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Author Topic: Is it difficult to walk in space?  (Read 637 times)

Offline thedoc

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Is it difficult to walk in space?
« on: 13/04/2016 19:50:02 »
Loyiso asked the Naked Scientists:
   Why is space walk such a big deal? Is it difficult and dangerous to walk in space - Why?
What do you think?
« Last Edit: 13/04/2016 19:50:02 by _system »


 

Offline evan_au

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Re: Is it difficult to walk in space?
« Reply #1 on: 13/04/2016 23:13:13 »
It might be hard to imagine these days, but it was a very big deal to launch a man (or woman) into space in a rigid spacecraft which weighed several tons. And get them back safely.

Not to mention that something as simple as appendicitis could easily be fatal. (Or a bit of washing up detergent in your eye, as happened to astronaut Chris Hadfield while on a spacewalk - you can't wipe your eye in a spacesuit!)

Now take all of that life-support, communication, meteoroid protection, temperature control, carbon dioxide scrubbing, humidity control, etc and compress it into something which is flexible and small enough to wear - let alone use tools and do useful work. That was a major technical achievement.

In space, there is no ground on which to gain traction, no up and down to orient you, dazzling extremes of bright and dark, heat and light - and if you get separated from the spaceship, no way to get back - you will keep separating farther away (with at best a small chance to return within visual range half an orbit later).

Early spacewalks used an umbilical that carried most of what the astronaut needed - and stopped them from drifting away. More recent spacesuits are more self-contained, and just use a tether.

These days it is even possible to have a maneuvering suit (as casually demonstrated by George Cluny in the movie Gravity). But on the ISS, it still takes several hours of breathing a special air mixture before a space walk to avoid a disease called "the bends".

Some of the challenges of life support when on the Moon are discussed here (2 hours): http://omegataupodcast.net/2012/06/97-how-apollo-explored-the-moon/comment-page-1/

PS: NASA's spacesuit contractor is still a company which started off making female underwear.
« Last Edit: 13/04/2016 23:21:16 by evan_au »
 

Offline evan_au

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Re: Is it difficult to walk in space?
« Reply #2 on: 14/04/2016 11:03:52 »
Other things that makes a spacewalk a challenge include:
  • The vestibular system in your ear that normally tells you which way is up & down malfunctions badly in space, producing vertigo and space sickness (like sea sickness or air sickness). You definitely do not want to throw up in a spacesuit helmet!
  • There are the usual problems of air, water, food and waste disposal, which had been addressed to some extent for long-duration and high-altitude aircraft flights.
  • Early astronauts were bolted into their capsules. Building a door which could be opened by an astronaut introduces a major structural weakness into the capsule. Ensuring that it can be reliably sealed again by the astronaut (despite outgassing of rubber seals in a vacuum) is mission-critical.
  • A spacesuit is basically a balloon. And the natural shape for an inflated balloon is a sphere, with maximum internal volume. So whenever the astronaut relaxes, the spacesuit reverts to a spherical shape (or as close as it can get to a sphere). To do anything, the astronaut has to fight the suit with every movement.
  • Astronauts are very fit, but an 8-hour shift in a spacesuit is exhausting - especially the fingers.
    An astronaut who can't do a spacewalk is like someone who can drive to work, but cannot get out of his car. Spacewalks are essential for assembly, and routine or emergency maintenance. The Canadarm on the ISS (and Space Shuttle) and ISS can help with some pre-planned assembly of large parts.
  • Space walk capability is an essential first step before setting foot on the Moon or Mars.
 

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Re: Is it difficult to walk in space?
« Reply #2 on: 14/04/2016 11:03:52 »

 

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