Mars Suit Outer Garment Fabric?

[Chris Vancil]

Hello Everyone,

I've been think about the requirements for the external garment worn
with a Mars Surface Spacesuit. Of course a TMG for Mars would be
greatly influenced by the type of suit under it whether it's a MCP or
soft or hard suit, still we should be able to narrow the types of
suitable fabrics for a TMG.

Typically Kevlar or Vectran are mentioned to me when a single material
is suggested and although they are in use in the space related
activities, Ortho-Fabric (Kevlar as rip-stop with Gor-Tex and Nomex)
of EMU and in the Pathfinder, MER and Beagle II Airbags (Vectran) they
quickly break down under UV.

Considering the possibilities of super peroxides, the abrasiveness of
the regolith, extreme cold environment, UV exposure and the long
duration these suits will be subjected to these conditions weaves of
several fibers maybe best. But these conditions will enviably expose
these weave's component fibers to things they don't tolerate well.
Anyway, for a variety of reasons I've been looking at current
sailcloths for the properties best suited for fabricating these TMGs
from. Some of my reasons being they spend lots of time looking for
performance characteristics similar to those need in a Mars Suit outer
garment. They require light weight, durable material with high
tenacity and flexure among other properties.

I think old standards of sailcloth making like Cotton Canvas, Nylon,
Dacron or Orlon might beat out such new comer as Spectra, Vectran and
Kevlar. Spectra is susceptible to creep, Vectran and Kevlar are
degrade exposed to UV and aren't as flexible.

So what material is your current favorite? What is your reasoning?

--Chris Vancil

[MSu1049321]

beta cloth. It's well understood.

[Chris Vancil]

(MSu1049321) wrote in message >...
> beta cloth. It's well understood.


Beta Cloth is made out of glass fibers. Some of the reasons that
Apollo era suits are now faling apart is Beta Cloth. It's primary
useful property is non-flammablity thus it's a good high temperature
flame barrier.

We need a fabric with many of the properties of heavy duty work jeans.
Kevlar and other High Modulus fabric are possible candidates. But
they need to be able to be stowed and folded and exposed to UV.

--Chris Vancil

[Ian Stirling]

Chris Vancil > wrote:
> (MSu1049321) wrote in message >...
>> beta cloth. It's well understood.
>
>
> Beta Cloth is made out of glass fibers. Some of the reasons that
> Apollo era suits are now faling apart is Beta Cloth. It's primary
> useful property is non-flammablity thus it's a good high temperature
> flame barrier.
>
> We need a fabric with many of the properties of heavy duty work jeans.
> Kevlar and other High Modulus fabric are possible candidates. But
> they need to be able to be stowed and folded and exposed to UV.

Do 'we' have a good handle on how mars dust will behave?

Lunar dust is (IIRC) horribly abrasive, and gets in between woven
fabric fibers and starts to erode them, in addition to making sealing
difficult.

Is martian dust as bad, or does the presence of atmosphere and erosion
make it a bit less sharp?>

--
http://inquisitor.i.am/ | | Ian Stirling.
---------------------------+-------------------------+--------------------------
All I want is a warm bed, a kind word and unlimited power -- Ashleigh Brilliant.

[Chris Vancil]

Ian Stirling > wrote in message >...
> Chris Vancil > wrote:
> > (MSu1049321) wrote in message >...
> >> beta cloth. It's well understood.
> >
> >
> > Beta Cloth is made out of glass fibers. Some of the reasons that
> > Apollo era suits are now faling apart is Beta Cloth. It's primary
> > useful property is non-flammablity thus it's a good high temperature
> > flame barrier.
> >
> > We need a fabric with many of the properties of heavy duty work jeans.
> > Kevlar and other High Modulus fabric are possible candidates. But
> > they need to be able to be stowed and folded and exposed to UV.
>
> Do 'we' have a good handle on how mars dust will behave?
>
> Lunar dust is (IIRC) horribly abrasive, and gets in between woven
> fabric fibers and starts to erode them, in addition to making sealing
> difficult.
>
> Is martian dust as bad, or does the presence of atmosphere and erosion
> make it a bit less sharp?>

The scientists that I've talked with on this subject are of two basic
opinions. One view is pretty much that the Moon's regolith is all we
know so we should assume it's like that. The other group see Mars
having erosion and say it is somewhere between Earth and the Moon.
The 64 million dollar question is where on a hypothetical erosion
graph does Mars regolith lay?

I will hazard a layman's unprofessional guess. It's at least as
eroded as ash from Mount St. Helens is now 23 years later.

There are ways to block the dust getting into the bearings of a
pressure suit, but more research needs to be done on this problem
before committing to a final choice of outer garment design. Still
picking fabrics that might be workable seem doable now.
--Chris Vancil

[Harmon Everett]

Duct tape.

[Thomas Billings]

In article >,
Ian Stirling > wrote:

> Henry Spencer > wrote:
> > In article >,
> > Ian Stirling > wrote:
> >>Do 'we' have a good handle on how mars dust will behave?
> >
> > Not a good one. Current guess is that it will be much like lunar dust,
> > but data is very limited.
>
> >>Lunar dust is (IIRC) horribly abrasive, and gets in between woven
> >>fabric fibers and starts to erode them, in addition to making sealing
> >>difficult.
> >
> > Correct. The Apollo suit joints were giving trouble after only three days
> > of exposure to it. The wear problems were reduced considerably by adding
> > expendable overgloves, but this wouldn't have sufficed forever.
>
> Was it especially irritating to skin, or did it not often get that far?

It did work into the skin, and there was concern about irritation and
worse over longer time periods. I was told by a few astronauts they just
had to let their skin *grow* it out.

All in all, for stays longer than a month or so, I would demand
*someplace* to get in out of the dust and get clean. Our team's choice
for this, as our papers point out, is a lavatube cave as a base site,
far enough into the tube from the cave entrance that the base isn't
contaminated with lunar surface dust.

Regards,

Tom Billings

--
Oregon L-5 Society

http://www.oregonl5.org/

[Henry Spencer]

In article >,
Ian Stirling > wrote:
>> Correct. The Apollo suit joints were giving trouble after only three days
>> of exposure to it. The wear problems were reduced considerably by adding
>> expendable overgloves, but this wouldn't have sufficed forever.
>
>Was it especially irritating to skin, or did it not often get that far?

It got everywhere within the LM -- the LM crew were notorious for looking
like coal miners by the time surface activities were over -- but I don't
recall any mention of skin irritation.

There has been some speculation that Mars dust might be chemically active,
which would require more stringent measures to control it. (On the other
hand, there were speculations like that about Moon dust too, which proved
totally unfounded.)
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

[Bill Bogen]

Ian Stirling > wrote in message >...
> Chris Vancil > wrote:
> > (MSu1049321) wrote in message >...
> >> beta cloth. It's well understood.
> >
> >
> > Beta Cloth is made out of glass fibers. Some of the reasons that
> > Apollo era suits are now faling apart is Beta Cloth. It's primary
> > useful property is non-flammablity thus it's a good high temperature
> > flame barrier.
> >
> > We need a fabric with many of the properties of heavy duty work jeans.
> > Kevlar and other High Modulus fabric are possible candidates. But
> > they need to be able to be stowed and folded and exposed to UV.
>
> Do 'we' have a good handle on how mars dust will behave?
>
> Lunar dust is (IIRC) horribly abrasive, and gets in between woven
> fabric fibers and starts to erode them, in addition to making sealing
> difficult.
>
> Is martian dust as bad, or does the presence of atmosphere and erosion
> make it a bit less sharp?>

Or it is _worse_ than lunar dust? Erosion may make finer particles,
dry conditions keep them from re-bonding to soil, wind can drive them
deeper into fabric/joints, and they may be more chemically active. Do
any Mars probes (current or proposed) include means to collect data on
dust (size,amount, composition)?

[Chris Vancil]

(Bill Bogen) wrote in message >...
> Ian Stirling > wrote in message >...
> > Chris Vancil > wrote:
> > > (MSu1049321) wrote in message >...
> > >> beta cloth. It's well understood.
> > >
> > >
> > > Beta Cloth is made out of glass fibers. Some of the reasons that
> > > Apollo era suits are now faling apart is Beta Cloth. It's primary
> > > useful property is non-flammablity thus it's a good high temperature
> > > flame barrier.
> > >
> > > We need a fabric with many of the properties of heavy duty work jeans.
> > > Kevlar and other High Modulus fabric are possible candidates. But
> > > they need to be able to be stowed and folded and exposed to UV.
> >
> > Do 'we' have a good handle on how mars dust will behave?
> >
> > Lunar dust is (IIRC) horribly abrasive, and gets in between woven
> > fabric fibers and starts to erode them, in addition to making sealing
> > difficult.
> >
> > Is martian dust as bad, or does the presence of atmosphere and erosion
> > make it a bit less sharp?>
>
> Or it is _worse_ than lunar dust? Erosion may make finer particles,
> dry conditions keep them from re-bonding to soil, wind can drive them
> deeper into fabric/joints, and they may be more chemically active. Do
> any Mars probes (current or proposed) include means to collect data on
> dust (size,amount, composition)?

Of coarse water wind erosion makes finer smoother particles. They are
very probably chemically active with peroxides. You want a very fine
weave or a possibly a solid barrier. I was hoping not to get into the
problems with the pressure suit itself by only focusing on the outer
garment.

Future testing of Mars' environment with a focus on manned visits:
MECA (Mars Environmental Compatibility Assessment)
http://mars.jpl.nasa.gov/2001/lander/meca/

--Chris Vancil

[Bill Bogen]

(Chris Vancil) wrote in message >...
> (Harmon Everett) wrote in message >...
> > Seriously. Whatever it starts out as, after a couple months, it will
> > end up covered/patched with duct tape. Don't you think so? :-)
> > Harmon
>
> No. If the outer garment is designed right duct tape should be the
> last thing you put on it. It is just as easy to have heavy duty knee
> pads and patches.

Cuts and tears will appear in unexpected places. When one is down to
the last few outer garments (OGs), you can bet that duct tape will be
applied to salvage discarded OGs. It may be wise to include peel-off,
replacable, transparent covers for helmet visors, windows, and solar
panels. In fact, I'd like to see a transparent, inflatable (low
pressure), disposable dome erected around the entire base or at least
the return vehicle. This would provide a first line of defense
against dust.

[Chris Vancil]

(MSu1049321) wrote in message >...
> So maybe the semi-hard suit is a better deal?

Exactly what is a semi-hard suit? A hybrid like the current EMU?
What makes this more desirable than a lighter massing more flexible
suit soft suit like the I-Suit? The whole point of having a TMG would
be to provide a barrier to dust.

-Chris Vancil

[Christopher]

On 23 Jul 2003 07:11:12 -0700, (Chris Vancil)
wrote:

(MSu1049321) wrote in message >...
>> So maybe the semi-hard suit is a better deal?
>
>Exactly what is a semi-hard suit? A hybrid like the current EMU?
>What makes this more desirable than a lighter massing more flexible
>suit soft suit like the I-Suit? The whole point of having a TMG would
>be to provide a barrier to dust.

If the object is to protect the Mars suits joints against Martian
dust, and prevent the dust getting through the weave, then the
solution is to have an outer layer of a PVC material, as PVC is
flexible, has no weave and its pretty tough, and as for being UV
proof, look at how long plastic bags last here on Earth.

A PVC layer would be like the human skin which also protects our
joints its also flexable and is impervious to dust, plus a PVC outer
layer can also be washed clean of dust, as PVC is also none water
permable, and as its not ment to breath no sweat induced problems
occur as the Mars suit.inner perssure bladder and life support deals
with persperation ect.




Christopher
+++++++++++++++++++++++++
"Only those who risk going too far,
can know how far they can go."
T.S. Elliot

[MSu1049321]

If there is such a high concentration of iron oxide in AMrs dust, perhaps it
can be repelled with a static charge? or active magnetic repulsion? Imagine,
flick a switch, the dust "explodes" off the suit and settles out, instant
clean...;-)

[Chris Vancil]

(MSu1049321) wrote in message >...
> If there is such a high concentration of iron oxide in AMrs dust, perhaps it
> can be repelled with a static charge? or active magnetic repulsion? Imagine,
> flick a switch, the dust "explodes" off the suit and settles out, instant
> clean...;-)

Actually DART(Dust Accumulation and Removal Test)would study amoung
other things the repulsive cleaning of solar cells...

The Martian atmospheric dust is expected to be charged. The
electrostatic experiment will use a high-voltage solar cell to provide
a potential of about 80 V to a transparent conductor on the front
surface of the solar cell cover-glass. It will test three
configurationsa positive potential applied to the cell cover, a
negative potential applied to the cell, and a transverse field applied
across the cellto determine whether electrostatic fields can be used
to mitigate the deposition of dust on solar arrays. These
configurations will be compared with the control cell with no applied
potential.

DART's sensors will provide both scientific information and important
engineering data on the operation of solar power systems on Mars. DART
will measure the dust accumulation rate and the transmitted spectrum
of the dust, and it will image individual settled particles to
determine the size distribution and the particle shape, as well as
gather information on electrostatic properties. DART was developed to
fly as part of the MIP experiment on the (now postponed) Mars-2001
Surveyor Lander. The flight hardware was designed, built, and
qualified for flight at the NASA Glenn Research Center, and it is
ready to go to Mars.

http://www.grc.nasa.gov/WWW/RT2000/5000/5410landis.html