Earthquake Monitors Track Space Junk Through sonic booms

The Associated Press

As more space junk comes crashing down, a study shows how earthquake monitors can better track incoming objects by tuning in to their sonic booms.

When a discarded module from a Chinese crew capsule reentered Earth’s atmosphere over Southern California in 2024, the sonic booms generated seismic readings. Scientists used those readings to place the object’s path nearly 30 kilometers farther south than radar had predicted from orbit.

Using this method to track uncontrolled objects plummeting at supersonic speeds could help recovery teams reach debris more quickly, which is crucial if the debris is dangerous.

“The problem at the moment is we can track stuff very well in space,” said lead researcher Benjamin Fernando of Johns Hopkins University in the United States. “But once it gets to the point that it’s actually breaking up in the atmosphere, it becomes very difficult to track.”

His team’s findings, published in January 2026 in the journal Science, focus on a single debris event. But the researchers already have used publicly available data from seismic networks to track a few dozen other reentries.

Scientists and others increasingly worry that space debris could strike a plane in flight.

“There are thousands, tens of thousands, more satellites in orbit than there were 10 years ago,” Fernando said. “Unfortunately, we don’t really have anything other than the word of the company to say that when they break up, they completely burn up in the atmosphere.”

Fernando and his colleagues gathered data from more than 120 seismometers that captured the sonic booms from the Chinese module’s reentry, using the data to plot the object’s suspected path.

The out-of-control module had been abandoned in a decaying orbit ever since it was cut loose from the Shenzhou-15 capsule returning three Chinese astronauts from their country’s space station in 2023. The 1,300-kilogram module broke into countless pieces as it plummeted through the atmosphere, resulting in multiple sonic booms.

The goal is to ascertain, within minutes or even seconds, the speed and direction of incoming space junk as well as its fragmentation. In remote areas such as the South Pacific, nuclear blast monitoring stations could potentially track the sonic booms to fine-tune the paths of descent.