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starship-design: Cryogenic Suspension

Cryogenic Suspended Animation

I've been familiar with this science fiction theme since my childhood.
Always, I've been a bit dubious about it, as a personal reaction as well as
technically. Having since learned the fundamental drawback to reviving a
frozen human is almost intractable, I shelved the concept. But it has been
recently mentioned here, in a casual throwaway line, and I did once come up
with a potential approach to this problem. Taken from the shelf and lightly
dusted off, here it is.

Ice crystals slowly forming in blood and tissue have a characteristic size
which is larger than the dimensions of cells. That's the problem. Freezing
tissue ruptures cell membranes, and that spells dead. OK, but some small
creatures, mouse size, can be frozen and revived. Protoplasm is water-based,
but has solutes and suspensions which disorder the ice crystals so that most
individual cells come out viable, and normal body processes can then replace
the minority of destroyed cells in a small organism which has been
successfully thawed.

Large creatures, however, will not freeze as fast as small ones, for their
body bulk is thermally insulating. Fast freezing occurs near the outer
surface, so skin and outer regions sustain little damage, but internal
organs retain heat, and suffer a slow freezing process which allows growth
of larger ice crystals, which spells dead. Obviously body passages, the
lungs and digestive tract, are amenable to coolant access to speed freezing,
but large organs are still left vulnerable. Among our favorite parts, the
central nervous system is protected within bone chambers, still left out of
the cold. To use our circulatory system to spread coolant as a temporary
replacement for our blood seems far too iffy.

My proposal would involve transfixing the entire body rapidly with fine
platinum needles, which are heat pipes containing liquid helium as their
working fluid. The object of this macabre "iron maiden" treatment is to
chill all parts of the body below freezing in less than a second. This
should allow large creatures, such as ourselves, to recover on thawing as
well as small animals can. Supplementary measures, such as antifreeze
proteins added to the blood to reduce ice crystal size, are also called for.

This sounds freaky for sure, to allow oneself to be rapidly pierced by
jillions of needles, but it could be a key to survival. The subject would of
course be unconscious for this ordeal. Later, when thawed and revived to
consciousness, it would hurt. Big deal, death hurts worse. Fine needles
actually cause little tissue damage, and in this case the body has no time
for a histamine response or other trauma. The tiny leaks of fluids would be
largely repaired in the thawing process, and nearly healed before the
subject regains consciousness.

It's just a thought. People here know I don't go for slow starship journeys,
but a technique like this would be good to have around anyway. There might
be all sorts of reasons for somebody to decide they didn't want to die.

Johnny Thunderbird