Tiny bursts of electrical energy from the collision of objects no larger than a pencil could one day track down pieces of space debris less than a millimeter in diameter, reducing the danger to spacecraft in Earth orbit.

As more and more satellites are launched into orbit, the potential danger of space debris increases. There are currently more than 25,000 objects larger than 10 cm (4 inches) in diameter orbiting the Earth, according to NASA, and when you zoom out the numbers get a little scary. From 1 to 10 cm the estimate increases to approximately 500,000. When you reduce that to 1 mm you get 100 million, this was in January 2022. In total, there were 170 million pieces, with a total weight of 9,000 tons, according to some estimates.

Some of this debris consists of dead satellites and the rockets that launched them. Others are a jumbled mass of assorted debris, such as nuts and bolts, pieces of rocket installations, and even lost astronaut toolboxes. Space agencies around the world are pouring money into tracking these objects, but these are just the tip of the iceberg.

The most concerning problem is the very small fragments that come from early space missions, especially those that did not use technologies aimed at minimizing space debris. Add to this the consequences of accidental satellite collisions and the remnants of irresponsible anti-satellite weapons testing in some countries, and the numbers swell. Some are the size of a paint drop, but a paint drop traveling at 22,000 miles (35,000 km) per hour can do as much damage as a rifle bullet.

Unfortunately, fine debris is very difficult to detect and track because it does not reflect enough sunlight or radar to be detected. As an alternative, researchers from the University of Michigan are considering another principle.

They found that when two particles, even small ones, collide in space, they release a cloud of gas and pieces of debris that create a burst of static electricity that charges the pieces. Not only is the initial collision detected, but when the charged parts briefly come close to each other, a small spark is created between them.

According to the team, if two pieces of aluminum collided at orbital speeds, the electrical explosion could be detected by a 26-meter (85-foot) radio antenna on Earth as well as larger, more sensitive antennas on NASA’s Deep Space Network. (DSN).

Although the idea has been supported as a concept, there is still work to be done before it becomes a practical tracking system. There are a number of factors that control the frequency of electrical signals, and there is also the issue of signals being attenuated by background radio signals and debris passing through the Earth’s atmosphere.

The next step will be to look for actual signals from space using DSN and look at data from hypervelocity probe experiments at the Naval Research Laboratory and NASA’s Ames Research Center. Additionally, the team will conduct experiments using lasers to launch different pieces of debris at different orbital velocities to create a database of electrical emissions.

“We want to know whether the object is hard or soft because that will affect its orbit and how much damage it can cause,” said Moytaba Akhavan-Tafti, assistant research assistant professor in the Department of Climate and Space Sciences and Engineering.