Deflecting an asteroid with X-rays: the side hit changes everything
· BehindLines newsroom
When people consider diverting an asteroid with the energy of a nuclear blast, which side of the asteroid receives the X-rays matters a great deal. That is the conclusion of simulations by researchers at Sandia National Laboratories (United States), published in the journal Icarus, relayed by ScienceDaily on 8 November 2026 from a Sandia release.
What the simulations show
The team, led by physicist Nathan Moore, modelled an explosion that releases X-rays at a distance from the asteroid. The rays vaporise material at the surface, and the ejected material pushes the asteroid the opposite way. For one simulated asteroid, the change in speed reaches 3.9 mm/s from one irradiation direction but only 0.8 mm/s from another: nearly five times less, per ScienceDaily and EurekAlert. For another asteroid, the change in spin rate differs 17-fold depending on the side targeted. Universe Today adds that, for three real bodies modelled (Bennu, Itokawa and Golevka), orientation at the moment of interception can raise the deflection by roughly two, four and five times compared with the least favourable case.
A more realistic method
Earlier models often treated asteroids as spheres, or gave up detailed physics to keep realistic shapes. The new approach combines both using two Sandia codes, ALEGRA and SPARTA, and rebuilds the 3D shape from images taken by spacecraft during flybys. Moore says the algorithm is more than 1,600 times faster than older models, which is what made the study possible. "We expected aim to matter," he says, but the size of the effect surprised the team.
Important limits
These are simulations, not real tests. The model only accounts for surface rocks breaking apart and cannot yet predict the breakup of the whole asteroid. It also needs fairly accurate shape data from every angle, which might be missing if an object were found late. Placing a device at the right distance and on the right side of a moving body would be tricky, notes the Sandia release carried by EurekAlert; Universe Today also notes that deploying nuclear weapons in space would be a problem in today's geopolitical climate.
What it changes
The preferred method remains the kinetic impactor, like NASA's DART mission, Universe Today reminds readers; the nuclear option is raised only as a last resort if an object is spotted too late. The study's value is to tell planners that knowing the target's shape precisely before any intervention could be decisive, and to provide a much faster calculation tool for comparing scenarios.