LIVERMORE, USA, Oct. 14, 2026 - Researchers at Lawrence Livermore National Laboratory have built three-dimensional simulations of how a nuclear device could deflect or disrupt an asteroid threatening Earth. The study, led by Isaiah Santistevan, is published in The Planetary Science Journal.

The team used LLNL's Spheral code to model a 1-megaton detonation near a 160-metre asteroid shaped like Bennu. X-rays from the blast vaporise the surface, and the escaping material changes the asteroid's velocity. Three scenarios varied the detonation distance and the asteroid's fracture properties, and two showed strong signs of disruption.

With the device 10 metres from the surface, 98.2 percent of the asteroid's material was damaged, and in the longest run 97 percent moved faster than the asteroid's escape velocity. In one test, a blast at 25 metres caused more widespread damage than one at 10 metres. Nuclear mitigation is an option for larger asteroids or short warning times; NASA's DART mission demonstrated the kinetic alternative in 2022.

The runs are costly and short: the longest took 59 days on 1,680 processors and covered only the immediate aftermath of the blast, so the fragments' final fate is not yet known.

Impact Insight. Planetary defenders have two broad tools: nudge an asteroid aside with an impactor, or break it into pieces that are small or dispersed enough to miss Earth or burn up in the atmosphere. Disruption is the fallback when warning time is short, and the question these runs leave open, whether the fragments scatter or pull back together under their own gravity, has to be answered before anyone could rely on it.