ignore poll please ... couldn't find the post button.

What a n00b!
0 (0%)
What an utter n00b!
1 (100%)

Total Members Voted: 1

Kristopher on July 16, 2010, 09:53:34 pm
Ermmm ... onel danger involved in opening his suit to get the communication device out is a chance of a case of the bends. This would be the equivalent of a crash ascent from 33 feet ... not a good idea, but not horribly dangerous. You may want to review the pod bay scene in "2001, a Space Odyssey" for an accurate depiction of such an emergency.

His head won't explode, and his lungs will be fine provided he empties them and continually tries to exhale while his suit is opened. Cold won't get to him, as vacuum is a pretty damned good insulator ... as long as he doesn't touch objects that have been in shadow for a long period of time, he won't freeze.

Another danger is taking too long to get the device out and losing consciousness from lack of oxygen while stressed ... if he doesn't trust his partner to suit him back up in that event, he might be hesitant to do it. Another one is keeping air in lungs. Any amount of breath-holding will result in burst aevoli and foam in the blood. Bad news that.
« Last Edit: July 16, 2010, 10:05:33 pm by Kristopher »

SandySandfort on July 16, 2010, 10:15:51 pm
Ermmm ... onel danger involved in opening his suit to get the communication device out is a chance of a case of the bends...

How about the danger of not being able to close his suit? The dangers clearly outweigh the benefits. Space is vast. Even if they had comms, the chances of anyone being close enough to get to them in time is very small. Compared that to the certainty of dying if the suit cannot be closed.

wdg3rd on July 17, 2010, 12:46:18 am
Ermmm ... onel danger involved in opening his suit to get the communication device out is a chance of a case of the bends. This would be the equivalent of a crash ascent from 33 feet ... not a good idea, but not horribly dangerous. You may want to review the pod bay scene in "2001, a Space Odyssey" for an accurate depiction of such an emergency.

The difference between two atmospheres of pressure (the 33-foot ascent you mention) and one atmosphere of pressure and between one and zero are not the same.  It's not a linear relationship, plus there can be phase changes.  Boyle early on realized that Boyle's law is not constant.
Ward Griffiths        wdg3rd@aol.com

Men will never be free until the last king is strangled with the entrails of the last priest.  --  Denis Diderot

J Thomas on July 17, 2010, 08:44:40 am
Ermmm ... onel danger involved in opening his suit to get the communication device out is a chance of a case of the bends...

How about the danger of not being able to close his suit? The dangers clearly outweigh the benefits. Space is vast. Even if they had comms, the chances of anyone being close enough to get to them in time is very small. Compared that to the certainty of dying if the suit cannot be closed.

It looks to me like something to try if they can't find anything better.

They are assuming that their opponents want them to die. There's always the possibility that the bad guys will show up and say "See, we could have killed you but if you give your word you'll do nothing against us then we'll rescue you". Not something I'd want to depend on....

If they can't find any better plan, he could open his suit and try to survived, and even if he dies the other guy can use the comm. It's a chance to get their story out and maybe cause trouble for their killers, even if nobody is close enough to rescue either one of them.

I'd sure look hard for a better plan first, though.

Kristopher on July 17, 2010, 11:24:43 am
How about the danger of not being able to close his suit? The dangers clearly outweigh the benefits. Space is vast. Even if they had comms, the chances of anyone being close enough to get to them in time is very small. Compared that to the certainty of dying if the suit cannot be closed.

Mentioned that in the last paragraph of my post. He's gotta trust his partner a lot to try it.

Kristopher on July 17, 2010, 11:30:04 am
Ermmm ... onel danger involved in opening his suit to get the communication device out is a chance of a case of the bends. This would be the equivalent of a crash ascent from 33 feet ... not a good idea, but not horribly dangerous. You may want to review the pod bay scene in "2001, a Space Odyssey" for an accurate depiction of such an emergency.

The difference between two atmospheres of pressure (the 33-foot ascent you mention) and one atmosphere of pressure and between one and zero are not the same.  It's not a linear relationship, plus there can be phase changes.  Boyle early on realized that Boyle's law is not constant.


Pulmonary circulatory system air bubbles from incompletely deflated lungs is a bigger danger here ... which will kill fast if, say, a face plate was ruptured by complete surprise. I think this is survivable, IF everyone does everything exactly right.

This has been done before ... the cosmonaut who did the first tethered space walk had to crack the seal on one of his gauntlets to deflate his suit in order to re-enter the capsule:
http://www.aerospaceguide.net/humansinspace/voskhod.html
« Last Edit: July 17, 2010, 11:42:55 am by Kristopher »

Rocketman on July 17, 2010, 01:09:27 pm
They're in a tough spot no doubt.  The military always teaches you that in an emergency situation you look at what you have to figure out a way to solve the problem.  If Bert can fit inside the mass driver and Ernie can cover the openings with a rock maybe then he can get into his suit and make an emergency call.  That's what I would try to do.  

Opps department:  Looks like I reversed Burt and Ernie names.  My bad!   ;D
« Last Edit: July 17, 2010, 08:33:57 pm by Rocketman »

ZeissIkon on July 17, 2010, 02:09:31 pm
Seems to me I recall the belter suits have a lot of duration -- another option might be to take a nap (everything always looks better when you're not dog tired), finish digging, and see if there's something useful to be done when they know what the mascon is.  Failing that, dismount the mass driver, bag up a lot of rocks, and ride the driver home...

Bob G on July 18, 2010, 11:04:28 am
Also, why assume one atmosphere of pressure? A lower pressure (with an oxygen 'enriched' gas mixture) would allow for lighter construction due to less stress. Also lower incidence of physiological pressure differential problems.

Of course, there would be trade-offs. (Apollo 10, anyone?)
Whatsoever, for any cause, seeketh to take or give
  Power above or beyond the Laws, suffer it not to live.
Holy State, or Holy King, or Holy People's Will.
  Have no truck with the senseless thing, order the guns and kill.

The penultimate stanza of Rudyard Kipling's MacDonough's Song

enemyofthestate on July 25, 2010, 06:09:57 am
Also, why assume one atmosphere of pressure? A lower pressure (with an oxygen 'enriched' gas mixture) would allow for lighter construction due to less stress. Also lower incidence of physiological pressure differential problems.
Comic book space suits almost always seem to assume an operating pressure of close to cabin pressure -- probably to avoid the problem of transitioning between a shirtsleeve environment to the suit pressure.  A space suit providing a pure O2 environment at 4.3 psi (would requires a pre-breathe of pure O2 for about four hours before sealing the suit if the cabin is at 14.7 psi.  If the cabin pressure is 10 psi this can be cut to 30 minutes.  After sealing the suit it takes another 30 to 40 minutes to lower the suit pressure to the final operating pressure.

Here is  NASA publication on EVA.
http://msis.jsc.nasa.gov/sections/section14.htm

Quote
Of course, there would be trade-offs. (Apollo 10, anyone?)
????  I donlt recall any problem on Apollo 10

Brugle on July 25, 2010, 11:06:45 am
Of course, there would be trade-offs. (Apollo 10, anyone?)
????  I donlt recall any problem on Apollo 10
I suspect Bob G meant to refer to Apollo 1.

Rocketman on July 25, 2010, 04:02:17 pm
I know.  But I was assuming that he was talking about Apollo 13

Bob G on July 25, 2010, 07:38:07 pm
Sorry, brain fart. I meant Apollo 1.

R.I.P. Chaffee, Grissom, & White.

Victims of GovThink.
Whatsoever, for any cause, seeketh to take or give
  Power above or beyond the Laws, suffer it not to live.
Holy State, or Holy King, or Holy People's Will.
  Have no truck with the senseless thing, order the guns and kill.

The penultimate stanza of Rudyard Kipling's MacDonough's Song

terry_freeman on July 25, 2010, 07:40:22 pm
You need an airlock to transition between "cabin pressure" and "vacuum", so why not transition between "cabin" and "suit" pressure? What are the physiological constraints on air pressure? Some athletes train in "high altitude" chambers. People who spend extended periods at high altitude, without acclimation, experience difficulties.

OPossumTX on July 30, 2010, 02:07:58 pm
Another good reason to run less than atmospheric in a suit is joint stiffness.  The lower the pressure differential inside to outside, the easier the joints including the gloves are to move. 

Still anohther reason is the earlier mentioned decompression risk.  If the pressure diferential, interior to outside of the suit, is low it stands to reason that there is less expansion of the disolved gasses in the subject's body so less probability of "the bends" when decompression does occurr.