Airlock – The Door to Space

Have you ever seen astronauts going for a spacewalk all suited up in their space suits?. You might have noticed them opening a door and locking it, then waiting for some time and then opening another door to get out to space. If not on live shows from the International Space Station (ISS) you might have noticed this scene in many space fiction movies. Why do they do so?

Video Credits: European Space Agency, ESA

Astronauts do this to avoid accidents such as blow outs and to keep the space station safe. The pressure inside... space station and outer space are not the same. There may be a sudden blow out if the door is instantly opened. This happens because of sudden de-pressurisation caused by opening the door. Normally space station is maintained at 101.3 kilo Pascal while it is 1.322 x 10 pascal in the outer space which is almost zero. 

So what is this transition zone called?

This transition zone between ISS and space is between known as airlock. Airlock consists of a chamber with twin door system. The doors are configured in such a way that both the doors do not open simultaneously. An astronaut wears a space suit which maintains his/ her body pressure. He/ She enters the airlock chamber, de-pressurises the chamber and then opens the exit door to enter into space.