We all know what to do if something harmful splashes into our eyes: wash with lots of water. As with many things in space, however, a simple operation on Earth can become quite complicated when floating around in weightlessness.

Imagine you are an astronaut on the International Space Station and a fleck of dust gets in your eye or you accidently splash chilli sauce or something even worse in there. Where do you get the water from and how do you rinse your eyes? There are no flowing-water taps and even if there were cupping water in your hands is impossible in zero-gravity.

And think of cleaning up afterwards – water floating around electrical equipment in space is not a good idea.

Engineers came up with the idea seen in this picture. ESA astronaut Alexander Gerst is practising the space version of “wash copiously under running water” at NASA’s Johnson Space Center in Houston, USA. The goggles are connected to an eyewash solution that is pumped around the eyes and then away.

Although the contraption might look painful, Alexander comments: “It feels somewhat strange, but not too bad, and of course it is good to know that we have these items onboard.”

This medical refresher course is getting Alexander ready for his Blue Dot mission that begins 28 May when he leaves for space with cosmonaut Maxim Suraev and NASA astronaut Reid Wiseman for a six-month expedition on the International Space Station.