Small chip in window of the International Space Station Photo: Tim Peake ESA/NASA
The international space station's windows are made of fused-silica and borosilicate-glass, but that doesn't stop them from being vulnerable to space debris.
The chip in the station's cupola window is less than a centimetre across and was most likely caused by something extremely small, like a flake of paint or a tiny piece of metal. As astronaut Tim Peake put it "glad it is quadruple glazed"
Jer-Chyi Liou is the Chief science officer of NASA Orbital Debris Program, he explains why space debris remains such a big risk.
