A team of academics is using magnets to tackle the increasingly pressing problem of space debris.
University of Utah mechanical engineering professor Jake J. Abbott is leading a team of researchers that has discovered a method to manipulate orbiting debris with spinning magnets. With this technology, robots could one day gently manoeuvre the scrap to a decaying orbit or further out into space without actually touching it, or they could repair malfunctioning objects to extend their life.
Their research is detailed in the paper, “Dexterous magnetic manipulation of conductive non-magnetic objects,” published in the science journal, Nature. The co-authors include University of Utah graduate students Lan Pham, Griffin Tabor and Ashkan Pourkand, former graduate student Jacob L. B. Aman, and School of Computing associate professor Tucker Hermans.
The concept involves moving metallic, non-magnetised objects in space with spinning magnets. When the metallic debris is subjected to a changing magnetic field, electrons circulate within the metal in circular loops, “like when you swirl your cup of coffee and it goes around and around,” explained Abbott.
The process turns the piece of debris into essentially an electromagnet that creates torque and force, which can allow the user to control where the debris goes without physically grabbing it.
While the idea of using these kinds of magnetic currents to manipulate objects in space is not new, what Abbott and his team have discovered is that using multiple magnetic-field sources in a coordinated fashion allows them to move the objects in six degrees of movement, including rotating them. Before, it was only known how to move them in one degree of movement, like just pushing them.
“What we wanted to do was to manipulate the thing, not just shove it but actually manipulate it like you do on Earth,” he said. “That form of dexterous manipulation has never been done before.”
With this new knowledge, scientists for example could stop a damaged satellite from wildly spinning in order to repair it, something that has not hitherto been possible.
“You have to take this crazy object floating in space, and you have to get it into a position where it can be manipulated by a robot arm,” Abbott said. “But if it’s spinning out of control, you could break the robot arm doing that, which would just create more debris.”
This method also allows scientists to manipulate objects that are especially fragile. While a robot arm could damage an object because its claw applies force to one part of it, these magnets would apply a gentler force to the entire object so no one section is harmed.
To test their research, the team used a series of magnets to move a copper ball on a plastic raft in a tank of water (the best way to simulate slow-moving objects in microgravity). The magnets moved the sphere not only in a square, but they also rotated the ball.
According to Abbott, this newly discovered process could be used with a spinning magnet on a robotic arm, a stationary magnet that creates spinning magnetic fields, or a spinning super-conductive electromagnet like those used in MRI scanners.
Abbott also believes this principle of manipulating non-magnetic metallic objects with magnets could also have applications beyond the clearing of space debris.