# Effects of suspended animation

Major Camila de Ocampo, "La Comandante", wakes with a start. As she's been trained to do when coming out of stasis, she flexes each muscle, beginning with her toes until she finally finishes by raising and lowering her eyebrows. She continues the stasis emergence process, as her muscles seem to be working properly. Careful not to over-exert herself, she removes the monitors and IVs and steps out of the chamber. Has it really been 13 years already? According to the display in the room, they left Earth orbit only 5 years ago. Despite her confusion, she initiates the emergence process for the rest of her team.

Set up

As implied in the text above, the setting is a long spaceflight. The characters will be on a large colony ship for about 15 years, cruising around $\frac23c$ to their new home on Tau Ceti e.

The time in suspended animation will be over a year less than the entire journey: they won't be in stasis while the ship is accelerating/decelerating to and from its cruising speed, which takes about 7 months on each end (if you're interested, the ship's acceration rate will be $10.1\ m/s^2$, or $1.03g$, to account for the low tolerance humans have to acceleration).

With the exception of rotating groups of technicians and pilots, everyone aboard the ship to Tau Ceti e will be in suspended animation, to make the journey more pleasant (read: less susceptible to mutiny).

Question

How can I implement believable suspended animation?

Some things to consider:

• Suspending animation: can this be chemically-induced, or will some more complicated process be required, such as replacing the colonists blood with some cooled liquid?
• Effects during the suspension: what biological processes will need to be maintained? What are the minimum caloric requirements? Can all of these processes be addressed through IV's and dialysis?
• After they emerge: How badly will muscles be atrophied? Can this be alleviated during the suspension with electric stimulation? Will the colonists emerge with caveman body hair and fingernails that are out of control? Would they be able to self-emerge, or would they require human/robotic assistance?

These are only some considerations I've thought of; I'd love to hear about any others. I'd like as much fact-based detail as you can give me, but seeing as how this technology isn't practical yet, I understand that some amount of speculation is necessary.

• The "science-based" tag might not be appropriate for a technology that, currently, must be entirely speculative. Pseudoscience would be required . Apr 15, 2015 at 17:46
• @Samuel the science-based tag has been abused to hell.....and back. Apr 15, 2015 at 18:12
• @DJMethaneMan That's like arguing "couldn't care less" and "could care less" now mean the same thing because of how often people misuse the latter when they actually mean the former. The tag has a definition, it's silly to ignore it just because people abuse it. Apr 15, 2015 at 18:16
• @Samuel suspended animation doesn't seem to be entirely speculative. Just because something is feasible in the realm of physics and has been observed and tested, but isn't practical for humans right now, makes it pseudoscience? Anyhow, there is no pseudoscience tag. The only science tags are "science-based" and "hard-science", and I'm not asking for proven hard-science facts, figures, or empirical data.
– Seth
Apr 15, 2015 at 18:54
• @Seth Moving from minutes of apparent suspended animation to years (18 years in your story) is entirely speculative. There is no evidence that animals can survive that. I'm not suggesting you tag it with pseudoscience, but you've included a tag that explicitly excludes it. Apr 15, 2015 at 19:03

### Suspended Animation using Chemicals

Although this technique seems (currently) to be less feasible for larger mammals like humans, I still feel it is suitable, since suspended animation has never really been trialled on humans. This technique involves putting the body into a similar state to hibernation, where the heart rate lowers, the temperature lowers, and metabolism decreases. This is carried out by putting the human into an air sealed room, containing a small amount of hydrogen sulphide (60 ppm). Then when the human needs to be reawakened, you just remove the hydrogen sulphide from the room, and eventually all natural body functions go back to normal.

### Using Temperature

This technique is more feasible for larger mammals, but is more complex. This is done by removing the blood, then replacing it with a cooled saline, which puts the human into stasis. The advantage to this method over using chemicals is, the human is "clinically dead" while in stasis, which means there is a lot less maintenance and resources needed for the humans. To revive, you simply slowly heat the human up, while also replacing the saline for blood, then providing a electric shock to the heart (like a defibrillator)

### Conclusion

The best method for suspended animation is likely temperature, because it is cheaper (the human is dead, rather than hibernating), and is safer according to current science. It also seems more interesting, I mean, you're replacing their blood.

• I think if you're removing hydrogen cyanide from the room, you're also removing a corpse. Also, what about a colder solution "puts the human into stasis"? If the colder solution were, say, their own cooled blood, does that work? Apr 15, 2015 at 18:50
• @Samuel I'm sorry, hydrogen cyanide was a typo (not sure why I got that wrong). I also can't see why using their own cooled blood wouldn't work, but I'd have to do more digging to make sure Apr 15, 2015 at 18:56
• @Samuel After some research: Unfortunately the process uses saline, which is a solution of water and NaCl (table salt). It would be interesting to see if the process could actually work just by decreasing the temperature of the blood, but so far the only tests have used saline Apr 15, 2015 at 19:24
• Presumably saline is used so the solution is isotonic. It's neat because space sailors can really claim their blood is made of salt water, but otherwise doesn't explain how it allows the human to not decay while dead for 18 years. Nor does it explain how such a murdered person is brought back to life. Any explanations for the maintenance and reviving of the suspended humans? Apr 15, 2015 at 19:32
• @Samuel The way it prevents decay is essentially cryogenics, so the methods in my answer are just ways of getting the human to that cryogenic state, without destroying cells from the sudden change in temperature. Revival is easy, you slowly warm the human up (as to not destroy any cells), while replacing the solution with blood, then shock the heart to start beating again. Maintenance is also simple because they are basically dead, so only require a constant flow of cooled saline. Apr 15, 2015 at 19:42