pieces of junk. And it ranges from tiny little specks of dust to huge rocket bodies. And the problem is they don't burn up fast enough. The orbit they're in is fairly stable. So they could be up there for many decades before they will eventually burn up in Earth's atmosphere. And the problem is, with each new piece of debris, you create more risk of collision. And when there's a collision between debris, it has this cascading effect where it creates more debris that flies off in every direction like bullets. And if we're not careful, we could eventually end up with a permanent ring of debris around our planet. So there's a big effort to figure out how to get this debris to burn up faster than it would naturally.

James - What amount of this material up in space is non-magnetic?

Jake - It's mostly aluminum. And so you have these huge pieces of aluminum that are typically viewed as non-magnetic. If you try to stick a magnet to aluminum, it won't stick to it. And using all the techniques that we've been using to manipulate ferromagnetic metals over the last 15 years, if you attempt to use those methods, nothing will happen. The aluminum object just won't even move.

James - So what's the solution?

Jake - So we sort of have recently come to the realization that there's an well-known old phenomenon known as eddy currents. If you change the magnetic fields rapidly, just during that period where the field is changing, you will generate electricity, electrical currents, in any conductive material. So now this is all of the other metals that aren't magnetic. And aluminum ends up being a fairly good conductor. And so when the magnetic field is changing, these eddy currents get generated in the metal. But what we've figured out how to do is use that eddy current generation to do manipulation. In that moment, you generate these circulating eddy currents inside of these metals. They're almost like little mini electromagnets. And those little mini electromagnets react against the same magnetic field you were using to generate them. And so then you generate forces and you generate torques on those little swirling currents. And so now we can rotate things. We can push things and pull things. It is a way for us to literally reach out into space away from us, pull that object into us. So it's something like a tractor beam.

James - Why do you need this level of precision to remove the pieces of space junk that you're able to achieve with your method? Why can't you just knock them physically to disrupt their course and make them burn up a bit more quickly?

Jake - Some of the pieces of space debris are truly junk, what you'd think of as debris. And really what you're trying to do is deorbit them as fast as possible, meaning make them burn up in the earth's atmosphere. Some of the things are maybe satellites that used to work, and they could work again if you could repair them. So the goal is not to deorbit them, but it's to add another 20 years to their life or something. Lots of people have solved the problem of finding an object of interest and synchronizing some robotic satellites orbit with that object. So now you can imagine the robot and the piece of debris in sort of a synchronous orbit where they're not moving relative to each other anymore. And you say, okay, I want to either repair this object or I want to attach something to it that will cause it to deorbit to slow it down. The problem is, that everyone encounters, is when you come upon this object that's been circulating around earth for a long time, it's often tumbling out of control. And there's no way to grab it safely. Because if you try and grab it, either you could break your robot and create more debris, or this tumbling object might have antenna sticking off of it or solar cells. And if you try and grab that, you might turn that one piece of debris into lots of pieces of debris. So this problem of, I've synchronized myself with this piece of junk, it's tumbling out of control. I wanna grab it and manipulate it, maybe using more traditional robotic methods, but I don't know how to grab it safely. So that's where we come in. We are creating a methodology in which we can de tumble this object without touching it. So now imagine the robot has two stages. The first stage is our technology where this, this object is tumbling out of control, and we use our magnetic fields to get it to stop tumbling. And then once it has stopped tumbling, then more traditional robotic hands reach out and do the manipulation.

James - And how's it going? Is this at the proof of concept stage? Is it being developed further? What's the status?

Jake - Yeah. Well, I mean we have demos in our paper. We have videos, so you can see us pulling on things. It's over relatively short distances. I've paired with a company called Rogue Space Systems, and we are trying to develop this technology to a point where it could be put in space in the very near future. We've actually had funding from the US Space Force to work on this.


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