According to Gravity, space debris causes untold damage to spacecraft—and space agencies do indeed spend a lot of time testing materials they put into orbit. This image shows what happens when a sand grain-sized piece of aluminium oxide strikes aluminum sheet at hypervelocity. Ouch.

At high speeds, even a small mass can cause untold damage. So researchers at the European Space Agency test materials, like this sheet aluminum, by firing samples towards them at extremely high speeds. Satellites normally get bombard with space debris and meteoroids at speeds of over 21,600mph. Tests in ESA labs mimic those collisions by firing very small projectiles at hypervelocities, which are over 6,700 mph. For some context, the main hole in the image is 28x12 millimeters across. Eek.