Space has become a garbage dump.

According to the National Aeronautics and Space Administration, there are currently more than 27,000 pieces of space debris larger than the size of a softball currently orbiting the earth. They travel at speeds of up to 17,500 miles per hour, fast enough to cause a small piece of debris to damage a satellite or spacecraft. For example, Interstellar Cannonball.

Therefore, if the agency wants to launch more rockets and satellites into orbit, cleaning up the space junk will be an important task. A team of researchers led by Jake J. Abbott, a professor of mechanical engineering at the University of Utah, has discovered a way to manipulate orbital debris with a rotating magnet. With this technology, robots can one day gently move waste to a decaying orbit or further into space without actual contact, or they can repair malfunctioning objects to extend their lifespan.

Their research is described in detail in the paper "Smart Magnetic Manipulation of Conductive Non-magnetic Objects" published this month in the scientific journal Nature. Co-authors include U graduate students Lan Pham, 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 paper here.

The concept involves the use of rotating magnets to move metallic, non-magnetic objects in space. When the metal fragments are affected by the changing magnetic field, the electrons circulate in a circular cycle within the metal, "just like when you spin your coffee cup, it moves around," Abbott said.

This process basically turns the debris into an electromagnet that produces torque and force, which allows you to control the whereabouts of the debris without physically grasping it.

Although the idea of ​​using these types of magnetic currents to manipulate objects in space is not new, Abbott and his team discovered that using multiple sources of magnetic fields in a coordinated manner allows them to move objects in six degrees of motion, including rotation. they. Before, I only knew how to move them at an angle, just like pushing them.

"What we want to do is manipulate this thing, not just push it, but manipulate it like you do on Earth," he said. "There has never been this type of dexterous operation before."

For example, with this new knowledge, scientists can prevent a damaged satellite from spinning frantically to repair it, which was impossible before.

"You have to take this crazy object floating in space to a position where it can be manipulated by a robot arm," Abbott said. "But if it loses control, you may damage the robot arm, which will only create more debris."

This method also allows scientists to manipulate particularly fragile objects. Although the robot arm may damage an object because its claws will apply force to a part of the object, these magnets will apply a gentler force to the entire object and therefore will not harm any part.

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-moving objects under microgravity). The magnet not only makes the sphere move into a square, but also makes the sphere rotate.

Abbott said that this newly discovered process can be used with rotating magnets on robotic arms, fixed magnets that generate rotating magnetic fields, or rotating superconducting magnets similar to those used in MRI scanners.

Abbott believes that this principle of using magnets to manipulate non-magnetic metal objects can also be applied to other applications besides removing space debris.

"I started to be open to potential applications," he said. "We have a new method to apply force to objects without touching them to achieve precise alignment."

But for now, this idea can be applied immediately to help solve the problem of space junk orbiting the earth.

"NASA is tracking thousands of space debris, just like air traffic controllers tracking airplanes. You have to know where they are because you might accidentally hit them," Abbott said. "The U.S. government and governments around the world are aware of this problem, because more and more of these things are accumulating every day."

To read a more detailed description of this research, click here. To listen to Abbott's Nature podcast talking about the project, click here.

Vincent Horiuchi Public Relations Assistant, School of Engineering vincent.horiuchi@utah.edu

© 2021 University of Utah