Space near Earth has become a garbage heap.
According to NASA, there are more than 27,000 space debris larger than the size of a softball orbiting the Earth, and they are moving at speeds of up to 17,500 mph, fast enough that a small piece damages a satellite or spacecraft like an intergalactic cannonball.
Therefore, cleaning up this space debris will be an important task if agencies are to launch more rockets and satellites into orbit. Jake J. Abbott, professor of mechanical engineering at the University of Utah, leads a team of researchers who have discovered a method to manipulate orbiting debris with rotating magnets. With this technology, robots could one day gently move scrap metal to a decaying orbit or further into space without actually touching it, or they could repair faulty objects to extend their lifespan.
Their research is detailed in the article “Skillful Magnetic Handling of Non-Magnetic Conductive Objects”, published this month in the scientific journal, Nature. Co-authors include U Lan Pham graduate students Griffin Tabor and Ashkan Pourkand, former graduate student Jacob LB Aman, and U School of Computing associate professor Tucker Hermans. You can read a copy of the document here.
The concept is to move non-magnetized metallic objects in space with rotating magnets. When the metallic debris is subjected to a changing magnetic field, electrons flow through the metal in circular loops, “like when you swirl your coffee mug and it spins constantly,” says Abbott.
The process turns the piece of debris into an electromagnet that creates torque and force, which can allow you to control where the debris goes without physically grabbing it.
While the idea of using these types of magnetic currents to manipulate objects in space is not new, what Abbott and his team found is that the use of multiple magnetic field sources from coordinated manner allows them to move objects in six degrees of movement, including their rotation. Before, we only knew how to move them one degree, like simply pushing them.
“What we wanted to do was manipulate the thing, not just push it, but actually manipulate it like you do on Earth,” he says. “This form of skillful manipulation has never been done before.”
With this new knowledge, scientists could, for example, prevent a damaged satellite from spinning wildly in order to repair it, which would not have been possible before.
“You have to take this crazy object floating in space, and you have to put it in a position where it can be manipulated by a robot arm,” says Abbott. “But if it gets out of hand, you might break the robot’s arm doing this, which would just create more debris.”
This method also allows scientists to handle particularly fragile objects. While a robot arm might damage an object because its claw applies force to part of it, these magnets would apply a smoother force to the entire object so that no section is injured.
To test their research, the team used a series of magnets to move a copper ball on a plastic raft in a water tank (the best way to simulate slow objects in microgravity). The magnets not only moved the sphere in a square, but they also made the ball spin.
Abbott says this recently discovered process could be used with a rotating magnet on a robotic arm, a stationary magnet that creates rotating magnetic fields, or a rotating superconducting electromagnet like those used in MRI scanners.
Abbott believes this principle of manipulating non-magnetic metal objects with magnets could also have applications beyond cleaning up space debris.
“I’m starting to open my mind to the potential applications that are out there,” he says. “We have a new way to apply force to an object for precise alignment without touching it.”
But for now, this idea could be immediately applied to help solve the problem of space debris orbiting the Earth.
“NASA tracks thousands of space debris the same way air traffic controllers track airplanes. You have to know where they are because you could accidentally run into them, ”says Abbott. “The US government and the governments of the world are aware of this problem because more and more things are piling up with each passing day.”
