"harmoneverett" wrote:

wrote:

You want an environment with enough pressure that
construction workers can promptly ditch their
space suits, or at least reduce them. That's
going to require ~3psi of air pressure (pure
oxygen).

why pure oxygen? The eventual goal is to be able
to breathe in it, but for the moment, an air tank
doesn't weigh anything.

Because if you're going to be sending gases up to
achieve ~3 psi of blood oxygen tension, the minimum
IIUC to sustain human life for extended periods, you
are money ahead to send oxygen, which is breathable,
and thus a money payload, not some inert gas, which
is pure waste (but see below) until and if you go on
to 1 atmosphere.

My hope was that sending a really bare minimum
shell, hardly able to constrain 1 or 2 psi would
allow workers to then work in a much less bulky
pressure suit over the next several years while
they pasted on a couple more of the fabric and
insulation layers for the main shell.

I think you're missing the point that if you put 3
psi of oxygen _inside_ the human body, you have to
put 3 psi _outside_ the human body as well, or the
person just explodes.

Working for long periods of time, like years, in
pressure suits in a container with pressure less
than the breathing gas pressure, is going to involve
too many really unphotogenic industrial accident
fatalities from suit failures to be acceptable.

The base law of gaskets is, now as ever: gaskets
fail. That's from a submariner whose seen far too
many such failures in working plumbing, including
one leaking radioactive fluids from a running
nuclear reactor.

You might as well plan for 3 psi, just to start, and
the space crew lost on the ground years ago because
pure O2 is a hellishly dangerous fire hazard modulo
incredible precautions in what you let come in
contact with it, impractical for a years-long
effort, suggests you plan for a cartload of pressure
capability for inerting gases as well, or some
safety board somewhere is going to set all your
planning efforts to no eventual value.

HTH

xanthian.



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