How would a cryofreeze work in order to keep the pilot alive long enough to survive an automated travel to some destination?

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    $\begingroup$ "How would a cryofreeze work.." Given no animal has been successfully frozen and thawed, it would seem any answer would have to be based on speculation, or divination. $\endgroup$ Nov 18, 2014 at 0:43
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    $\begingroup$ @AndrewThompson... of course because one can't understand the theory without having a practical example... or do a quick google: voices.nationalgeographic.com/2013/08/21/… $\endgroup$
    – NPSF3000
    Nov 18, 2014 at 7:38
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    $\begingroup$ It wouldn't. Long-term hibernation is a sci-fi plot device. While it is theoretically possible there's no basis for any actual technology, so no answer to this question. $\endgroup$
    – GdD
    Nov 18, 2014 at 10:14
  • $\begingroup$ ...if hybernation / cryogenic sleep worked at all, yes, it would help and keep the crew alive for the travel. Considering we're nowhere near to have it working - no, currently not. $\endgroup$
    – SF.
    Nov 18, 2014 at 14:42

1 Answer 1


The objective of cryofreezing is to slow or stop the body’s metabolism. Essentially, put you to sleep for a very long time without aging and thaw you out when you get to where you’re going.

While it sounds whacky it’s actually closer to reality than it sounds. Slowing of the metabolic rate happens naturally in many animals during hibernation, and there is some speculation that it may be possible to induce hibernation in humans.

Nasa is even looking at this technique for mars missions.

And it’s being trialled for trauma patients.

However hibernation will only get you so far, it only slows, not stops the metabolism, and it hasn’t yet been attempted for more than a few days at a time.

In principle entering cryofreeze (or cryostasis is another technical term) is easy, find a massive freezer, anesthetise the patient, and sling them in. The problems come when we try to thaw them out. Currently the biggest problem is that as the water in the body freezes it forms crystals that puncture cell membranes. Think: full body freezer burn. While there are potential solutions, mostly involving completely replacing the water with an antifreeze solution, they are still very much works in progress.

Another problem is bacteria; with the human immune system offline there’s nothing to stop bacteria from slowly munching through whatever they please. So on entering long term cryofreeze you’d need to be completely sterilised (both inside and out). Here is a good paper on low temperature bacteria.

So there are many unsolved problems before we can bring someone back from the freezer, and it’ll probably take another few decades before cryofreeze or induced hibernation can be seriously considered for use in crewed missions.

  • $\begingroup$ Actually, flash-freeze currently allows to freeze humans without piercing the cell membranes (and keeping you at LN2 temperatures, bacteria are not a problem). It's the thawing part though that still has to be worked out; rapid enough that whole volume is thawed simultaneously (you won't survive with brain thawed but heart frozen), and rapidly enough that re-forming ice doesn't destroy the cells. Nevertheless, supposedly desperates exist who got flash-frozen in hopes future will develop a way to thaw them safely. $\endgroup$
    – SF.
    Nov 18, 2014 at 11:12
  • $\begingroup$ Yes, there was an urban myth that Walt Disney had himself frozen, and there are plenty of companies that you can go to if you want to be a posthumous popsicle. Their websites can make interesting reading: biostase.de/us/cryonics.html. $\endgroup$ Nov 18, 2014 at 11:20
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    $\begingroup$ Might be worth mentioning that even ignoring aging, hibernation or cryogenics can help to greatly reduce both the resources needed (Air, food, space, entertainment equipment) and the mental stresses of long confined journeys. $\endgroup$
    – NPSF3000
    Nov 18, 2014 at 12:21

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