X-Message-Number: 1874
Date: 03 Mar 93 04:46:49 EST
From: "Steven B. Harris" <>
Subject: CRYONICS Apollo Fire & 100% O2

Dear Cryofolks:

   As a longtime spacenut, I have to add a bit about oxygen
atmospheres and Apollo, since a couple of people have been rather
horrified by my suggestion that in Mike D.'s experiment with -135
C ambient, cooling with LOx in the dewar might be the best thing.

Really, this is not as foolish as it sounds.

   First, it is NOT true that Apollo 1 had a 100% O2 atmosphere
at reduced pressure.  That was indeed the way the early Apollo
system was intended to operate *in space* (100% O2 at 1/3
atmosphere), but that's pretty safe.  In fact, that low pressure
100% O2 system continued in use inside spacesuits, and also in
the Apollo program on the surface of the moon in the LEM, after
the first EVA (the LEM carried only oxygen in its tanks, and
therefore the LEM atmosphere was pure O2 after recharge; people
worked in this, surrounded by electrical equipment, for as long
as 3 days on the lunar surface).  In fact, 100% O2 at low
pressure is what they use in spacesuits to this day. 

   It's no accident that the Apollo 1 fire occurred ON THE
GROUND.  There was a lot of sloppy engineering and magnesium (as
has been noted), but the main problem was 100% O2 at 1 atmo-
sphere.  The planned Apollo launch sequence, rather than to
induce unnatural extra implosion strains on the capsule by trying
to partly evacuate it on the ground, instead involved letting the
capsule run with 100% O2 at ambient pressure, and naturally de-
pressurize during ascent until it reached the equivalent altitude
for the cruse mode pressure of 5 psi (maybe 30,000 ft).  Bad idea
in retrospect, but we'd got away with it on Mercury and Gemini,
hadn't we?  Anyway, after the Apollo fire they put some nitrogen
into spacecraft atmospheres, and that continues to the present. 
The shuttle (for some unfathomable reason) runs on a full 14.7
psi system at 21% O2, which gives them no end of problems with
spacesuits, which still can't take more than a third of that.  

   In any case, a person in a dewar in pure O2 at -135 has two
advantages over White, Grissom, and Chaffee:  1) it's a whole lot
colder so reactions will be much, much slower, 2) it's a lot
easier to get out of a tilted Dewar than a sealed early Apollo
capsule (I've heard stories from NASA people that there was
screaming and pounding on the hatch for some minutes in the
Apollo, despite the stories of "instant death" that aired on the
news), and 3) there won't be anything electrical in there, and I
fancy that antistatic stuff can be used.  That ought to do it,
and if anyone has cold feet about it (besides Mike, that is) you
can in addition have somebody standing by with a Halon fire
extinguisher.  These bromoflorocarbons work even in pure O2 by
damping the free radical reactions necessary to keep a flame
going, and they do this at concentrations far lower than those
that cause any danger of asphyxia (especially in 100% O2 atmo-
spheres!).  

   Finally, yes, LOx in direct contact has some odd reactivity
problems with certain fuels, but that only means that Mike
shouldn't carry any of these with him and drop them at his feet. 
Duh.  If he can avoid that, he'll be fine.  If not, it will
indeed by ironic.  Remember that when James H. Bedford, the first
cryonaut, was frozen in early 1967, the LIFE mag story about it
got frozen out of most printings by an late extra insert on the
Apollo 1 fire (!)   Maybe if Mike gets incinerated doing the same
kind of thing, then, we can get cryonics back in the news as some
kind of karmic payback for that slight of fate so many years ago.


                                     Steve Harris




Some say the world will end in fire
Some say in ice.
>From what I've tasted of desire
I'd hold with those who favor fire.
But if it had to perish twice
I know enough of hate
To know that for destruction ice
Is also great
And would suffice.

                      Robert Frost

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