Seismic Networks Track Space Junk Reentry: A New Approach

Scientists use earthquake sensors to monitor falling space debris in real-time

Apr. 11, 2026 at 6:35am

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A highly structured abstract painting in soft blues, greens, and grays, depicting sweeping geometric arcs, concentric circles, and precise spirals, conceptually representing the complex forces and trajectories of falling space debris as detected by seismic networks.Seismic sensors provide a new way to track the unpredictable return of space debris, offering critical data to manage the environmental impact of our activities in near-Earth space.Santa Barbara Today

Researchers have discovered a new method to track the reentry of space debris using existing seismometers designed to detect earthquakes. By analyzing seismic data from the reentry of China's Shenzhou 15 spacecraft, the team from Johns Hopkins University and Imperial College London was able to reconstruct the module's trajectory and predict where debris might have landed. This approach complements traditional radar tracking and could provide critical real-time information to authorities about the movement of potentially hazardous particles released during reentry.

Why it matters

As the number of satellites and space objects in orbit continues to grow, reentries are becoming more frequent. This new seismic tracking method offers a way to better monitor the return of human-made objects from space, which is crucial for managing the environmental and safety risks associated with space debris. Traditional radar tracking can be inaccurate, but seismometers provide a direct measurement of reentry behavior that can help locate potential impact zones and recover valuable debris.

The details

The researchers used data from 127 seismometers to track the reentry of China's Shenzhou 15 spacecraft, which was roughly the size of a small car. As the module plunged through the atmosphere at speeds exceeding Mach 25-30, it generated sonic booms that were picked up by the seismometers across southern California. By mapping these seismic signals, the team could estimate the module's trajectory and predict where any debris might have landed. The intensity of the seismic readings also allowed them to pinpoint the moment the module began to break apart.

  • On April 11, 2026, the Shenzhou 15 spacecraft reentered the Earth's atmosphere.

The players

Benjamin Fernando

An expert in earthquakes on Earth and other planets, and the lead author of the study.

Constantinos Charalambous

A colleague of Benjamin Fernando who worked on the study.

Johns Hopkins University

The institution where Benjamin Fernando is based and where the research was conducted.

Imperial College London

The institution where Constantinos Charalambous is based and where the research was conducted.

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What they’re saying

“By mapping these signals, the team could estimate the module's trajectory and even predict where any debris might have landed.”

— Benjamin Fernando, Lead author

What’s next

The researchers argue that with dense seismometer networks already monitoring tectonic activity, we can immediately improve space debris tracking worldwide with minimal modifications. Automated systems could screen seismic data for sonic boom signatures, rapidly compute trajectory estimates, and provide valuable information to emergency responders and recovery teams.

The takeaway

This new seismic tracking method offers a promising solution to the growing space junk problem by providing a complementary approach to traditional radar tracking. By repurposing existing ground-based instruments, scientists can better monitor the reentry of space debris and mitigate the environmental and safety risks associated with these events.