New material lattice
... which looks similar to a 3d honeycomb, and whose cells have 14 sides each, 3d printed from flexible polymer, then heated until only pure carbon remained.
They shot sand-like particles at the lattice (similar to what space debris does). At low speeds it bounced off. At high speeds it gouged out craters, crushing the lattice, and remained lodged in the material (didn't pierce the material).
