We’re going inside a place so clean and spotless that paper, pencils or make-up aren’t allowed inside.
This is one of the cleanest clean rooms in Europe, a unique facility where lasers are made to measure the surface of planets like Mars and Mercury. Inside these rooms, owned by Thales Alenia Space in Zurich, Switzerland, there are 10,000 fewer dust particles than in your office.
How is everything kept so clean?
Before going inside, all equipment has to be cleaned at least twice. Everything is wiped with isopropyl alcohol, blown clear of dust with ionized nitrogen and then checked under UV lights to make sure no particles remain.
Scientists are very strict about what goes inside these rooms: it’s not only a matter of the equipment containing dust on its surface, they also want to make sure it won’t produce dust once inside.
Even the most common objects don’t make it through the doors. For example, ordinary paper produce tiny particles when scribbled over. Pencils also release tiny graphite particles when you write with them. For this reason, only a special paper and pen are allowed inside these rooms in order to maintain optimal cleanliness.
The people who work there also need to be extremely precautions about not letting dust particles into the room. Make-up, for example, isn’t allowed. Everyone needs to go into a changing room and from a certain point onwards, no outdoor clothes are allowed, just sterilized ‘pyjamas’ or overalls. Workers also have to wear white boots, gloves, masks and hair nets on a full-time basis.
There are no shortcuts taken. If ever someone has forgotten a tool outside, or simply has to go to the toilet, they need to go through the entire painstaking changing process again.
These rooms are also kept in positive air pressure so, if there is a small breach, clean air will flow out of the room rather than the dusty air from outside flowing in.
But why is all this necessary?
Dust levels have to be kept as low as possible because, in this facility, the satellite instruments built use powerful lasers to function. If a dust particle were to get in the way of the laser beam, they would affect the way the light travels, degrading the instrument’s performance.
Also, these dust particles absorb light from the laser beam and heat up. As their temperature rises these particles are burned up, creating what could be considered as ‘mini-explosions’ that may damage the instrument.