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Comment by yyyuuu | Hacker News Reader

how far is our current tech from cryo sleep?

Most science fiction assumes that humans will survive long duration space travel through chemical induced sleep, waking up only when they are about to reach the destination.

Is it just science fiction or do we have someone working aggressively on this.

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Handily, PZ Myers wrote about cryogenics recently - http://freethoughtblogs.com/pharyngula/2016/01/29/how-can-yo...

TL;DR: "No chance"

6 months seems to be the outer extremes of medically induced comas (http://www.scientificamerican.com/article/what-is-a-medicall...) and that's nowhere near long enough to get anywhere useful.

Although I guess you could wake people up every 3 months for some muscle replenishment exercise and mission updates.

But as far as I know you still age while in a coma. So while you may be in a unconscious sleep - it won't do you any good for long term space travel. Then you might as well be awake and look at the scenery along the way.

Can't find any definitive pages but a quick search indicates you're correct - plus there are many disadvantages to being in a long-term coma. Which are avoided by waking up every 3 months but then I guess you're not really avoiding the aging there...

I guess the bigger problem is that you'd almost certainly need a staff of medical personnel to monitor and manage the sleeping people (whether they're in a medical coma, held at a low temperature to slow everything, etc.) and you're back to the same problem of how they cope with the time and distance.

With the biology education I've had I don't think true cryosleep will ever be truly realistic. Closest we could likely get is genetic modification allowing for slowed cellular metabolism or allowing cells to enter a dormant state in some way, similar to what we see in some bacteria. Even that might be fanciful imagination but it feels like a more promising approach to me.

There's the field of cryonics, aimed at preserving people who can't be helped by contemporary medicine, in hopes that the future technology will be able to save their lives. While the goal is slightly different, it seems to be pretty much the same research that's needed for space travel cryopreservation.

There's at least one very big difference: the equipment for reactivating the frozen tissue, which modern cryonics does not even attempt to create, needs to be put on the spaceship at launch. Otherwise, even if perfectly preserved tissue arrives at its destination in a few centuries, it will just remain in that state until power runs down or something breaks.

It's pretty far out. Currently we can't even freeze and thaw organs. As that would be quite useful for transplantation, there are people working on it. Depending on how you define "aggressive", this might not be aggressive though.

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