It usually takes a fairly large rock to crack the average car windshield, but when you’re up in space, a speck of dust can wreak all kinds of havoc. Case in point: the International Space Station (ISS).
The European Space Agency (ESA) has released a photo of a 7 mm-diameter crack in the window of the Cupola room of the station, which was apparently caused by a tiny piece of space debris (i.e. a paint flake or small metal fragment) no bigger than a few thousandths of a millimeter across. Put simply: Something smaller than a speck of dust caused this noticeable crack in the window.
Thankfully, the folks at the ESA and NASA aren’t dummies, so those windows are quadruple glazed and designed to handle “small” impacts like this. The windows of the Cupola are made from fused-silica and borosilicate-glass, which is extremely tough and durable.
Though this crack is a cautionary tale, anything larger could have proven to be extremely dangerous. The ESA notes an object up to 1 cm in size could disable an instrument or a critical flight system, and anything above 1 cm could penetrate the shields of the station’s crew modules. Something 10 cm or larger (i.e. the size of a bagel) could be a doomsday hit, shattering a spacecraft/satellite into pieces.
Check out the terrifying (though non-threatening) crack below:
(Via European Space Agency)