I read that our current method of cryonics involves replacing blood with other fluid and keeping the body submerged in liquid as well as on ice (these things being done to the dead, for now, instead of intergalactic explorers and such), and that the process of waking a person up from this sort of 'cryosleep' (if they were alive when put under) would be intensive and time-taking.

I'm wondering if there are any (probably hypothetical) alternatives to the method we have now that would have a shorter wake-up interval or no real protocol for that at all (where a person in cryosleep could just wake up without assistance or any real, serious injury). How could this sort of technology realistically exist?


5 Answers 5


I have a few ideas about this, though only the first is really relevant to your question.



Often associated with low temperatures, the function of hibernation is to conserve energy during a period when sufficient food is unavailable. To achieve this energy saving, an endotherm will first decrease its metabolic rate, which then decreases body temperature. Hibernation may last several days, weeks, or months depending on the species, ambient temperature, time of year, and individual's body condition.

So, assuming we figured out a way to introduce this ability into humans, then people would be able to go into a deep sleep for up to months as a time, or even longer if an outside source of nutrients were provided to the sleeping patient. In a sense this would be similar to an induced coma, and would be a good way to pass the time by if that was your goal, but it would have detrimental effects on things like muscle mass.

NASA I believe is actually contracting a company to create a system to put astronauts asleep for most of the journey during any future trips to Mars. This will be so they can greatly reduce the required size of any crewed ship they may someday send to the red planet.



Use the method that you mentioned. Sometime this year there will be an attempted head transplant (yes, I did say head). They will have their blood drained and all that good stuff and we will be able to see if they're able to wake up after words, although there will be additional concerns that this guy will literally have a new body as well.


If this involves space travel, then reduce the need all together by traveling near the speed of light. This will cause a time effect that will make it so that for passengers on the ship only a fraction of the time required for the journey will have passed for them.

Hopefully one of these has helped or given you some ideas.

  • $\begingroup$ If you could find a link to NASA, some articles about sleep during Mars voyage, it would be great. $\endgroup$
    – Mołot
    Commented Feb 11, 2017 at 10:06
  • $\begingroup$ No problem! Paper about it on NASA site is now linked into my answer. $\endgroup$
    – rclev
    Commented Feb 11, 2017 at 14:58

Larry Niven's 'Tales of known space' stories used 'stasis fields'; where he postulated devices that could stop (or slow greatly) any passage of time inside a limited volume. Stasis fields (and stasis boxes) have been used repeatedly as a science fiction concept not only as a replacement for cold sleep during star travel but also to replace refrigerators to preserve food, a way to safely store anti-matter or dangerous creatures, as weapons, and many other uses.


The problem with freezing is that tice crystals form in the blood and rupture cell walls. Removing the blood prevents this problem. Freezing the body slows the metabolic processes almost to a stop and frozen cells kind of get surspended.

Replacing cryofluid with blood takes time, and I guess you probably want to warm up rather slowly. (I am not a mad scientist but if you warm things up rapidly they can heat unevenly and rupture)

If you want to revive quickly, freezing is probably out. I guess you could invent a substance which prevented ice crystals from forming, this would remove the need for the transfusion, but raising the body temperature from way below freezing to body temperature and restarting metabolic processes is going to take some time.

Freezing mimics time slowdown by reducing molecular motion, is there some way to fake that? ( I mean unless you just want to posit time stasis pods). Ok this is going to be a long trip, so stay with me. Freezing slows the vibration of molecules, nothing moving means metabolic process just kind of pause. No glucose is consumed, no oxygen is required. Freezing is a faked time out.

But heat is just the vibration of molecules. Vibration can be countered by an opposite vibration (noise canceling headphones work this way). Each substance has a different vibrational frequency (this is why earthquakes can cause the tops of buildings to explode --match the structure's vibrational frequency and the energy builds and builds). So, scan the body, you need to invent a scanner, something that passes through normal matter almost effortlessly, the key being almost. The interference pattern for each type of molecule will be different. A supercomputer then needs to map the body and calculate the opposite vibrational frequency at every point. The stasis pod protects an opposite vibrational frequency for every part of the body, trillions of different beams. (You also need to invent the beam transmitter which can project the beam to precisely the right point --maybe two beams that only cause an effect when they meet) Molecular activity ceases instantly. Also can be switched off instantly. BAM, instant cruogenic sleep and wake cycles.


Realistically, yes. You could build a capsule that slows the time for a single person. Capsule would probably need to be spherical. How to achieve that is beyond our knowledge though.

This guy takes a crack at time dilation as a field, might help: http://file.scirp.org/pdf/JMP20120200010_34720787.pdf

  • 1
    $\begingroup$ I don't want to be a naysayer, but I suggest looking at this Wikipedia entry. en.wikipedia.org/wiki/Scientific_Research_Publishing I looked at the cited paper and decided it should be taken with a large pinch of salt. $\endgroup$
    – a4android
    Commented Feb 11, 2017 at 8:02
  • $\begingroup$ Well, I wouldn't use it as a scientific source, but might give ideas. After all, we are not really building this device. I read the wiki article, their practices are quite funny. $\endgroup$ Commented Feb 11, 2017 at 8:42
  • $\begingroup$ Certainly as a source of ideas that isn't a problem. It's tricky to know if the author does know what he's talking about though. The publishers are what we here call shonky. It's Australian slang, could be British too. $\endgroup$
    – a4android
    Commented Feb 11, 2017 at 9:25
  • $\begingroup$ We call them predatory, they send mails to trick you into publishing for them. If it isn't listed on sci index, steer clear of it. $\endgroup$ Commented Feb 11, 2017 at 10:51
  • $\begingroup$ Your capsule would have to generate an ultrastrong gravitational field, and an extremely well balanced one at that, to create the necessary time dilation. $\endgroup$
    – a4android
    Commented Feb 11, 2017 at 11:04

I don't know much on the topic, but I think worthy of thought is the possibility of genetic engineering of individuals selected for space travel to allow relative stasis and thus long time travel in space.

As rclev has already noted, hibernation is a possible option and this would probably be the most easily achieved, possibly this could be partnered with some kind of anti aging technology (https://en.m.wikipedia.org/wiki/Biological_immortality as i am aware that aging continues but may be slowed during hibernation. However this might cause problems for other aspects of your world, so maybe aging in hibernation could be explained away, slowed sufficiently or ignored.

While this might take more time than hibernation for wake up, there is also the possibility of genetic engineering to allow simply freezing and thawing be viable options for cryosleep. There are organisms that exist that have developed the ability to withstand/survive freezing temperatures (https://en.m.wikipedia.org/wiki/Cryobiology) and maybe this ability could be passed on somehow to your intergalactic travellers, possibly by genetic engineering or by some sort of injection of antifreeze proteins or some substance that stops nucleation and crystal formation. As I understand it some of the problems with freezing organisms are due to the formation of large ice crystals which destroy cells, so possibly some mechanism which allowed cells to withstand more stretching and stopped large/sharp crystal formation could be implemented.


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