Spacesuits - personal spaceship

BWhite · 2005-08-30 14:14:58

Perhaps rear entry spacesuit could be docked to an airlock system where the suit stays in a pressurized vestibule with two hatches. The ILS Dover link is very good.

The astronaut enters the suit and both hatches are closed and the astronaut then de-pressurizes the vestibule to go outside.

= = =

Robert, you do not want the lunar fines inside the spacecraft, period. The potential for lung damage is very real, from what I read.

John Creighton · 2005-08-30 14:40:24

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 But, and this is important, it has been done, back in the 60's.
Jon

I was thinking Perhaps about an inch of rubber that could be pressed against the chest and biceps by tightening some cables. Cables could also attach the head/chest unit to the pants if needed. I am not sure what should go over the stomach.

JonClarke · 2005-08-30 14:57:11

Without checking Webb's original papers, I think this was how he did it. Whay people are trying to is do it better with modern materials that are more comfortable and easier to get on and off.

Jon

TwinBeam · 2005-08-30 16:01:55

A few more ideas on a 'dust room' (mud room):

Have the dust-off room at Mars pressure, so dust settles faster. (Probably the default, but I figured it should be made explicit.)

Wear tube socks over the MCP suit, so you can strip them off as you step from the dustroom into a clean area, avoiding tracking in dust.

Have an open "grill" floor so most dust falls through - reducing dust kicked up while changing. The grill can just be a stretched heavy plastic net. A quick dry mopping will further reduce dust on the floor.

Have a small clean anteroom between the airlock and the dustroom, with a light but well sealed door to keep dust away from the airlock. Kick on a fan only when anyone steps into the chamber, or starts to open the door.

RobertDyck · 2005-08-30 16:03:47

Dr. Webb's first paper detailing his work in 1967 and published in April 1968 covered his initial work and the first prototype suit. That suit was all MCP with a head-worn helmet and pressurized boots. He was worried about filling the gap in arm pits but found it wasn't necessary, only a gel filled pad along the trough of the lumbo-dorsal spine (small of your back and upper back). The test subject found the tight fabric around his chest made breathing difficult so the later version described in their November 1971 NASA contractor report added an air bladder over the chest and upper abdomen. To ensure pressure was the same as inside the lungs he connected the bladder to the helmet with a hose. Pretty simple. The later version also had a body-worn helmet like Apollo suits. I asked him about the helmet at the conference. He said he always intended to use a body-worn helmet but couldn't afford one for the initial suit; the manufacturer donated one for use with his later suit.

He also said at the conference he's working with new fabrics that provide constant strain force while stretching, and other places using fabric that doesn't stretch much. For example, long the top of knuckes you need constant elastic force while bending but around the same knuckle you need to ensure fabric doesn't stretch while maintaining constant pressure. This is true of all joints, it must expand/contract on the outside/inside of the joint while around the joint it remains constant.

He's been working on gloves lately. He came up with a frame that grabs glove fabric and holds it open while you slip your hand in, then the frame slides off to let the glove contract around your hand. He said it's as easy as sliding on surgeon's gloves.

He said the body would have an underlayer of fabric that draws moisture away while providing a layer that the tight elastic layer can slide against. The liner prevents abrasion from your suit rubbing. I image that under layer would be made of the same DryWeave of women's sanitary napkins. Since the under layer isn't elastic it should be as easy to put on as long underwear, and a smooth layer makes pulling the elastic easier.

RobertDyck · 2005-08-30 16:11:07

Mud room: take off the spacesuit in the EVA prep room. Wear clean clothes inside.

One local member raised the question of HEPA filter clogging. He suggested bubbling air through water. I think some fines could get through the water so a HEPA filter is needed anyway, but the water tank could extend the filter life. I didn't think enough fines would get in to need the tank but if astronauts go out on EVA every day it might. Again, water tank simple. You can do that sort of thing in gravity.

JonClarke · 2005-08-31 02:21:18

Given that pressurised volume is going to be at a premium on initial missions, and that staged cleaning may be neccessary, the question I would like to seehow much suit cleaning can be done under ambient martian conditions in an unpressurised porch? Before tracking dirt inside?

Using water for cleaning is to be avoided if possible - you need extra filters, a new water cleaning loop etc. And it is an extra demand on water supplies.

Jon

SpaceNut · 2005-08-31 05:07:22

That is why one of the thoughts in the compressed Co2 thread was to liquify it and use it to wash the outside of the suit.
As far as static cling you can use an air ionizer or attachment that ionizes the air as it comes out of the nozzle.

Mace · 2005-08-31 14:14:58

Question: couldn't we just put on a pair of swim goggles, pug the nose, put on a mouthpiece attached to oxygen, and cover the rest of the head with a tight ski-mask?

I like the suit port idea, but crawling out from the top could be a bit hard. Getting out of such a tight fitting suit will be the hard part. Maybe we could coat the outside with a air tight "spandex" then blow the suit up like a balloon. Getting out and in would then be easy and then, when we want to go out again, we could deflate the suit, somehow get rid of the outside air tight stuff, and walk away happily.

JonClarke · 2005-08-31 16:25:19

That is why one of the thoughts in the compressed Co2 thread was to liquify it and use it to wash the outside of the suit.

The problem is you will end up with a dry ice snowman astronaut if you do it. Compressed liquid sprayed out in Martian surface conditions will undergone decompressive cooling and form dry ice. Compressed (not liquid) CO2 yets would be better.

Jon

SpaceNut · 2005-08-31 20:31:31

When using the wash you are inside the mud room entry hatch and it is a climate controlled location causing it to Vaporize

GCNRevenger · 2005-09-01 06:07:23

I don't think that these ideas are quite stringent enough, that thanks to how dry the air and dust are, the dust is going to get everywhere. It is not enough for an astronaut to remove his suit and then get the dust off, because the astronaut himself will carry too much dust back into the HAB. The dust absolutely has to be nearly completly removed before even taking off the helmet/gloves, and before the inner airlock door is opend.

Water is, barring drilling into a glacier on Mars on location, too valuble and heavy to wash the exterior of the suit with. Liquified CO2 will do no good, since it is only a liquid under pretty high pressure, too high for astronauts suit or no suit.

BWhite · 2005-09-01 06:58:23

Some say lunar dust will respond well to magnetism. Thus, use a magnetic brush.

Martian dust may need a different fix. Especially if it contains asbestos (I read somewhere that Mars dust might) then opening up the helmet and brushing is straightaway out as a strategy.

RobS · 2005-09-01 07:48:17

Neither lunar nor Martian dust should respond to magnetism; they are mostly silicates.

There is an interesting article on Space Daily today about using electrostatic forces to repell dust off of solar arrays. I'm not sure that would work with space suits, though. Maybe the suits could have an outer layer that one could charge up to repell any dust still on the suit after you blow most of the dust off with compressed CO2. Actually, the compressed CO2 blast might very well charge any dust still on the suit, so an electrostatic charge would repell the rest.

-- RobS

BWhite · 2005-09-01 09:10:01

Neither lunar nor Martian dust should respond to magnetism; they are mostly silicates.
-- RobS

Rob, at the Return to the Moon conference held in Las Vegas, I saw a demonstration using actual Apollo 17 samples inside a glass jar. The stuff did respond very nicely to magnetism.

Why? Vapor deposited nanophase iron.

The other "cool" aspect of nanophase iron being found in lunar regolith concerns what happens when actual regolith is subjcted to microwaves. Microwave JSC-1 simulant and little happens of any interest. Taylor microwaved actual Apollo 17 samples and the nanophase iron was sintered in fascinating and useful ways.

One of Taylor's conclusions is that JSC-1 is wrong (inaccurate) in certain critical aspects. Robotic lunar sample return may be more important (and thus commercially viable) than previously believed.

= = =

This paper mentions greatly increased magnetic properties of regolith due to the vapor deposition of nanophase iron.

GCNRevenger · 2005-09-01 12:20:19

Hmmmm nanoscopic iron particles, interesting. Just what kind of magnetic system did you have in mind, Bill?

I bet that Martian dust won't be quite so convienant though, and some sort of electrostatic or mechanical (CO2 jets) system would be needed.

Charging the exterior of a suit should not be really really hard, flexible conductive polymers exsist.

JonClarke · 2005-09-01 14:48:42

Martian dust also contains a fraction of magnetite and maghaemite, both of which, of course, magnetic.

The fact is, some dust will get inside. The question is, how much can be tolerated? That requires characterisation of its physical, chemical, mineralogical, and biological nature. If there are organisms known to be in the dust beforehand I am willing to bet that manned landings will be out for the foreseeable future. Whether the concerns are justfied or not will be irrelevant. Paranoia will ensure that.

f not then we are doing to be working with a dust hazard not too dissimilar to what we are already familiar with on earth. We can live and worth safely with dust on earth, including highly hazardous dusts (corrosive, carcinogenic, radioactive, explosive, posionous), we can live and work safely with dust on Mars.

Aerospace engineers are used to working with conditions of extreme hygiene. They are going to have to get used to getting down and dirty with the rest of us

Jon

GCNRevenger · 2005-09-01 16:51:39

Unless just about all the Martian dust has magnetic species in it, then magnetic means alone won't do. Same thing with the Moon.

There is a biiig difference between simply being able to work in a dusty environment and being able to live in it. If the vast majority of the dust cannot be excluded from the HAB beyond the airlock, then we aren't spending much time on the Moon or Mars, since you aren't going to live in such a condition. You can't live in a tiny tin can that is perpetually filthy, nor can you expect the astronauts to live with dust masks inside the HAB. If you can't keep the place reasonably free of dust, then living there long term is not happening.

If you can't ever live in a fairly clean place, particularly if the dust is harmful, then living there is not going to happen.

RobertDyck · 2005-09-01 17:49:17

I expect the manned mission to land a location within the tropics (±25.19° latitude) for warmth, low altitude to reduce radiation (practically no heavy ion radiation gets below the datum), and high concentration of water in the soil. The bottom of a valley (vallis) should have both low altitude and high water. The water mass fraction in the upper metre of Mars soil was mapped by Mars Odyssey's gamma ray spectrometer suite that included neutron spectrometers.
Water Mass Map

You can see from this map there are spots in the tropics with 10% water mass, especially Meridiani Planum. I'm hoping to get better data from ground penetrating radar on Mars Express and Mars Reconnaissance Orbiter.

JonClarke · 2005-09-02 03:01:24

Unless just about all the Martian dust has magnetic species in it, then magnetic means alone won't do. Same thing with the Moon.
There is a biiig difference between simply being able to work in a dusty environment and being able to live in it. If the vast majority of the dust cannot be excluded from the HAB beyond the airlock, then we aren't spending much time on the Moon or Mars, since you aren't going to live in such a condition. You can't live in a tiny tin can that is perpetually filthy, nor can you expect the astronauts to live with dust masks inside the HAB. If you can't keep the place reasonably free of dust, then living there long term is not happening.
If you can't ever live in a fairly clean place, particularly if the dust is harmful, then living there is not going to happen.

It all a matter of sequential removal. If a magnetic separator removes half the dust that is a half that does not need to be removed by other means.

No argument from me at all about the importance of Martian domestic hygiene. The fact is people live and work in dusty environments on earth. Take a large mine and process plant in the desrt. It is a busty environment to start with. Add blasting, excavation transport, stock piling and milling and things get a lot dustier. There is lots of dust and larger bits of dirt to get tracked round. In the mill there are toxic fumes as well - acid vapours, cyanide, exhaust gases. Many areas in the plant will require protective clothing and respiratory apparatus against dust and fumes. But in the same complex you will also have office and dining areas where the air has to be kept as clean as in a normal work environment. There will be other areas which have to be kept cleaner - laboratories for example, and the medical office. Dirt is kept to safe levels by keeping doors closed, having double doors, making sure people leave dirty gear outside, good airconditioning with appropriate filters, and cleaning regularly. Dust levels are monitored regularly and can be kept within specified levels approrpirate to different areas. It's no big deal, it happens at hundreds of places.

Same on Mars. Assuming people use a normal airlock rather than a suit port systems, this is the type of proceedure. We know that an air shower will easily remove most of the adhering dust. This can be done on the hab porch. Once pressurised inside the airlock you then vacuum the suits and the hab interior. We know this will be effective. Any airborne dust not picked by the the vaccum cleaner will be removed by the air filters. You then remove and stow the suits in a storage area, before moving into the main part of the hab where you can wash. Any dust that enters the main hab will be minor. It will either be removed by the air filters if airborne or cleaned up as part of the daily housekeeping if not. There are lots of simple ways for the routine monitoring of airborne dust to ensure it does not exceed the specified levels.

Dust is an issue on mars but for it to be a problem requires us to say we can manage dust on earth but on Mars we can't .

Jon

GCNRevenger · 2005-09-02 06:32:27

Staged removal is probobly a good idea, but how you do the removal is what I am thinking about. Simply vacuuming the airlock may not be effective enough against Lunar/Martian dust, and so a system like a "walk in washing machine" except with gasses might be needed.

Also, using gas sprays on the Moon to remove dust isn't practical, since wasting valuble gasses is a bad idea, and would have to be done in the airlock to recycle the gasses.

SpaceNut · 2005-09-02 07:37:38

NASA's Desert Rats Take On Harsh Mobility Challenges

Meaningful exploration in the hostile environs of the moon and Mars will depend on mobility. Tough, dependable equipment will be needed to get there, work there and get back safely.
NASA's Desert Research and Technology Studies (RATS) "torment" some of the latest vehicles and gear in the harsh world of Arizona's high desert. Their job is to better understand just what it takes to be mobile in a rough, unforgiving environment.

JonClarke · 2005-09-02 17:06:36

Staged removal is probobly a good idea, but how you do the removal is what I am thinking about. Simply vacuuming the airlock may not be effective enough against Lunar/Martian dust, and so a system like a "walk in washing machine" except with gasses might be needed.
Also, using gas sprays on the Moon to remove dust isn't practical, since wasting valuble gasses is a bad idea, and would have to be done in the airlock to recycle the gasses.

We know that the dust is easily moved from fabricated materials by even Martian winds. Why would vaccuming not be effective? On the Moon is there any reason why it won't be effective on lunar dust? Remember it does not have to remove all of it, just most of it.

One reason why the Apollo suits got so filthy is the way that dust got ground into the fabric. Ground in dirt, as the ads remind us, is difficult to deal with, especially if it is fine (I am still trying to remove soot stains (tpically 1 micron) from white jumper). A different weave or choice of materials would reduce the problem, as would a disposable outer layer.

Jon

GCNRevenger · 2005-09-02 20:46:56

The Martian wind removes some of the dust from flat, smooth solar pannels, which may also have some electrostatic properties due to the type of cells used, and we have no idea what size or type of dust may be preferentially adhered.

Fabric? Apollo? The Apollo suits were not made of any sort of fabric, their exteriors were smooth, slick, Teflon to avoid abraison damage to the underlying membrane. The dust stuck to it most likly because of the static electric effects, just like a plastic comb will build up a charge in dry air.

A disposable outter layer is a non-starter, since you obviously can't bring that many. Nor would putting on or taking off an outter layer be simple enough, and during removal too much dust could be carried over to the underlying suit, which defeats the purpose.

BWhite · 2005-09-02 21:27:39

Hmmmm nanoscopic iron particles, interesting. Just what kind of magnetic system did you have in mind, Bill?
I bet that Martian dust won't be quite so convienant though, and some sort of electrostatic or mechanical (CO2 jets) system would be needed.
Charging the exterior of a suit should not be really really hard, flexible conductive polymers exsist.

The idea I heard was a simple magnetized brush (magnetic wire whatever you call brush bristles) to collect dust from the exterior of spacesuits. Just get the dust to stick to the brush rather than the suit.

Anyway ALL of this is from Larry Taylor at Univ of Tenn who spoke at "Return to the Moon" and articles he passed out co-authored by Harrison Schmidt among others.

Per my memory. . .

= = =

But d'oh, GCNR, I had forgetten the very best part.

These nanophase bits of iron ABSORB microwaves very efficiently. No frying out your unit like when you stick an iron nail in your home microwave.

This (as best as I can recall) allows the heating of regolith using far less electricity than other means. Therefore, pyrolysis is much cheaper using microwaves.

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#51 2005-08-30 14:14:58

Re: Spacesuits - personal spaceship

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