What is the difference of underwater sims & 0 Gravity

[fatal291]

Hello I have long wondered what is the difference between the underwater sims they do for space walks and actually being in 0 Gravity. Other than knowing what environment you're in (suppose you were blind and could not hear the water) how would you be able to tell the difference? I would love to ask a real NASA Astronaut this question.

 

[venator_3000]

I believe there is a great difference between the viscosity of water and that of a vacuum. When moving an arm in space the astronaut can not feel the same drag as in a neutral buoyancy tank. I remember Storey Musgrave commenting on this.<br /><br />I would also think vision and clarity of seeing are extraordinarily different in the 2 environments.<br /><br />v3k <div class="Discussion_UserSignature"> </div>

 

[michaelmozina]

Well, unfortunately I've never been to space, but I did sleep at a Holiday Inn Express last night. <img src="/images/icons/smile.gif" /><br /><br />I would imagine that it would be similar in many respects, but not quite exactly the same. Their suit is pressurized and self contained. so it would not be like breathing through a regulator when they are underwater inside their suit. <br /><br />I would think that the resistance of the water to physical movement would help to stabilize the astronaut underwater, whereas in space there is no friction to stabilize the astronaut, so every move is probably amplified in space. It's probably much easier to get the suit on and off while in space however.<br /><br />All in all, I would think they would be a similar experiences, but not quite identical experiences. <div class="Discussion_UserSignature"> It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. - Kristian Birkeland </div>

 

[MeteorWayne]

Yeah, it simulates the lack of gravity, but certainly does not simulate the vaccuum of space as far as viscosity is concerned. What a difference when moving ( or more importantly stopping) tons with a fingertip <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[venator_3000]

Here are some links if you are interested...<br /><br />NASA-Marshall<br />http://www.nasa.gov/centers/marshall/news/background/facts/nbs.htm<br /><br />And an old article from the Houston Chronicle:<br />http://www.chron.com/content/interactive/space/station/stories/2000/20000813.html<br /><br />good reads!<br />v3k <div class="Discussion_UserSignature"> </div>

 

[MannyPim]

The main difference is that when under water you are still in a gravity field.<br />That means that your body fluids pool at the lowest parts of your body. So, if you are in a water tank but floating upside down, you will feel your blood rush to your head. Your vestibular system in your inner ear is also subjected to the same gravity and it also responds to yoru orientation sending your body signals of which way is up and down. These things don't happen in zero G. <div class="Discussion_UserSignature"> <font size="2" color="#0000ff"><em>The only way to know what is possible is to attempt the impossible.</em></font> </div>

 

[erioladastra]

One other point - the astronauts get used to moving their bodies with the extra drag. When they get out on a space walk they tend to initially overshoot their stopping point or gripping the rails much, much harder. Takes a while for them to reach the Story "gentle touch".

 

[erioladastra]

"when they are under water and upside down the blood still rushes to their heads "<br /><br />And they slump down in their HUT therby hurting shoulders as well.

 

[kiwigavin]

Tom Jones comments at length about this in his book. No matter what your orientation you slump in your suit in the pool causing sore toes, fingertips, heads, joints etc.

 

[15203700700579]

Whoah! I must be wrong but I thought ZERO G wasn't possible due to the ever impending nearness of a celestial object. (And also due to the fabric of the cosmos.) Well I had always heard it as Micro G also I read something on Micro G on NASA. Explain which is right?