January 30, 2026

expert reaction to reports that debris from a Chinese rocket is coming to Earth

Scientists comment on reports that debris from a Chinese rocket (Zhuque-3) is coming to earth and may crash into Britain. 

Dr Constantinos Charalambous, Research Fellow, Imperial College London, said

What we know right now:

“This is an uncontrolled re-entry of the Chinese ZQ-3 R/B (Zhuque-3 Y1 second stage). EU SST describes it as a large object (~11 tonnes, ~12–13 m long) and says it may still have a dummy payload attached.

“Prediction windows shrink fast near the end. Earlier public trackers can show multi-hour uncertainty windows (for example, The Aerospace Corporation’s re-entry list shows Jan 30, 2026 12:30 UTC ± 15 hours for “ZQ-3 R/B”).

“The key point is that the window tightens quickly late in the process – EU SST’s latest update this morning (30 Jan 2026) gives a much tighter estimate: 11:20:33 UTC ± 48 minutes (so an uncertainty of < 1 hour).

“Because different trackers update on different cadences and use different data/assumptions, you may still hear different “corridors” (e.g., “North Atlantic”) in some briefings until everyone converges on the latest window.

“Based on EU SST’s latest estimate, the predicted re-entry window would have been earlier today and has now passed. If it hasn’t already re-entered, updated tracking will shift that estimate, so the key thing is to follow the latest official updates rather than any single timestamp (e.g., see https://www.eusst.eu/newsroom/news/eu-sst-closely-monitors-upcoming-re-entry-space-object-zq-3-rb)”

What we don’t know yet:

“We don’t yet know the precise re-entry time, so we can’t know the exact ground track until the window tightens.

“We also don’t know the breakup outcome: many objects fragment and ablate heavily, but denser components can survive longer.

“The uncertainty can look dramatic because even a tens-of-minutes shift in the predicted re-entry time can move the possible ground track by thousands of kilometres along the orbit.

“In our Shenzhou-15 case study [1], some public forecasts pointed to ocean corridors (including the North Atlantic), but the re-entry was actually observed over California. A Space-Track TIP listed 09:06 UTC over the North Atlantic, while eyewitnesses reported a bright, fragmenting fireball over the Los Angeles region around 08:40 UTC, so about 25 minutes earlier and ~8,600 km away. That illustrates how small timing errors in orbit can “move” the predicted ground track by huge distances, translating into huge geographic errors. Our seismic reconstruction then showed the in-atmosphere track was offset from the predicted corridor by tens of kilometres.

“The final disintegration phase is inherently chaotic and hard to forecast precisely, because small uncertainties in atmospheric drag and orientation can translate into big differences in timing. Hence timing shifts move the expected ground track by thousands of kilometres.

What investigations will resolve this?

“Tracking agencies (EU SST and others) will keep updating the re-entry window and corridor as new orbit solutions and atmospheric-drag modelling come in.

“Once the object is in the atmosphere, confirmation can come from multiple independent sources (radar/optical where available, eyewitness video, infrasound). If a strong enough sonic boom couples into the ground over a seismic network, seismic data can also help reconstruct the actual in-atmosphere path after the fact, as we showed recently with Shenzhou-15 uncontrolled re-entry over Southern California.”

How worrying is this?

“For the public, the risk is very low. Most of Earth is ocean and sparsely populated land, and much of the mass typically burns up. The real issue is uncertainty, which can force cautious measures (e.g., aviation routing or preparedness planning) even when the probability of harm is low.”

When would we know if it could affect the UK, and what can people do?

“Meaningful certainty typically arrives late, often in the final hours as the time window narrows.

“Practical advice: follow official updates. If debris is ever found, don’t touch it – report it.”

Could it break up?

“Yes. Uncontrolled re-entries usually undergo a rapid, chaotic fragmentation phase, and that’s often when conventional tracking becomes most challenging.”

Here’s couple of links to our recent Shenzhou-15 Science paper:

“In our recent Shenzhou-15 Science case study [1], a widely circulated pre-entry prediction pointed to a different ocean corridor, but the event was actually observed over California, and our seismic reconstruction showed the in-atmosphere track was offset from the predicted corridor by tens of kilometres.

“The point isn’t that prediction systems are “bad”; they use radar/optical tracking plus drag and attitude/tumbling models, but the final phase is inherently chaotic and tracking can become patchy. Our approach shows how seismic networks could provide rapid, independent re-entry forensics once shockwaves are produced, helping shrink uncertainty about what actually happened.”

Reference:

[1] https://www.science.org/doi/10.1126/science.adz4676

Dr Mike Peel, Research Associate in the Department of Physics, Imperial College London, said:

“I can’t comment on the specifics of this case, but on the bigger picture side: there’s an ever-increasing amount of rockets and satellites being launched into orbit these days, both by commercial companies and governments, which will increase the risk of similar situations arising in the future. While most re-entering debris burns up in the atmosphere, there have been recent events of debris reaching the ground, for example, debris from a SpaceX launch landing in Saskatchewan in 2024. Tracking and managing the space environment is becoming increasingly important, as is understanding the effects that satellite de-orbiting will have on the atmosphere.”

Declared interests

Dr Mike Peel: My work includes researching the impact of satellite constellations on astronomy.

For all other experts, no reply to our request for DOIs was received.