Space Forum / Space Flight / July 2003

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