SpaceWalking
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During the rest of this year, as the Shuttles go up one after another to work on the International Space Station (ISS), there will be plenty of space walks to witness. Here are some interesting things to know to make your viewing more pleasurable.
Space is one deadly place, to be sure. It is a near vacuum, flooded in
deadly radiation, and subject to extreme changes in temperature.
If you’re going “out there” you’d better be ready.
Weighing in at nearly 300 pounds (but which is, of course, weightless
in orbit) the spacesuit is a miniature space station in itself.
First, the suit is pressurized, which is why it has that Michelin Man
look. And it’s pressurized for a good reason. If, for some reason,
the suit lost its pressure the astronaut would soon die.
Think of what happens when you open up a 2-liter soda bottle. The sudden
lowering of pressure when you twist off the cap causes the dissolved gases
to bubble right out.
This is what would happen in our blood if the air pressure on our body
dropped to zero – it would literally boil in our body. It’s
best to always keep the “cap” on the spacesuit.
As to breathing: All the oxygen the astronaut needs to inhale is in a
pressurized tank on the suit’s backpack. All the lethal carbon dioxide
exhaled by the astronaut is absorbed by small canisters of lithium hydroxide.
Our
atmosphere protects us on the Earth’s surface from the sun’s
lethal radiation. Above the atmosphere, the suit’s special multiple
layers protect the astronaut from those same rays of death.
Being exposed to the sun also heats up the Shuttle and spacewalkers to
a fare-thee-well, over 250 degrees. But going into a shadow of the Shuttle
or ISS can instantly drop the temperature by over 400 degrees. The suit’s
layers also act, then, as a terrific insulator.
But there’s more! The astronaut’s own body heat can get the
inside temperature of the suit a little toasty. No problem. NASA has devised
special long underwear fitted with water tubes that carry away body heat.
A lot of what the Shuttle astronauts will be doing on ISS is bolting things
together. Sounds easy, huh? It isn’t.
In your garage, when you turn a wrench, friction with the ground keeps
your feet firmly planted in one place.
In space, when you turn a wrench clockwise your whole body goes counterclockwise
because you have no floor to keep you in one place. So the astronauts
are constantly having to consciously brace themselves for even the simplest
movements lest they tumble end over end.
This is why they practice for spacewalks in a gigantic pool. Under the
water, and specially weighted so they hover at one depth, they can practice
putting things together with this action-reaction effect. This can save
a lot of time – and money - when doing the real thing in orbit.
But what if the astronaut gets hungry or thirsty on an hours-long walk?
NASA has thoughtfully velcroed a tiny energy bar and a water bag on the
neck of the suit. When she is feeling a wee peckish, she just ducks her
head down a bit a takes a bite (or a sip).
A spacewalk is quite the big deal production. Watch it next time and be
amazed.
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Posted by Administrator at 2001.04.29 08:34 AM | Comments (0)
