How does a spacesuit work?
Short of an X-Factor audition in front of an alcopop-fuelled mob, there are few more
hostile and unwelcoming environments than space.
Here on earth, we wear clothes to keep our bodies in a comfortable temperature range,
protect us from the elements -- and to express our daring individuality with some herringbone-patterned
loon pants.
But in space, a specially designed multi-layer suit is vital just to keep you alive.
Without one, you'd be dead in approximately 15 seconds.
And that's even if you hold your breath and close your eyes to prevent your eyeballs from
popping out.
Curiously, like the rocket, the space suit was 'invented' decades before anyone travelled
into space, certainly in the minds of early science fiction authors and artists.
Buck Rogers was wearing one in the 1920s.
Which looked very like the spacesuits that real astronauts wore four decades later.
Possibly because of course the designers of the spacesuits grew up reading Buck Rogers.
The spacesuit has two main functions -- providing its wearer with what's required to stay alive,
but also protecting him or her from the heat, cold and vacuum of space.
Let's do them in order: Most important, is an oxygen supply and a means of pressurising
the suit.
Without something to breathe you really will be in trouble, and pressure is also necessary
to prevent the vacuum of space from effectively sucking your body inside out.
Unprotected exposure to it would cause your flesh to balloon to about twice its normal
size.)
Most spacesuits are pressurised to about 4.7 PSI.
It's also, obviously, necessary for the suit to be able to safely dispose of the carbon
dioxide that you breathe out.
This will be done using a closed-loop system similar to a diver's re-breather, allowing
unused oxygen to be used again.
This system also has to deal with the moisture you exhale, to avoid the suit steaming up,
and also powerful odors.
Although it's probably still a good idea not to go for a king prawn bhuna the night before.
Temperature regulation is also critical.
Although space itself technically has no temperature -- having no atmosphere -- that won't stop
you from being either frozen or boiled to death if exposed to it unprotected.
With no way to conduct heat, anything exposed directly to sunlight can reach a temperature
of up to 120 degrees, while at the same time the other side of you -- in shadow -- will
be at a bracing minus-100.
This is why in space nobody can make ice cream.
The suit has to deal with both extremes.
That means lots of layers of insulation and a reflective outer layer -- the reason spacesuits
are usually white or silver.
It's also necessary to remove body heat from inside the suit, either with heat exchangers
or, in some cases, water-filled underpants.
The suit also has to provide protection against both radiation -- of which you'll be receiving
a large dose if you're exposed to sunlight -- and also from collisions with small pieces
of debris, or micrometeoroids.
Then there's the small business of going to the lavvy.
Put simply, you can't: anything you expose to space is going to suffer from either frostbite
or third degree burns within a couple of seconds.
So you have to go in the spacesuit; NASA has designed something for the occasion -- the
Maximum Absorbency Garment.
It's a nappy.
Finally the spacesuit will need both a communications system, some form of telemetry to report on
the astronaut's status, oxygen levels etc. and potentially also a cool propulsion system
to enable you to actually move around in space and do stuff.
All of this doesn't come cheap, of course.
Figure on about $12m for a state-of-the-art spacesuit.
Considerably more than the majority of houses, but rather less, er, spacious.