Scientists Just Learned How To Track Space Junk Slamming Into Earth With Sonic Booms

by Aaron Leong — Friday, January 23, 2026, 10:57 AM EDT

Researchers have discovered that the same sensors used to detect earthquakes are the key to tracking the growing swarm of space junk plummeting toward Earth.

As the orbital highway becomes increasingly congested, the European Space Agency’s (ESA) 2025 Space Environment Report paints a sobering picture: intact satellites and rocket bodies are now re-entering our atmosphere at an average rate of more than three times a day. While many are designed to incinerate upon entry, the sheer volume of debris (estimated at over 1.2 million objects larger than a centimeter) poses a persistent threat to aviation and infrastructure.

mach cone — *Illustration depicting a falling object's sonic wake (Credit: Economom/Fernando)*

Now, researchers from Johns Hopkins University and Imperial College London are proposing a solution by listening for a thump in the sky. Specifically, as space debris enters the atmosphere at supersonic speeds exceeding Mach 25, it creates powerful sonic booms. Apparently, these booms strike the ground with enough force to be registered by sensitive seismometers. To test the efficacy of this tracking method, the research team was able to successfully reconstruct the final moments of a 1.5-ton Chinese Shenzhou-15 module that fell in 2024 by analyzing data from 127 seismic stations in Southern California and Nevada.

The seismic data allowed the team to plot the module's path nearly 20 miles farther south than radar had predicted. Beyond just pinpointing the crash zone, the sensors were able to capture a cascading signature of multiple smaller booms, effectively creating a real-time record of the spacecraft as it shattered into fragments. This capability is vital for emergency responders, as it can help distinguish between a clean burn-up and a dangerous fragmentation event.

esa space junk — *Artist impression of space debris field around Earth, based on actual data (Credit ESA)*

With tens of thousands of new satellites planned for the coming years, the risk of a runaway chain reaction of collisions (i.e. the Kessler Syndrome) is higher than ever. ESA’s report spotlights that even if we stopped launching today, the amount of debris would continue to grow as existing objects collide and shatter.

It must also be noted that sonic boom tracking is currently being refined to reduce the time between detection and analysis, but one can't deny that's it's a relatively cost-effective solution to a growing crisis. Instead of building multi-billion dollar radar arrays, scientists can simply teach existing earthquake monitors how to listen to the sky.