Author Topic: Mechanical counterpressure suits  (Read 26591 times)

Offline mmeijeri

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Mechanical counterpressure suits
« on: 03/24/2013 03:13 pm »
A new thread for discussion of mechanical counterpressure suits.

See Space activity suit and BioSuit.
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Offline guckyfan

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Re: Mechanical counterpressure suits
« Reply #1 on: 03/24/2013 03:21 pm »
Those suits will help a lot with activities on Mars, no doubt, if they can be developed to maturity.

But clicking on the links you see immediately on both webpages that there is a helmet. The pressure needs to be applied, no matter if it is through elastic pressure from the biosuit or with internal air pressure. The eyes and face need the air pressure as you can see in the pictures.

Offline mmeijeri

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Re: Mechanical counterpressure suits
« Reply #2 on: 03/24/2013 03:24 pm »
They might also be handy for use inside an unpressurised orbital hangar. Not as good as a shirt-sleeve environment, but better than a clunky rigid suit. I'm not sure if it would be better than a force-feedback suit controlling a robot though.
« Last Edit: 03/24/2013 03:28 pm by mmeijeri »
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Offline Nomadd

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Re: Mechanical counterpressure suits
« Reply #3 on: 03/24/2013 03:36 pm »
  I guess I still don't see it. it seems like designing a suit to structurally keep perfectly even pressure on every square inch of skin would be much harder than one with a thin layer of gas between the suit and the skin. Spacesuits aren't large and bulky because they need that much gas in them to maintain pressure. A 1 millimeter layer works just as goes as an inch.
 Put it this way. I see the old trick of comparing what we have now to what might be in 15 years. If all the advances and technology that are needed for this new type of suit were applied to conventional gas filled suits, the comparison would be a lot different. And, scaling back the requirements because you're not spending all day in open space would allow a whole different level of suit design for conventional pressure suits.
 One thing I just realized I know nothing about is the effect of vacuum on a body that's been in 14.7 psi air compared to the effect on a body that was in 5 psi O2.
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Offline manboy

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Re: Mechanical counterpressure suits
« Reply #4 on: 03/24/2013 03:39 pm »
Also, at the elevation airplanes fly at, pure oxygen is sufficient for human survival for short periods. At the elevation spaceships travel, pure oxygen isn't sufficient and your blood would boil without a pressure vessel of some sort.

I've read the blood boiling is a myth. Work is being done on flexible spacesuits that aren't airtight and mainly serve to keep the heat in and to keep the astronaut from swelling up. See Space activity suit and BioSuit.
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Offline R7

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Re: Mechanical counterpressure suits
« Reply #5 on: 03/24/2013 04:19 pm »
  I guess I still don't see it. it seems like designing a suit to structurally keep perfectly even pressure on every square inch of skin would be much harder than one with a thin layer of gas between the suit and the skin. Spacesuits aren't large and bulky because they need that much gas in them to maintain pressure. A 1 millimeter layer works just as goes as an inch.

It's about mobility. Ordinary space suits resist movement because they are flexible walled pressure vessels. When you move your arms and legs the volume inside the suit changes which means you have to do work against the internal pressure. Webb/Bio-suit circumvents this using mechanical means, load paths directed so that work is not done when joints move. I'm hoping this tech will go forward. It would also enable using additional external flexible clothing depending on working environment (MMOD protection / thermal etc.).

And Joe 6pack will be more understanding for the need of HSF when he sees female astronauts doing spacewalks in figure hugging costumes...

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Offline guckyfan

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Re: Mechanical counterpressure suits
« Reply #6 on: 03/24/2013 04:56 pm »
It's about mobility. Ordinary space suits resist movement because they are flexible walled pressure vessels. When you move your arms and legs the volume inside the suit changes which means you have to do work against the internal pressure. Webb/Bio-suit circumvents this using mechanical means, load paths directed so that work is not done when joints move. I'm hoping this tech will go forward. It would also enable using additional external flexible clothing depending on working environment (MMOD protection / thermal etc.).

That's the idea, right. But I do have a serious problem imagining a suit that achieves the goal of providing very homogenous pressure to every inch of the body. Particularly those parts that protrude a bit.

Quote
And Joe 6pack will be more understanding for the need of HSF when he sees female astronauts doing spacewalks in figure hugging costumes...

Good point. ;D

Offline Nomadd

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Re: Mechanical counterpressure suits
« Reply #7 on: 03/24/2013 04:57 pm »

It's about mobility. Ordinary space suits resist movement because they are flexible walled pressure vessels. When you move your arms and legs the volume inside the suit changes which means you have to do work against the internal pressure. Webb/Bio-suit circumvents this using mechanical means, load paths directed so that work is not done when joints move. I'm hoping this tech will go forward. It would also enable using additional external flexible clothing depending on working environment (MMOD protection / thermal etc.).

And Joe 6pack will be more understanding for the need of HSF when he sees female astronauts doing spacewalks in figure hugging costumes...


As somebody who works in level A hazmat on occasion, I definitely wouldn't mind seeing something like that. Nothing like working in Louisiana in July with one of those medieval things.
  On a side note, why is the ISS regular air? Any suit would be a lot more convenient if they didn't have to transit from one mix and pressure to the other all the time.
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Offline ddunham

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Re: Mechanical counterpressure suits
« Reply #8 on: 03/24/2013 05:40 pm »
On a side note, why is the ISS regular air? Any suit would be a lot more convenient if they didn't have to transit from one mix and pressure to the other all the time.

It's a lot easier to use equipment that you know works in 1atm in 1atm.  Making/testing/certifying all the equipment to work in reduced pressure would be a significant expense.  Cooling in particular can be a big issue.

Offline Robotbeat

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Re: Mechanical counterpressure suits
« Reply #9 on: 03/24/2013 06:10 pm »
On a side note, why is the ISS regular air? Any suit would be a lot more convenient if they didn't have to transit from one mix and pressure to the other all the time.

It's a lot easier to use equipment that you know works in 1atm in 1atm.  Making/testing/certifying all the equipment to work in reduced pressure would be a significant expense.  Cooling in particular can be a big issue.

Plus, both the shuttle and Soyuz used regular air... there was absolutely no way either NASA or the Russians were going to build a space station with an atmosphere that didn't match that of their manned spacecraft.
This is totally rational for a space station in LEO, much less so beyond LEO.
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Offline QuantumG

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Re: Mechanical counterpressure suits
« Reply #10 on: 03/24/2013 10:01 pm »
Another alternative is 3d printed hard suits. Perfect fit, low friction vacuum bearings on all the joints.

Human spaceflight is basically just LARPing now.

Offline Robotbeat

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Re: Mechanical counterpressure suits
« Reply #11 on: 03/25/2013 02:18 am »
Another alternative is 3d printed hard suits. Perfect fit, low friction vacuum bearings on all the joints.


Significantly worse, actually. Much more cumbersome. Besides, 3d printing isn't good for thin-walled pressure vessels AT ALL. Might be useful for making a mold that you overlay material on (some sort of electrodeposition method?) and then melt out the mold, but you could do that with CNC machines. Still much more cumbersome.
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Offline Dalhousie

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Re: Mechanical counterpressure suits
« Reply #12 on: 03/25/2013 02:38 am »
That's the idea, right. But I do have a serious problem imagining a suit that achieves the goal of providing very homogenous pressure to every inch of the body. Particularly those parts that protrude a bit.

It is difficult, but it has basically been done.  And the pressure does not have to be homogeneous, but sufficient.
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Offline Robotbeat

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Re: Mechanical counterpressure suits
« Reply #13 on: 03/25/2013 03:22 am »
I imagine these things will be pretty difficult to get in an out of, but I actually think that eventually they will have to be used (at least in some circumstances) because regular suits (and most alternatives to regular suits) are quite cumbersome. Putting on mechanical counter-pressure suits will be a huge pain, but once they're on, you can be far more capable, fit in more places, be able to handle smaller objects and thus fix/assemble things that otherwise wouldn't be feasible to fix/assemble, etc. It's an elegant solution to a very complicated engineering problem.

And I think that the 80/20 solution would be mechanical counter-pressure gloves. They have already been tested in some circumstances: http://www.ncbi.nlm.nih.gov/pubmed/15828639
"Sensitivity was significantly better for MCP [edit: Mechanical Counter-pressure glove] compared with the EMU [edit:Existing suit glove]."
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Offline jded

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Re: Mechanical counterpressure suits
« Reply #14 on: 03/25/2013 07:44 am »
I imagine these things will be pretty difficult to get in an out of, but I actually think that eventually they will have to be used (at least in some circumstances) because regular suits (and most alternatives to regular suits) are quite cumbersome. Putting on mechanical counter-pressure suits will be a huge pain, but once they're on, you can be far more capable, fit in more places, be able to handle smaller objects and thus fix/assemble things that otherwise wouldn't be feasible to fix/assemble, etc. It's an elegant solution to a very complicated engineering problem.

And I think that the 80/20 solution would be mechanical counter-pressure gloves. They have already been tested in some circumstances: http://www.ncbi.nlm.nih.gov/pubmed/15828639
"Sensitivity was significantly better for MCP [edit: Mechanical Counter-pressure glove] compared with the EMU [edit:Existing suit glove]."

Weird, from what I understood the glove is the hardest part to make (lots of tiny moving things). If they work, the whole suit should work too.

This has a lot of potential, anyway. If the risk shows to be manageable, it could be made active, e.g. weaving a net of tiny strings with some kind of micro spinning engines on end, dynamically adjusting tension (applied pressure should be constant). That would eliminate the need to make the suit fit perfectly and make puting it on easier.
« Last Edit: 03/25/2013 09:23 am by jded »

Offline KelvinZero

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Re: Mechanical counterpressure suits
« Reply #15 on: 03/25/2013 07:47 am »
On a side note, why is the ISS regular air? Any suit would be a lot more convenient if they didn't have to transit from one mix and pressure to the other all the time.

It's a lot easier to use equipment that you know works in 1atm in 1atm.  Making/testing/certifying all the equipment to work in reduced pressure would be a significant expense.  Cooling in particular can be a big issue.

Plus, both the shuttle and Soyuz used regular air... there was absolutely no way either NASA or the Russians were going to build a space station with an atmosphere that didn't match that of their manned spacecraft.
This is totally rational for a space station in LEO, much less so beyond LEO.

I heard somewhere one big reason was to not complicate experimental results especially for zero-g health. If we go further than LEO we probably have a different purpose in mind so that motivation would go away.

An earlier thread, sort of related: http://forum.nasaspaceflight.com/index.php?topic=24049.0

During my search I also found an interesting thread on robotic gloves btw.
http://forum.nasaspaceflight.com/index.php?topic=28335.msg872586#msg872586
« Last Edit: 03/25/2013 07:48 am by KelvinZero »

Offline Robotbeat

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Re: Mechanical counterpressure suits
« Reply #16 on: 03/25/2013 02:15 pm »
On a side note, why is the ISS regular air? Any suit would be a lot more convenient if they didn't have to transit from one mix and pressure to the other all the time.

It's a lot easier to use equipment that you know works in 1atm in 1atm.  Making/testing/certifying all the equipment to work in reduced pressure would be a significant expense.  Cooling in particular can be a big issue.

Plus, both the shuttle and Soyuz used regular air... there was absolutely no way either NASA or the Russians were going to build a space station with an atmosphere that didn't match that of their manned spacecraft.
This is totally rational for a space station in LEO, much less so beyond LEO.

I heard somewhere one big reason was to not complicate experimental results especially for zero-g health. If we go further than LEO we probably have a different purpose in mind so that motivation would go away.
...
I'm sure you're quite aware of this, but just a reminder to everyone: We have gone beyond LEO before and we didn't use sea-level pressure. The only example of beyond-LEO HSF we have involves significantly lower than sea level internal pressure. For very good reasons.
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Offline Oli

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Re: Mechanical counterpressure suits
« Reply #17 on: 03/25/2013 02:52 pm »

Must be terribly uncomfortable, what happens if you sweat?

Offline starsilk

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Re: Mechanical counterpressure suits
« Reply #18 on: 03/25/2013 03:43 pm »

Must be terribly uncomfortable, what happens if you sweat?

right through the fabric into space; it makes a lot of the 'space suit' issues go away because your skin can do what it is supposed to.

the major issue is the form fitting, no wrinkling thing (pinched skin would be BAD), and how to get in/out of the suit.

Offline RanulfC

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Re: Mechanical counterpressure suits
« Reply #19 on: 03/25/2013 04:01 pm »
Quote from: Oli
Must be terribly uncomfortable, what happens if you sweat?
Point of fact that's how the MCP suit maintains thermal control :) Hot? You sweat and it evaporates just like people normally do :) Cold? Put on a jacket and/or insulation layers.

As for comfort the suits have been found to need to be "worked-in" a bit to be broken in, but once they've been fitted they are very, VERY comfortable compared to "normal" balloon suits. Currently the largest issue with the designs is donning/doffing because of the need of the suits to fit tightly when in use.

The leading idea to date is to use a similar system to the Capstan Partial Pressure High Altitude suit where the suit would fit rather "loosly" until the capstan system activated which would pull the suit tight applying the needed counter-pressure for use. (http://airandspace.si.edu/collections/artifact.cfm?id=A19730755000)

One thing everyone should keep in mind is that these suits HAVE been tested under vacuum conditions and no major issue have been found other than the aforementioned don/doff issue.

Randy
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