Ways to cushion an un-augmented human against high, prolonged g-forces?

Question

Soft sci-fi uses inertial dampeners. Harder sci-fi uses stuff like advanced crash couches, robotic exoskeletons, or (my personal favorite) drug cocktails filled with stimulants and other medication like the Expanse’s “juice”. I’m looking for something a little different and a little bit out-there. Ideas for handling high acceleration that involve a lot of thinking outside the box. I wasn’t quite sure where to start researching technologies like this, but I have some (pretty silly) ideas I came up with myself. Stuff like cryogenics that freezes everything except the brain (probably pretty silly), submerging the crew in tanks of water or nutrient-rich, oxygenated liquid to take the weight off their bones and muscles (definitely pretty silly), and even keeping the crew in a constant state of free-fall with a giant wind tunnel that provides upward thrust equivalent to the current artificial thrust gravity (really, really silly). Does anyone here have any other ideas that are a bit more out-there or might work better?

To clarify, I’m specifically looking for unique, creative, and/or novel methods for dealing with a prolonged period of high acceleration aboard a spaceship when the crew doesn’t have the luxury of cyborging themselves up for the trip. Something like a constant 3-5 gs at least, probably more like 9-12 for a period of a few months with minimal zero-g breaks. This method or technology would also need to be capable of handling short bursts lasting a few seconds to a few minutes at up to 30-40 gs (like the rocket sled used by John Stapp). And above all else, it has to be scientifically plausible (which some of my ideas probably aren’t lol).

Answer 1

You can do this, perhaps, with a very precise combination of ultrastrong magnetic fields. This is called diamagnetic levitation and has effect on anything contaning water. In the video you see a frog subjected to a force of exactly 1 g, thereby floating in microgravity. Nothing would stop you from increasing that force and counteract a greater acceleration.

Currently, next to nothing is known on diamagnetic levitation's biological side effects except it not being immediately lethal (the frog survived with no ill effects). If being subjected to the field caused cancer, bone calcium depletion or cardiac arrest, or even temporary mental impairment, then of course this method would be a no go... but, for now, nobody can shoot down a levitation inertial dampener on those grounds (humans appear to feel no significant effects from MNR imagers; although some researches - e.g. by Persinger et al. - seem to indicate that thought processes are somewhat affected)

Differential acceleration between body parts with different water contents (say, the bones in the cranium and the eyeballs, or the brain) would be felt as discomfort, so you won't be able to compensate arbitrarily large accelerations.

Even if it worked, there would be severe limitations on mobility while within the field. With enough energy it would be possible to screen a whole room (two meters height) so that it only experienced one g vertically, but I think it would be ruinously expensive. The larger the habitable volume, the greater the tidal force you would experience (bringing blood away or towards your extremities) unless you made the actual volume larger.

Another difficulty would be field orientation. If, as seems likely, the field can be sufficiently redirected, then lateral acceleration can be compensated too. But if for any reason this can't be done, you're restricted to compensating vertical acceleration, e.g. a takeoff, and manoeuvering will be limited to one or two g's worth for short periods - no high-accel dogfighting.

Also, I wouldn't want to be an electronic gadget immersed in that field. Lorentz forces alone would play hell on current-conducting coppers, chips would find themselves polarized by Hall effects, and so on. You could design fixed consoles to be shielded against the field (and subject to the full acceleration), but no watches, portable assistants or anything that needs to be lifted or lowered by muscle power; almost surely, no implants, pacemakers or piercings as well.

Answer 2

Well their are a few options I see. One is in your definitely pretty silly category and that is liquid breathing. If I remember correctly this is an idea that was looked at for mars travel. You could combine that with a G-Suit and you would probably do pretty well. The biggest issue is allowing blood to flow to and from your brain. But if you have an external liquid like perfluorocarbons (commonly used in liquid breathing), pressing against your legs it might help to push the blood back up to your brain.

So I guess I am proposing liquid respiration. Submerge your travelers in oxygen enriched perfluorocarbon liquids that are more dense than blood. When you hit the (X)g maneuver, the perfluorocarbons push against the legs forcing blood to the brain. Just be sure your liquid breathing rig is constantly supplied with oxygen. Not 100% sure how non-oxygen enriched perfluorocarbons act in relation to oxygen enriched perfluorocarbons.

Answer 3

I believe that a very similar question has already been asked here which you might find of interest.

Reportedly 1.5g has been survived for 7 days, but I doubt the sort of acceleration you are talking about would be endurable for that long. The brief periods which have been endured might be extended to a few hours perhaps using the special pressure suits that jet fighter pilots use, but I doubt much more than that. Normal human bodily functions like eating and drinking would present major issues; people could easily choke to death.

Answer 4

It is pretty much impossible. the biggest problems can't be prevented, namely the the bodily fluids separating out and not being able to cycle properly. There really is no way to counter this with the human body as it is, even immersing the person entirely in liquid (including breathing) and handling everything via tubes will not prevent this.