X-Message-Number: 1896
Date: 05 Mar 93 04:51:46 EST
From: "Steven B. Harris" <>
Subject: CRYONICS The Sirens of Titan
Dear Cryonet:
A boiling liquid stays at constant temperature, whether it be
boiling water or boiling nitrogen. Tim Freeman is right that
it's quite easy and automatic to construct a constant temp system
that self-regulates around -130 C, if only you can "concoct" a
liquid that boils at that temperature. But easier said than
done. Unfortunately there just aren't many gases that boil in
that range, and a successful azeotropic or eutectic mixture would
likely have to be made of things that boil near there anyway. I
remember that Mike Darwin pointed this out to me in a personal
letter on the cracking problem in very early 1986 (some weeks
before I actually first saw an operating cryonics facility for
myself!), reminding me that about the only pure chemical sub-
stance that boils in those ranges at atmospheric pressure is CF4
(Freon-14), and that CF4 is prohibitively expensive. So we
cryonicists (or some of us, like Mike) have been thinking about
this sort of thing in terms of the glass-transition temp problem
for a long time, and still haven't gotten anywhere. Nature
hasn't been kind about the properties of gasses at pressures we
humans are used to.
I like Tim's idea of a metal expansion valve for regulating
refrigeration, but it may be a lot easier to simply build a
thermocouple switch from such a piece of metal, and use it to
operate an electrical valve. I find it really ridiculous that
people working with necessary cryonics things like computers,
microwave pager systems, heart-lung machines and liquid nitrogen,
should feel some compelling need to go back to 19th century
technology when it comes to temperature regulation. Is this Andy
Griffith syndrome we see in cryonicists talking about dewar
design just an innocent Thoreauvian quest for simplicity and
reliability? Or is it maybe a more semi-religious yearning for
self-sufficiency and the fabled lower anxiety levels of former
and ostensibly better times? If the latter, that's all well and
good, but let's not let it get the better of our common sense.
We're in a high tech business, folks, and I much as some of us
distrust electronics I don't think we can really afford to be
Amish or Hasidic about our gear.
"Seek simplicity," as a wise physicist once said, "and
distrust it."
Steve Harris
P.S. Regarding Mike D.'s flirtation with the possibility of
making a statue to himself in our own time <just kidding, Mike>:
I think that Garret Smyth's idea about using a Momson Lung
type rebreather/CO2 absorber is a good one. Of course, something
like this is what they do in modern spacesuits. This whole thing
we're discussing really is a fascinating problem: the question
is, can one put together something you could wear on the surface
of Titan for an hour, just from off-the-shelf stuff like surplus
submarine escape gear and high altitude mountain-climbing togs?
I wonder. Anybody know, for instance, what -135 C in moderately
still air translates to in wind velocity for temperatures (say,
-40 C or F) which would be more realistic on Earth?
And here's another idea so long as we're going to be forced to
mostly go the off the shelf commercial route for temp protection:
Why not do it in style? How about contacting the Eddie Bauer Co.
in Washington and getting them to donate gratis one or more
complete goosedown "Kara-Korem" or polar explorer outfits for
this adventure, in return for the advertising value of being able
to say that their equipment has actually been man-tested down to
200 degrees F below zero? With a couple of good photos of Mike
in the Bigfoot dewar in their magazine, such a firm could really
have fun with this. If you at Alcor bill yourself as cryogenics
researchers (true enough) and leave cryonics out of it, I'll bet
you Eddie Bauer would go for it. They equip on this basis lots
of Himalaya expeditions, at a lot more value in equipment than
you'd want for this demo.
/post
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