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#26 2005-08-16 22:20:27

John Creighton
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From: Nova Scotia, Canada
Registered: 2001-09-04
Posts: 2,401
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Re: Spacesuits - personal spaceship

The Rocket Company, an on-going scientifically sound novel, has a whole chapter (well, some pages...) dedicated to suits and cheap toilets

it's about a 'hard' suit, though, not to be used on Mars etc, but still an interesting read, because there's a lot of history in it.

one citation: "...But, as information about the Russian space program came out in the 1980s, especially during the American experience on Mir, it became apparent that manned space systems could be awfully unsophisticated and still work..."

Sounds like a really good book Rxke.

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#27 2005-08-17 04:31:25

Rxke
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From: Belgium
Registered: 2003-11-03
Posts: 3,667

Re: Spacesuits - personal spaceship

Sounds like a really good book Rxke.

Hm. It used to be online, but they decided to make it a 'real' book (it's now being sold) so they pulled the online version sad

(maybe wayback engine has a copy...)

(edit:) it has! Mwuahaha! http://web.archive.org/web/200402272027 … page1.html

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#28 2005-08-25 20:43:40

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 26,753

Re: Spacesuits - personal spaceship

Not only will any new space suit designs require being able to allow for better flexability but they must also keep out the elements. The removeable of the dirt and dust from outside the suit seems quite straight forward but keep it out of the suit seems more daunting.
Dust up at Marshall Space center lab studies dangers of lunar particles

For most people on Earth, dust bunnies are the subjects of jokes and targets of dust mops.
But dust is a serious subject for scientists at NASA's Marshall Space Flight Center, who are studying how moon dust could hurt people and equipment when the space agency starts setting up bases on other planets.

Beside the dust there is also the static cling that we need to deal with as well.

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#29 2005-08-26 01:31:41

Rxke
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From: Belgium
Registered: 2003-11-03
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Re: Spacesuits - personal spaceship

That dust will prove the #1 priority before soon...

I happen to be reading the Apollo Lunar Surface Journal stuff, lots of very good stuff in there, esp. when you consider we're going back... I think this should be required reading for missionplanners, in tandem with a regular get-together with the people that walked on Luna.

In the technical debriefings, dustproblems seem to be a recurring theme. I don't remember exactly who said it, maybe Deke Slayton, but one of the astronauts kept coming back to the dust-related issues, and they're really, really serious...

These guys did one or two EVA's and already some equipment started to act up in potentially very problematic ways, like lids on containers that didn't close anymore, joints locking up, even velcro losing its 'stickyness!' :shock:

The astronaut in question said something like: if we don't solve these problems, we're in deep problems.

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#30 2005-08-26 07:40:48

srmeaney
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Re: Spacesuits - personal spaceship

Short of a biological layer in the suits (like a fungus or a yeast), Suits will continue to be a problem. Liquid Crystals the other option-they can be used to create anartificial cell membrane, but they are most unflexible.

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#31 2005-08-26 14:32:05

publiusr
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Re: Spacesuits - personal spaceship

I think they are going to release a suit in space on purpose as part of the Suitsat program--according to PopSci--or was that PopMech?

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#32 2005-08-27 11:57:14

mboeller
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From: germany
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Posts: 53

Re: Spacesuits - personal spaceship

WoW !!!  What a great Thread.  RobertDyck, thank you for all this information about MCP-spacesuits. Especially the information that an MCP-suit has not to be air-tight is rather intriguing. I never thought that this would be possible.

I see only one real drawback of an MCP-spacesuit and that is the dressing and undressing of the suit due to the tight shape and the strong fibers.

So IMHO I would prefer an hybrid suit with an combination of two different "pressurisation" systems. IMHO the best could be an combination of the normal MCP-system using strong fibers with an pneumatic of hydrostatic pressurisation system like the one used for the LIBELLE G-Multiplus Anti-G suit pilots use when they fly the new Typhoon-Fighter. Well the Libelle-suit is completely passive cause the G-forces alone are sufficient to do the work, but in the space-suit the pressure would have to come from an external source like the breathing system.

With such an rather simple additional system the dressing and undressing should be much simpler cause the suit has not to fit so tight without the additional pressure.


One additional problem I see with the MCP-spacesuit is that you use an "open" spacesuit to allow sweating. NASA will never use such an spacesuit (and all the scientist will agree) because the sweating can and IMHO will contaminate Mars so the search for life will never be conclusive.
Also, due to the "open" MCP-spacesuit the danger exist that the rather toxic marsian dust will contaminate the suit and the astronaut inside the suit. But IMHO an simple and straight-forward protection could be to wear something like an paint-overall over the MCP-suit. (from an german website: https://www.lackcenter-berlin.de/images … 842_0.jpg) Such an protective overall could be undressed even outside of the air-lock and so most of the contamination would stay outside of the habitat. The overall then could be put in an bin or cleaned in an closed system


Manfred

a few links to the AntiG-suit:

http://www.prospective-concepts.ch/html … le_en.html
http://www.autofluglibelle.com/html/libelle.html

Prospective Concepts developed the concept and the AntiG-suit at the beginning, then the company Autoflug developed it further and produces it now at least for the german Luftwaffe.

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#33 2005-08-27 14:55:40

Rxke
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From: Belgium
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Re: Spacesuits - personal spaceship

re: the breathing= contamination hazard.

How big a hazard would this really be? There are already textiles around that only let fluids through in only vapour phase state (goretex being the most widely known)

so i'd guess it'll block larger particles and bacteria etc.

Of course, one tiny hole and you have a chance of contamination.  But consider a hard pressure suit: one hole and you have a veritable 'geyser' spewing out, an atmosphere under pressure, hydrated, mixed with sweat etc.... good growth medium, heh.

And... anyhow, once on Mars (humans) contamination will prove all but impossible to prevent, IMO... Or you should build everything like Biohazard V facilities, and then still be only 90% sure nothing will escape, because Murphy will surely hitch a free ride to the Red Planet.

I like the breathing suits, they have a lot to say for them.
If it's too cold, just put on a regular overgarment, etc.

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#34 2005-08-27 18:25:03

RobertDyck
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Re: Spacesuits - personal spaceship

Chris McKay is the advocate for "reversible" exploration. At one Mars Society conference (2003) he argued if even a primitive archaea type microbe was found we should remove all traces of humanity and return to Earth. I most strongly disagree, but you do have to ensure you don't contaminate your samples. I don't think we convinced Dr. McKay but he hasn't made that claim at Mars Society conferences again. The reason I bring up Chris McKay is he's the one who studies faint traces of microbial life in the Atacama desert. He doesn't wear a hazmat suit or any other form of bio-isolation suit when he samples the desert, he just wears clothes. The same procedures can be used on Mars. An MCP suit will have a sealed, pressurized helmet and boots, and the 1971 contractor report added an air bladder over the torso and upper abdomen make breathing easier. The air bladder has an constant exterior volume, and you inhale your expanding chest squeezes air out of the bladder but you intake an equal volume of air into your lungs. To ensure pressure outside the chest and inside the lungs is exactly the same he connected the bladder with a hose to the helmet. Over all that you'll wear warm clothing, no skin directly exposed. It's a lot more sealed than desert clothes. Established field sample acquisition procedures work fine, they'll work on Mars.

I discovered water repellent Gore-tex is formed by sandwiching a plastic membrane between two layers of fabric. The fabric is PTFE fibre spin into yarn and woven into fabric, the membrane is PTFE film with careful controlled holes that will permit water vapour to pass but are too small for liquid water. The outer most layer of current spacesuits is Gore-tex fabric, but has a backing of Nomex with Kevlar replacing some threads in the Nomex in a rip-stop pattern. Nomex is fireproof and stiff, it's the same stuff that fire fighter jacket and pants are made from. Kevlar is very strong, bullet proof vests are made from it. You really don't need a fireproof layer in the vacuum of space or a [tex:ed8c4e206e]CO_2[/tex:ed8c4e206e] atmosphere; fire won't burn without oxygen. EMU isn't worn inside the space shuttle or ISS, it's too heavy and the legs don't move. An MCP suit is comfortable in vacuum but very uncomfortable in normal pressure, you can't wear it inside. There's no need for a fireproof layer. The Nomex/Kevlar layer also serves as a micrometeoroid shield, but Mars has an atmosphere so micrometeoroids will burn up literally miles up in the air; there aren't any micrometeoroids at the surface. But Mars has wind and blowing fines. To keep fines out use the same PTFE membrane that permits water vapour to pass but is too small for fines. For the surface of Mars you want fabric with finer yarn than EMU, more like an Alpine mountain climbing parka. So 80 denier Gore-tex fabric instead of 400 denier. Commercial winter jackets use an oleophobic (oil repellent) fabric for the exterior finish, not necessarily PTFE fabric. It could be polysulfone but Gore-tex has been proven to work in space so let's stick with that.

Since the outer layer is separate from the MCP layer, the outer layer doesn't have to be sealed. It can be separate parka and ski pants. If the torso & upper abdomen bladder is covered in Gore-tex fabric, the jacket could be opened when the astronaut gets hot. By the way, I met Dr. Paul Webb at this year's Mars Society conference. I asked him about cooling, the trunk is a large portion of the body's surface area and a prime location for cooling. If that's covered in an air tight bladder how will it affect sweat? He said in vacuum sweat moves along the surface between skin and bladder very quickly. It isn't a problem. This makes me think a Mars parka may need pit zips.

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#35 2005-08-27 18:42:06

RobertDyck
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Re: Spacesuits - personal spaceship

One interesting statistic from Dr. Webb's 1968 paper, human skin tears with a force of 1600 grams per square millimetre. That would require being in hard vacuum with pressure inside the body is 155 atmospheres. Pressure inside the body would be 1 atmosphere if you came from a habitat pressurized to that level, the EMU is pressurized to 4.3 psi or 0.2926 atmospheres. Skin is just too strong to rupture from vacuum. He also pointed out [tex:b641b42e0b]O_2[/tex:b641b42e0b] does not leak through skin, hemoglobin in the blood holds it quite well, and [tex:b641b42e0b]CO_2[/tex:b641b42e0b] diffusion through the skin is less than the leakage rate of current spacesuits. Besides, getting rid of [tex:b641b42e0b]CO_2[/tex:b641b42e0b] is a good thing. So human skin is strong and air tight. The problem is that fluids in the human body can't handle vacuum, so you need to apply pressure. That's the job of the MCP layer.

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#36 2005-08-28 01:48:41

Shaun Barrett
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From: Cairns, Queensland, Australia
Registered: 2001-12-28
Posts: 2,843

Re: Spacesuits - personal spaceship

Mboeller:-

WoW !!! What a great Thread. RobertDyck, thank you for all this information about MCP-spacesuits.

I agree.
This whole MPV concept is fascinating and RobertD, as so often, is a mine of interesting technical details.

I find it interesting, too, that some people seem concerned about humans contaminating Mars with bacteria. We shouldn't forget that past probes which have landed (or crash-landed!) on Mars were not always well sterilized. And yet, when they have been described as very probably conveying millions of viable microbes to Mars, there appears to have been a consensus of opinion here that Martian conditions would quickly kill them.

I'm confused. :!:

If bacteria emanating from a human in an MCP spacesuit can survive and contaminate the planet, won't that have occurred already, when bacteria-laden spacecraft have broken open and half buried themselves in the regolith during crash landings? [Remember, even one microbe, delivered intact into the subsurface regolith, can become trillions very quickly.]
-- Or, if the regolith is rich in antiseptic hydrogen peroxide and other sterilizing super-oxides (as Viking scientists concluded), and the frozen dessicated Martian surface is bathed in deadly levels of UV light, then what are some people so worried about?

Is there a confusing contradiction inherent in our reasoning here?  :?:  :?


The word 'aerobics' came about when the gym instructors got together and said: If we're going to charge $10 an hour, we can't call it Jumping Up and Down.   - Rita Rudner

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#37 2005-08-28 06:28:33

Grypd
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From: Scotland, Europe
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Posts: 1,876

Re: Spacesuits - personal spaceship

I suspect that with the Martian probes we have sent being confined primarily to the surface of Mars then those surface conditions will quickly kill any micro life sent assuming they survived the trip to Mars.

But Humans are living and as such are Microbacterial factories and we are frankly going to be delving deep into Mars and looking for life. That means finding those places where life could exist like permanent ice and water deposits and underground aquifers etc. If we leak bacteria etc then we will contaminate those spots and making ourselves sterile is a lot harder than doing so for a probe.

So we will just have to use a bit more caution and have to accept that if there was no life on Mars before we came there certainly will be when we leave. And is that really a bad thing.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

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#38 2005-08-29 09:37:51

SpaceNut
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Posts: 26,753

Re: Spacesuits - personal spaceship

With any new design for a differing environment than any previously functional unit comes the search for new materials to which to make it from. Of course that said, many materials can be used else where when we must meet the goals of -200 to +200 degrees Fahrenheit or to be able to obsorb 20 g's worth of energy. Maybe even usefull for Bigelows hotels.

[url=http://www.boston.com/business/technology/articles/2005/08/29/the_goal_fabric_that_can_stop_a_micrometeorite/]The goal: fabric that can stop a micrometeorite
Tiax researchers strive to design materials for NASA[/url]

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#39 2005-08-29 16:26:38

JonClarke
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From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Spacesuits - personal spaceship

I see only one real drawback of an MCP-spacesuit and that is the dressing and undressing of the suit due to the tight shape and the strong fibers. 

So IMHO I would prefer an hybrid suit with an combination of two different "pressurisation" systems. IMHO the best could be an combination of the normal MCP-system using strong fibers with an pneumatic of hydrostatic pressurisation system like the one used for the LIBELLE G-Multiplus Anti-G suit pilots use when they fly the new Typhoon-Fighter. Well the Libelle-suit is completely passive cause the G-forces alone are sufficient to do the work, but in the space-suit the pressure would have to come from an external source like the breathing system.

With such an rather simple additional system the dressing and undressing should be much simpler cause the suit has not to fit so tight without the additional pressure.

Different levels of hybrid suits are feasible.  One with MCP gloves only would be feasible and have huge impact on EVA operations.  Gloves are the biggest problem for GP suits.  Suitable gloves already exist (James Waldie's PhD project) and are relatively easy to don and doff ( maybe two minutes.  The interface with the rest of the suit is also easy.  Although uncomfortably tight at atmospheric pressure they are not impossibly painful.  I have worn James' glove for over and our at one atmosphere.  The next level would be a GP torso and MCP limbs.  This would allow significant mass reduction, increased safety and better mobility.  Interfaces beteen MCP and GP components would also be useful.  It should not be too much harder to don and doff either.

The ultimate solution to the doning and doffing problem may well be electroactive fibres that relax when a current passes through them.  You would connect your suit to a power source, but it on and then turn the power off when ready to prepressurise, the fibres would then tighten to a preset sension.  As I understand it, such fabrics already exist.

One additional problem I see with the MCP-spacesuit is that you use an "open" spacesuit to allow sweating. NASA will never use such an spacesuit (and all the scientist will agree) because the sweating can and IMHO will contaminate Mars so the search for life will never be conclusive.

Also, due to the "open" MCP-spacesuit the danger exist that the rather toxic marsian dust will contaminate the suit and the astronaut inside the suit. But IMHO an simple and straight-forward protection could be to wear something like an paint-overall over the MCP-suit.  Such an protective overall could be undressed even outside of the air-lock and so most of the contamination would stay outside of the habitat. The overall then could be put in an bin or cleaned in an closed system.

An outer Hazmat layer is certainly feasible and has been proposed by James Waldie as an option.  It may not be neccessary, however.   We don't know that the Martian surface is toxic, some people have postulated that it might be.  But it may not be any more toxic than terrestrial dust, at least to skin contact.  You will want to exclude dust from the hab interior anyway, because any respirable dust on earth or Mars is bad news.

As for contaminating Mars, any suit will do this.  Gas pressure suits leak, airlocks are a source of contamination as well.  It can be kept to a minimum, but not eliminated, If contamination of Mars is such a big issue then we should not land there, work with telreoperated robots from Mars orbit.

With respect to spacecraft that have landed on Mars, it is my understanding that only the Vikings had full sterilisation.  Other spacecraft had level III (Mars, Pathfinder, MER, DS2), IV (MPL) or IV+ (Beagle) cleaning or equivalent.  Steve Squyres made the interesting point recently than modern electronics would not be able to to withstand a Viking style heat treatment.

Jon

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#40 2005-08-29 17:05:57

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Spacesuits - personal spaceship

One of the biggest issues that needs to be addressed before astronauts spend much time on Mars or the Moon is how to get the dust off a suit so you don't contaminate the HAB.

In a perfect world, you would have enough water so that you could literally shower a suit off while the astronaut stands on a metal grating to catch the dust-bearing water. This would take an awful lot of water to do however, and the water would have to be distilled before it could be used again due to disolved salts, which could be a substantial energy drain... However, the waste heat might be useful to warm the HAB.

Astronauts could also use a "dry" system, where powerful blowers or compressors would blow the dust off them and deposit it onto a circulation filter, but this probobly won't be as effective, especially for charged dust. Air circulation might be a problem, where dust would "pool" in the corners of the room, unless jets were installed there to counter that. Alot of plumbing... Perhaps if the airlock were carefully shaped to be a smooth-walled cylinder, that wouldn't be a problem.

Any other bright ideas? Coat the suit with a conductive material (conductive polymers exsist) and see if you can knock the dust off it electrostatically? Could dust be negatively polarized with Ultraviolet lamps and then knocked off by a like charge jolt to the suits' exterior? This would have the added bennefit of helping to sterilize the exterior.

I'm pretty sure that just going over the suit & airlock with a hand-held vacuum is not going to be effective enough.

As far as biological contamination of Martian soil giving a "false positive" for the presence of life, I think that is kind of silly... Earth microbes don't stand a chance on the ice-cold, dessicating, UV-blasted, peroxide-laced surface where the astronauts will be. And neither will the Martian microbes, either... We drill on Earth into glaciers to look for interesting microbes, why not Mars? This is a big reason that I don't like MarsDirect, since it doesn't afford enough surface payload to bring a heavy-duty drill.

And can't we recognize our own microbes well enough not to get them confused? I'm pretty sure that Martian life won't look the same under the microscope.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#41 2005-08-29 18:57:22

Fledi
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From: in my own little world (no,
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Posts: 325

Re: Spacesuits - personal spaceship

What if the suit is designed in a way that the top of the suit can be fitted into some sort of docking adapter and opened wide enough that the astronauts can climb out through the top.

The suits would stay outside all the time connected to these locks like the gloves in a sandblast machine or a sterile room. They could be turned inward to clean the inside and cleaned by compressed CO2 on the outer side.

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#42 2005-08-29 22:08:45

John Creighton
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Re: Spacesuits - personal spaceship

What do we need to pressurize? Mostly the head right? For a good seal it will probably come some over the chest and biceps.

Could everything else be like extra tight support stalking not necessarily connected? So you put on you head gear then pull on some extra stretchy pants. Or gloves. I am not sure about the stomach. Perhaps a bunch of pads with some cables you can tighten once you get it on.

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#43 2005-08-30 02:52:51

JonClarke
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From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Spacesuits - personal spaceship

One of the biggest issues that needs to be addressed before astronauts spend much time on Mars or the Moon is how to get the dust off a suit so you don't contaminate the HAB.

I suspect a multi-step process will be taken.  First, as people step onto the porch they will brush/scrape off the larger clumps.  Then compressed air jets (air showers will blow off most of the remaining dust.  Remember how effective even wind has been cleaning the rovers. In the airlock people may first vacuum their suit exteriors after repressurisation before doffing an outer protective suit, if needed. They may then vacuum and doff pressure suits or opening the interior hatch.  Good design of suits and surfaces would minmise dust adhering to them.  Good air filters will be able to handle any remaining airborne particles down to 0.1 microns.  This will eliminate everything except virii. 

It is important to remember that there are lots working environments on earth that have high levels of harmful dust - mines, metallurgical plants, drill rigs, etc. Millions of people work in these environments every day. There is a lot of experience in mitigating the risks posed by such dust.  The solutions require clever engineering, but are not particularly complex.

Jon

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#44 2005-08-30 03:08:33

JonClarke
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From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Spacesuits - personal spaceship

What if the suit is designed in a way that the top of the suit can be fitted into some sort of docking adapter and opened wide enough that the astronauts can climb out through the top.

The suits would stay outside all the time connected to these locks like the gloves in a sandblast machine or a sterile room. They could be turned inward to clean the inside and cleaned by compressed CO2 on the outer side.

The suit port idea is very interesting.  If the surface is deemed very toxic, then it would be a good way to go.  However if the surface is that toxic it means that EVAs would be limited and most stuff will be done by teloperation from inside rovers or habs.  In that case it might be better to cut the risk entirely and just work from orbit.

Another issue with suit ports is that they work only with GP suits, they are not compatible with MCP as far as I can tell.  So you are left with a great idea to manage dust but a lousy suit. 

You will still need an ordinary airlock with all the dust control gear as backup anyway.  You will need this in the event of an emergency or if you want to bring the suits inside for servicing.  This will be inevitable in all but the shortest surface stays.

NASA Ames have developed the suit port idea in conjunction with a modified M113 APC and hazmat suits for use in contaminated areas. See http://dart.arc.nasa.gov/HazMat/R&D/rd.html and Figure 5 in this reference http://www.spacearchitect.org/pubs/SAE-2000-01-2389.pdf

Jon

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#45 2005-08-30 03:12:10

JonClarke
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From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Spacesuits - personal spaceship

What do we need to pressurize? Mostly the head right? For a good seal it will probably come some over the chest and biceps.

Could everything else be like extra tight support stalking not necessarily connected? So you put on you head gear then pull on some extra stretchy pants. Or gloves. I am not sure about the stomach. Perhaps a bunch of pads with some cables you can tighten once you get it on.

I think this is certainly one way to go.  Getting a good seal between the gas pressuised heat (which you must have) and the toro is a challenge.  Not only is the upper chest a complex shape (unlike the lower and upper limbs) you also have to allow for breathing movement.  It can't be too high either, otherwise you constrict the neck, not a good idea wink   But, and this is important, it has been done, back in the 60's.

Jon

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#46 2005-08-30 07:56:11

Fledi
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From: in my own little world (no,
Registered: 2003-09-14
Posts: 325

Re: Spacesuits - personal spaceship

The port idea could also be a simple outer layer over the actual suit (transparent plastics over the head piece), which could be an MCP type also in this case.
If this outer layer is damaged it could be just thrown away still leaving you with a working suit inside.

But I agree this is only relevant if the dust proves to be really toxic. I would still be for going down and work there even then.
Space isn't that harmless with all the radiation and micrometeorites either, after all, and it will be way cheaper to build heavy structures to protect against these down on the planet than in orbit.
And I think any dome or greenhouse can be protected from the dust well enough, even in the case of a leak the gas (and dust) would stream outward from the pressurized place offering a natural protection mechanism.

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#47 2005-08-30 08:17:15

Grypd
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From: Scotland, Europe
Registered: 2004-06-07
Posts: 1,876

Re: Spacesuits - personal spaceship

It is not its toxicity that is the main problem rather the shape of the particles of dust. Toxicity is likely just an additional problem.

Still im all for the idea of powered suits using mechanical and electrical means to increase the explorers strength and capability. If this means the suits are just walk in conditions this may prove a better idea as there is a need to have astronauts to be instantly ready to operate and if the need arises just to step into the suit and go. This basically removes the heavy breathing exercises and pre use techniques that the current USA suit requires to operate.

Power should not be a problem as crews should not go too far from the ability to recharge the suits as the Hab and crewed rover should have the capability to recharge suits batteries.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

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#48 2005-08-30 08:34:03

SpaceNut
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From: New Hampshire
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Re: Spacesuits - personal spaceship

Sort of like the unit that was used in the movie alien by weaver to fight the alien with and to move cargo containers.

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#49 2005-08-30 09:51:08

Grypd
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From: Scotland, Europe
Registered: 2004-06-07
Posts: 1,876

Re: Spacesuits - personal spaceship

yes but definitly a lot smaller something between a deep sea hardsuit and that aliens mechanical lifter.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

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#50 2005-08-30 13:28:39

RobertDyck
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From: Winnipeg, Canada
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Re: Spacesuits - personal spaceship

If fines are a concern why not an MCP suit designed to be machine washable? As Larry pointed out at the Mars Society conference, 5 layers of aluminized Mylar in vacuum acts as a super insulator due to the thermos bottle effect. Even in the low pressure of Mars that doesn't work, convection and conduction transports heat; in fact the aluminum acts as a heat sink to conduct heat away. I think we need Thinsulate, the same insulation fibre as ski jackets. Use 80 denier Gore-tex fabric for the outer layer with the same water repellent Gore-tex membrane as water repellent jackets on Earth. That membrane will keep fines out of the insulation fibre. Gore-tex membrane has tiny holes too small for liquid water to pass but water vapour can, so sweat from an astronaut's body will evaporate (not sublimate) through the Spandex MCP layer and through the parka. That means the parka and ski pants will literally be made as Alpine mountain climbing gear. Gore-tex is PTFE, a fluoropolymer made by Gore. Dupont sells fluoropolymers under the brand name Teflon; that tells you how non-stick the stuff is. Gore-tex is machine washable and tumble dry at low temperature. Spandex is obviously machine washable. From Dr. Webb's presentation at this year's conference, there are new fabrics you would incorporate in the MCP garment, but I suspect the whole thing can designed to be machine washable. To keep dust and fines in the EVA prep room, put the washing machine in that room. So the EVA prep room functions as a mud room of a house.

Add a fan with a HEPA filter to the EVA prep room, ventilation just strong enough to ensure air flows into the room through an open door, not out. That means filtered air ducted into the rest of the hab, and a fan about as strong as a bathroom exhaust fan.

This reference shows a regolith analog produced fines smaller than 1µm diameter, although it's less than 0.2%. Figure 3 chart d shows particle size after 72 hours of abrasion, a large percentage is ~3µm diameter.
Aeolian abrasion and fine particle production from red sands: an experimental study.

This reference says HEPA filters remove 99.97% of particles at 0.3 microns (µm).
IQ Air

A HEPA filter will not only block Mars fines, the particle size is so close that you couldn't ask for a better match. Hmm, mud room, bathroom exhaust fan, HEPA filter, washing machine, this isn't some complicated hi-tech stuff. We can go now. To keep things compact and light weight you may want an apartment size washing machine, but again we can go now.

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