Last week an unusual event took place in International Space Station. Crew noticed that the pressure is dropping, which is a big problem. You see, ISS is a big air container placed in the vacuum of space. This means that any leak could result in all the air being sucked out or even structural damage done. But everything turned out to be ok – Alexander Gerst from the European Space Agency plugged the hole with his thumb.
You’ve seen what a vacuum can do to a drop of water or an inflated balloon. You’ve also seen movies, where people get sucked out of planes through relatively small holes. So how Gerst wasn’t pulled out of the station through that tiny little hole? Was he risking damage to his tissues? Was it a completely reckless move, having in mind that temperatures outside of the ISS range from -156 degrees to +121 degrees Celsius? Did this astronaut put his life on the line to prevent bigger accidents and to save fellow crew members?
Well, let’s see these questions one by one. First of all, could Gerst be pulled out into space through that little hole essentially turning into a liquid? And the answer is no. He wasn’t risking it at all and didn’t have problems pulling his finger away. The atmospheric pressure in International Space Station is pretty much the same as on Earth – around 101.3 kPa. That means that every square centimetre is pressed with 1.03 kg of force. Outside pressure, of course, is nothing, which means that Gerst’s finger was being squeezed out with everything atmospheric pressure could do. But it wasn’t one square centimetre – it was 4 square millimetres or 0.04 square centimetres. So the force on astronaut’s finger was pretty minimal – around 41 grams.
Those 52 grams don’t sound like much, but remember that they were acting on a small area of skin. So could it be damaged? Again, no. Gerst could easily move his finger around to a new spot on his skin to avoid irritation. Don’t mind the water in his finger either. Even though water boils in a vacuum chamber, there is not much water in such a tiny are of skin to cause any problems. In fact, our skin is very good at containing the water so no damage could be done. And finally, even though outside temperatures vary a lot, Gerst wasn’t really touching anything. Remember that vacuum is a pretty good isolator. The outside surfaces of the ISS do get very cold or very hot, but Gerst wasn’t touching them. And he didn’t hold his thumb there for a long time – duct tape was on its way.
So was it a heroic action? Well, it was a professional one. Such a tiny hole cannot really do anything to a person, but it was leaking precious air outside of the International Space Station. It had to be plugged as soon as possible so that was Alexander Gerst did. By the way, duct tape also didn’t stay there for long – a permanent patch is already there.