Abstract: Closely spaced conventional optical fibers are arranged in a grid placed between a first surface and a second surface. A penetrating impact onto the first surface results in a hole of a size proportional to the diameter and velocity of the impacting object. The size and shape of the debris plume that travels between the first and second surfaces is also proportional to the diameter and velocity of the impacting object. If the debris plume is sufficiently energetic, a number of the fibers in the grid are broken. The size and shape of the area defined by the broken fibers can be determined simply by determining which fibers are no longer transmitting light. Analytical methods are then used to relate the extent of the damaged area to the location of an MOD impact, the direction from which the impact occurred, and the size of the impacting object.