In space, even tiny particles of meteoroids or space debris can inflict catastrophic damage on spacecraft if they strike at hypervelocity. Spacecraft materials must be engineered to withstand these impacts and the resulting shockwaves. However, current impact tests lack the temporal and spatial resolution to measure how materials respond to sudden and violent impacts. This limits the development of shielding materials for spacecraft. Now writing in Nature Communications, Edwin Chan, Yoan Simon and colleagues have developed a polymer platform that reports its own damage after being struck by a microprojectile.

The team then blasted individual silica microparticles at a film of the mechanosensitive polymer, impacting it at velocities between 100 and 520 ms−1. The impacts created shallow craters with raised ridges around the perimeters, a sign of energy dissipation by plastic deformation; these pushed-up perimeters were also fluorescent, indicating that the cratering events were powerful enough to rupture mechanophores. The mechanophores could effectively quantify the local damage: as the impact velocity increased, so did the crater depth and fluorescence intensity.