Asteroid metals harden under extreme particle blasts

by Sophie Jenkins
London, UK (SPX) Jan 09, 2026

Physicists at the University of Oxford have contributed to a study showing that iron-rich asteroids can withstand much higher energy inputs than expected without breaking apart, a result that affects assessments of planetary defence strategies against hazardous objects. The work, published in Nature Communications, indicates that under rapid, intense heating these bodies can even become tougher as internal stresses develop.

Recent missions such as NASA's Double Asteroid Redirection Test (DART), which changed the orbit of the asteroid Dimorphos in 2022, demonstrate that redirecting an asteroid is technically possible. To make such interventions reliable, however, researchers need to know how asteroid materials behave under the fast, extreme loading conditions produced by impacts or radiation, rather than the slow, destructive tests commonly used in laboratories.

In the new experiments, an international team including Oxford physicists used CERN's High Radiation to Materials (HiRadMat) facility to irradiate a sample of the Campo del Cielo iron meteorite, treated as a stand-in for a metal-rich asteroid, with 440 GeV proton beams. Using laser Doppler vibrometry, which employs lasers to measure tiny vibrations at the surface, they recorded the evolution of stress, strain, and deformation in real time as the energy pulse moved through the sample. Because the procedure was non-destructive, the same meteorite piece could be monitored continuously as it responded to repeated extreme loading.

The results show that the meteorite absorbed substantially more energy than conventional models predict without fragmenting and that its mechanical response changed as stress accumulated. The material acted like a complex composite whose heterogeneous internal structure redistributed and sometimes amplified stresses in ways that simple descriptions do not capture. A key observation was strain-rate dependent damping: the faster the meteorite was stressed, the more effectively it dissipated energy.

These findings address a longstanding gap between strengths measured for meteorites in standard laboratory tests and the lower strengths inferred from how meteors disintegrate in Earth's atmosphere. The new data suggest that internal stress redistribution across the irregular microstructure of meteorites can explain much of this discrepancy, improving understanding of how real asteroid fragments behave under sudden energy inputs.

For planetary defence, the study indicates that it may be practical to drive energy deep inside an asteroid while keeping it intact rather than simply blowing it apart. This could support deflection methods that impart a controlled push to a target body while avoiding the creation of a dispersing cloud of debris that might still pose a threat. The project was developed in partnership with the Outer Solar System Company (OuSoCo), which is examining the feasibility of in-space high-energy proton beam systems.

Research Report:Dynamical development of strength and stability of asteroid material under 440 GeV proton beam irradiation