Design satellites to hunt small space debris

University of Alaska Fairbanks scientists are taking part in the US government’s efforts to design satellites and instruments that can detect space debris of less than a centimeter, or less than half.

Small debris that cannot be detected from the current ground can damage satellites and other spacecraft in low Earth orbit.

The idea is to equip future satellites that are essential to communication systems.

The universe’s fragments travel at a high speed of approximately 17,500 mph. A 1-centimeter object traveling at that speed has the same impact energy as a small explosive object, such as a hand-ren bullet.

Space debris comes in many shapes and sizes, consisting of abolished satellites, rocket stages, fragments from collisions, and other human-made objects that no longer serve their purpose.

Professor Paul Bernhard, a research professor at the UAF Institute of Geophysics, and his colleagues at the University of Calgary, Canada, have devised a method for determining the distance of a small object from a satellite or spacecraft and the angle of its approach.

This method is based on the discovery that objects in orbit create waves as they pass through naturally occurring plasma obstacles that occur along the Earth’s magnetic field lines. Plasma is a gaseous state of matter made up of free floating negative electrons and cations.

Bernhardt and colleagues are developing equipment that uses that method. He is also designing satellites carrying instruments for this first test. He calls it a Space Debris Hunter.

“The whole satellite is dedicated to detecting debris in space that are too small to see from the ground,” he said.

The direction to the debris of the universe is determined by an onboard sensor that simultaneously measures the fields of electrical and magnetic waves to detect signals emitted from electrical objects. Individual sensors record changes in signal frequency over time. Analysis of these data is used to determine the direction and distance to the debris of space and to reveal its location.

“Some measurements of this type are sufficient to predict future pathways for debris,” Bernhard said. “That’s the new science we are exploring.”

That knowledge will allow satellites to move away from the path of debris, Bernhardt said Starlink system operators will take 20,000 collision avoidance measures a year.

The new detection method is explained in detail in the January 8 paper on Plasma Physics. Bent Eliason, University of Strathslide, England, is the lead author.

This work is part of the US government’s efforts to track debris in space. It was carried out in collaboration with contractor Blue Halo on the IARPA Space Debris Identification and Tracking Program.

The US debris tracking program estimates that over 100 million objects are orbiting Earth with a size greater than a millimeter, but it estimates that less than 1% of debris that can cause mission-termination damage are being tracked. That’s why the program’s website states that there is “high interest” in tracking small pieces.