What's the lightest "emergency spacesuit" you could have in a locker?

[fredinno]

14 hours ago, SomeGuy123 said:

Now, hmm.  I know space is relatively cheap on a spacecraft, since it doesn't have to be any particular shape and you really only pay for mass, not volume, and adding more volume inside a spaceship is cheap.  Still, the unused space inside each "atomo-coffin"..inelegant.  Must be a way to combine functions.

Oh.  Of course.   Just make the door on each crew quarters module seal and give it a life support module.  If you were really god's gift to engineering, you'd make the normal air recycler unit for the crew quarter module - the one that keeps the carbon dioxide out of your face - also be detachable and usable as a backpack.

So then the only thing you have to have is a light space suit in there.  Russians can do it in 10 kg, so it's possible.  Still, wonder what you do if 2 crewmembers happen to pile into the same module and they happen to be the only survivors?  There's only 1 suit...

 

But more volume increases mass. Also, you are limited by your payload faring+ how much your module inflates.

[Nothalogh]

So, each one of of these cabinets is basically a forged titanium coffin with a mesh hammock inside, a fuel cell, an RTG, and life support.

Oh yeah, and a beacon, in case the box is ripped free in a structural failure. 

[SomeGuy123]

2 hours ago, fredinno said:

But more volume increases mass. Also, you are limited by your payload faring+ how much your module inflates.

If you read my post a little more carefully, I address that.  " adding more volume inside a spaceship is cheap "

I don't say free, I say cheap.  As in, because of the whole surface area/volume law, the amount of extra "skin" on the spacecraft needed is smaller the bigger is.  A very large spacecraft you can add another m^3 of volume for almost nothing, especially if you also take advantage of inflatable fabrics and other very low mass skins.

I'm assuming for this exercise that everything has been manufactured from parts in orbit.

 

[cantab]

10 hours ago, radonek said:

This is why skinsuits are all the rage, but those have to be custom made.
 

I previously suggested that the tightness in a space activity suit might come from some sort of active system, mainly so it's not uncomfortably tight in one atmo, but perhaps that same active system would also remove the need for custom fitting.

As for what it would be, I don't know the details but I'm thinking some kind of shape memory wire or electrical "muscle" or something like that. I know there are materials that can exert a force in response to a controlled input like an electrical current, we're some way off using them in a spacesuit but then we're also some way off the emergency in space scenario.

[gooddog15]

Why not use the actual lockers themselves? In the event of a emergency where sealing up your ship is impossible, all you would have to do is throw everything that was inside the locker, (all the stuff would be in a inner liner, keeping everything from flying everywhere) put yourself in it, and close. Life support could be supplied by the spacecrafts own systems and if that has failed, it would use an oxygen bottle until help arrives. When help finally arrives, rescuers donning EVA suits would disconnect the locker, attach an external life support device (or their own suits), and send it to the rescue ship.

[fredinno]

28 minutes ago, gooddog15 said:

Why not use the actual lockers themselves? In the event of a emergency where sealing up your ship is impossible, all you would have to do is throw everything that was inside the locker, (all the stuff would be in a inner liner, keeping everything from flying everywhere) put yourself in it, and close. Life support could be supplied by the spacecrafts own systems and if that has failed, it would use an oxygen bottle until help arrives. When help finally arrives, rescuers donning EVA suits would disconnect the locker, attach an external life support device (or their own suits), and send it to the rescue ship.

This might be a good option on military ships, or ships with a lot of expensive cargo (like polititans), as expense is less of an issue, and you are more vulnerable to attack.

[gooddog15]

37 minutes ago, fredinno said:

This might be a good option on military ships, or ships with a lot of expensive cargo (like polititans), as expense is less of an issue, and you are more vulnerable to attack.

Heck, we just could get rid of the pressurized compartments and transport everyone in the lockers. It'll be inconvenient, but it would be significantly cheaper and easier to both build, fly, and protect. We could go even further and make the whole ship a drone.

We could also just blame the failure of the container in the event if we wanted to have certain unpopular politicians "accidentally" die.

Edited January 25, 2016 by gooddog15

[wizzlebippi]

Why not a compression fit skin suit with a smoke hood like hood and portable oxygen generator. The hood is in a pouch at the base of the neck with a tab. You grab the tab, which also starts the oxygen generator, pull it over your head and make sure it seals around your neck. It's no space suit, but it can be donned quickly and it would give you a few minutes to either patch the hole or move to a pressurized area of the ship.

[fredinno]

1 hour ago, gooddog15 said:

Heck, we just could get rid of the pressurized compartments and transport everyone in the lockers. It'll be inconvenient, but it would be significantly cheaper and easier to both build, fly, and protect. We could go even further and make the whole ship a drone.

We could also just blame the failure of the container in the event if we wanted to have certain unpopular politicians "accidentally" die.

I'm pretty sure a politian wants to move around... 

And unless it's cryptofreesing, keeping one in a locker for a long time really sucks for that person.

[radonek]

11 hours ago, cantab said:

I previously suggested that the tightness in a space activity suit might come from some sort of active system, mainly so it's not uncomfortably tight in one atmo, but perhaps that same active system would also remove the need for custom fitting.

As for what it would be, I don't know the details but I'm thinking some kind of shape memory wire or electrical "muscle" or something like that. I know there are materials that can exert a force in response to a controlled input like an electrical current, we're some way off using them in a spacesuit but then we're also some way off the emergency in space scenario.

In short, you are describing smart- or meta-materials. Embed some control electronics and you have material that can change its properties on demand. Like, suit that can download users profile and reconfigure itself to fit. Or, if its really smart, will make user perform some exercises and adjust itself dynamically.   And, yeah, I believe this is the future of space suits - in a long term. But if you have technology to do this stuff, you can also use it as self-sealing construction material for your ships. I would dare to make this a rule: "Emergency" suits are useless, because anything that will work for them, can work for compartmelization as well. 

[AngelLestat]

On 23/1/2016 at 5:00 PM, SomeGuy123 said:

Ok, so an adult man uses about 0.3 liters/minute of oxygen.
Blood has "19.7 mL O2/deciliter".  So you need 1.55 liters of blood to live a minute. (your blood flow rate is faster than that because you don't consume all of the oxygen)
So the article says "The suspension carries three to four times the oxygen content of our own red blood cells."
So a minute would be 381 milliliters.  Too much fluid to carry around.
I also found a rule for decompression, the "one-one-ten-hundred rule: "
A one square-centimeter hole in a one cubic-meter volume will cause the pressure to drop by a factor of ten in roughly a hundred seconds. 
If you started at 1 atmosphere, that's about how long you have to stay conscious if you are breathing pure oxygen.
So, I'm not sure.   All the gear that a person could have "on them" all the time seems like it would be not much smaller than just wearing a space suit all the time with an inflatable helmet of some kind. 

No.. the article said that 1 injection of that side "video"  would work for 15 to 30 min.  Is tested in animals who had the same oxygen limit in their blood although the amount injected was different. 
About your 0.3liter by min is wrong.  "The human lung consumes about 5-6 ml oxygen per minute"  Source.

Your pressure drop calculation is fine for 1cm square to 1m3, but the thing change fast when diameter increase due cm2 area and lower friction surface for the same area.  This mean pressure drop by a factor of ten in 2 seconds for a 5 cm orifice diameter or a flow rate of 10m3 of air by second for a 20cm diameter orifice.

Any suit that work under pressure reduce a lot the mobility and its weight is high,  skinsuits (which are better) are hard to design for different body sizes and sex.
So, I am not saying that this injection should be the only safety mechanism in these cases, but your chances of survival would increase a lot if all people carries one of these all the time.. Maybe an automated mechanism that when detect low pressure activate the injection.. 

[radonek]

4 hours ago, AngelLestat said:

So, I am not saying that this injection should be the only safety mechanism in these cases, but your chances of survival would increase a lot if all people carries one of these all the time

Maybe. AFAIK decompression will kill you much faster then lack of oxygen. If you had exposure AND somebody got you through airlock really fast AND there is doctor at hand who can deal with frozen tissue, massive lung damage and god knows what else… then yes, it could help a lot. Or it could just prolong your agony. 

[AngelLestat]

you have a source to support all that?  From what I read..  those are issues only after several minutes..  

[radonek]

My source is mainly atomic rockets. Lots of lovely stuff there, including this one about decompression and Armstrong limit:

Quote

But in any event if your saliva starts to boil, be aware that you have only ten seconds to get to safety before you lose consiousness, and 80 additional seconds for your buddies to drag you into somewhere pressurized before you die. Be quick or be dead.

I reasoned that man can survive several minutes breathless before brain damage sets in… but I was wrong, there is one other effect mentioned later in the text:

Quote

The air from her last breath moves down its partial pressure gradient from high concentration in her lungs, to the low concentration in her blood. Abruptly finding herself in a vacuum, this gas exchange is reversed. Oxygen diffuses out from the relatively high partial pressure in her venous blood back into the zero-pressure environment that her lungs are exposed to.

So yeah, vacuum really sucks.  No idea what with nitrogenated atmosphere and the bends, but if you happened to come from pure oxygen atmosphere it really could give you some time.  

And if its not enough…

[AngelLestat]

2 hours ago, radonek said:

My source is mainly atomic rockets. Lots of lovely stuff there, including this one about decompression and Armstrong limit:

That source is not very accurate.  Take into account that is build with the idea to provide guide for those who play RPG space games.
Is not the first time I found errors in that site, some are commented in discussion over this same forum, here there are few more and I did not read the full page, so is not a recommended source..

Atomic Rockets shows as source Dr. Geoffrey Landis words, but is funny how then contradicts its own sources.
To understand many of these issues we need to put the time into perspective.

1-"Blood starts to boils", Landis explains why this does not happen. In the Ebullism link also is mentioned that this does not happen, but that after several minutes starts to happen in a small scale (for long time flys) and symptoms appears with the word "may".

2-Freeze or burn.  This also contradicts its sources. If you are in space with some cloth, you will feel just a little cool sensation due surface liquids evaporating. But in space is harder to get rid of heat than gain it..   Those numbers that we always see as  -270c vs 120c on light.. does not has real meaning.  Up there in orbit the sun power is 1300w/m2, in earth surface is 1000w/m2, you have UV that can intensify your skin burns, but instead 30 min as in earth, you will have the same burn in 5 min (constant exposure with no rotation or cloth to block it).

3-lungs damage over explosión decompression. To have that a big part of your ship needs to break on half, and the damage is not so severe upto the case of no being able to breath again...  Most decompression happens in 20 seconds or hours.

Facts: some monkeys or animals was exposure to vacuum by 3 to 10 min (no oxygen), and then they survive when they was reanimated. The main cause of death is always lack of oxygen..  this is the thing you solve with the syringe idea. And it gives you enough time to put you in save (wearing a spacesuit or reaching a pressurized area)

[cantab]

On 25/01/2016 at 2:44 AM, fredinno said:

This might be a good option on military ships, or ships with a lot of expensive cargo (like polititans), as expense is less of an issue, and you are more vulnerable to attack.

On the contrary, I would expect that on a military spacecraft you want the crew active and either fighting the enemy or doing damage control on the spacecraft. Not holed up helplessly in metal boxes while the ship burns.

[DBowman]

7 hours ago, radonek said:

So yeah, vacuum really sucks

re the diffusion of oxygen out of the blood into vacuum in the lungs:

• O2 is 'held' by haemoglobin so it might well not act like a straight gas in solution, I cannot remember how it works it might need some trigger conditions to let go of the O2 (ph or something). I guess it would still be pumping through the lungs and so being exposed via alveoli 
• if you shut yr mouth and nose then the 'air space' would fill up with low pressure stuff (H2O, N2, ...) out gassing from yr body - that might mitigate O2 loss in blood and tissue by creating some partial pressure in the lungs
• As I understand it the oxy injection is some kind of O2 source (synthetic haemoglobin-ish) if it's supporting life for a few minutes then it's some kind of time release effect and so even if the body is outgassing O2 form the lungs it'll be being topped up by the oxy inject. Clearly the oxy inject would not last as long if the body is out gassing O2 rather than using it. 

[fredinno]

33 minutes ago, DBowman said:

re the diffusion of oxygen out of the blood into vacuum in the lungs:

• O2 is 'held' by haemoglobin so it might well not act like a straight gas in solution, I cannot remember how it works it might need some trigger conditions to let go of the O2 (ph or something). I guess it would still be pumping through the lungs and so being exposed via alveoli 
• if you shut yr mouth and nose then the 'air space' would fill up with low pressure stuff (H2O, N2, ...) out gassing from yr body - that might mitigate O2 loss in blood and tissue by creating some partial pressure in the lungs
• As I understand it the oxy injection is some kind of O2 source (synthetic haemoglobin-ish) if it's supporting life for a few minutes then it's some kind of time release effect and so even if the body is outgassing O2 form the lungs it'll be being topped up by the oxy inject. Clearly the oxy inject would not last as long if the body is out gassing O2 rather than using it. 

You can't just shut your mouth. That's why people drown in cold water- the shock causes them to reflexively breath in.

[DBowman]

45 minutes ago, fredinno said:

You can't just shut your mouth. That's why people drown in cold water- the shock causes them to reflexively breath in.

I meant after the initial shock and evacuation, the lungs would be evacuated but with some internal volume from tissue elasticity etc, then if you closed nose and mouth any out gassing would be trapped in that volume. I wonder how high the pressure would go (very low still I imagine) and if it would have any effect that could mitigate/slow tissue damage and/or O2 loss from blood and tissue.

Also I wonder how much internal pressure one could maintain safely in the pulmonary cavities with vacuum outside. Probably people have some experience trying to equalise pressure when descending in an aeroplane or snorkeling, if you over pressure then it feel like your eardrums are the limiting factor (at least they hurt the most...) - but I've no idea how much pressure that is.

[fredinno]

4 hours ago, cantab said:

On the contrary, I would expect that on a military spacecraft you want the crew active and either fighting the enemy or doing damage control on the spacecraft. Not holed up helplessly in metal boxes while the ship burns.

You're right, during combat situations, you would want everyone it spacesuits and weapon gear, ready to fight. That was a mistake on my part.

[sgt_flyer]

Mmmh - was rethinking about the o2 syringe, (for cases of fast but non explosive decompressions) - ISS atmosphere has nitrogen in it - would there be a risk of nitrogen bubble formation in the astronaut's body in case of decompression without at least a mechanical counterpressure suit ? - after all, they already need to pre breath pure oxygen before EVAs (for 2h20mn !) to get nitrogen out of their system, because the spacesuits use partial pressure pure oxygen.

[Agent86]

A face mask to keep your eyes from bleeding and to keep your lungs pressurized, and a booth which sprays your naked body with a rapid-setting, oxygen infused foam which sets to a thick, flexible consistency to insulate and augment your skin tension, which reacts to low pressure by forming a very tough outer skin, while the inner layer remains gooey and permits the oxygen within it to migrate around and interact with your mask in a way to give you extra oxygen. Any breaches due to cutting or impact would self-heal like one of those self-patching bicycle tires as soon as it met vacuum. One size fits most, and no bulky life support tanks. Its basically a booth that turns you into the Michelin man.