An 2.8-mm diameter aluminium bullet moving at 7 km/s pierces through a candidate shielding for spacecraft, captured by a high-speed camera  at  Germany’s  Fraunhofer Institute for High-Speed Dynamics. 

This light-gas gun testing took place to evaluate the shielding potential of various kinds of ‘fibre metal laminates’ (FML) – produced for ESA by GTM Structures BV – which are several thin metal layers bonded together with composite material.” 

To avoid micrometeorite object damage (MMOD) an onboard protection system is needed against  small debris, typically consisting of one or more shields. An often-applied variant is the ‘Whipple shield’ – originally devised to guard against comet dust – with two layers, a bumper and a rear wall, with a mutual distance of 10 to 30 cm. 

The high-speed video shows solid aluminium bullet breaking apart into a cloud of fragments and vapour, which becomes easier for the next layer to capture or deflect.